Groups > linux.kernel > #1263117 > unrolled thread

[PATCH v14 00/22] Richacls (Core and Ext4)

Started by	Andreas Gruenbacher <agruenba@redhat.com>
First post	2015-11-05 12:40 +0100
Last post	2015-11-06 22:10 +0100
Articles	13 on this page of 33 — 2 participants

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  [PATCH v14 00/22] Richacls (Core and Ext4) Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:40 +0100
    [PATCH v14 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 09/22] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 10/22] posix_acl: Unexport acl_by_type and make it static Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 16/22] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 22/22] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
      Re: [PATCH v14 22/22] ext4: Add richacl feature flag Andreas Dilger <adilger@dilger.ca> - 2015-11-08 09:20 +0100
    [PATCH v14 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
      Re: [PATCH v14 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Dilger <adilger@dilger.ca> - 2015-11-06 21:50 +0100
    [PATCH v14 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 17/22] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 21/22] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 05/22] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 20/22] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
      Re: [PATCH v14 11/22] vfs: Cache base_acl objects in inodes Andreas Dilger <adilger@dilger.ca> - 2015-11-08 09:10 +0100
    [PATCH v14 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 18/22] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
      Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-06 22:00 +0100
        Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-07 18:50 +0100
          Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-08 09:20 +0100
    [PATCH v14 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:50 +0100
    [PATCH v14 07/22] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 13:00 +0100
    [PATCH v14 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 13:00 +0100
    [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 13:00 +0100
      Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-06 22:30 +0100
        Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD  permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-07 21:50 +0100
      Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-06 22:30 +0100
    [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 13:00 +0100
      Re: [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Dilger <adilger@dilger.ca> - 2015-11-06 22:10 +0100

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#1263142 — [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 12:50 +0100
Subject	[PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags
Message-ID	<qrrdh-64e-45@gated-at.bofh.it>
In reply to	#1263117

Richacls distinguish between creating non-directories and directories. To
support that, add an isdir parameter to may_create(). When checking
inode_permission() for create permission, pass in an additional
MAY_CREATE_FILE or MAY_CREATE_DIR mask flag.

To allow checking for delete *and* create access when replacing an existing
file via vfs_rename(), add a replace parameter to may_delete().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/namei.c         | 43 +++++++++++++++++++++++++------------------
 include/linux/fs.h |  2 ++
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 224ecf1..0259392 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,7 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
  * this, letting us set arbitrary permissions for filesystem access without
  * changing the "normal" UIDs which are used for other things.
  *
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
+ * MAY_CREATE_DIR are set.  That way, file systems that don't support these
+ * permissions will check for MAY_WRITE instead.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -2549,10 +2551,11 @@ EXPORT_SYMBOL(__check_sticky);
  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
  *     nfs_async_unlink().
  */
-static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+static int may_delete(struct inode *dir, struct dentry *victim,
+		      bool isdir, bool replace)
 {
 	struct inode *inode = d_backing_inode(victim);
-	int error;
+	int error, mask = MAY_WRITE | MAY_EXEC;
 
 	if (d_is_negative(victim))
 		return -ENOENT;
@@ -2561,7 +2564,9 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
 	BUG_ON(victim->d_parent->d_inode != dir);
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
-	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	if (replace)
+		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+	error = inode_permission(dir, mask);
 	if (error)
 		return error;
 	if (IS_APPEND(dir))
@@ -2592,14 +2597,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
  *  3. We should have write and exec permissions on dir
  *  4. We can't do it if dir is immutable (done in permission())
  */
-static inline int may_create(struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
 {
+	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
 	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
 	if (child->d_inode)
 		return -EEXIST;
 	if (IS_DEADDIR(dir))
 		return -ENOENT;
-	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
 }
 
 /*
@@ -2649,7 +2656,7 @@ EXPORT_SYMBOL(unlock_rename);
 int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		bool want_excl)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
@@ -3494,7 +3501,7 @@ EXPORT_SYMBOL(user_path_create);
 
 int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -3586,7 +3593,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, true);
 	unsigned max_links = dir->i_sb->s_max_links;
 
 	if (error)
@@ -3667,7 +3674,7 @@ EXPORT_SYMBOL(dentry_unhash);
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_delete(dir, dentry, 1);
+	int error = may_delete(dir, dentry, true, false);
 
 	if (error)
 		return error;
@@ -3789,7 +3796,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
 int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
 {
 	struct inode *target = dentry->d_inode;
-	int error = may_delete(dir, dentry, 0);
+	int error = may_delete(dir, dentry, false, false);
 
 	if (error)
 		return error;
@@ -3923,7 +3930,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 
 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -4006,7 +4013,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 	if (!inode)
 		return -ENOENT;
 
-	error = may_create(dir, new_dentry);
+	error = may_create(dir, new_dentry, false);
 	if (error)
 		return error;
 
@@ -4194,19 +4201,19 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (source == target)
 		return 0;
 
-	error = may_delete(old_dir, old_dentry, is_dir);
+	error = may_delete(old_dir, old_dentry, is_dir, false);
 	if (error)
 		return error;
 
 	if (!target) {
-		error = may_create(new_dir, new_dentry);
+		error = may_create(new_dir, new_dentry, is_dir);
 	} else {
 		new_is_dir = d_is_dir(new_dentry);
 
 		if (!(flags & RENAME_EXCHANGE))
-			error = may_delete(new_dir, new_dentry, is_dir);
+			error = may_delete(new_dir, new_dentry, is_dir, true);
 		else
-			error = may_delete(new_dir, new_dentry, new_is_dir);
+			error = may_delete(new_dir, new_dentry, new_is_dir, true);
 	}
 	if (error)
 		return error;
@@ -4469,7 +4476,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
 
 int vfs_whiteout(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4efa435..d6e2330 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -82,6 +82,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_CHDIR		0x00000040
 /* called from RCU mode, don't block */
 #define MAY_NOT_BLOCK		0x00000080
+#define MAY_CREATE_FILE		0x00000100
+#define MAY_CREATE_DIR		0x00000200
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.5.0

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#1264536 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

From	Andreas Dilger <adilger@dilger.ca>
Date	2015-11-06 22:00 +0100
Subject	Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags
Message-ID	<qrWh5-13l-35@gated-at.bofh.it>
In reply to	#1263142

[Multipart message — attachments visible in raw view] — view raw

On Nov 5, 2015, at 4:39 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
> 
> Richacls distinguish between creating non-directories and directories. To
> support that, add an isdir parameter to may_create(). When checking
> inode_permission() for create permission, pass in an additional
> MAY_CREATE_FILE or MAY_CREATE_DIR mask flag.
> 
> To allow checking for delete *and* create access when replacing an existing
> file via vfs_rename(), add a replace parameter to may_delete().

I thought you proposed adding an enum for these parameters, and possibly
making them a single parameter flag, to make the code in the caller more
readable.  Flags like below for example, though I'm not stuck on "MAY_IS"
as a prefix, just my first thought:

enum may_flags {
	MAY_IS_FILE	= 0x0,	/* Essentially !MAY_IS_DIR */
	MAY_IS_DIR	= 0x1,	/* Operation only allowed on directory */
	MAY_IS_REPLACE	= 0x2,	/* Operation only
};

would make it immediately clear what is being passed to the function.
Some examples inline below.  If Al hates it, fine, but having functions
with multiple "true, false" or "false, true" arguments is ugly and error
prone, IMHO.

> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
> ---
> fs/namei.c         | 43 +++++++++++++++++++++++++------------------
> include/linux/fs.h |  2 ++
> 2 files changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 224ecf1..0259392 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -453,7 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
>  * this, letting us set arbitrary permissions for filesystem access without
>  * changing the "normal" UIDs which are used for other things.
>  *
> - * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
> + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
> + * MAY_CREATE_DIR are set.  That way, file systems that don't support these
> + * permissions will check for MAY_WRITE instead.
>  */
> int inode_permission(struct inode *inode, int mask)
> {
> @@ -2549,10 +2551,11 @@ EXPORT_SYMBOL(__check_sticky);
>  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
>  *     nfs_async_unlink().
>  */
> -static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> +static int may_delete(struct inode *dir, struct dentry *victim,
> +		      bool isdir, bool replace)
> {
> 	struct inode *inode = d_backing_inode(victim);
> -	int error;
> +	int error, mask = MAY_WRITE | MAY_EXEC;
> 
> 	if (d_is_negative(victim))
> 		return -ENOENT;
> @@ -2561,7 +2564,9 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> 	BUG_ON(victim->d_parent->d_inode != dir);
> 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
> 
> -	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
> +	if (replace)
> +		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> +	error = inode_permission(dir, mask);
> 	if (error)
> 		return error;
> 	if (IS_APPEND(dir))
> @@ -2592,14 +2597,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
>  *  3. We should have write and exec permissions on dir
>  *  4. We can't do it if dir is immutable (done in permission())
>  */
> -static inline int may_create(struct inode *dir, struct dentry *child)
> +static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
> {
> +	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> +
> 	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
> 	if (child->d_inode)
> 		return -EEXIST;
> 	if (IS_DEADDIR(dir))
> 		return -ENOENT;
> -	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
> +	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
> }
> 
> /*
> @@ -2649,7 +2656,7 @@ EXPORT_SYMBOL(unlock_rename);
> int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
> 		bool want_excl)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);

	int error = may_create(dir, dentry, MAY_IS_FILE);

> 	if (error)
> 		return error;
> 
> @@ -3494,7 +3501,7 @@ EXPORT_SYMBOL(user_path_create);
> 
> int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 
> 	if (error)
> 		return error;
> @@ -3586,7 +3593,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
> 
> int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, true);

	int error = may_create(dir, dentry, MAY_IS_DIR);

> 	unsigned max_links = dir->i_sb->s_max_links;
> 
> 	if (error)
> @@ -3667,7 +3674,7 @@ EXPORT_SYMBOL(dentry_unhash);
> 
> int vfs_rmdir(struct inode *dir, struct dentry *dentry)
> {
> -	int error = may_delete(dir, dentry, 1);
> +	int error = may_delete(dir, dentry, true, false);


The cases where there are multiple parameters is where it makes the most
improvement, since the code is more readable:

	int error = may_delete(dir, dentry, MAY_IS_DIR);

> 	if (error)
> 		return error;
> @@ -3789,7 +3796,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
> int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
> {
> 	struct inode *target = dentry->d_inode;
> -	int error = may_delete(dir, dentry, 0);
> +	int error = may_delete(dir, dentry, false, false);

	int error = may_delete(dir, dentry, MAY_IS_FILE);

Cheers, Andreas

> 	if (error)
> 		return error;
> @@ -3923,7 +3930,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
> 
> int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 
> 	if (error)
> 		return error;
> @@ -4006,7 +4013,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
> 	if (!inode)
> 		return -ENOENT;
> 
> -	error = may_create(dir, new_dentry);
> +	error = may_create(dir, new_dentry, false);
> 	if (error)
> 		return error;
> 
> @@ -4194,19 +4201,19 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
> 	if (source == target)
> 		return 0;
> 
> -	error = may_delete(old_dir, old_dentry, is_dir);
> +	error = may_delete(old_dir, old_dentry, is_dir, false);
> 	if (error)
> 		return error;
> 
> 	if (!target) {
> -		error = may_create(new_dir, new_dentry);
> +		error = may_create(new_dir, new_dentry, is_dir);
> 	} else {
> 		new_is_dir = d_is_dir(new_dentry);
> 
> 		if (!(flags & RENAME_EXCHANGE))
> -			error = may_delete(new_dir, new_dentry, is_dir);
> +			error = may_delete(new_dir, new_dentry, is_dir, true);
> 		else
> -			error = may_delete(new_dir, new_dentry, new_is_dir);
> +			error = may_delete(new_dir, new_dentry, new_is_dir, true);

> 	}
> 	if (error)
> 		return error;
> @@ -4469,7 +4476,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
> 
> int vfs_whiteout(struct inode *dir, struct dentry *dentry)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 	if (error)
> 		return error;
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 4efa435..d6e2330 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -82,6 +82,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
> #define MAY_CHDIR		0x00000040
> /* called from RCU mode, don't block */
> #define MAY_NOT_BLOCK		0x00000080
> +#define MAY_CREATE_FILE		0x00000100
> +#define MAY_CREATE_DIR		0x00000200
> 
> /*
>  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
> --
> 2.5.0
> 


Cheers, Andreas

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#1264898 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-07 18:50 +0100
Subject	Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags
Message-ID	<qsfMK-5mf-9@gated-at.bofh.it>
In reply to	#1264536

On Fri, Nov 6, 2015 at 9:58 PM, Andreas Dilger <adilger@dilger.ca> wrote:
> I thought you proposed adding an enum for these parameters, and possibly
> making them a single parameter flag, to make the code in the caller more
> readable.

No, the result would just be different but not any better; vfs_rename would
become messy.  I've played with this patch some more, and I find the approach
below which splits may_delete into may_delete and may_replace much better.
What do you think?

Thanks,
Andreas

---------- 8< ----------

Richacls distinguish between creating non-directories and directories. To
support that, add an isdir parameter to may_create(). When checking
inode_permission() for create permission, pass in an additional
MAY_CREATE_FILE or MAY_CREATE_DIR mask flag.

Add may_replace() to allow checking for delete and create access when
replacing an existing file in vfs_rename().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/namei.c         | 49 +++++++++++++++++++++++++++++++++----------------
 include/linux/fs.h |  2 ++
 2 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 224ecf1..4e5dc2f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,7 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
  * this, letting us set arbitrary permissions for filesystem access without
  * changing the "normal" UIDs which are used for other things.
  *
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
+ * MAY_CREATE_DIR are set.  That way, file systems that don't support these
+ * permissions will check for MAY_WRITE instead.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -2549,7 +2551,8 @@ EXPORT_SYMBOL(__check_sticky);
  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
  *     nfs_async_unlink().
  */
-static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+static int may_delete_replace(struct inode *dir, struct dentry *victim,
+			      bool isdir, int mask)
 {
 	struct inode *inode = d_backing_inode(victim);
 	int error;
@@ -2561,7 +2564,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
 	BUG_ON(victim->d_parent->d_inode != dir);
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
-	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	error = inode_permission(dir, mask | MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;
 	if (IS_APPEND(dir))
@@ -2584,6 +2587,18 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
 	return 0;
 }
 
+static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+{
+	return may_delete_replace(dir, victim, isdir, 0);
+}
+
+static int may_replace(struct inode *dir, struct dentry *victim, bool isdir)
+{
+	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
+	return may_delete_replace(dir, victim, isdir, mask);
+}
+
 /*	Check whether we can create an object with dentry child in directory
  *  dir.
  *  1. We can't do it if child already exists (open has special treatment for
@@ -2592,14 +2607,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
  *  3. We should have write and exec permissions on dir
  *  4. We can't do it if dir is immutable (done in permission())
  */
-static inline int may_create(struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
 {
+	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
 	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
 	if (child->d_inode)
 		return -EEXIST;
 	if (IS_DEADDIR(dir))
 		return -ENOENT;
-	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
 }
 
 /*
@@ -2649,7 +2666,7 @@ EXPORT_SYMBOL(unlock_rename);
 int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		bool want_excl)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
@@ -3494,7 +3511,7 @@ EXPORT_SYMBOL(user_path_create);
 
 int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -3586,7 +3603,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, true);
 	unsigned max_links = dir->i_sb->s_max_links;
 
 	if (error)
@@ -3667,7 +3684,7 @@ EXPORT_SYMBOL(dentry_unhash);
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_delete(dir, dentry, 1);
+	int error = may_delete(dir, dentry, true);
 
 	if (error)
 		return error;
@@ -3789,7 +3806,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
 int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
 {
 	struct inode *target = dentry->d_inode;
-	int error = may_delete(dir, dentry, 0);
+	int error = may_delete(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -3923,7 +3940,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 
 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -4006,7 +4023,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 	if (!inode)
 		return -ENOENT;
 
-	error = may_create(dir, new_dentry);
+	error = may_create(dir, new_dentry, false);
 	if (error)
 		return error;
 
@@ -4199,14 +4216,14 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		return error;
 
 	if (!target) {
-		error = may_create(new_dir, new_dentry);
+		error = may_create(new_dir, new_dentry, is_dir);
 	} else {
 		new_is_dir = d_is_dir(new_dentry);
 
 		if (!(flags & RENAME_EXCHANGE))
-			error = may_delete(new_dir, new_dentry, is_dir);
+			error = may_replace(new_dir, new_dentry, is_dir);
 		else
-			error = may_delete(new_dir, new_dentry, new_is_dir);
+			error = may_replace(new_dir, new_dentry, new_is_dir);
 	}
 	if (error)
 		return error;
@@ -4469,7 +4486,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
 
 int vfs_whiteout(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4efa435..d6e2330 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -82,6 +82,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_CHDIR		0x00000040
 /* called from RCU mode, don't block */
 #define MAY_NOT_BLOCK		0x00000080
+#define MAY_CREATE_FILE		0x00000100
+#define MAY_CREATE_DIR		0x00000200
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.5.0

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#1265036 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

From	Andreas Dilger <adilger@dilger.ca>
Date	2015-11-08 09:20 +0100
Subject	Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags
Message-ID	<qstmF-64m-3@gated-at.bofh.it>
In reply to	#1264898

[Multipart message — attachments visible in raw view] — view raw

On Nov 7, 2015, at 10:44 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
> 
> On Fri, Nov 6, 2015 at 9:58 PM, Andreas Dilger <adilger@dilger.ca> wrote:
>> I thought you proposed adding an enum for these parameters, and possibly
>> making them a single parameter flag, to make the code in the caller more
>> readable.
> 
> No, the result would just be different but not any better; vfs_rename would
> become messy.  I've played with this patch some more, and I find the approach
> below which splits may_delete into may_delete and may_replace much better.
> What do you think?

This is definitely better than the previous patch.  You can add:

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

Cheers, Andreas

> ---------- 8< ----------
> 
> Richacls distinguish between creating non-directories and directories. To
> support that, add an isdir parameter to may_create(). When checking
> inode_permission() for create permission, pass in an additional
> MAY_CREATE_FILE or MAY_CREATE_DIR mask flag.
> 
> Add may_replace() to allow checking for delete and create access when
> replacing an existing file in vfs_rename().
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
> ---
> fs/namei.c         | 49 +++++++++++++++++++++++++++++++++----------------
> include/linux/fs.h |  2 ++
> 2 files changed, 35 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 224ecf1..4e5dc2f 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -453,7 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
>  * this, letting us set arbitrary permissions for filesystem access without
>  * changing the "normal" UIDs which are used for other things.
>  *
> - * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
> + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
> + * MAY_CREATE_DIR are set.  That way, file systems that don't support these
> + * permissions will check for MAY_WRITE instead.
>  */
> int inode_permission(struct inode *inode, int mask)
> {
> @@ -2549,7 +2551,8 @@ EXPORT_SYMBOL(__check_sticky);
>  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
>  *     nfs_async_unlink().
>  */
> -static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> +static int may_delete_replace(struct inode *dir, struct dentry *victim,
> +			      bool isdir, int mask)
> {
> 	struct inode *inode = d_backing_inode(victim);
> 	int error;
> @@ -2561,7 +2564,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> 	BUG_ON(victim->d_parent->d_inode != dir);
> 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
> 
> -	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
> +	error = inode_permission(dir, mask | MAY_WRITE | MAY_EXEC);
> 	if (error)
> 		return error;
> 	if (IS_APPEND(dir))
> @@ -2584,6 +2587,18 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> 	return 0;
> }
> 
> +static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> +{
> +	return may_delete_replace(dir, victim, isdir, 0);
> +}
> +
> +static int may_replace(struct inode *dir, struct dentry *victim, bool isdir)
> +{
> +	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> +
> +	return may_delete_replace(dir, victim, isdir, mask);
> +}
> +
> /*	Check whether we can create an object with dentry child in directory
>  *  dir.
>  *  1. We can't do it if child already exists (open has special treatment for
> @@ -2592,14 +2607,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
>  *  3. We should have write and exec permissions on dir
>  *  4. We can't do it if dir is immutable (done in permission())
>  */
> -static inline int may_create(struct inode *dir, struct dentry *child)
> +static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
> {
> +	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> +
> 	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
> 	if (child->d_inode)
> 		return -EEXIST;
> 	if (IS_DEADDIR(dir))
> 		return -ENOENT;
> -	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
> +	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
> }
> 
> /*
> @@ -2649,7 +2666,7 @@ EXPORT_SYMBOL(unlock_rename);
> int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
> 		bool want_excl)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 	if (error)
> 		return error;
> 
> @@ -3494,7 +3511,7 @@ EXPORT_SYMBOL(user_path_create);
> 
> int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 
> 	if (error)
> 		return error;
> @@ -3586,7 +3603,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
> 
> int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, true);
> 	unsigned max_links = dir->i_sb->s_max_links;
> 
> 	if (error)
> @@ -3667,7 +3684,7 @@ EXPORT_SYMBOL(dentry_unhash);
> 
> int vfs_rmdir(struct inode *dir, struct dentry *dentry)
> {
> -	int error = may_delete(dir, dentry, 1);
> +	int error = may_delete(dir, dentry, true);
> 
> 	if (error)
> 		return error;
> @@ -3789,7 +3806,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
> int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
> {
> 	struct inode *target = dentry->d_inode;
> -	int error = may_delete(dir, dentry, 0);
> +	int error = may_delete(dir, dentry, false);
> 
> 	if (error)
> 		return error;
> @@ -3923,7 +3940,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
> 
> int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 
> 	if (error)
> 		return error;
> @@ -4006,7 +4023,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
> 	if (!inode)
> 		return -ENOENT;
> 
> -	error = may_create(dir, new_dentry);
> +	error = may_create(dir, new_dentry, false);
> 	if (error)
> 		return error;
> 
> @@ -4199,14 +4216,14 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
> 		return error;
> 
> 	if (!target) {
> -		error = may_create(new_dir, new_dentry);
> +		error = may_create(new_dir, new_dentry, is_dir);
> 	} else {
> 		new_is_dir = d_is_dir(new_dentry);
> 
> 		if (!(flags & RENAME_EXCHANGE))
> -			error = may_delete(new_dir, new_dentry, is_dir);
> +			error = may_replace(new_dir, new_dentry, is_dir);
> 		else
> -			error = may_delete(new_dir, new_dentry, new_is_dir);
> +			error = may_replace(new_dir, new_dentry, new_is_dir);
> 	}
> 	if (error)
> 		return error;
> @@ -4469,7 +4486,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
> 
> int vfs_whiteout(struct inode *dir, struct dentry *dentry)
> {
> -	int error = may_create(dir, dentry);
> +	int error = may_create(dir, dentry, false);
> 	if (error)
> 		return error;
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 4efa435..d6e2330 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -82,6 +82,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
> #define MAY_CHDIR		0x00000040
> /* called from RCU mode, don't block */
> #define MAY_NOT_BLOCK		0x00000080
> +#define MAY_CREATE_FILE		0x00000100
> +#define MAY_CREATE_DIR		0x00000200
> 
> /*
>  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
> --
> 2.5.0
> 


Cheers, Andreas

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#1263143 — [PATCH v14 06/22] richacl: In-memory representation and helper functions

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 12:50 +0100
Subject	[PATCH v14 06/22] richacl: In-memory representation and helper functions
Message-ID	<qrrdh-64e-47@gated-at.bofh.it>
In reply to	#1263117

A richacl consists of an NFSv4 acl and an owner, group, and other mask.
These three masks correspond to the owner, group, and other file
permission bits, but they contain NFSv4 permissions instead of POSIX
permissions.

Each entry in the NFSv4 acl applies to the file owner (OWNER@), the
owning group (GROUP@), everyone (EVERYONE@), or to a specific uid or
gid.

As in the standard POSIX file permission model, each process is the
owner, group, or other file class.  A richacl grants a requested access
only if the NFSv4 acl in the richacl grants the access (according to the
NFSv4 permission check algorithm), and the file mask that applies to the
process includes the requested permissions.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/Makefile                  |   2 +
 fs/richacl_base.c            |  67 ++++++++++++++++
 include/linux/richacl.h      | 179 +++++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/Kbuild    |   1 +
 include/uapi/linux/richacl.h |  99 ++++++++++++++++++++++++
 5 files changed, 348 insertions(+)
 create mode 100644 fs/richacl_base.c
 create mode 100644 include/linux/richacl.h
 create mode 100644 include/uapi/linux/richacl.h

diff --git a/fs/Makefile b/fs/Makefile
index f79cf40..fe3e9dd 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -48,6 +48,8 @@ obj-$(CONFIG_COREDUMP)		+= coredump.o
 obj-$(CONFIG_SYSCTL)		+= drop_caches.o
 
 obj-$(CONFIG_FHANDLE)		+= fhandle.o
+obj-$(CONFIG_FS_RICHACL)	+= richacl.o
+richacl-y			:= richacl_base.o
 
 obj-y				+= quota/
 
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
new file mode 100644
index 0000000..c3ec928
--- /dev/null
+++ b/fs/richacl_base.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruenba@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/richacl.h>
+
+MODULE_LICENSE("GPL");
+
+/**
+ * richacl_alloc  -  allocate a richacl
+ * @count:	number of entries
+ */
+struct richacl *
+richacl_alloc(int count, gfp_t gfp)
+{
+	size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+	struct richacl *acl = kzalloc(size, gfp);
+
+	if (acl) {
+		atomic_set(&acl->a_refcount, 1);
+		acl->a_count = count;
+	}
+	return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_alloc);
+
+/**
+ * richacl_clone  -  create a copy of a richacl
+ */
+struct richacl *
+richacl_clone(const struct richacl *acl, gfp_t gfp)
+{
+	int count = acl->a_count;
+	size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+	struct richacl *dup = kmalloc(size, gfp);
+
+	if (dup) {
+		memcpy(dup, acl, size);
+		atomic_set(&dup->a_refcount, 1);
+	}
+	return dup;
+}
+
+/**
+ * richace_copy  -  copy an acl entry
+ */
+void
+richace_copy(struct richace *to, const struct richace *from)
+{
+	memcpy(to, from, sizeof(struct richace));
+}
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
new file mode 100644
index 0000000..edb8480
--- /dev/null
+++ b/include/linux/richacl.h
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruenba@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __RICHACL_H
+#define __RICHACL_H
+
+#include <uapi/linux/richacl.h>
+
+struct richace {
+	unsigned short	e_type;
+	unsigned short	e_flags;
+	unsigned int	e_mask;
+	union {
+		kuid_t		uid;
+		kgid_t		gid;
+		unsigned int	special;
+	} e_id;
+};
+
+struct richacl {
+	atomic_t	a_refcount;
+	unsigned int	a_owner_mask;
+	unsigned int	a_group_mask;
+	unsigned int	a_other_mask;
+	unsigned short	a_count;
+	unsigned short	a_flags;
+	struct richace	a_entries[0];
+};
+
+#define richacl_for_each_entry(_ace, _acl)			\
+	for (_ace = (_acl)->a_entries;				\
+	     _ace != (_acl)->a_entries + (_acl)->a_count;	\
+	     _ace++)
+
+#define richacl_for_each_entry_reverse(_ace, _acl)		\
+	for (_ace = (_acl)->a_entries + (_acl)->a_count - 1;	\
+	     _ace != (_acl)->a_entries - 1;			\
+	     _ace--)
+
+/**
+ * richacl_get  -  grab another reference to a richacl handle
+ */
+static inline struct richacl *
+richacl_get(struct richacl *acl)
+{
+	if (acl)
+		atomic_inc(&acl->a_refcount);
+	return acl;
+}
+
+/**
+ * richacl_put  -  free a richacl handle
+ */
+static inline void
+richacl_put(struct richacl *acl)
+{
+	if (acl && atomic_dec_and_test(&acl->a_refcount))
+		kfree(acl);
+}
+
+/**
+ * richace_is_owner  -  check if @ace is an OWNER@ entry
+ */
+static inline bool
+richace_is_owner(const struct richace *ace)
+{
+	return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+	       ace->e_id.special == RICHACE_OWNER_SPECIAL_ID;
+}
+
+/**
+ * richace_is_group  -  check if @ace is a GROUP@ entry
+ */
+static inline bool
+richace_is_group(const struct richace *ace)
+{
+	return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+	       ace->e_id.special == RICHACE_GROUP_SPECIAL_ID;
+}
+
+/**
+ * richace_is_everyone  -  check if @ace is an EVERYONE@ entry
+ */
+static inline bool
+richace_is_everyone(const struct richace *ace)
+{
+	return (ace->e_flags & RICHACE_SPECIAL_WHO) &&
+	       ace->e_id.special == RICHACE_EVERYONE_SPECIAL_ID;
+}
+
+/**
+ * richace_is_unix_user  -  check if @ace applies to a specific user
+ */
+static inline bool
+richace_is_unix_user(const struct richace *ace)
+{
+	return !(ace->e_flags & RICHACE_SPECIAL_WHO) &&
+	       !(ace->e_flags & RICHACE_IDENTIFIER_GROUP);
+}
+
+/**
+ * richace_is_unix_group  -  check if @ace applies to a specific group
+ */
+static inline bool
+richace_is_unix_group(const struct richace *ace)
+{
+	return !(ace->e_flags & RICHACE_SPECIAL_WHO) &&
+	       (ace->e_flags & RICHACE_IDENTIFIER_GROUP);
+}
+
+/**
+ * richace_is_inherit_only  -  check if @ace is for inheritance only
+ *
+ * ACEs with the %RICHACE_INHERIT_ONLY_ACE flag set have no effect during
+ * permission checking.
+ */
+static inline bool
+richace_is_inherit_only(const struct richace *ace)
+{
+	return ace->e_flags & RICHACE_INHERIT_ONLY_ACE;
+}
+
+/**
+ * richace_is_inheritable  -  check if @ace is inheritable
+ */
+static inline bool
+richace_is_inheritable(const struct richace *ace)
+{
+	return ace->e_flags & (RICHACE_FILE_INHERIT_ACE |
+			       RICHACE_DIRECTORY_INHERIT_ACE);
+}
+
+/**
+ * richace_is_allow  -  check if @ace is an %ALLOW type entry
+ */
+static inline bool
+richace_is_allow(const struct richace *ace)
+{
+	return ace->e_type == RICHACE_ACCESS_ALLOWED_ACE_TYPE;
+}
+
+/**
+ * richace_is_deny  -  check if @ace is a %DENY type entry
+ */
+static inline bool
+richace_is_deny(const struct richace *ace)
+{
+	return ace->e_type == RICHACE_ACCESS_DENIED_ACE_TYPE;
+}
+
+/**
+ * richace_is_same_identifier  -  are both identifiers the same?
+ */
+static inline bool
+richace_is_same_identifier(const struct richace *a, const struct richace *b)
+{
+	return !((a->e_flags ^ b->e_flags) &
+		 (RICHACE_SPECIAL_WHO | RICHACE_IDENTIFIER_GROUP)) &&
+	       !memcmp(&a->e_id, &b->e_id, sizeof(a->e_id));
+}
+
+extern struct richacl *richacl_alloc(int, gfp_t);
+extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
+extern void richace_copy(struct richace *, const struct richace *);
+
+#endif /* __RICHACL_H */
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index f7b2db4..8c82010 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -348,6 +348,7 @@ header-y += reboot.h
 header-y += reiserfs_fs.h
 header-y += reiserfs_xattr.h
 header-y += resource.h
+header-y += richacl.h
 header-y += rfkill.h
 header-y += romfs_fs.h
 header-y += rose.h
diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h
new file mode 100644
index 0000000..08856f8
--- /dev/null
+++ b/include/uapi/linux/richacl.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruenba@redhat.com>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#ifndef __UAPI_RICHACL_H
+#define __UAPI_RICHACL_H
+
+/* a_flags values */
+#define RICHACL_WRITE_THROUGH			0x40
+#define RICHACL_MASKED				0x80
+
+/* e_type values */
+#define RICHACE_ACCESS_ALLOWED_ACE_TYPE		0x0000
+#define RICHACE_ACCESS_DENIED_ACE_TYPE		0x0001
+
+/* e_flags bitflags */
+#define RICHACE_FILE_INHERIT_ACE		0x0001
+#define RICHACE_DIRECTORY_INHERIT_ACE		0x0002
+#define RICHACE_NO_PROPAGATE_INHERIT_ACE	0x0004
+#define RICHACE_INHERIT_ONLY_ACE		0x0008
+#define RICHACE_IDENTIFIER_GROUP		0x0040
+#define RICHACE_SPECIAL_WHO			0x4000
+
+/* e_mask bitflags */
+#define RICHACE_READ_DATA			0x00000001
+#define RICHACE_LIST_DIRECTORY			0x00000001
+#define RICHACE_WRITE_DATA			0x00000002
+#define RICHACE_ADD_FILE			0x00000002
+#define RICHACE_APPEND_DATA			0x00000004
+#define RICHACE_ADD_SUBDIRECTORY		0x00000004
+#define RICHACE_READ_NAMED_ATTRS		0x00000008
+#define RICHACE_WRITE_NAMED_ATTRS		0x00000010
+#define RICHACE_EXECUTE				0x00000020
+#define RICHACE_DELETE_CHILD			0x00000040
+#define RICHACE_READ_ATTRIBUTES			0x00000080
+#define RICHACE_WRITE_ATTRIBUTES		0x00000100
+#define RICHACE_WRITE_RETENTION			0x00000200
+#define RICHACE_WRITE_RETENTION_HOLD		0x00000400
+#define RICHACE_DELETE				0x00010000
+#define RICHACE_READ_ACL			0x00020000
+#define RICHACE_WRITE_ACL			0x00040000
+#define RICHACE_WRITE_OWNER			0x00080000
+#define RICHACE_SYNCHRONIZE			0x00100000
+
+/* e_id values */
+#define RICHACE_OWNER_SPECIAL_ID		0
+#define RICHACE_GROUP_SPECIAL_ID		1
+#define RICHACE_EVERYONE_SPECIAL_ID		2
+
+#define RICHACL_VALID_FLAGS (					\
+	RICHACL_WRITE_THROUGH |					\
+	RICHACL_MASKED )
+
+#define RICHACE_VALID_FLAGS (					\
+	RICHACE_FILE_INHERIT_ACE |				\
+	RICHACE_DIRECTORY_INHERIT_ACE |				\
+	RICHACE_NO_PROPAGATE_INHERIT_ACE |			\
+	RICHACE_INHERIT_ONLY_ACE |				\
+	RICHACE_IDENTIFIER_GROUP |				\
+	RICHACE_SPECIAL_WHO )
+
+#define RICHACE_INHERITANCE_FLAGS (				\
+	RICHACE_FILE_INHERIT_ACE |				\
+	RICHACE_DIRECTORY_INHERIT_ACE |				\
+	RICHACE_NO_PROPAGATE_INHERIT_ACE |			\
+	RICHACE_INHERIT_ONLY_ACE )
+
+/* Valid RICHACE_* flags for directories and non-directories */
+#define RICHACE_VALID_MASK (					\
+	RICHACE_READ_DATA | RICHACE_LIST_DIRECTORY |		\
+	RICHACE_WRITE_DATA | RICHACE_ADD_FILE |			\
+	RICHACE_APPEND_DATA | RICHACE_ADD_SUBDIRECTORY |	\
+	RICHACE_READ_NAMED_ATTRS |				\
+	RICHACE_WRITE_NAMED_ATTRS |				\
+	RICHACE_EXECUTE |					\
+	RICHACE_DELETE_CHILD |					\
+	RICHACE_READ_ATTRIBUTES |				\
+	RICHACE_WRITE_ATTRIBUTES |				\
+	RICHACE_WRITE_RETENTION |				\
+	RICHACE_WRITE_RETENTION_HOLD |				\
+	RICHACE_DELETE |					\
+	RICHACE_READ_ACL |					\
+	RICHACE_WRITE_ACL |					\
+	RICHACE_WRITE_OWNER |					\
+	RICHACE_SYNCHRONIZE )
+
+#endif /* __UAPI_RICHACL_H */
-- 
2.5.0

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#1263145 — [PATCH v14 07/22] richacl: Permission mapping functions

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 13:00 +0100
Subject	[PATCH v14 07/22] richacl: Permission mapping functions
Message-ID	<qrrmW-69O-3@gated-at.bofh.it>
In reply to	#1263117

We need to map from POSIX permissions to NFSv4 permissions when a
chmod() is done, from NFSv4 permissions to POSIX permissions when an acl
is set (which implicitly sets the file permission bits), and from the
MAY_READ/MAY_WRITE/MAY_EXEC/MAY_APPEND flags to NFSv4 permissions when
doing an access check in a richacl.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/richacl_base.c            | 118 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h      |   3 ++
 include/uapi/linux/richacl.h |  44 ++++++++++++++++
 3 files changed, 165 insertions(+)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index c3ec928..a393001 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -65,3 +65,121 @@ richace_copy(struct richace *to, const struct richace *from)
 {
 	memcpy(to, from, sizeof(struct richace));
 }
+
+/*
+ * richacl_mask_to_mode  -  compute the file permission bits from mask
+ * @mask:	%RICHACE_* permission mask
+ *
+ * Compute the file permission bits corresponding to a particular set of
+ * richacl permissions.
+ *
+ * See richacl_masks_to_mode().
+ */
+static int
+richacl_mask_to_mode(unsigned int mask)
+{
+	int mode = 0;
+
+	if (mask & RICHACE_POSIX_MODE_READ)
+		mode |= S_IROTH;
+	if (mask & RICHACE_POSIX_MODE_WRITE)
+		mode |= S_IWOTH;
+	if (mask & RICHACE_POSIX_MODE_EXEC)
+		mode |= S_IXOTH;
+
+	return mode;
+}
+
+/**
+ * richacl_masks_to_mode  -  compute file permission bits from file masks
+ *
+ * When setting a richacl, we set the file permission bits to indicate maximum
+ * permissions: for example, we set the Write permission when a mask contains
+ * RICHACE_APPEND_DATA even if it does not also contain RICHACE_WRITE_DATA.
+ *
+ * Permissions which are not in RICHACE_POSIX_MODE_READ,
+ * RICHACE_POSIX_MODE_WRITE, or RICHACE_POSIX_MODE_EXEC cannot be represented
+ * in the file permission bits.  Such permissions can still be effective, but
+ * not for new files or after a chmod(); they must be explicitly enabled in the
+ * richacl.
+ */
+int
+richacl_masks_to_mode(const struct richacl *acl)
+{
+	return richacl_mask_to_mode(acl->a_owner_mask) << 6 |
+	       richacl_mask_to_mode(acl->a_group_mask) << 3 |
+	       richacl_mask_to_mode(acl->a_other_mask);
+}
+EXPORT_SYMBOL_GPL(richacl_masks_to_mode);
+
+/**
+ * richacl_mode_to_mask  - compute a file mask from the lowest three mode bits
+ * @mode:	mode to convert to richacl permissions
+ *
+ * When the file permission bits of a file are set with chmod(), this specifies
+ * the maximum permissions that processes will get.  All permissions beyond
+ * that will be removed from the file masks, and become ineffective.
+ */
+unsigned int
+richacl_mode_to_mask(umode_t mode)
+{
+	unsigned int mask = 0;
+
+	if (mode & S_IROTH)
+		mask |= RICHACE_POSIX_MODE_READ;
+	if (mode & S_IWOTH)
+		mask |= RICHACE_POSIX_MODE_WRITE;
+	if (mode & S_IXOTH)
+		mask |= RICHACE_POSIX_MODE_EXEC;
+
+	return mask;
+}
+
+/**
+ * richacl_want_to_mask  - convert the iop->permission want argument to a mask
+ * @want:	@want argument of the permission inode operation
+ *
+ * When checking for append, @want is (MAY_WRITE | MAY_APPEND).
+ *
+ * Richacls use the iop->may_create and iop->may_delete hooks which are used
+ * for checking if creating and deleting files is allowed.  These hooks do not
+ * use richacl_want_to_mask(), so we do not have to deal with mapping MAY_WRITE
+ * to RICHACE_ADD_FILE, RICHACE_ADD_SUBDIRECTORY, and RICHACE_DELETE_CHILD
+ * here.
+ */
+unsigned int
+richacl_want_to_mask(unsigned int want)
+{
+	unsigned int mask = 0;
+
+	if (want & MAY_READ)
+		mask |= RICHACE_READ_DATA;
+	if (want & MAY_DELETE_SELF)
+		mask |= RICHACE_DELETE;
+	if (want & MAY_TAKE_OWNERSHIP)
+		mask |= RICHACE_WRITE_OWNER;
+	if (want & MAY_CHMOD)
+		mask |= RICHACE_WRITE_ACL;
+	if (want & MAY_SET_TIMES)
+		mask |= RICHACE_WRITE_ATTRIBUTES;
+	if (want & MAY_EXEC)
+		mask |= RICHACE_EXECUTE;
+	/*
+	 * differentiate MAY_WRITE from these request
+	 */
+	if (want & (MAY_APPEND |
+		    MAY_CREATE_FILE | MAY_CREATE_DIR |
+		    MAY_DELETE_CHILD)) {
+		if (want & MAY_APPEND)
+			mask |= RICHACE_APPEND_DATA;
+		if (want & MAY_CREATE_FILE)
+			mask |= RICHACE_ADD_FILE;
+		if (want & MAY_CREATE_DIR)
+			mask |= RICHACE_ADD_SUBDIRECTORY;
+		if (want & MAY_DELETE_CHILD)
+			mask |= RICHACE_DELETE_CHILD;
+	} else if (want & MAY_WRITE)
+		mask |= RICHACE_WRITE_DATA;
+	return mask;
+}
+EXPORT_SYMBOL_GPL(richacl_want_to_mask);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index edb8480..9102ef0 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -175,5 +175,8 @@ richace_is_same_identifier(const struct richace *a, const struct richace *b)
 extern struct richacl *richacl_alloc(int, gfp_t);
 extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
 extern void richace_copy(struct richace *, const struct richace *);
+extern int richacl_masks_to_mode(const struct richacl *);
+extern unsigned int richacl_mode_to_mask(umode_t);
+extern unsigned int richacl_want_to_mask(unsigned int);
 
 #endif /* __RICHACL_H */
diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h
index 08856f8..1ed48ac 100644
--- a/include/uapi/linux/richacl.h
+++ b/include/uapi/linux/richacl.h
@@ -96,4 +96,48 @@
 	RICHACE_WRITE_OWNER |					\
 	RICHACE_SYNCHRONIZE )
 
+/*
+ * The POSIX permissions are supersets of the following richacl permissions:
+ *
+ *  - MAY_READ maps to READ_DATA or LIST_DIRECTORY, depending on the type
+ *    of the file system object.
+ *
+ *  - MAY_WRITE maps to WRITE_DATA or RICHACE_APPEND_DATA for files, and to
+ *    ADD_FILE, RICHACE_ADD_SUBDIRECTORY, or RICHACE_DELETE_CHILD for directories.
+ *
+ *  - MAY_EXECUTE maps to RICHACE_EXECUTE.
+ *
+ *  (Some of these richacl permissions have the same bit values.)
+ */
+#define RICHACE_POSIX_MODE_READ (			\
+		RICHACE_READ_DATA |			\
+		RICHACE_LIST_DIRECTORY)
+#define RICHACE_POSIX_MODE_WRITE (			\
+		RICHACE_WRITE_DATA |			\
+		RICHACE_ADD_FILE |			\
+		RICHACE_APPEND_DATA |			\
+		RICHACE_ADD_SUBDIRECTORY |		\
+		RICHACE_DELETE_CHILD)
+#define RICHACE_POSIX_MODE_EXEC RICHACE_EXECUTE
+#define RICHACE_POSIX_MODE_ALL (			\
+		RICHACE_POSIX_MODE_READ |		\
+		RICHACE_POSIX_MODE_WRITE |		\
+		RICHACE_POSIX_MODE_EXEC)
+
+/*
+ * These permissions are always allowed no matter what the acl says.
+ */
+#define RICHACE_POSIX_ALWAYS_ALLOWED (			\
+		RICHACE_SYNCHRONIZE |			\
+		RICHACE_READ_ATTRIBUTES |		\
+		RICHACE_READ_ACL)
+
+/*
+ * The owner is implicitly granted these permissions under POSIX.
+ */
+#define RICHACE_POSIX_OWNER_ALLOWED (			\
+		RICHACE_WRITE_ATTRIBUTES |		\
+		RICHACE_WRITE_OWNER |			\
+		RICHACE_WRITE_ACL)
+
 #endif /* __UAPI_RICHACL_H */
-- 
2.5.0

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#1263148 — [PATCH v14 08/22] richacl: Compute maximum file masks from an acl

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 13:00 +0100
Subject	[PATCH v14 08/22] richacl: Compute maximum file masks from an acl
Message-ID	<qrrmW-69O-9@gated-at.bofh.it>
In reply to	#1263117

Compute upper bound owner, group, and other file masks with as few
permissions as possible without denying any permissions that the NFSv4
acl in a richacl grants.

This algorithm is used when a file inherits an acl at create time and
when an acl is set via a mechanism that does not provide file masks
(such as setting an acl via nfsd).  When user-space sets an acl via
setxattr, the extended attribute already includes the file masks.

Setting an acl also sets the file mode permission bits: they are
determined by the file masks; see richacl_masks_to_mode().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/richacl_base.c       | 157 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |   1 +
 2 files changed, 158 insertions(+)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index a393001..69b806c 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -183,3 +183,160 @@ richacl_want_to_mask(unsigned int want)
 	return mask;
 }
 EXPORT_SYMBOL_GPL(richacl_want_to_mask);
+
+/*
+ * Note: functions like richacl_allowed_to_who(), richacl_group_class_allowed(),
+ * and richacl_compute_max_masks() iterate through the entire acl in reverse
+ * order as an optimization.
+ *
+ * In the standard algorithm, aces are considered in forward order.  When a
+ * process matches an ace, the permissions in the ace are either allowed or
+ * denied depending on the ace type.  Once a permission has been allowed or
+ * denied, it is no longer considered in further aces.
+ *
+ * By iterating through the acl in reverse order, we can compute the same
+ * result without having to keep track of which permissions have been allowed
+ * and denied already.
+ */
+
+/**
+ * richacl_allowed_to_who  -  permissions allowed to a specific who value
+ *
+ * Compute the maximum mask values allowed to a specific who value, taking
+ * everyone@ aces into account.
+ */
+static unsigned int richacl_allowed_to_who(struct richacl *acl,
+					   struct richace *who)
+{
+	struct richace *ace;
+	unsigned int allowed = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+		if (richace_is_same_identifier(ace, who) ||
+		    richace_is_everyone(ace)) {
+			if (richace_is_allow(ace))
+				allowed |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				allowed &= ~ace->e_mask;
+		}
+	}
+	return allowed;
+}
+
+/**
+ * richacl_group_class_allowed  -  maximum permissions of the group class
+ *
+ * Compute the maximum mask values allowed to a process in the group class
+ * (i.e., a process which is not the owner but is in the owning group or
+ * matches a user or group acl entry).  This includes permissions granted or
+ * denied by everyone@ aces.
+ *
+ * See richacl_compute_max_masks().
+ */
+static unsigned int richacl_group_class_allowed(struct richacl *acl)
+{
+	struct richace *ace;
+	unsigned int everyone_allowed = 0, group_class_allowed = 0;
+	int had_group_ace = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace) ||
+		    richace_is_owner(ace))
+			continue;
+
+		if (richace_is_everyone(ace)) {
+			if (richace_is_allow(ace))
+				everyone_allowed |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				everyone_allowed &= ~ace->e_mask;
+		} else {
+			group_class_allowed |=
+				richacl_allowed_to_who(acl, ace);
+
+			if (richace_is_group(ace))
+				had_group_ace = 1;
+		}
+	}
+	/*
+	 * If the acl doesn't contain any group@ aces, richacl_allowed_to_who()
+	 * wasn't called for the owning group.  We could make that call now, but
+	 * we already know the result (everyone_allowed).
+	 */
+	if (!had_group_ace)
+		group_class_allowed |= everyone_allowed;
+	return group_class_allowed;
+}
+
+/**
+ * richacl_compute_max_masks  -  compute upper bound masks
+ *
+ * Computes upper bound owner, group, and other masks so that none of the
+ * permissions allowed by the acl are disabled.
+ *
+ * We don't make assumptions about who the owner is so that the owner can
+ * change with no effect on the file masks or file mode permission bits; this
+ * means that we must assume that all entries can match the owner.
+ */
+void richacl_compute_max_masks(struct richacl *acl)
+{
+	unsigned int gmask = ~0;
+	struct richace *ace;
+
+	/*
+	 * @gmask contains all permissions which the group class is ever
+	 * allowed.  We use it to avoid adding permissions to the group mask
+	 * from everyone@ allow aces which the group class is always denied
+	 * through other aces.  For example, the following acl would otherwise
+	 * result in a group mask of rw:
+	 *
+	 *	group@:w::deny
+	 *	everyone@:rw::allow
+	 *
+	 * Avoid computing @gmask for acls which do not include any group class
+	 * deny aces: in such acls, the group class is never denied any
+	 * permissions from everyone@ allow aces, and the group class cannot
+	 * have fewer permissions than the other class.
+	 */
+
+restart:
+	acl->a_owner_mask = 0;
+	acl->a_group_mask = 0;
+	acl->a_other_mask = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+
+		if (richace_is_owner(ace)) {
+			if (richace_is_allow(ace))
+				acl->a_owner_mask |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				acl->a_owner_mask &= ~ace->e_mask;
+		} else if (richace_is_everyone(ace)) {
+			if (richace_is_allow(ace)) {
+				acl->a_owner_mask |= ace->e_mask;
+				acl->a_group_mask |= ace->e_mask & gmask;
+				acl->a_other_mask |= ace->e_mask;
+			} else if (richace_is_deny(ace)) {
+				acl->a_owner_mask &= ~ace->e_mask;
+				acl->a_group_mask &= ~ace->e_mask;
+				acl->a_other_mask &= ~ace->e_mask;
+			}
+		} else {
+			if (richace_is_allow(ace)) {
+				acl->a_owner_mask |= ace->e_mask & gmask;
+				acl->a_group_mask |= ace->e_mask & gmask;
+			} else if (richace_is_deny(ace) && gmask == ~0) {
+				gmask = richacl_group_class_allowed(acl);
+				if (likely(gmask != ~0))
+					/* should always be true */
+					goto restart;
+			}
+		}
+	}
+
+	acl->a_flags &= ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED);
+}
+EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 9102ef0..3559b2c 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -178,5 +178,6 @@ extern void richace_copy(struct richace *, const struct richace *);
 extern int richacl_masks_to_mode(const struct richacl *);
 extern unsigned int richacl_mode_to_mask(umode_t);
 extern unsigned int richacl_want_to_mask(unsigned int);
+extern void richacl_compute_max_masks(struct richacl *);
 
 #endif /* __RICHACL_H */
-- 
2.5.0

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#1263150 — [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 13:00 +0100
Subject	[PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Message-ID	<qrrmW-69O-17@gated-at.bofh.it>
In reply to	#1263117

Normally, deleting a file requires MAY_WRITE access to the parent
directory.  With richacls, a file may be deleted with MAY_DELETE_CHILD access
to the parent directory or with MAY_DELETE_SELF access to the file.

To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
when checking for delete access inside a directory, and MAY_DELETE_SELF
when checking for delete access to a file itelf.

The MAY_DELETE_SELF permission overrides the sticky directory check.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/namei.c         | 21 ++++++++++++---------
 include/linux/fs.h |  2 ++
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0259392..2eab19e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
  * this, letting us set arbitrary permissions for filesystem access without
  * changing the "normal" UIDs which are used for other things.
  *
- * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
- * MAY_CREATE_DIR are set.  That way, file systems that don't support these
- * permissions will check for MAY_WRITE instead.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
+ * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set.  That way, file systems that
+ * don't support these permissions will check for MAY_WRITE instead.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -2555,7 +2555,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 		      bool isdir, bool replace)
 {
 	struct inode *inode = d_backing_inode(victim);
-	int error, mask = MAY_WRITE | MAY_EXEC;
+	int error, mask = MAY_EXEC;
 
 	if (d_is_negative(victim))
 		return -ENOENT;
@@ -2565,15 +2565,18 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
 	if (replace)
-		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
-	error = inode_permission(dir, mask);
+		mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
+	error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
+	if (!error && check_sticky(dir, inode))
+		error = -EPERM;
+	if (error && IS_RICHACL(inode) &&
+	    inode_permission(inode, MAY_DELETE_SELF) == 0)
+		error = 0;
 	if (error)
 		return error;
 	if (IS_APPEND(dir))
 		return -EPERM;
-
-	if (check_sticky(dir, inode) || IS_APPEND(inode) ||
-	    IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
 		return -EPERM;
 	if (isdir) {
 		if (!d_is_dir(victim))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d6e2330..402acd7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -84,6 +84,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_NOT_BLOCK		0x00000080
 #define MAY_CREATE_FILE		0x00000100
 #define MAY_CREATE_DIR		0x00000200
+#define MAY_DELETE_CHILD	0x00000400
+#define MAY_DELETE_SELF		0x00000800
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.5.0

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#1264571 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From	Andreas Dilger <adilger@dilger.ca>
Date	2015-11-06 22:30 +0100
Subject	Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Message-ID	<qrWK6-1yP-11@gated-at.bofh.it>
In reply to	#1263150

[Multipart message — attachments visible in raw view] — view raw

On Nov 5, 2015, at 4:39 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
> 
> Normally, deleting a file requires MAY_WRITE access to the parent
> directory.  With richacls, a file may be deleted with MAY_DELETE_CHILD access
> to the parent directory or with MAY_DELETE_SELF access to the file.
> 
> To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
> when checking for delete access inside a directory, and MAY_DELETE_SELF
> when checking for delete access to a file itelf.
> 
> The MAY_DELETE_SELF permission overrides the sticky directory check.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
> ---
> fs/namei.c         | 21 ++++++++++++---------
> include/linux/fs.h |  2 ++
> 2 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 0259392..2eab19e 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
>  * this, letting us set arbitrary permissions for filesystem access without
>  * changing the "normal" UIDs which are used for other things.
>  *
> - * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
> - * MAY_CREATE_DIR are set.  That way, file systems that don't support these
> - * permissions will check for MAY_WRITE instead.
> + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
> + * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set.  That way, file systems that
> + * don't support these permissions will check for MAY_WRITE instead.
>  */
> int inode_permission(struct inode *inode, int mask)
> {
> @@ -2555,7 +2555,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
> 		      bool isdir, bool replace)
> {
> 	struct inode *inode = d_backing_inode(victim);
> -	int error, mask = MAY_WRITE | MAY_EXEC;
> +	int error, mask = MAY_EXEC;
> 
> 	if (d_is_negative(victim))
> 		return -ENOENT;
> @@ -2565,15 +2565,18 @@ static int may_delete(struct inode *dir, struct dentry *victim,
> 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
> 
> 	if (replace)
> -		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> -	error = inode_permission(dir, mask);
> +		mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
> +	error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
> +	if (!error && check_sticky(dir, inode))
> +		error = -EPERM;
> +	if (error && IS_RICHACL(inode) &&
> +	    inode_permission(inode, MAY_DELETE_SELF) == 0)
> +		error = 0;

This looks like a serious bug, as it is overriding other errors returned
from inode_permission() such as -EROFS from sb_permission() or even from
generic_permission->acl_permission_check().  Clearing the error returned
by an earlier check doesn't seem safe, only new errors should be added.

The call to inode_permission(inode) is also duplicating the sb_permission()
check from inode_permission(dir), so at most should be __inode_permission().

It looks like this would be correct if you check MAY_DELETE_SELF together
with check_sticky():

	if (!error && check_sticky(dir, inode) &&
	    !__inode_permission(inode, MAY_DELETE_SELF))
		error = -EPERM;

I ommitted the IS_RICHACL() check here, since that should probably be in
__inode_permission() when MAY_DELETE_SELF is passed?

Cheers, Andreas

> 	if (error)
> 		return error;
> 	if (IS_APPEND(dir))
> 		return -EPERM;

> -
> -	if (check_sticky(dir, inode) || IS_APPEND(inode) ||
> -	    IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
> +	if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
> 		return -EPERM;

> 	if (isdir) {
> 		if (!d_is_dir(victim))
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index d6e2330..402acd7 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -84,6 +84,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
> #define MAY_NOT_BLOCK		0x00000080
> #define MAY_CREATE_FILE		0x00000100
> #define MAY_CREATE_DIR		0x00000200
> +#define MAY_DELETE_CHILD	0x00000400
> +#define MAY_DELETE_SELF		0x00000800
> 
> /*
>  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
> --
> 2.5.0
> 


Cheers, Andreas

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#1264930 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-07 21:50 +0100
Subject	Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Message-ID	<qsiAV-79R-5@gated-at.bofh.it>
In reply to	#1264571

On Fri, Nov 6, 2015 at 10:26 PM, Andreas Dilger <adilger@dilger.ca> wrote:
> On Nov 5, 2015, at 4:39 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
>>
>> Normally, deleting a file requires MAY_WRITE access to the parent
>> directory.  With richacls, a file may be deleted with MAY_DELETE_CHILD access
>> to the parent directory or with MAY_DELETE_SELF access to the file.
>>
>> To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
>> when checking for delete access inside a directory, and MAY_DELETE_SELF
>> when checking for delete access to a file itelf.
>>
>> The MAY_DELETE_SELF permission overrides the sticky directory check.
>>
>> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
>> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
>> ---
>> fs/namei.c         | 21 ++++++++++++---------
>> include/linux/fs.h |  2 ++
>> 2 files changed, 14 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/namei.c b/fs/namei.c
>> index 0259392..2eab19e 100644
>> --- a/fs/namei.c
>> +++ b/fs/namei.c
>> @@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
>>  * this, letting us set arbitrary permissions for filesystem access without
>>  * changing the "normal" UIDs which are used for other things.
>>  *
>> - * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
>> - * MAY_CREATE_DIR are set.  That way, file systems that don't support these
>> - * permissions will check for MAY_WRITE instead.
>> + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
>> + * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set.  That way, file systems that
>> + * don't support these permissions will check for MAY_WRITE instead.
>>  */
>> int inode_permission(struct inode *inode, int mask)
>> {
>> @@ -2555,7 +2555,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
>>                     bool isdir, bool replace)
>> {
>>       struct inode *inode = d_backing_inode(victim);
>> -     int error, mask = MAY_WRITE | MAY_EXEC;
>> +     int error, mask = MAY_EXEC;
>>
>>       if (d_is_negative(victim))
>>               return -ENOENT;
>> @@ -2565,15 +2565,18 @@ static int may_delete(struct inode *dir, struct dentry *victim,
>>       audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
>>
>>       if (replace)
>> -             mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
>> -     error = inode_permission(dir, mask);
>> +             mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
>> +     error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
>> +     if (!error && check_sticky(dir, inode))
>> +             error = -EPERM;
>> +     if (error && IS_RICHACL(inode) &&
>> +         inode_permission(inode, MAY_DELETE_SELF) == 0)
>> +             error = 0;
>
> This looks like a serious bug, as it is overriding other errors returned
> from inode_permission() such as -EROFS from sb_permission() or even from
> generic_permission->acl_permission_check().  Clearing the error returned
> by an earlier check doesn't seem safe, only new errors should be added.

See further below ...

> The call to inode_permission(inode) is also duplicating the sb_permission()
> check from inode_permission(dir), so at most should be __inode_permission().

This could be optimized, but that would make the code harder to read.
I don't think it really matters: this only affects file with the
MAY_DELETE_SELF permission, and sb_permissions is really cheap anyway.

> It looks like this would be correct if you check MAY_DELETE_SELF together
> with check_sticky():
>
>         if (!error && check_sticky(dir, inode) &&
>             !__inode_permission(inode, MAY_DELETE_SELF))
>                 error = -EPERM;

Nope, this version would deny users with MAY_DELETE_SELF access to a
file and MAY_EXEC access to the directory the right to delete the file
because @error would already be set then.

You are right that the check for MAY_DELETE_SELF overrides too much
here though; we need an additional inode_permission(dir, ...) check in
there.

I've pushed a fixed version here that I will do some more testing on
before reposting:

  git://git.kernel.org/pub/scm/linux/kernel/git/agruen/linux-richacl.git
richacl-wip

> I ommitted the IS_RICHACL() check here, since that should probably be in
> __inode_permission() when MAY_DELETE_SELF is passed?

The IS_RICHACL() check is indeed done in inode_permission ->
__inode_permission -> do_inode_permission -> generic_permission ->
acl_permission_check. I've duplicated that check here to avoid slowing
down may_delete in the common case where the filesystem doesn't
support richacls.

Thanks,
Andreas
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#1264573 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From	Andreas Dilger <adilger@dilger.ca>
Date	2015-11-06 22:30 +0100
Subject	Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Message-ID	<qrWK6-1yP-7@gated-at.bofh.it>
In reply to	#1263150

[Multipart message — attachments visible in raw view] — view raw

On Nov 5, 2015, at 4:39 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
> 
> Normally, deleting a file requires MAY_WRITE access to the parent
> directory.  With richacls, a file may be deleted with MAY_DELETE_CHILD access
> to the parent directory or with MAY_DELETE_SELF access to the file.
> 
> To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
> when checking for delete access inside a directory, and MAY_DELETE_SELF
> when checking for delete access to a file itelf.
> 
> The MAY_DELETE_SELF permission overrides the sticky directory check.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
> ---
> fs/namei.c         | 21 ++++++++++++---------
> include/linux/fs.h |  2 ++
> 2 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 0259392..2eab19e 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
>  * this, letting us set arbitrary permissions for filesystem access without
>  * changing the "normal" UIDs which are used for other things.
>  *
> - * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
> - * MAY_CREATE_DIR are set.  That way, file systems that don't support these
> - * permissions will check for MAY_WRITE instead.
> + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
> + * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set.  That way, file systems that
> + * don't support these permissions will check for MAY_WRITE instead.
>  */
> int inode_permission(struct inode *inode, int mask)
> {
> @@ -2555,7 +2555,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
> 		      bool isdir, bool replace)
> {
> 	struct inode *inode = d_backing_inode(victim);
> -	int error, mask = MAY_WRITE | MAY_EXEC;
> +	int error, mask = MAY_EXEC;
> 
> 	if (d_is_negative(victim))
> 		return -ENOENT;
> @@ -2565,15 +2565,18 @@ static int may_delete(struct inode *dir, struct dentry *victim,
> 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
> 
> 	if (replace)
> -		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
> -	error = inode_permission(dir, mask);
> +		mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
> +	error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
> +	if (!error && check_sticky(dir, inode))
> +		error = -EPERM;
> +	if (error && IS_RICHACL(inode) &&
> +	    inode_permission(inode, MAY_DELETE_SELF) == 0)
> +		error = 0;

This looks like a serious bug, as it is overriding other errors returned
from inode_permission() such as -EROFS from sb_permission() or even from
generic_permission->acl_permission_check().  Clearing the error returned
by an earlier check doesn't seem safe, only new errors should be added.

The call to inode_permission(inode) is also duplicating the sb_permission()
check from inode_permission(dir), so at most should be __inode_permission().

It looks like this would be correct if you check MAY_DELETE_SELF together
with check_sticky():

	if (!error && check_sticky(dir, inode) &&
	    !__inode_permission(inode, MAY_DELETE_SELF))
		error = -EPERM;

I ommitted the IS_RICHACL() check here, since that should probably be in
__inode_permission() when MAY_DELETE_SELF is passed?

Cheers, Andreas

> 	if (error)
> 		return error;
> 	if (IS_APPEND(dir))
> 		return -EPERM;

> -
> -	if (check_sticky(dir, inode) || IS_APPEND(inode) ||
> -	    IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
> +	if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
> 		return -EPERM;

> 	if (isdir) {
> 		if (!d_is_dir(victim))
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index d6e2330..402acd7 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -84,6 +84,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
> #define MAY_NOT_BLOCK		0x00000080
> #define MAY_CREATE_FILE		0x00000100
> #define MAY_CREATE_DIR		0x00000200
> +#define MAY_DELETE_CHILD	0x00000400
> +#define MAY_DELETE_SELF		0x00000800
> 
> /*
>  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
> --
> 2.5.0
> 


Cheers, Andreas

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#1263153 — [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const

From	Andreas Gruenbacher <agruenba@redhat.com>
Date	2015-11-05 13:00 +0100
Subject	[PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const
Message-ID	<qrrmX-69O-23@gated-at.bofh.it>
In reply to	#1263117

We will need to call iop->permission and iop->get_acl from
inode_change_ok() for additional permission checks, and both take a
non-const inode.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/attr.c          | 2 +-
 include/linux/fs.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index 6530ced..328be71 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -28,7 +28,7 @@
  * Should be called as the first thing in ->setattr implementations,
  * possibly after taking additional locks.
  */
-int inode_change_ok(const struct inode *inode, struct iattr *attr)
+int inode_change_ok(struct inode *inode, struct iattr *attr)
 {
 	unsigned int ia_valid = attr->ia_valid;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 402acd7..aab32c8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2871,7 +2871,7 @@ extern int buffer_migrate_page(struct address_space *,
 #define buffer_migrate_page NULL
 #endif
 
-extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int inode_change_ok(struct inode *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
 
-- 
2.5.0

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#1264554 — Re: [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const

From	Andreas Dilger <adilger@dilger.ca>
Date	2015-11-06 22:10 +0100
Subject	Re: [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const
Message-ID	<qrWqK-1nS-19@gated-at.bofh.it>
In reply to	#1263153

[Multipart message — attachments visible in raw view] — view raw

> On Nov 5, 2015, at 4:39 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
> 
> We will need to call iop->permission and iop->get_acl from
> inode_change_ok() for additional permission checks, and both take a
> non-const inode.

Seems unfortunate that those functions cannot themselves be changed to
take a const struct inode, but it doesn't look possible.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
> ---
> fs/attr.c          | 2 +-
> include/linux/fs.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/attr.c b/fs/attr.c
> index 6530ced..328be71 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -28,7 +28,7 @@
>  * Should be called as the first thing in ->setattr implementations,
>  * possibly after taking additional locks.
>  */
> -int inode_change_ok(const struct inode *inode, struct iattr *attr)
> +int inode_change_ok(struct inode *inode, struct iattr *attr)
> {
> 	unsigned int ia_valid = attr->ia_valid;
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 402acd7..aab32c8 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2871,7 +2871,7 @@ extern int buffer_migrate_page(struct address_space *,
> #define buffer_migrate_page NULL
> #endif
> 
> -extern int inode_change_ok(const struct inode *, struct iattr *);
> +extern int inode_change_ok(struct inode *, struct iattr *);
> extern int inode_newsize_ok(const struct inode *, loff_t offset);
> extern void setattr_copy(struct inode *inode, const struct iattr *attr);
> 
> --
> 2.5.0
> 


Cheers, Andreas

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csiph-web

[PATCH v14 00/22] Richacls (Core and Ext4)

Contents

#1263142 — [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

#1264536 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

#1264898 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

#1265036 — Re: [PATCH v14 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

#1263143 — [PATCH v14 06/22] richacl: In-memory representation and helper functions

#1263145 — [PATCH v14 07/22] richacl: Permission mapping functions

#1263148 — [PATCH v14 08/22] richacl: Compute maximum file masks from an acl

#1263150 — [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

#1264571 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

#1264930 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

#1264573 — Re: [PATCH v14 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

#1263153 — [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const

#1264554 — Re: [PATCH v14 04/22] vfs: Make the inode passed to inode_change_ok non-const