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Groups > linux.kernel > #1219505
| From | Andreas Gruenbacher <agruenba@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [RFC v7 09/41] richacl: Update the file masks in chmod() |
| Date | 2015-09-05 12:40 +0200 |
| Message-ID | <q5j36-6jH-67@gated-at.bofh.it> (permalink) |
| References | <q5iTn-686-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Doing a chmod() sets the file mode, which includes the file permission
bits. When a file has a richacl, the permissions that the richacl
grants need to be limited to what the new file permission bits allow.
This is done by setting the file masks in the richacl to what the file
permission bits map to. The richacl access check algorithm takes the
file masks into account, which ensures that the richacl cannot grant too
many permissions.
It is possible to explicitly add permissions to the file masks which go
beyond what the file permission bits can grant (like the
RICHACE_WRITE_ACL permission). The POSIX.1 standard calls this an
alternate file access control mechanism. A subsequent chmod() would
ensure that those permissions are disabled again.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/richacl_base.c | 40 ++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 1 +
2 files changed, 41 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index fc544f7..6c69234 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -339,3 +339,43 @@ restart:
acl->a_flags &= ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED);
}
EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
+
+/**
+ * richacl_chmod - update the file masks to reflect the new mode
+ * @mode: new file permission bits including the file type
+ *
+ * Return a copy of @acl where the file masks have been replaced by the file
+ * masks corresponding to the file permission bits in @mode, or returns @acl
+ * itself if the file masks are already up to date. Takes over a reference
+ * to @acl.
+ */
+struct richacl *
+richacl_chmod(struct richacl *acl, mode_t mode)
+{
+ unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD;
+ unsigned int owner_mask, group_mask, other_mask;
+ struct richacl *clone;
+
+ owner_mask = richacl_mode_to_mask(mode >> 6) & ~x;
+ group_mask = richacl_mode_to_mask(mode >> 3) & ~x;
+ other_mask = richacl_mode_to_mask(mode) & ~x;
+
+ if (acl->a_owner_mask == owner_mask &&
+ acl->a_group_mask == group_mask &&
+ acl->a_other_mask == other_mask &&
+ (acl->a_flags & (RICHACL_WRITE_THROUGH | RICHACL_MASKED)))
+ return acl;
+
+ clone = richacl_clone(acl, GFP_KERNEL);
+ richacl_put(acl);
+ if (!clone)
+ return ERR_PTR(-ENOMEM);
+
+ clone->a_flags |= (RICHACL_WRITE_THROUGH | RICHACL_MASKED);
+ clone->a_owner_mask = owner_mask;
+ clone->a_group_mask = group_mask;
+ clone->a_other_mask = other_mask;
+
+ return clone;
+}
+EXPORT_SYMBOL_GPL(richacl_chmod);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index e81144a..e00f313 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -298,5 +298,6 @@ extern int richacl_masks_to_mode(const struct richacl *);
extern unsigned int richacl_mode_to_mask(mode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
+extern struct richacl *richacl_chmod(struct richacl *, mode_t);
#endif /* __RICHACL_H */
--
2.4.3
--
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[RFC v7 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:30 +0200
[RFC v7 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 21:40 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 23:50 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-22 04:00 +0200
[RFC v7 26/41] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 33/41] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 28/41] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 02/41] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 38/41] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode bfields@fieldses.org (J. Bruce Fields) - 2015-09-17 20:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-18 03:00 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-09-21 16:00 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 16:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-09-21 19:10 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 19:50 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 17:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode bfields@fieldses.org (J. Bruce Fields) - 2015-09-17 20:40 +0200
[RFC v7 23/41] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 23/41] richacl: Set the owner permissions to the owner mask bfields@fieldses.org (J. Bruce Fields) - 2015-09-21 23:10 +0200
[RFC v7 11/41] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 10/41] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 23:20 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-12 00:20 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-17 19:40 +0200
[RFC v7 07/41] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 34/41] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 12/41] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 01/41] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 17/41] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 18/41] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 30/41] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 14/41] richacl: Create-time inheritance bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 20:00 +0200
Re: [RFC v7 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 22:40 +0200
[RFC v7 40/41] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 29/41] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 16/41] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 08/41] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 20/41] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 20/41] richacl: acl editing helper functions bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 21:00 +0200
[RFC v7 05/41] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 24/41] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 31/41] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 39/41] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 20:50 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 23:30 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-22 04:00 +0200
[RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 23:40 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:50 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces bfields@fieldses.org (J. Bruce Fields) - 2015-09-19 00:00 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 21:30 +0200
[RFC v7 41/41] richacl: uapi header split Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 09/41] richacl: Update the file masks in chmod() bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 22:40 +0200
[RFC v7 03/41] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[PATCH] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-06 10:20 +0200
Re: [PATCH] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 22:40 +0200
[RFC v7 27/41] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 25/41] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 19/41] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 32/41] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 37/41] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
[RFC v7 36/41] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
[RFC v7 35/41] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
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