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Groups > linux.kernel > #1505864

[PATCH 07/26] ubifs: Massage ubifs_listxattr() for encryption context

From Richard Weinberger <richard@nod.at>
Newsgroups linux.kernel
Subject [PATCH 07/26] ubifs: Massage ubifs_listxattr() for encryption context
Date 2016-10-21 15:00 +0200
Message-ID <suHAu-5DG-11@gated-at.bofh.it> (permalink)
References <suHqN-5zP-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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We have to make sure that we don't expose our internal
crypto context to userspace.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 fs/ubifs/xattr.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index b390902c48aa..54ec2b9fd506 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -394,6 +394,20 @@ out_unlock:
 	return err;
 }
 
+static bool xattr_visible(const char *name)
+{
+	/* File encryption related xattrs are for internal use only */
+	if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
+		return false;
+
+	/* Show trusted namespace only for "power" users */
+	if (strncmp(name, XATTR_TRUSTED_PREFIX,
+		    XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
+		return false;
+
+	return true;
+}
+
 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 {
 	union ubifs_key key;
@@ -429,10 +443,7 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 		nm.name = xent->name;
 		nm.len = le16_to_cpu(xent->nlen);
 
-		/* Show trusted namespace only for "power" users */
-		if (strncmp(xent->name, XATTR_TRUSTED_PREFIX,
-			    XATTR_TRUSTED_PREFIX_LEN) ||
-		    capable(CAP_SYS_ADMIN)) {
+		if (xattr_visible(xent->name)) {
 			memcpy(buffer + written, nm.name, nm.len + 1);
 			written += nm.len + 1;
 		}
-- 
2.7.3

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Thread

[PATCH 00/26] UBIFS File Encryption Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 26/26] ubifs: Raise write version to 5 Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
    Re: [PATCH 26/26] ubifs: Raise write version to 5 Michael Halcrow <mhalcrow@google.com> - 2016-10-21 19:40 +0200
      Re: [PATCH 26/26] ubifs: Raise write version to 5 Theodore Ts'o <tytso@mit.edu> - 2016-10-21 19:50 +0200
        Re: [PATCH 26/26] ubifs: Raise write version to 5 Eric Biggers <ebiggers@google.com> - 2016-10-21 20:20 +0200
          Re: [PATCH 26/26] ubifs: Raise write version to 5 Theodore Ts'o <tytso@mit.edu> - 2016-10-22 00:40 +0200
        Re: [PATCH 26/26] ubifs: Raise write version to 5 Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 05/26] ubifs: Define UBIFS crypto context xattr Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 10/26] ubifs: Enforce crypto policy in ->link and ->rename Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Michael Halcrow <mhalcrow@google.com> - 2016-10-21 19:20 +0200
      Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 19:30 +0200
        Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Michael Halcrow <mhalcrow@google.com> - 2016-10-21 20:00 +0200
          Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 20:30 +0200
    Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Eric Biggers <ebiggers@google.com> - 2016-10-21 20:30 +0200
      Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 07/26] ubifs: Massage ubifs_listxattr() for encryption context Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 13/26] ubifs: Enforce crypto policy in mmap Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 11/26] ubifs: Preload crypto context in ->lookup() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 21/26] ubifs: Rename tnc_read_node_nm Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 12/26] ubifs: Massage assert in ubifs_xattr_set() wrt. fscrypto Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 02/26] fscrypto: Constify struct inode pointer Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 02/26] fscrypto: Constify struct inode pointer Theodore Ts'o <tytso@mit.edu> - 2016-10-21 17:00 +0200
      Re: [PATCH 02/26] fscrypto: Constify struct inode pointer Richard Weinberger <richard@nod.at> - 2016-10-21 17:20 +0200
  [PATCH 22/26] ubifs: Add full hash lookup support Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 24/26] ubifs: Implement UBIFS_FLG_DOUBLE_HASH Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Eric Biggers <ebiggers@google.com> - 2016-10-21 20:40 +0200
      Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Richard Weinberger <richard@nod.at> - 2016-10-24 09:00 +0200
        Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Theodore Ts'o <tytso@mit.edu> - 2016-10-24 15:50 +0200
  [PATCH 17/26] ubifs: Make r5 hash binary string aware Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 20/26] ubifs: Add support for encrypted symlinks Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 20/26] ubifs: Add support for encrypted symlinks Eric Biggers <ebiggers@google.com> - 2016-10-21 20:50 +0200
      Re: [PATCH 20/26] ubifs: Add support for encrypted symlinks Richard Weinberger <richard@nod.at> - 2016-10-24 09:00 +0200
  [PATCH 23/26] ubifs: Use a random number for cookies Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 08/26] ubifs: Implement directory open operation Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 14/26] ubifs: Introduce new data node field, compr_size Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 16/26] ubifs: Relax checks in ubifs_validate_entry() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 18/26] ubifs: Constify struct inode pointer in ubifs_crypt_is_encrypted() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 06/26] ubifs: Add skeleton for fscrypto Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  Re: [PATCH 01/26] fscrypto: Add buffer operations Christoph Hellwig <hch@infradead.org> - 2016-10-21 15:10 +0200
    Re: [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-21 15:20 +0200
      Re: [PATCH 01/26] fscrypto: Add buffer operations Christoph Hellwig <hch@infradead.org> - 2016-10-21 15:30 +0200
        Re: [PATCH 01/26] fscrypto: Add buffer operations Theodore Ts'o <tytso@mit.edu> - 2016-10-21 17:20 +0200
        Re: [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 09/26] ubifs: Implement file open operation Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 03/26] ubifs: Export ubifs_check_dir_empty() Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 04/26] ubifs: Export xattr get and set functions Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200

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