diff options
| author | Jan Kara <jack@suse.cz> | 2015-05-21 16:05:56 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-06-24 00:01:10 +0200 |
| commit | a6de82cab123beaf9406024943caa0242f0618b0 (patch) | |
| tree | 747d73350fb02ca51306530630766dd28b8d0548 | |
| parent | fs: Call security_ops->inode_killpriv on truncate (diff) | |
| download | linux-a6de82cab123beaf9406024943caa0242f0618b0.tar.xz linux-a6de82cab123beaf9406024943caa0242f0618b0.zip | |
xfs: Correctly lock inode when removing suid and file capabilities
Currently XFS calls file_remove_privs() without holding i_mutex. This is
wrong because that function can end up messing with file permissions and
file capabilities stored in xattrs for which we need i_mutex held.
Fix the problem by grabbing iolock exclusively when we will need to
change anything in permissions / xattrs.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/xfs/xfs_file.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index f3e4fbb59985..71c2c712e609 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -563,6 +563,13 @@ restart: if (error) return error; + /* For changing security info in file_remove_privs() we need i_mutex */ + if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) { + xfs_rw_iunlock(ip, *iolock); + *iolock = XFS_IOLOCK_EXCL; + xfs_rw_ilock(ip, *iolock); + goto restart; + } /* * If the offset is beyond the size of the file, we need to zero any * blocks that fall between the existing EOF and the start of this @@ -623,7 +630,9 @@ restart: * setgid bits if the process is not being run by root. This keeps * people from modifying setuid and setgid binaries. */ - return file_remove_privs(file); + if (!IS_NOSEC(inode)) + return file_remove_privs(file); + return 0; } /* |