3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dwight Engen <dwight.en...@oracle.com>
commit 8c567a7fab6e086a0284eee2db82348521e7120c upstream.
Check for CAP_SYS_ADMIN since the caller can truncate preallocated
blocks from files they do not own nor have write access to. A more
fine grained access check was considered: require the caller to
specify their own uid/gid and to use inode_permission to check for
write, but this would not catch the case of an inode not reachable
via path traversal from the callers mount namespace.
Add check for read-only filesystem to free eofblocks ioctl.
Reviewed-by: Brian Foster <bfos...@redhat.com>
Reviewed-by: Dave Chinner <dchin...@redhat.com>
Reviewed-by: Gao feng <gaof...@cn.fujitsu.com>
Signed-off-by: Dwight Engen <dwight.en...@oracle.com>
Signed-off-by: Ben Myers <b...@sgi.com>
Cc: Kees Cook <keesc...@google.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
fs/xfs/xfs_ioctl.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1717,6 +1717,12 @@ xfs_file_ioctl(
if (mp->m_flags & XFS_MOUNT_RDONLY)
return -XFS_ERROR(EROFS);
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (mp->m_flags & XFS_MOUNT_RDONLY)
+ return -XFS_ERROR(EROFS);
+
if (copy_from_user(&eofb, arg, sizeof(eofb)))
return -XFS_ERROR(EFAULT);
--
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