3.11.10.2 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Dwight Engen <dwight.engen@xxxxxxxxxx>
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 <bfoster@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Reviewed-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
Signed-off-by: Dwight Engen <dwight.engen@xxxxxxxxxx>
Signed-off-by: Ben Myers <bpm@xxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
fs/xfs/xfs_ioctl.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 6e2bca5..bccd2a3 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1612,6 +1612,12 @@ xfs_file_ioctl(
case XFS_IOC_FREE_EOFBLOCKS: {
struct xfs_eofblocks eofb;
+ 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);
--
1.8.3.2
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