From bdd0a8e5ace90cad14c1bf1bf49c3bfabb77f831 Mon Sep 17 00:00:00 2001 From: Dwight Engen Date: Thu, 15 Aug 2013 14:08:03 -0400 Subject: xfs: add capability check to free eofblocks ioctl 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 Reviewed-by: Dave Chinner Reviewed-by: Gao feng Signed-off-by: Dwight Engen Signed-off-by: Ben Myers Cc: Kees Cook Signed-off-by: Greg Kroah-Hartman --- 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 5e999680094a..ca01d830e989 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); -- cgit v1.2.3