From: "Darrick J. Wong" <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== Commit ef388e2054feedaeb05399ed654bdb06f385d294 upstream. The on-disk field di_size is used to set i_size, which is a signed integer of loff_t. If the high bit of di_size is set, we'll end up with a negative i_size, which will cause all sorts of problems. Since the VFS won't let us create a file with such length, we should catch them here in the verifier too. [nborisov: Backported to 3.12] Signed-off-by: Darrick J. Wong <[email protected]> Reviewed-by: Dave Chinner <[email protected]> Signed-off-by: Dave Chinner <[email protected]> Signed-off-by: Nikolay Borisov <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- fs/xfs/xfs_inode_buf.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/xfs/xfs_inode_buf.c b/fs/xfs/xfs_inode_buf.c index 03d237a0f58b..1c62be0b0d0f 100644 --- a/fs/xfs/xfs_inode_buf.c +++ b/fs/xfs/xfs_inode_buf.c @@ -301,6 +301,14 @@ xfs_dinode_verify( if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC)) return false; + /* don't allow invalid i_size */ + if (be64_to_cpu(dip->di_size) & (1ULL << 63)) + return false; + + /* No zero-length symlinks. */ + if (S_ISLNK(be16_to_cpu(dip->di_mode)) && dip->di_size == 0) + return false; + /* only version 3 or greater inodes are extensively verified here */ if (dip->di_version < 3) return true; -- 2.12.2
