From 3c6f46eacd876bd723a9bad3c6882714c052fd8e Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 17 Jan 2017 11:41:41 -0800 Subject: [PATCH] xfs: sanity check directory inode di_size This changes fixes an assertion hit when fuzzing on-disk i_mode values. The easy case to fix is when changing an empty file i_mode to S_IFDIR. In this case, xfs_dinode_verify() detects an illegal zero size for directory and fails to load the inode structure from disk. For the case of non empty file whose i_mode is changed to S_IFDIR, the ASSERT() statement in xfs_dir2_isblock() is replaced with return -EFSCORRUPTED, to avoid interacting with corrupted jusk also when XFS_DEBUG is disabled. Suggested-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Amir Goldstein Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_dir2.c | 3 ++- fs/xfs/libxfs/xfs_inode_buf.c | 7 +++++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c index c58d72c220f5..4f7913f84b28 100644 --- a/fs/xfs/libxfs/xfs_dir2.c +++ b/fs/xfs/libxfs/xfs_dir2.c @@ -631,7 +631,8 @@ xfs_dir2_isblock( if ((rval = xfs_bmap_last_offset(args->dp, &last, XFS_DATA_FORK))) return rval; rval = XFS_FSB_TO_B(args->dp->i_mount, last) == args->geo->blksize; - ASSERT(rval == 0 || args->dp->i_d.di_size == args->geo->blksize); + if (rval != 0 && args->dp->i_d.di_size != args->geo->blksize) + return -EFSCORRUPTED; *vp = rval; return 0; } diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c index dd483e2767f7..0091ac3f5241 100644 --- a/fs/xfs/libxfs/xfs_inode_buf.c +++ b/fs/xfs/libxfs/xfs_inode_buf.c @@ -386,6 +386,7 @@ xfs_dinode_verify( xfs_ino_t ino, struct xfs_dinode *dip) { + uint16_t mode; uint16_t flags; uint64_t flags2; @@ -396,8 +397,10 @@ xfs_dinode_verify( 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) + mode = be16_to_cpu(dip->di_mode); + + /* No zero-length symlinks/dirs. */ + if ((S_ISLNK(mode) || S_ISDIR(mode)) && dip->di_size == 0) return false; /* only version 3 or greater inodes are extensively verified here */