From 1524af3685b35feac76662cc551cbc37bd14775f Mon Sep 17 00:00:00 2001 From: Deepanshu Kartikey Date: Fri, 12 Dec 2025 10:51:32 +0530 Subject: [PATCH] ocfs2: validate inline data i_size during inode read When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count). This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory. In the syzbot report: - i_size was 1099511627576 bytes (~1TB) - Actual inline data capacity (id_count) is typically <256 bytes - A garbage rec_len (54648) caused ctx->pos to jump out of bounds - This triggered a UAF in ocfs2_check_dir_entry() Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data. Link: https://lkml.kernel.org/r/20251212052132.16750-1-kartikey406@gmail.com Signed-off-by: Deepanshu Kartikey Reported-by: syzbot+c897823f699449cc3eb4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c897823f699449cc3eb4 Tested-by: syzbot+c897823f699449cc3eb4@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/20251211115231.3560028-1-kartikey406@gmail.com/T/ [v1] Link: https://lore.kernel.org/all/20251212040400.6377-1-kartikey406@gmail.com/T/ [v2] Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Signed-off-by: Andrew Morton --- fs/ocfs2/inode.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index c95c998811ae5..03a51662ea8e7 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -1494,12 +1494,25 @@ int ocfs2_validate_inode_block(struct super_block *sb, goto bail; } - if ((le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) && - le32_to_cpu(di->i_clusters)) { - rc = ocfs2_error(sb, "Invalid dinode %llu: %u clusters\n", - (unsigned long long)bh->b_blocknr, - le32_to_cpu(di->i_clusters)); - goto bail; + if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL) { + struct ocfs2_inline_data *data = &di->id2.i_data; + + if (le32_to_cpu(di->i_clusters)) { + rc = ocfs2_error(sb, + "Invalid dinode %llu: %u clusters\n", + (unsigned long long)bh->b_blocknr, + le32_to_cpu(di->i_clusters)); + goto bail; + } + + if (le64_to_cpu(di->i_size) > le16_to_cpu(data->id_count)) { + rc = ocfs2_error(sb, + "Invalid dinode #%llu: inline data i_size %llu exceeds id_count %u\n", + (unsigned long long)bh->b_blocknr, + (unsigned long long)le64_to_cpu(di->i_size), + le16_to_cpu(data->id_count)); + goto bail; + } } if (le32_to_cpu(di->i_flags) & OCFS2_CHAIN_FL) { -- 2.47.3