From 44acc46d182ff36d40cea69db3875440fab72ba5 Mon Sep 17 00:00:00 2001 From: Ivan Pravdin Date: Mon, 7 Jul 2025 20:10:09 -0400 Subject: [PATCH] ocfs2: avoid NULL pointer dereference in dx_dir_lookup_rec() When a directory entry is not found, ocfs2_dx_dir_lookup_rec() prints an error message that unconditionally dereferences the 'rec' pointer. However, if 'rec' is NULL, this leads to a NULL pointer dereference and a kernel panic. Add an explicit check empty extent list to avoid dereferencing NULL 'rec' pointer. Link: https://lkml.kernel.org/r/20250708001009.372263-1-ipravdin.official@gmail.com Reported-by: syzbot+20282c1b2184a857ac4c@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67cd7e29.050a0220.e1a89.0007.GAE@google.com/ Signed-off-by: Ivan Pravdin Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Signed-off-by: Andrew Morton --- fs/ocfs2/dir.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index 7799f4d16ce99..8c9c4825f9841 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -798,6 +798,14 @@ static int ocfs2_dx_dir_lookup_rec(struct inode *inode, } } + if (le16_to_cpu(el->l_next_free_rec) == 0) { + ret = ocfs2_error(inode->i_sb, + "Inode %lu has empty extent list at depth %u\n", + inode->i_ino, + le16_to_cpu(el->l_tree_depth)); + goto out; + } + found = 0; for (i = le16_to_cpu(el->l_next_free_rec) - 1; i >= 0; i--) { rec = &el->l_recs[i]; -- 2.47.2