Commit 44acc46d authored by Ivan Pravdin's avatar Ivan Pravdin Committed by Andrew Morton
Browse files

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: default avatar <syzbot+20282c1b2184a857ac4c@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/67cd7e29.050a0220.e1a89.0007.GAE@google.com/


Signed-off-by: default avatarIvan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: default avatarJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 988f451e

fs/ocfs2/dir.c

+8 −0
Original line number Diff line number Diff line
@@ -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];