linux-kernel - Re: [syzbot] Re: KASAN: use-after-free Read in ocfs2_search_extent

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <675825a6.050a0220.a30f1.01cc.GAE@google.com>
Date: Tue, 10 Dec 2024 03:27:34 -0800
From: syzbot <syzbot+2313dda4dc4885c93578@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] Re: KASAN: use-after-free Read in ocfs2_search_extent_list()

For archival purposes, forwarding an incoming command email to
linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com.

***

Subject: Re: KASAN: use-after-free Read in ocfs2_search_extent_list()
Author: dmantipov@...dex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 7cb1b466315004af98f6ba6c2546bb713ca3c237

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 395e23920632..841135341898 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -770,6 +770,10 @@ int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster)
 	struct ocfs2_extent_rec *rec;
 	u32 rec_end, rec_start, clusters;
 
+	/* Do not search over an invalid extent list. */
+	if (le16_to_cpu(el->l_next_free_rec) >= le16_to_cpu(el->l_count))
+		return ret;
+
 	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 		rec = &el->l_recs[i];