linux-kernel - Re: Null-ptr-deref due to "sanitized pathwalk machinery (v4)"

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20200325021327.GJ23230@ZenIV.linux.org.uk>
Date:   Wed, 25 Mar 2020 02:13:27 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Qian Cai <cai@....pw>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: Null-ptr-deref due to "sanitized pathwalk machinery (v4)"

On Tue, Mar 24, 2020 at 09:49:48PM -0400, Qian Cai wrote:

> It does not catch anything at all with the patch,

You mean, oops happens, but neither WARN_ON() is triggered?
Lovely...  Just to make sure: could you slap the same couple
of lines just before
                if (unlikely(!d_can_lookup(nd->path.dentry))) {
in link_path_walk(), just to check if I have misread the trace
you've got?

Does that (+ other two inserts) end up with
	1) some of these WARN_ON() triggered when oops happens or
	2) oops is happening, but neither WARN_ON() triggers or
	3) oops not happening / becoming harder to hit?