linux-kernel - Re: [PATCH v3 perf/core] perf script: fix a use after free crash.

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]

Date:   Fri, 20 Jan 2017 17:48:50 -0800
From:   Krister Johansen <kjlx@...pleofstupid.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Namhyung Kim <namhyung@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Frédéric Weisbecker <fweisbec@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 perf/core] perf script: fix a use after free crash.

Hey Arnaldo,

On Thu, Jan 05, 2017 at 10:23:31PM -0800, Krister Johansen wrote:
> If dso__load_kcore frees all of the existing maps, but one has already
> been attached to a callchain cursor node, then we can get a SIGSEGV in
> any function that happens to try to use this invalid cursor.  Use the
> existing map refcount mechanism to forestall cleanup of a map until the
> cursor iterates past the node.

It's been a couple of weeks since I sent you the v3 of this patch.  Last
time I fiddled with it, I was able to reproduce your 'perf top' core,
and was able to verify that the latest patch I sent out could survive
running 'perf top' through the course of a full kernel build.

Is there anything else I can do to help with this one?

Thanks,

-K