linux-kernel - Re: [PATCH v3] md: fix an incorrect NULL check in md_reload

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] [day] [month] [year] [list]

Date:   Fri, 8 Apr 2022 09:36:14 -0700
From:   Song Liu <song@...nel.org>
To:     Xiaomeng Tong <xiam0nd.tong@...il.com>
Cc:     rgoldwyn@...e.com, Guoqing Jiang <guoqing.jiang@...ux.dev>,
        linux-raid <linux-raid@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        stable@...r.kernel.org
Subject: Re: [PATCH v3] md: fix an incorrect NULL check in md_reload_sb

On Fri, Apr 8, 2022 at 1:47 AM Xiaomeng Tong <xiam0nd.tong@...il.com> wrote:
>
> The bug is here:
>         if (!rdev || rdev->desc_nr != nr) {
>
> The list iterator value 'rdev' will *always* be set and non-NULL
> by rdev_for_each_rcu(), so it is incorrect to assume that the
> iterator value will be NULL if the list is empty or no element
> found (In fact, it will be a bogus pointer to an invalid struct
> object containing the HEAD). Otherwise it will bypass the check
> and lead to invalid memory access passing the check.
>
> To fix the bug, use a new variable 'iter' as the list iterator,
> while using the original variable 'pdev' as a dedicated pointer to
> point to the found element.
>
> Cc: stable@...r.kernel.org
> Fixes: 70bcecdb1534 ("md-cluster: Improve md_reload_sb to be less error prone")
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@...il.com>

Applied to md-next. Thanks!