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From:   Jens Axboe <axboe@kernel.dk>
To:     "Md. Haris Iqbal" <haris.iqbal@ionos.com>,
        Kees Cook <keescook@chromium.org>
Cc:     kernel test robot <lkp@intel.com>,
        Jack Wang <jinpu.wang@ionos.com>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
In-Reply-To: <20231212214738.work.169-kees@kernel.org>
References: <20231212214738.work.169-kees@kernel.org>
Subject: Re: [PATCH] block/rnbd-srv: Check for unlikely string overflow
Message-Id: <170248056905.41187.18405305753131685807.b4-ty@kernel.dk>
Date:   Wed, 13 Dec 2023 08:16:09 -0700
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On Tue, 12 Dec 2023 13:47:42 -0800, Kees Cook wrote:
> Since "dev_search_path" can technically be as large as PATH_MAX,
> there was a risk of truncation when copying it and a second string
> into "full_path" since it was also PATH_MAX sized. The W=1 builds were
> reporting this warning:
> 
> drivers/block/rnbd/rnbd-srv.c: In function 'process_msg_open.isra':
> drivers/block/rnbd/rnbd-srv.c:616:51: warning: '%s' directive output may be truncated writing up to 254 bytes into a region of size between 0 and 4095 [-Wformat-truncation=]
>   616 |                 snprintf(full_path, PATH_MAX, "%s/%s",
>       |                                                   ^~
> In function 'rnbd_srv_get_full_path',
>     inlined from 'process_msg_open.isra' at drivers/block/rnbd/rnbd-srv.c:721:14: drivers/block/rnbd/rnbd-srv.c:616:17: note: 'snprintf' output between 2 and 4351 bytes into a destination of size 4096
>   616 |                 snprintf(full_path, PATH_MAX, "%s/%s",
>       |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   617 |                          dev_search_path, dev_name);
>       |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> [...]

Applied, thanks!

[1/1] block/rnbd-srv: Check for unlikely string overflow
      commit: 9e4bf6a08d1e127bcc4bd72557f2dfafc6bc7f41

Best regards,
-- 
Jens Axboe