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From:   Michael Chan <michael.chan@broadcom.com>
Date:   Mon, 13 Aug 2018 14:47:50 -0700
Message-ID: <CACKFLi=6s-mpTiD4KwJPjFexCdVC6aiKSexhY4wr43ouTWKzXg@mail.gmail.com>
Subject: Re: [PATCH] bnxt_en: avoid string overflow for record->system_name
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Vasundhara Volam <vasundhara-v.volam@broadcom.com>,
        Scott Branden <scott.branden@broadcom.com>,
        Andy Gospodarek <gospo@broadcom.com>,
        Netdev <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Mon, Aug 13, 2018 at 2:26 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> The utsname()->nodename string may be 64 bytes long, and it gets
> copied without the trailing nul byte into the shorter record->system_name,
> as gcc now warns:
>
> In file included from include/linux/bitmap.h:9,
>                  from include/linux/ethtool.h:16,
>                  from drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:13:
> In function 'strncpy',
>     inlined from 'bnxt_fill_coredump_record' at drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:2863:2:
> include/linux/string.h:254:9: error: '__builtin_strncpy' output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
>
> Using strlcpy() at least avoids overflowing the destination buffer
> and adds proper nul-termination. It may still truncate long names
> though, which probably can't be solved here.
>
> Fixes: 6c5657d085ae ("bnxt_en: Add support for ethtool get dump.")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks.

Acked-by: Michael Chan <michael.chan@broadcom.com>