Re: [PATCH] bnxt_en: avoid string overflow for record->system_name

From: Michael Chan
Date: Mon Aug 13 2018 - 17:47:55 EST

On Mon, Aug 13, 2018 at 2:26 PM, Arnd Bergmann <arnd@xxxxxxxx> 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@xxxxxxxx>


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