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Message-ID: <230cd4f790544b01a26afa26e4186454@AcuMS.aculab.com>
Date: Mon, 30 Sep 2019 15:35:42 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Denis Efremov' <efremov@...ux.com>,
"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: Pontus Fuchs <pontus.fuchs@...il.com>,
Kalle Valo <kvalo@...eaurora.org>,
"David S. Miller" <davem@...emloft.net>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH] ar5523: check NULL before memcpy() in ar5523_cmd()
From: Denis Efremov
> Sent: 30 September 2019 15:02
>
> memcpy() call with "idata == NULL && ilen == 0" results in undefined
> behavior in ar5523_cmd(). For example, NULL is passed in callchain
> "ar5523_stat_work() -> ar5523_cmd_write() -> ar5523_cmd()". This patch
> adds idata check before memcpy() call in ar5523_cmd() to prevent an
> undefined behavior.
>
...
> Signed-off-by: Denis Efremov <efremov@...ux.com>
> ---
> drivers/net/wireless/ath/ar5523/ar5523.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
> index b94759daeacc..f25af5bc5282 100644
> --- a/drivers/net/wireless/ath/ar5523/ar5523.c
> +++ b/drivers/net/wireless/ath/ar5523/ar5523.c
> @@ -255,7 +255,8 @@ static int ar5523_cmd(struct ar5523 *ar, u32 code, const void *idata,
>
> if (flags & AR5523_CMD_FLAG_MAGIC)
> hdr->magic = cpu_to_be32(1 << 24);
> - memcpy(hdr + 1, idata, ilen);
> + if (idata)
> + memcpy(hdr + 1, idata, ilen);
That would be better as if (ilen) ...
David
-
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