From: Denis Efremov <efremov@xxxxxxxxx> commit 315cee426f87658a6799815845788fde965ddaad upstream. 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 ilen check before memcpy() call in ar5523_cmd() to prevent an undefined behavior. Cc: Pontus Fuchs <pontus.fuchs@xxxxxxxxx> Cc: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: David Laight <David.Laight@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Denis Efremov <efremov@xxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/ath/ar5523/ar5523.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 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, if (flags & AR5523_CMD_FLAG_MAGIC) hdr->magic = cpu_to_be32(1 << 24); - memcpy(hdr + 1, idata, ilen); + if (ilen) + memcpy(hdr + 1, idata, ilen); cmd->odata = odata; cmd->olen = olen;
