Re: [alsa-devel] [PATCH] ALSA: usb-audio: Fix out-of-bound error

15 Nov 2017

On Wed, 15 Nov 2017 09:57:56 +0100,
Jaejoong Kim wrote:
...

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index e630813..5a83c2c 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -204,7 +204,8 @@ static int snd_usb_copy_string_desc(struct mixer_build
*state,
                                    int index, char *buf, int maxlen)
 {
        int len = usb_string(state->chip->dev, index, buf, maxlen - 1);

  buf[len] = 0;




  if (len > 0)


          buf[len] = 0;
  return len;



I'd rather put an explicit error bail-out, i.e.
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 91bc8f18791e..296a63a9d09c 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -204,6 +204,10 @@ static int snd_usb_copy_string_desc(struct mixer_build *state,
    			    int index, char *buf, int maxlen)
 {
    int len = usb_string(state->chip->dev, index, buf, maxlen - 1);
+
+	if (len < 0)
+		return len;
+
    buf[len] = 0;
    return len;
 }
thanks,
Takashi

    

Takashi Iwai