ALSA: core: Copy string more safely

Replace the remaining strcpy() and sprintf() usages in the ALSA core
code with the safer versions.

The first strcpy() points actually to card->id, hence just use
strscpy() with card->id instead.

The append of suffix string is slightly rewritten so that we can use
scnprintf() and strscpy().

Only for safety, no actual behavior change.

Signed-off-by: Takashi Iwai <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

sound/core/init.c

···
 	 * ("card" conflicts with proc directories)
 	 */
 	if (!*id || !strncmp(id, "card", 4)) {
-		strcpy(id, "Default");
+		strscpy(card->id, "Default");
 		is_default = true;
 	}
 
 	len = strlen(id);
 	for (loops = 0; loops < SNDRV_CARDS; loops++) {
-		char *spos;
 		char sfxstr[5]; /* "_012" */
-		int sfxlen;
+		int sfxlen, slen;
 
 		if (card_id_ok(card, id))
 			return; /* OK */
 
 		/* Add _XYZ suffix */
-		sprintf(sfxstr, "_%X", loops + 1);
-		sfxlen = strlen(sfxstr);
+		sfxlen = scnprintf(sfxstr, sizeof(sfxstr), "_%X", loops + 1);
 		if (len + sfxlen >= sizeof(card->id))
-			spos = id + sizeof(card->id) - sfxlen - 1;
+			slen = sizeof(card->id) - sfxlen - 1;
 		else
-			spos = id + len;
-		strcpy(spos, sfxstr);
+			slen = len;
+		strscpy(id + slen, sfxstr, sizeof(card->id) - slen);
 	}
 	/* fallback to the default id */
 	if (!is_default) {
···
 	guard(mutex)(&snd_card_mutex);
 	if (!card_id_ok(NULL, buf1))
 		return -EEXIST;
-	strcpy(card->id, buf1);
+	strscpy(card->id, buf1);
 	snd_info_card_id_change(card);
 
 	return count;