ALSA: hda: Use scnprintf() for printing texts for sysfs/procfs

commit 44eeb081b8630bb3ad3cd381d1ae1831463e48bb upstream.

Some code in HD-audio driver calls snprintf() in a loop and still
expects that the return value were actually written size, while
snprintf() returns the expected would-be length instead.  When the
given buffer limit were small, this leads to a buffer overflow.

Use scnprintf() for addressing those issues.  It returns the actually
written size unlike snprintf().

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200218091409.27162-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/hda/hdmi_chmap.c b/sound/hda/hdmi_chmap.c
index f21633c..acbe61b 100644
--- a/sound/hda/hdmi_chmap.c
+++ b/sound/hda/hdmi_chmap.c
@@ -249,7 +249,7 @@
 
 	for (i = 0, j = 0; i < ARRAY_SIZE(cea_speaker_allocation_names); i++) {
 		if (spk_alloc & (1 << i))
-			j += snprintf(buf + j, buflen - j,  " %s",
+			j += scnprintf(buf + j, buflen - j,  " %s",
 					cea_speaker_allocation_names[i]);
 	}
 	buf[j] = '\0';	/* necessary when j == 0 */
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 1b5e217..2ad28ce 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -4104,7 +4104,7 @@
 
 	for (i = 0, j = 0; i < ARRAY_SIZE(bits); i++)
 		if (pcm & (AC_SUPPCM_BITS_8 << i))
-			j += snprintf(buf + j, buflen - j,  " %d", bits[i]);
+			j += scnprintf(buf + j, buflen - j,  " %d", bits[i]);
 
 	buf[j] = '\0'; /* necessary when j == 0 */
 }
diff --git a/sound/pci/hda/hda_eld.c b/sound/pci/hda/hda_eld.c
index ba7fe9b..864cc8c 100644
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -373,7 +373,7 @@
 
 	for (i = 0, j = 0; i < ARRAY_SIZE(alsa_rates); i++)
 		if (pcm & (1 << i))
-			j += snprintf(buf + j, buflen - j,  " %d",
+			j += scnprintf(buf + j, buflen - j,  " %d",
 				alsa_rates[i]);
 
 	buf[j] = '\0'; /* necessary when j == 0 */
diff --git a/sound/pci/hda/hda_sysfs.c b/sound/pci/hda/hda_sysfs.c
index 9739fce..f3ac19d 100644
--- a/sound/pci/hda/hda_sysfs.c
+++ b/sound/pci/hda/hda_sysfs.c
@@ -221,7 +221,7 @@
 	mutex_lock(&codec->user_mutex);
 	for (i = 0; i < codec->init_verbs.used; i++) {
 		struct hda_verb *v = snd_array_elem(&codec->init_verbs, i);
-		len += snprintf(buf + len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
 				"0x%02x 0x%03x 0x%04x\n",
 				v->nid, v->verb, v->param);
 	}
@@ -271,7 +271,7 @@
 	mutex_lock(&codec->user_mutex);
 	for (i = 0; i < codec->hints.used; i++) {
 		struct hda_hint *hint = snd_array_elem(&codec->hints, i);
-		len += snprintf(buf + len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
 				"%s = %s\n", hint->key, hint->val);
 	}
 	mutex_unlock(&codec->user_mutex);