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

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>

diff --git a/sound/hda/hdmi_chmap.c b/sound/hda/hdmi_chmap.c
index 5fd6d575e123b0e4cb20a986ecf8010d1795023c..aad5c4bf4d3441754b0ec1d5d046b438b1ee6c5e 100644 (file)
--- a/sound/hda/hdmi_chmap.c
+++ b/sound/hda/hdmi_chmap.c
@@ -250,7 +250,7 @@ void snd_hdac_print_channel_allocation(int spk_alloc, char *buf, int buflen)
 
        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 5dc42f932739f3b385f826cb4431e0ed85731a0f..53e7732ef75209b63617ecc700c55cf994064bf8 100644 (file)
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -4022,7 +4022,7 @@ void snd_print_pcm_bits(int pcm, char *buf, int buflen)
 
        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 bb46c89b7f63d9c06e8500065170bbabbc8205e7..136477ed46ae2673db07fcd200b61871063dab07 100644 (file)
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -360,7 +360,7 @@ static void hdmi_print_pcm_rates(int pcm, char *buf, int buflen)
 
        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 0607ed5d1959958da12647ba6b4b165c5683d4da..eb8ec109d7adb5ce187567b2a5a8c10bdc3eec05 100644 (file)
--- a/sound/pci/hda/hda_sysfs.c
+++ b/sound/pci/hda/hda_sysfs.c
@@ -222,7 +222,7 @@ static ssize_t init_verbs_show(struct device *dev,
        int i, len = 0;
        mutex_lock(&codec->user_mutex);
        snd_array_for_each(&codec->init_verbs, i, v) {
-               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);
        }
@@ -272,7 +272,7 @@ static ssize_t hints_show(struct device *dev,
        int i, len = 0;
        mutex_lock(&codec->user_mutex);
        snd_array_for_each(&codec->hints, i, hint) {
-               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);