[PATCH 4.19 02/97] ALSA: hda: Use scnprintf() for printing texts for sysfs/procfs

Greg Kroah-Hartman
2020-02-27T14:31:48Z

From: Takashi Iwai <tiwai@suse.de>

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>

---
sound/hda/hdmi_chmap.c | 2 +-
sound/pci/hda/hda_codec.c | 2 +-
sound/pci/hda/hda_eld.c | 2 +-
sound/pci/hda/hda_sysfs.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)

--- a/sound/hda/hdmi_chmap.c
+++ b/sound/hda/hdmi_chmap.c
@@ -249,7 +249,7 @@ void snd_hdac_print_channel_allocation(i

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 */
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -4019,7 +4019,7 @@ void snd_print_pcm_bits(int pcm, char *b

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 */
}
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -373,7 +373,7 @@ static void hdmi_print_pcm_rates(int pcm

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 */
--- a/sound/pci/hda/hda_sysfs.c
+++ b/sound/pci/hda/hda_sysfs.c
@@ -221,7 +221,7 @@ static ssize_t init_verbs_show(struct de
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);
}
@@ -271,7 +271,7 @@ static ssize_t hints_show(struct device
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);