From 757ed44a19a3a26f3c70aedb74ecc42c2f24346b Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 18 Feb 2020 12:17:37 +0100 Subject: ASoC: pcm: Fix possible buffer overflow in dpcm state sysfs output commit 6c89ffea60aa3b2a33ae7987de1e84bfb89e4c9e upstream. dpcm_show_state() invokes multiple snprintf() calls to concatenate formatted strings on the fixed size buffer. The usage of snprintf() is supposed for avoiding the buffer overflow, but it doesn't work as expected because snprintf() doesn't return the actual output size but the size to be written. Fix this bug by replacing all snprintf() calls with scnprintf() calls. Fixes: f86dcef87b77 ("ASoC: dpcm: Add debugFS support for DPCM") Signed-off-by: Takashi Iwai Acked-by: Cezary Rojewski Link: https://lore.kernel.org/r/20200218111737.14193-4-tiwai@suse.de Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- sound/soc/soc-pcm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'sound/soc/soc-pcm.c') diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index 8712a91e0e3e..d978df95c5c6 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -3169,16 +3169,16 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe, unsigned long flags; /* FE state */ - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, "[%s - %s]\n", fe->dai_link->name, stream ? "Capture" : "Playback"); - offset += snprintf(buf + offset, size - offset, "State: %s\n", + offset += scnprintf(buf + offset, size - offset, "State: %s\n", dpcm_state_string(fe->dpcm[stream].state)); if ((fe->dpcm[stream].state >= SND_SOC_DPCM_STATE_HW_PARAMS) && (fe->dpcm[stream].state <= SND_SOC_DPCM_STATE_STOP)) - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, "Hardware Params: " "Format = %s, Channels = %d, Rate = %d\n", snd_pcm_format_name(params_format(params)), @@ -3186,10 +3186,10 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe, params_rate(params)); /* BEs state */ - offset += snprintf(buf + offset, size - offset, "Backends:\n"); + offset += scnprintf(buf + offset, size - offset, "Backends:\n"); if (list_empty(&fe->dpcm[stream].be_clients)) { - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, " No active DSP links\n"); goto out; } @@ -3199,16 +3199,16 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe, struct snd_soc_pcm_runtime *be = dpcm->be; params = &dpcm->hw_params; - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, "- %s\n", be->dai_link->name); - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, " State: %s\n", dpcm_state_string(be->dpcm[stream].state)); if ((be->dpcm[stream].state >= SND_SOC_DPCM_STATE_HW_PARAMS) && (be->dpcm[stream].state <= SND_SOC_DPCM_STATE_STOP)) - offset += snprintf(buf + offset, size - offset, + offset += scnprintf(buf + offset, size - offset, " Hardware Params: " "Format = %s, Channels = %d, Rate = %d\n", snd_pcm_format_name(params_format(params)), -- cgit v1.2.3