ASoC: SOF: Intel: hda: Fix potential buffer overflow by snprintf()

[ Upstream commit 94c1ceb043c1a002de9649bb630c8e8347645982 ]

snprintf() returns the would-be-filled size when the string overflows
the given buffer size, hence using this value may result in the buffer
overflow (although it's unrealistic).

This patch replaces with a safer version, scnprintf() for papering
over such a potential issue.

Fixes: 29c8e4398f02 ("ASoC: SOF: Intel: hda: add extended rom status dump to error log")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20220801165420.25978-4-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
index e733c40..35cbef1 100644 (file)
--- a/sound/soc/sof/intel/hda.c
+++ b/sound/soc/sof/intel/hda.c
@@ -413,7 +413,7 @@ static void hda_dsp_dump_ext_rom_status(struct snd_sof_dev *sdev, u32 flags)
        chip = get_chip_info(sdev->pdata);
        for (i = 0; i < HDA_EXT_ROM_STATUS_SIZE; i++) {
                value = snd_sof_dsp_read(sdev, HDA_DSP_BAR, chip->rom_status_reg + i * 0x4);
-               len += snprintf(msg + len, sizeof(msg) - len, " 0x%x", value);
+               len += scnprintf(msg + len, sizeof(msg) - len, " 0x%x", value);
        }
 
        sof_dev_dbg_or_err(sdev->dev, flags & SOF_DBG_DUMP_FORCE_ERR_LEVEL,