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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Takashi Iwai <tiwai@suse.de>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 156/244] ASoC: SOF: Intel: hda: Fix potential buffer overflow by snprintf()
Date:   Tue, 23 Aug 2022 10:25:15 +0200
Message-Id: <20220823080104.402123475@linuxfoundation.org>
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From: Takashi Iwai <tiwai@suse.de>

[ 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>
---
 sound/soc/sof/intel/hda.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
index e733c401562f..35cbef171f4a 100644
--- 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,
-- 
2.35.1