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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>
Subject: [PATCH 5.19 178/365] ASoC: SOF: Intel: hda: Fix potential buffer overflow by snprintf()
Date:   Tue, 23 Aug 2022 10:01:19 +0200
Message-Id: <20220823080125.671237572@linuxfoundation.org>
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From: Takashi Iwai <tiwai@suse.de>

commit 94c1ceb043c1a002de9649bb630c8e8347645982 upstream.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 sound/soc/sof/intel/hda.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/soc/sof/intel/hda.c
+++ b/sound/soc/sof/intel/hda.c
@@ -467,7 +467,7 @@ static void hda_dsp_dump_ext_rom_status(
 	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);
 	}
 
 	dev_printk(level, sdev->dev, "extended rom status: %s", msg);