From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C12124DCF6; Mon, 13 Apr 2026 16:25:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097520; cv=none; b=K4VvfLOBjObxdYMR6/vAn/AiXacD7KgxRbvIc4NY8v+K+LKHmYJ4EMkxyTSga2VP4wtuA/zNdEKGgyTGVfZL0H0ypFOFWHwF9Nq/tGLOWc9cJb8fI9sZ8yTBy0PV+QVoq8Vw8lzhlpqcIZzp1Y3N4nkNTiBZJArJ/Dh9w8eJK4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097520; c=relaxed/simple; bh=uNR+mhYmyZsZdr6j5ONMH6XKtGug5ph5CSFsqQvMhVI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nGrVBvpRmqcE5vaJ/g7VB9cAPHpKV/NebgYhcVcg/kZV8G/5yQWxgrJ1GzqvzGDsqpzUIzad0oQ4RJCfndUSMNb7N1hse/QN4Gan3eWenS6WW9haBzHww5hf4Acv1PSzs7lCnlR1ZCNa8AfSas+wu+Z7tJLsV4gLVHzGbSydg68= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=egL3K/bv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="egL3K/bv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF777C2BCAF; Mon, 13 Apr 2026 16:25:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776097520; bh=uNR+mhYmyZsZdr6j5ONMH6XKtGug5ph5CSFsqQvMhVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=egL3K/bvxC0bemiO6U3VfAnJVDygCVzn8951oMXUShq+ACx8Zn9DIw7Kk6MfNqMgS yNA0l8YQ4JYOkIjytINcgVq+YS1PmltT/6793Da+dvq0q9HTkJSD08bbyUpcovPaKC /PBCQRLpjPzY2s+YKzg5T67GSMId9WOCJtu7SqLo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sanman Pradhan , Guenter Roeck Subject: [PATCH 5.15 169/570] hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read Date: Mon, 13 Apr 2026 17:55:00 +0200 Message-ID: <20260413155836.784696204@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sanman Pradhan commit 25dd70a03b1f5f3aa71e1a5091ecd9cd2a13ee43 upstream. The q54sj108a2_debugfs_read function suffers from a stack buffer overflow due to incorrect arguments passed to bin2hex(). The function currently passes 'data' as the destination and 'data_char' as the source. Because bin2hex() converts each input byte into two hex characters, a 32-byte block read results in 64 bytes of output. Since 'data' is only 34 bytes (I2C_SMBUS_BLOCK_MAX + 2), this writes 30 bytes past the end of the buffer onto the stack. Additionally, the arguments were swapped: it was reading from the zero-initialized 'data_char' and writing to 'data', resulting in all-zero output regardless of the actual I2C read. Fix this by: 1. Expanding 'data_char' to 66 bytes to safely hold the hex output. 2. Correcting the bin2hex() argument order and using the actual read count. 3. Using a pointer to select the correct output buffer for the final simple_read_from_buffer call. Fixes: d014538aa385 ("hwmon: (pmbus) Driver for Delta power supplies Q54SJ108A2") Cc: stable@vger.kernel.org Signed-off-by: Sanman Pradhan Link: https://lore.kernel.org/r/20260304235116.1045-1-sanman.p211993@gmail.com Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/pmbus/q54sj108a2.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/drivers/hwmon/pmbus/q54sj108a2.c +++ b/drivers/hwmon/pmbus/q54sj108a2.c @@ -77,7 +77,8 @@ static ssize_t q54sj108a2_debugfs_read(s int idx = *idxp; struct q54sj108a2_data *psu = to_psu(idxp, idx); char data[I2C_SMBUS_BLOCK_MAX + 2] = { 0 }; - char data_char[I2C_SMBUS_BLOCK_MAX + 2] = { 0 }; + char data_char[I2C_SMBUS_BLOCK_MAX * 2 + 2] = { 0 }; + char *out = data; char *res; switch (idx) { @@ -148,27 +149,27 @@ static ssize_t q54sj108a2_debugfs_read(s if (rc < 0) return rc; - res = bin2hex(data, data_char, 32); - rc = res - data; - + res = bin2hex(data_char, data, rc); + rc = res - data_char; + out = data_char; break; case Q54SJ108A2_DEBUGFS_FLASH_KEY: rc = i2c_smbus_read_block_data(psu->client, PMBUS_FLASH_KEY_WRITE, data); if (rc < 0) return rc; - res = bin2hex(data, data_char, 4); - rc = res - data; - + res = bin2hex(data_char, data, rc); + rc = res - data_char; + out = data_char; break; default: return -EINVAL; } - data[rc] = '\n'; + out[rc] = '\n'; rc += 2; - return simple_read_from_buffer(buf, count, ppos, data, rc); + return simple_read_from_buffer(buf, count, ppos, out, rc); } static ssize_t q54sj108a2_debugfs_write(struct file *file, const char __user *buf,