lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list] 
Message-ID: <20230712214307.2424810-1-azeemshaikh38@gmail.com>
Date:   Wed, 12 Jul 2023 21:43:07 +0000
From:   Azeem Shaikh <azeemshaikh38@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        Kees Cook <keescook@...omium.org>
Cc:     linux-hardening@...r.kernel.org,
        Azeem Shaikh <azeemshaikh38@...il.com>,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jean Delvare <jdelvare@...e.com>
Subject: [PATCH v2] hwmon: (pmbus/max20730) Remove strlcpy occurences

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with direct assignment.

strlcpy in this file is used to copy fixed-length strings which can be
completely avoided by direct assignment and is safe to do so. strlen()
is used to return the length of @tbuf.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@...il.com>
---
v2:
 * Includes driver name in commit header.
 * Removes unrelated change tbuf{ 0 } -> tbuf{}.
 * Fixes bug where @tbuf was being passed instead of @result.

v1:
 * https://lore.kernel.org/all/20230712144429.2845940-1-azeemshaikh38@gmail.com/

 drivers/hwmon/pmbus/max20730.c |   64 +++++++++++++++++++++--------------------
 1 file changed, 33 insertions(+), 31 deletions(-)

diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c
index 7bcf27995033..1de34da177c9 100644
--- a/drivers/hwmon/pmbus/max20730.c
+++ b/drivers/hwmon/pmbus/max20730.c
@@ -114,6 +114,7 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 	const struct pmbus_driver_info *info;
 	const struct max20730_data *data;
 	char tbuf[DEBUG_FS_DATA_MAX] = { 0 };
+	char *result = tbuf;
 	u16 val;

 	info = pmbus_get_driver_info(psu->client);
@@ -148,13 +149,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			>> MAX20730_MFR_DEVSET1_TSTAT_BIT_POS;

 		if (val == 0)
-			len = strlcpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX);
+			result = "2000\n";
 		else if (val == 1)
-			len = strlcpy(tbuf, "125\n", DEBUG_FS_DATA_MAX);
+			result = "125\n";
 		else if (val == 2)
-			len = strlcpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX);
+			result = "62.5\n";
 		else
-			len = strlcpy(tbuf, "32\n", DEBUG_FS_DATA_MAX);
+			result = "32\n";
 		break;
 	case MAX20730_DEBUGFS_INTERNAL_GAIN:
 		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_RGAIN_MASK)
@@ -163,35 +164,35 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 		if (data->id == max20734) {
 			/* AN6209 */
 			if (val == 0)
-				len = strlcpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX);
+				result = "0.8\n";
 			else if (val == 1)
-				len = strlcpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX);
+				result = "3.2\n";
 			else if (val == 2)
-				len = strlcpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX);
+				result = "1.6\n";
 			else
-				len = strlcpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX);
+				result = "6.4\n";
 		} else if (data->id == max20730 || data->id == max20710) {
 			/* AN6042 or AN6140 */
 			if (val == 0)
-				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
+				result = "0.9\n";
 			else if (val == 1)
-				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
+				result = "3.6\n";
 			else if (val == 2)
-				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
+				result = "1.8\n";
 			else
-				len = strlcpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX);
+				result = "7.2\n";
 		} else if (data->id == max20743) {
 			/* AN6042 */
 			if (val == 0)
-				len = strlcpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX);
+				result = "0.45\n";
 			else if (val == 1)
-				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
+				result = "1.8\n";
 			else if (val == 2)
-				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
+				result = "0.9\n";
 			else
-				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
+				result = "3.6\n";
 		} else {
-			len = strlcpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX);
+			result = "Not supported\n";
 		}
 		break;
 	case MAX20730_DEBUGFS_BOOT_VOLTAGE:
@@ -199,26 +200,26 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			>> MAX20730_MFR_DEVSET1_VBOOT_BIT_POS;

 		if (val == 0)
-			len = strlcpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX);
+			result = "0.6484\n";
 		else if (val == 1)
-			len = strlcpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX);
+			result = "0.8984\n";
 		else if (val == 2)
-			len = strlcpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX);
+			result = "1.0\n";
 		else
-			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
+			result = "Invalid\n";
 		break;
 	case MAX20730_DEBUGFS_OUT_V_RAMP_RATE:
 		val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_VRATE)
 			>> MAX20730_MFR_DEVSET2_VRATE_BIT_POS;

 		if (val == 0)
-			len = strlcpy(tbuf, "4\n", DEBUG_FS_DATA_MAX);
+			result = "4\n";
 		else if (val == 1)
-			len = strlcpy(tbuf, "2\n", DEBUG_FS_DATA_MAX);
+			result = "2\n";
 		else if (val == 2)
-			len = strlcpy(tbuf, "1\n", DEBUG_FS_DATA_MAX);
+			result = "1\n";
 		else
-			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
+			result = "Invalid\n";
 		break;
 	case MAX20730_DEBUGFS_OC_PROTECT_MODE:
 		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK)
@@ -230,13 +231,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			>> MAX20730_MFR_DEVSET2_SS_BIT_POS;

 		if (val == 0)
-			len = strlcpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX);
+			result = "0.75\n";
 		else if (val == 1)
-			len = strlcpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX);
+			result = "1.5\n";
 		else if (val == 2)
-			len = strlcpy(tbuf, "3\n", DEBUG_FS_DATA_MAX);
+			result = "3\n";
 		else
-			len = strlcpy(tbuf, "6\n", DEBUG_FS_DATA_MAX);
+			result = "6\n";
 		break;
 	case MAX20730_DEBUGFS_IMAX:
 		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK)
@@ -287,10 +288,11 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 				"%d.%d\n", ret / 10000, ret % 10000);
 		break;
 	default:
-		len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
+		result = "Invalid\n";
 	}

-	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
+	len = strlen(result);
+	return simple_read_from_buffer(buf, count, ppos, result, len);
 }

 static const struct file_operations max20730_fops = {
--
2.41.0.255.g8b1d071c50-goog

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ