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From: Romain Perier <romain.perier@gmail.com>
To: Kees Cook <keescook@chromium.org>,
	kernel-hardening@lists.openwall.com,
	Guenter Roeck <linux@roeck-us.net>
Cc: Romain Perier <romain.perier@gmail.com>,
	linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 11/20] hwmon: Manual replacement of the deprecated strlcpy() with return values
Date: Mon, 22 Feb 2021 16:12:22 +0100	[thread overview]
Message-ID: <20210222151231.22572-12-romain.perier@gmail.com> (raw)
In-Reply-To: <20210222151231.22572-1-romain.perier@gmail.com>

The strlcpy() reads the entire source buffer first, it is dangerous if
the source buffer lenght is unbounded or possibility non NULL-terminated.
It can lead to linear read overflows, crashes, etc...

As recommended in the deprecated interfaces [1], it should be replaced
by strscpy.

This commit replaces all calls to strlcpy that handle the return values
by the corresponding strscpy calls with new handling of the return
values (as it is quite different between the two functions).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy

Signed-off-by: Romain Perier <romain.perier@gmail.com>
---
 drivers/hwmon/pmbus/max20730.c |   66 +++++++++++++++++++++--------------------
 1 file changed, 35 insertions(+), 31 deletions(-)

diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c
index 9dd3dd79bc18..a384b57b7327 100644
--- a/drivers/hwmon/pmbus/max20730.c
+++ b/drivers/hwmon/pmbus/max20730.c
@@ -107,7 +107,8 @@ struct max20730_debugfs_data {
 static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 				     size_t count, loff_t *ppos)
 {
-	int ret, len;
+	int ret;
+	ssize_t len;
 	int *idxp = file->private_data;
 	int idx = *idxp;
 	struct max20730_debugfs_data *psu = to_psu(idxp, idx);
@@ -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);
+			len = strscpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX);
 		else if (val == 1)
-			len = strlcpy(tbuf, "125\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "125\n", DEBUG_FS_DATA_MAX);
 		else if (val == 2)
-			len = strlcpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX);
 		else
-			len = strlcpy(tbuf, "32\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "32\n", DEBUG_FS_DATA_MAX);
 		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);
+				len = strscpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX);
 			else if (val == 1)
-				len = strlcpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX);
 			else if (val == 2)
-				len = strlcpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX);
 			else
-				len = strlcpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX);
 		} else if (data->id == max20730 || data->id == max20710) {
 			/* AN6042 or AN6140 */
 			if (val == 0)
-				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
 			else if (val == 1)
-				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
 			else if (val == 2)
-				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
 			else
-				len = strlcpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX);
 		} else if (data->id == max20743) {
 			/* AN6042 */
 			if (val == 0)
-				len = strlcpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX);
 			else if (val == 1)
-				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
 			else if (val == 2)
-				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
 			else
-				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
+				len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
 		} else {
-			len = strlcpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX);
 		}
 		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);
+			len = strscpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX);
 		else if (val == 1)
-			len = strlcpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX);
 		else if (val == 2)
-			len = strlcpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX);
 		else
-			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
 		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);
+			len = strscpy(tbuf, "4\n", DEBUG_FS_DATA_MAX);
 		else if (val == 1)
-			len = strlcpy(tbuf, "2\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "2\n", DEBUG_FS_DATA_MAX);
 		else if (val == 2)
-			len = strlcpy(tbuf, "1\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "1\n", DEBUG_FS_DATA_MAX);
 		else
-			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
 		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);
+			len = strscpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX);
 		else if (val == 1)
-			len = strlcpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX);
 		else if (val == 2)
-			len = strlcpy(tbuf, "3\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "3\n", DEBUG_FS_DATA_MAX);
 		else
-			len = strlcpy(tbuf, "6\n", DEBUG_FS_DATA_MAX);
+			len = strscpy(tbuf, "6\n", DEBUG_FS_DATA_MAX);
 		break;
 	case MAX20730_DEBUGFS_IMAX:
 		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK)
@@ -287,9 +288,12 @@ 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);
+		len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
 	}
 
+	if (len == -E2BIG)
+		return -E2BIG;
+
 	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 


  parent reply	other threads:[~2021-02-22 15:15 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22 15:12 [PATCH 00/20] Manual replacement of all strlcpy in favor of strscpy Romain Perier
2021-02-22 15:12 ` Romain Perier
2021-02-22 15:12 ` Romain Perier
2021-02-22 15:12 ` Romain Perier
2021-02-22 15:12 ` [PATCH 01/20] cgroup: Manual replacement of the deprecated strlcpy() with return values Romain Perier
2021-02-23 16:13   ` Michal Koutný
2021-02-23 16:13     ` Michal Koutný
2021-02-23 17:49     ` Romain Perier
2021-02-22 15:12 ` [PATCH 02/20] crypto: " Romain Perier
2021-03-04  4:37   ` Herbert Xu
2021-03-04 10:08     ` Romain Perier
2021-02-22 15:12 ` [PATCH 03/20] devlink: " Romain Perier
2021-02-23  0:56   ` Jakub Kicinski
2021-02-22 15:12 ` [PATCH 04/20] dma-buf: " Romain Perier
2021-02-22 15:12   ` Romain Perier
2021-02-22 15:12 ` [PATCH 05/20] kobject: " Romain Perier
2021-02-22 15:12 ` [PATCH 06/20] ima: " Romain Perier
2021-03-02 13:29   ` Mimi Zohar
2021-02-22 15:12 ` [PATCH 07/20] SUNRPC: " Romain Perier
2021-03-01 18:25   ` Chuck Lever
2021-03-01 18:25     ` Chuck Lever
2021-03-02  6:43     ` Romain Perier
2021-02-22 15:12 ` [PATCH 08/20] kernfs: " Romain Perier
2021-02-22 15:12 ` [PATCH 09/20] m68k/atari: " Romain Perier
2021-02-22 15:12 ` [PATCH 10/20] module: " Romain Perier
2021-02-22 15:12 ` Romain Perier [this message]
2021-02-22 15:46   ` [PATCH 11/20] hwmon: " Guenter Roeck
2021-02-23  9:43     ` Romain Perier
2021-02-28 11:50     ` Joe Perches
2021-02-28 11:50       ` Joe Perches
2021-02-22 15:12 ` [PATCH 12/20] s390/hmcdrv: " Romain Perier
2021-02-22 15:12 ` [PATCH 13/20] scsi: zfcp: " Romain Perier
2021-02-22 16:04   ` Benjamin Block
2021-02-22 15:12 ` [PATCH 14/20] target: " Romain Perier
2021-02-22 16:00   ` Bodo Stroesser
2021-02-22 18:09   ` kernel test robot
2021-02-22 18:09     ` kernel test robot
2021-02-22 15:12 ` [PATCH 15/20] ALSA: usb-audio: " Romain Perier
2021-02-22 15:12   ` Romain Perier
2021-02-22 15:39   ` Takashi Iwai
2021-02-22 15:39     ` Takashi Iwai
2021-02-22 15:12 ` [PATCH 16/20] tracing/probe: " Romain Perier
2021-02-22 17:49   ` Steven Rostedt
2021-02-25  8:38     ` Romain Perier
2021-02-22 15:12 ` [PATCH 17/20] vt: " Romain Perier
2021-02-26  9:49   ` Jiri Slaby
2021-02-26 15:09     ` Romain Perier
2021-02-22 15:12 ` [PATCH 18/20] usb: gadget: f_midi: " Romain Perier
2021-02-22 15:12 ` [PATCH 19/20] usbip: usbip_host: " Romain Perier
2021-02-22 16:21   ` Shuah Khan
2021-02-28  9:03   ` Sergei Shtylyov
2021-02-28 16:00   ` Andy Shevchenko
2021-02-22 15:12 ` [PATCH 20/20] s390/watchdog: " Romain Perier
2021-02-22 15:55   ` Guenter Roeck
2021-02-22 16:36 ` [PATCH 00/20] Manual replacement of all strlcpy in favor of strscpy Shuah Khan
2021-02-22 16:36   ` Shuah Khan
2021-02-22 16:36   ` Shuah Khan
2021-02-22 16:36   ` Shuah Khan
2021-02-23  9:31   ` Romain Perier
2021-02-23  9:31     ` Romain Perier
2021-02-23  9:31     ` Romain Perier
2021-02-23  9:31     ` Romain Perier

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