linux-kernel - [PATCH] misc: ds1682: fix out-of-bounds access in EEPROM functions

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: <CA+LcPJ3nAdBmuSBQ0mgzFmUL=ZE5RKkfp_4dQf-ycTiHxH=PXA@mail.gmail.com>
Date: Sat, 9 Aug 2025 20:54:57 +0500
From: wajahat iqbal <wajahatiqbal22@...il.com>
To: gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH] misc: ds1682: fix out-of-bounds access in EEPROM functions

Found a couple of issues in the ds1682 driver while reviewing the code:

The EEPROM read/write functions don't check if offset and count exceed
the 10-byte EEPROM size, which could lead to out-of-bounds I2C access.

Also replaced sprintf with scnprintf in the sysfs show function for
better safety.

For reads beyond EEPROM size, return 0. For writes, return -EINVAL if
starting beyond bounds, otherwise truncate to fit within the EEPROM.

Signed-off-by: Wajahat Iqbal <wajahatiqbal22@...il.com>
---
 drivers/misc/ds1682.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ds1682.c b/drivers/misc/ds1682.c
index cb09e056531a..4cf4b43e5355 100644
--- a/drivers/misc/ds1682.c
+++ b/drivers/misc/ds1682.c
@@ -92,7 +92,7 @@ static ssize_t ds1682_show(struct device *dev,
struct device_attribute *attr,
  * Special case: the 32 bit regs are time values with 1/4s
  * resolution, scale them up to milliseconds
  */
- return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val);
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", (sattr->nr == 4) ? (val *
250) : val);
 }

 static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
@@ -163,6 +163,11 @@ static ssize_t ds1682_eeprom_read(struct file
*filp, struct kobject *kobj,
  dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
  buf, off, count);

+ if (off >= DS1682_EEPROM_SIZE)
+ return 0;
+ if (off + count > DS1682_EEPROM_SIZE)
+ count = DS1682_EEPROM_SIZE - off;
+
  rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
     count, buf);
  if (rc < 0)
@@ -180,6 +185,11 @@ static ssize_t ds1682_eeprom_write(struct file
*filp, struct kobject *kobj,
  dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
  buf, off, count);

+ if (off >= DS1682_EEPROM_SIZE)
+ return -EINVAL;
+ if (off + count > DS1682_EEPROM_SIZE)
+ count = DS1682_EEPROM_SIZE - off;
+
  /* Write out to the device */
  if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
     count, buf) < 0)
-- 
2.49.0.windows.1