CVE-2026-52948: i2c: dev: prevent integer overflow in I2C_TIMEOUT ioctl

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

i2c: dev: prevent integer overflow in I2C_TIMEOUT ioctl

While fuzzing with Syzkaller, a persistent `schedule_timeout: wrong
timeout value` warning was observed, accompanied by SMBus controller
state machine corruption.

The I2C_TIMEOUT ioctl accepts a user-provided timeout in multiples of
10 ms. The user argument is checked against INT_MAX, but it is
subsequently multiplied by 10 before being passed to msecs_to_jiffies().

A malicious user can pass a large value (e.g., 429496729) that passes
the `arg > INT_MAX` check but overflows when multiplied by 10. This
results in a truncated 32-bit unsigned value that bypasses the
internal `(int)m < 0` check in `msecs_to_jiffies()`.

The truncated value is then assigned to `client->adapter->timeout`
(a signed 32-bit int), which is reinterpreted as a negative number.
When passed to wait_for_completion_timeout(), this negative value
undergoes sign extension to a 64-bit unsigned long, triggering the
`schedule_timeout` warning and causing premature returns. This leaves
the SMBus state machine in an unrecoverable state, constituting a
local Denial of Service (DoS).

Fix this by bounding the user argument to `INT_MAX / 10`.

[wsa: move the comment as well]

The Linux kernel CVE team has assigned CVE-2026-52948 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.10.259 with commit e9ffd5f5050fbb199d270a85614cd27ebed6fbac
	Fixed in 5.15.210 with commit 0b88ecfbc9dc33b4db8836c37b50cf174e6c0691
	Fixed in 6.1.176 with commit 943e318eedbeaeea08ece3f5dd44c982f4ed2ef5
	Fixed in 6.6.143 with commit aa6ef734016912653a909477fb30aeb66c98b3a2
	Fixed in 6.12.94 with commit ff02add34ffd03449b8115904ebe2ec4fed022d4
	Fixed in 6.18.36 with commit ffbcf31f032eb454ebfd29309f51366fe57f4ac4
	Fixed in 7.0.13 with commit 4576621dc6577f21a032acfd16c3ad61907a5ea7
	Fixed in 7.1 with commit 617eb7c0961a8dfcfc811844a6396e406b2923ea

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-52948
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/i2c/i2c-dev.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/e9ffd5f5050fbb199d270a85614cd27ebed6fbac
	https://git.kernel.org/stable/c/0b88ecfbc9dc33b4db8836c37b50cf174e6c0691
	https://git.kernel.org/stable/c/943e318eedbeaeea08ece3f5dd44c982f4ed2ef5
	https://git.kernel.org/stable/c/aa6ef734016912653a909477fb30aeb66c98b3a2
	https://git.kernel.org/stable/c/ff02add34ffd03449b8115904ebe2ec4fed022d4
	https://git.kernel.org/stable/c/ffbcf31f032eb454ebfd29309f51366fe57f4ac4
	https://git.kernel.org/stable/c/4576621dc6577f21a032acfd16c3ad61907a5ea7
	https://git.kernel.org/stable/c/617eb7c0961a8dfcfc811844a6396e406b2923ea