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]