CVE-2022-50394

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

i2c: ismt: Fix an out-of-bounds bug in ismt_access()

When the driver does not check the data from the user, the variable data->block[0] may be very large to cause an out-of-bounds bug.

The following log can reveal it:

[ 33.995542] i2c i2c-1: ioctl, cmd=0x720, arg=0x7ffcb3dc3a20 [ 33.995978] ismt_smbus 0000:00:05.0: I2C_SMBUS_BLOCK_DATA: WRITE [ 33.996475] ================================================================== [ 33.996995] BUG: KASAN: out-of-bounds in ismt_access.cold+0x374/0x214b [ 33.997473] Read of size 18446744073709551615 at addr ffff88810efcfdb1 by task ismt_poc/485 [ 33.999450] Call Trace: [ 34.001849] memcpy+0x20/0x60 [ 34.002077] ismt_access.cold+0x374/0x214b [ 34.003382] __i2c_smbus_xfer+0x44f/0xfb0 [ 34.004007] i2c_smbus_xfer+0x10a/0x390 [ 34.004291] i2cdev_ioctl_smbus+0x2c8/0x710 [ 34.005196] i2cdev_ioctl+0x5ec/0x74c

Fix this bug by checking the size of data->block[0] first.

Affected Software

References

• https://git.kernel.org/stable/c/03b7ef7a6c5ca1ff553470166b4919db88b810f6
• https://git.kernel.org/stable/c/233348a04becf133283f0076e20b317302de21d9
• https://git.kernel.org/stable/c/39244cc754829bf707dccd12e2ce37510f5b1f8d
• https://git.kernel.org/stable/c/4a7bb1d93addb2f67e36fed00a53cb7f270d7b7a
• https://git.kernel.org/stable/c/96c12fd0ec74641295e1c3c34dea3dce1b6c3422
• https://git.kernel.org/stable/c/9ac541a0898e8ec187a3fa7024b9701cffae6bf2
• https://git.kernel.org/stable/c/a642469d464b2780a25a49b51ae56623c65eac34
• https://git.kernel.org/stable/c/bfe41d966c860a8ad4c735639d616da270c92735
• https://git.kernel.org/stable/c/cdcbae2c5003747ddfd14e29db9c1d5d7e7c44dd