[ Upstream commit 39244cc754 ]
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.
Fixes: 13f35ac14c ("i2c: Adding support for Intel iSMT SMBus 2.0 host controller")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
233348a04b