From: Zheyu Ma zheyuma97@gmail.com
[ Upstream commit 39244cc754829bf707dccd12e2ce37510f5b1f8d ]
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: 13f35ac14cd0 ("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 --- drivers/i2c/busses/i2c-ismt.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c index b51adffa4841..e689c7acea62 100644 --- a/drivers/i2c/busses/i2c-ismt.c +++ b/drivers/i2c/busses/i2c-ismt.c @@ -495,6 +495,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr, if (read_write == I2C_SMBUS_WRITE) { /* Block Write */ dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA: WRITE\n"); + if (data->block[0] < 1 || data->block[0] > I2C_SMBUS_BLOCK_MAX) + return -EINVAL; + dma_size = data->block[0] + 1; dma_direction = DMA_TO_DEVICE; desc->wr_len_cmd = dma_size;