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

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[ 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: 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>
This commit is contained in:
Zheyu Ma 2022-07-29 19:02:16 +08:00 committed by Greg Kroah-Hartman
parent f3f65c4177
commit cdcbae2c50
1 changed files with 3 additions and 0 deletions
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3
drivers/i2c/busses/i2c-ismt.c
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@ -506,6 +506,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
if (read_write == I2C_SMBUS_WRITE) { if (read_write == I2C_SMBUS_WRITE) {
/* Block Write */ /* Block Write */
dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA: WRITE\n"); 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_size = data->block[0] + 1;
dma_direction = DMA_TO_DEVICE; dma_direction = DMA_TO_DEVICE;
desc->wr_len_cmd = dma_size; desc->wr_len_cmd = dma_size;