On a I2C_SMBUS_I2C_BLOCK_DATA read request, if data->block[0] is
greater than I2C_SMBUS_BLOCK_MAX + 1, the underlying I2C driver writes
data out of the msgbuf1 boundary.
It is possible from a user application to run into that issue by call
the I2C_SMBUS ioctl with data.block[0] greater than
I2C_SMBUS_BLOCK_MAX + 1.
Call Trace:
[<ffffffff8139f695>] dump_stack+0x67/0x92
[<ffffffff811802a4>] panic+0xc5/0x1eb
[<ffffffff810ecb5f>] ? vprintk_default+0x1f/0x30
[<ffffffff817456d3>] ? i2cdev_ioctl_smbus+0x303/0x320
[<ffffffff8109a68b>] __stack_chk_fail+0x1b/0x20
[<ffffffff817456d3>] i2cdev_ioctl_smbus+0x303/0x320
[<ffffffff81745aed>] i2cdev_ioctl+0x4d/0x1e0
[<ffffffff811f761a>] do_vfs_ioctl+0x2ba/0x490
[<ffffffff81336e43>] ? security_file_ioctl+0x43/0x60
[<ffffffff811f7869>] SyS_ioctl+0x79/0x90
[<ffffffff81a22e97>] entry_SYSCALL_64_fastpath+0x12/0x6a
Signed-off-by: Jeremy Compostella <jeremy.compostella@xxxxxxxxx>
---
drivers/i2c/i2c-core-smbus.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 10f00a8..f0be621 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -398,6 +398,12 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
case I2C_SMBUS_I2C_BLOCK_DATA:
if (read_write == I2C_SMBUS_READ) {
msg[1].len = data->block[0];
+ if (msg[1].len > I2C_SMBUS_BLOCK_MAX) {
+ dev_err(&adapter->dev,
+ "Invalid block read size %d\n",
+ data->block[0]);
+ return -EINVAL;
+ }
} else {
msg[0].len = data->block[0] + 1;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
--
2.9.4
