| Message ID | 20250615233306.498536-1-alexguo1023@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: i801: Fix out-of-bounds bug in i801_block_transaction _byte_by_byte | expand |
Hi Alex, On Sun, 15 Jun 2025 19:33:06 -0400, Alex Guo wrote: > The data->block[0] variable comes from user. Without proper check, > the variable may be very large to cause an out-of-bounds bug. > > Fix this bug by checking the value of data->block[0] first. The same check is already present in i801_smbus_block_transaction() and i801_i2c_block_transaction(), which are the only 2 functions calling i801_block_transaction_byte_by_byte(). So the out-of-bounds bug you describe does not exist.
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 7503418be39a..aed4473fb9ba 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -678,6 +678,8 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, return -EOPNOTSUPP; len = data->block[0]; + if (len < 1 || len > I2C_SMBUS_BLOCK_MAX) + return -EINVAL; if (read_write == I2C_SMBUS_WRITE) { iowrite8(len, SMBHSTDAT0(priv));
The data->block[0] variable comes from user. Without proper check, the variable may be very large to cause an out-of-bounds bug. Fix this bug by checking the value of data->block[0] first. Similar commit: 1. commit 39244cc7548 ("i2c: ismt: Fix an out-of-bounds bug in ismt_access()") 2. commit 92fbb6d1296 ("i2c: xgene-slimpro: Fix out-of-bounds bug in xgene_slimpro_i2c_xfer()") Signed-off-by: Alex Guo <alexguo1023@gmail.com> --- drivers/i2c/busses/i2c-i801.c | 2 ++ 1 file changed, 2 insertions(+)