i2c: mux: harden i2c_mux_alloc() against integer overflows

A couple years back we went through the kernel an automatically
converted size calculations to use struct_size() instead.  The
struct_size() calculation is protected against integer overflows.

However it does not make sense to use the result from struct_size()
for additional math operations as that would negate any safeness.

Fixes: 1f3b69b6b9 ("i2c: mux: Use struct_size() in devm_kzalloc()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Dan Carpenter 2022-09-15 14:30:58 +03:00 committed by Wolfram Sang
parent 37f071ec32
commit b7af938f43

View File

@ -243,9 +243,10 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
int (*deselect)(struct i2c_mux_core *, u32))
{
struct i2c_mux_core *muxc;
size_t mux_size;
muxc = devm_kzalloc(dev, struct_size(muxc, adapter, max_adapters)
+ sizeof_priv, GFP_KERNEL);
mux_size = struct_size(muxc, adapter, max_adapters);
muxc = devm_kzalloc(dev, size_add(mux_size, sizeof_priv), GFP_KERNEL);
if (!muxc)
return NULL;
if (sizeof_priv)