Messages in this thread | | | Date | Thu, 15 Sep 2022 15:36:58 +0200 | Subject | Re: [PATCH] i2c: mux: harden i2c_mux_alloc() against integer overflows | From | Peter Rosin <> |
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Hi Dan,
2022-09-15 at 13:30, Dan Carpenter wrote: > 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.
Indeed. Nice catch!
> Fixes: 1f3b69b6b939 ("i2c: mux: Use struct_size() in devm_kzalloc()") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Peter Rosin <peda@axentia.se>
Cheers, Peter
> --- > drivers/i2c/i2c-mux.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c > index 774507b54b57..313904be5f3b 100644 > --- a/drivers/i2c/i2c-mux.c > +++ b/drivers/i2c/i2c-mux.c > @@ -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)
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