Re: [PATCH v4] net: don't call strlen on non-terminated string in dev_set_alias()

[David Miller]

From: Alexander Potapenko <glider@xxxxxxxxxx>
Date: Tue,  6 Jun 2017 15:56:54 +0200

> KMSAN reported a use of uninitialized memory in dev_set_alias(),
> which was caused by calling strlcpy() (which in turn called strlen())
> on the user-supplied non-terminated string.
> 
> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>

We should not be allowing non-NULL terminated strings for the
IFLA_IFALIAS attribute.  It's defined as type NLA_STRING in
the ifla_policy[] array.

Please figure out why we aren't enforcing the attribute policy
properly, rather than adding a workaround.

Thanks.