Re: [PATCH v4 0/4] MR8991: iphlpapi: Implement GetBestRoute2() and GetBestInterfaceEx().

[Bernhard Übelacker]

Bernhard Übelacker (@bernhardu) commented about dlls/iphlpapi/iphlpapi_main.c:
> }
>      }
>
> +    uni_row = NULL;
> +    if (!src && !(v6 && IN6_IS_ADDR_LINKLOCAL(&dst->Ipv6.sin6_addr)))
> +    {
> +        static const struct in6_addr ipv6_default_addr = {{{ 0x20, 0x01, 0x0d, 0xb8 }}};
> +        SOCKADDR_INET src_addr, dst_addr;
> +        WORD ver = MAKEWORD (2, 2);
> +        WSADATA data;
> +        SOCKET s;
> +        int len;
> +
> +        WSAStartup ( ver, &data );
> +        if ((s = socket( dst->si_family, SOCK_DGRAM, IPPROTO_UDP )) == -1) goto skip_system_route;
> +        dst_addr = *dst;

Hello @gofman, I fear asan gets triggered by this assignment.

[This is the full output with a backtrace running the iphlpapi:iphlpapi test](https://gitlab.winehq.org/bernhardu/wine/-/blob/asan-pe_2025-09-13_wine-10.1...)

If I understand it right, the size of `dst_addr` is 28 bytes, that much it tries to read from the `dst` pointer.

Unfortunately this `dst` is reserved on the stack in `GetBestInterface` as `struct sockaddr_in sa_in;` which is just 16 bytes.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8991#note_117605