xsk: fix an integer overflow in xp_create_and_assign_umem()

Since the i and pool->chunk_size variables are of type 'u32',
their product can wrap around and then be cast to 'u64'.
This can lead to two different XDP buffers pointing to the same
memory area.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.

Fixes: 94033cd ("xsk: Optimize for aligned case")
Cc: stable@vger.kernel.org
Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov@infotecs.ru>
Link: https://patch.msgid.link/20250313085007.3116044-1-Ilia.Gavrilov@infotecs.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Gavrilov Ilia

net/xdp/xsk_buff_pool.c

@@ -105,7 +105,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 		if (pool->unaligned)
 			pool->free_heads[i] = xskb;
 		else
-			xp_init_xskb_addr(xskb, pool, i * pool->chunk_size);
+			xp_init_xskb_addr(xskb, pool, (u64)i * pool->chunk_size);
 	}
 
 	return pool;