On Sun, 27 Mar 2022 19:38:31 +0300, Leon Romanovsky wrote:
On Sun, Mar 27, 2022 at 03:35:42PM +0800, Xiaomeng Tong wrote:
The bug is here: if (!pdev) {
The list iterator value 'pdev' will *always* be set and non-NULL by for_each_netdev(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element found (in this case, the check 'if (!pdev)' can be bypassed as it always be false unexpectly).
To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'pdev' as a dedicated pointer to point to the found element.
I don't think that the description is correct. We are talking about loopback interface which received packet, the pdev will always exist.
Do the both conditions impossible? 1. the list is empty or 2. we can not found a pdev due to this check if (ipv6_chk_addr(&init_net, (struct in6_addr *)peer_ip, pdev, 1)) iter, 1))
Most likely. the check of "if (!pdev)" is to catch impossible situation where IPV6 packet was sent over loopback, but IPV6 is not enabled.
-- Xiaomeng Tong