Re: [PATCH net 1/2] ipv6: rpl: fix loop detection for separated local addresses

On Fri, Sep 11, 2026 at 04:11:21PM -0700, Mark Amirkan via B4 Relay wrote:

From: Mark Amirkan <redacted>

RFC 6554 requires an RPL router to drop a packet when two or more
addresses assigned to the router are separated in the SRH by an address
not assigned to it.

ipv6_chk_rpl_srh_loop() checks found > 1 before counting the current
local address. For the shortest invalid sequence -- local, non-local,
local -- found is 1 at the second local address and the SRH is accepted.

Check whether a local address was seen before the separation instead.
The receive path calls this helper before forwarding an RPL SRH, and
RFC 6554 requires the check to mitigate bandwidth-exhaustion attacks.

Fixes: f37c60593634 ("addrconf: add functionality to check on rpl requirements")
Cc: stable@vger.kernel.org
Signed-off-by: Mark Amirkan <redacted>
Assisted-by: Symbolic

Code looks fine, but your SoB should be the last tag. Also, if
"Symbolic" is an LLM, then please use:

Assisted-by: LLM

See:

https://docs.kernel.org/next/process/coding-assistants.html#attribution
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=816d9992d9ed434ec52cfbd63080d518e535a41b