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A malformed inner destination-options header can then make > the HAO lookup and address swap run past the end of the quoted packet > and corrupt skb_shared_info. > > Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the > reply path does not reuse metadata left by the outer IPv6 stack. > > Fixes: e490d1d85cf5 ("[IPV6] IP6TUNNEL: Split out generic routine in ip6ip6_err().") > Cc: stable@vger.kernel.org > Reported-by: Vega > Signed-off-by: Zhiling Zou Regarding: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/fe1a5e765fbca88d69391887f0ed26a19e3e4d39.1785736562.git.zhilinz%40nebusec.ai 1. "Could this description be tightened up, given it is going to stable?" Nitpick. 2. "Is this the right commit to blame?" Nitpick. We can blame 793832361fe7 ("[IPV6] MIP6: Revert address to send ICMPv6 error."), but it doesn't matter in practice. 3. "Does clearing the whole inet6_skb_parm here also throw away IP6CB->iif, which was valid and is still consumed by the reply path?" Yes and it's fine. It needs to encode the iif of the packet that icmpv6_send() is going to quote and it's not IP6CB->iif. It's rt->dst.dev->ifindex, but passing 0 is legitimate. 4. "This isn't a bug introduced by this patch, but should the consumer be hardened as well, rather than only this call site?" Separate issue. Reviewed-by: Ido Schimmel