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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org, syzbot+01f005f9c6387ca6f6dd@syzkaller.appspotmail.com Subject: Re: [PATCH v1 net] ipv6: Fix null-ptr-deref in fib6_mtu(). 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[0] > > When res->f6i->fib6_pmtu is 0 in fib6_mtu(), it fetches MTU from > __in6_dev_get(nh->fib_nh_dev)->cnf.mtu6. > > However, __in6_dev_get() could return NULL when the device is > being unregistered. > > Let's return 0 MTU if __in6_dev_get() returns NULL in fib6_mtu(). [...] > Fixes: dcd1f572954f ("net/ipv6: Remove fib6_idev") > Reported-by: syzbot+01f005f9c6387ca6f6dd@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/netdev/69f83f22.170a0220.13cc2.0004.GAE@google.com/ > Signed-off-by: Kuniyuki Iwashima Reviewed-by: Ido Schimmel