Messages in this thread | | | From | Eric Dumazet <> | Date | Thu, 7 Dec 2023 13:38:23 +0100 | Subject | Re: [syzbot] [net?] KMSAN: uninit-value in ipgre_xmit |
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On Thu, Dec 7, 2023 at 6:03 AM xingwei lee <xrivendell7@gmail.com> wrote: > > Hello Eric. > I reproduced this bug with repro.c and repro.txt > HEAD commit: 815fb87b753055df2d9e50f6cd80eb10235fe3e9 > kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=f711bc2a7eb1db25 > as the same in https://syzkaller.appspot.com/bug?extid=2cb7b1bd08dc77ae7f89 >
I think the patch has been merged in net tree, thanks.
commit 80d875cfc9d3711a029f234ef7d680db79e8fa4b Author: Shigeru Yoshida <syoshida@redhat.com> AuthorDate: Sun Dec 3 01:14:41 2023 +0900 Commit: Paolo Abeni <pabeni@redhat.com> CommitDate: Wed Dec 6 10:08:05 2023 +0100
ipv4: ip_gre: Avoid skb_pull() failure in ipgre_xmit()
In ipgre_xmit(), skb_pull() may fail even if pskb_inet_may_pull() returns true. For example, applications can use PF_PACKET to create a malformed packet with no IP header. This type of packet causes a problem such as uninit-value access.
This patch ensures that skb_pull() can pull the required size by checking the skb with pskb_network_may_pull() before skb_pull().
Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Suman Ghosh <sumang@marvell.com> Link: https://lore.kernel.org/r/20231202161441.221135-1-syoshida@redhat.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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