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SubjectRe: [PATCH] xfrm: Use correct address family in xfrm_state_find
On Fri, Sep 25, 2020 at 02:42:56PM +1000, Herbert Xu wrote:
> Resend with proper subject.
>
> ---8<---
> The struct flowi must never be interpreted by itself as its size
> depends on the address family. Therefore it must always be grouped
> with its original family value.
>
> In this particular instance, the original family value is lost in
> the function xfrm_state_find. Therefore we get a bogus read when
> it's coupled with the wrong family which would occur with inter-
> family xfrm states.
>
> This patch fixes it by keeping the original family value.
>
> Note that the same bug could potentially occur in LSM through
> the xfrm_state_pol_flow_match hook. I checked the current code
> there and it seems to be safe for now as only secid is used which
> is part of struct flowi_common. But that API should be changed
> so that so that we don't get new bugs in the future. We could
> do that by replacing fl with just secid or adding a family field.
>
> Reported-by: syzbot+577fbac3145a6eb2e7a5@syzkaller.appspotmail.com
> Fixes: 48b8d78315bf ("[XFRM]: State selection update to use inner...")
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Applied, thanks a lot Herbert!

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