xfrm: policy: delete inexact policies from inexact list on hash rebuild

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An xfrm hash rebuild has to reset the inexact policy list before the
policies get re-inserted: A change of hash thresholds will result in
policies to get moved from inexact tree to the policy hash table.

If the thresholds are increased again later, they get moved from hash
table to inexact tree.

We must unlink all policies from the inexact tree before re-insertion.

Otherwise 'migrate' may find policies that are in main hash table a
second time, when it searches the inexact lists.

Furthermore, re-insertion without deletion can cause elements ->next to
point back to itself, causing soft lockups or double-frees.

Reported-by: syzbot+9d971dd21eb26567036b@syzkaller.appspotmail.com
Fixes: 9cf545ebd5 ("xfrm: policy: store inexact policies in a tree ordered by destination address")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

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Florian Westphal 2019-01-04 14:17:02 +01:00 • committed by Steffen Klassert

parent 7a474c3658

commit 1548bc4e05

1 changed files with 10 additions and 13 deletions

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net/xfrm/xfrm_policy.c

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