xfrm: policy: fix infinite loop when merging src-nodes

With very small change to test script we can trigger softlockup due to
bogus assignment of 'p' (policy to be examined) on restart.

Previously the two to-be-merged nodes had same address/prefixlength pair,
so no erase/reinsert was necessary, we only had to append the list from
node a to b.

If prefix lengths are different, the node has to be deleted and re-inserted
into the tree, with the updated prefix length.  This was broken; due to
bogus update to 'p' this loops forever.

Add a 'restart' label and use that instead.

While at it, don't perform the unneeded reinserts of the policies that
are already sorted into the 'new' node.

A previous patch in this series made xfrm_policy_inexact_list_reinsert()
use the relative position indicator to sort policies according to age in
case priorities are identical.

Fixes: 6ac098b2a9 ("xfrm: policy: add 2nd-level saddr trees for inexact policies")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>
This commit is contained in:
Florian Westphal 2019-01-04 14:17:05 +01:00 • committed by Steffen Klassert
commit 12750abad5
2 changed files with 9 additions and 10 deletions

View file

@ -78,8 +78,8 @@ do_overlap()
# adds a new node in the 10.0.0.0/24 tree (dst node exists).
ip -net $ns xfrm policy add src 10.2.0.0/24 dst 10.0.0.0/24 dir fwd priority 200 action block
# adds a 10.2.0.0/24 node, but for different dst.
ip -net $ns xfrm policy add src 10.2.0.0/24 dst 10.0.1.0/24 dir fwd priority 200 action block
# adds a 10.2.0.0/23 node, but for different dst.
ip -net $ns xfrm policy add src 10.2.0.0/23 dst 10.0.1.0/24 dir fwd priority 200 action block
# dst now overlaps with the 10.0.1.0/24 ESP policy in fwd.
# kernel must 'promote' existing one (10.0.0.0/24) to 10.0.0.0/23.