From 13ead5c4f2e3b649156c74892f3cf4b62c8e3d0c Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 6 Aug 2017 10:19:07 +0200 Subject: [PATCH] xfrm: check that cached bundle is still valid Quoting Ilan Tayari: 1. Set up a host-to-host IPSec tunnel (or transport, doesn't matter) 2. Ping over IPSec, or do something to populate the pcpu cache 3. Join a MC group, then leave MC group 4. Try to ping again using same CPU as before -> traffic doesn't egress the machine at all Ilan debugged the problem down to the fact that one of the path dsts devices point to lo due to earlier dst_dev_put(). In this case, dst is marked as DEAD and we cannot reuse the bundle. The cache only asserted that the requested policy and that of the cached bundle match, but its not enough - also verify the path is still valid. Fixes: ec30d78c14a813 ("xfrm: add xdst pcpu cache") Reported-by: Ayham Masood Tested-by: Ilan Tayari Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- net/xfrm/xfrm_policy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 06c3bf7ab86b..8da428f56aec 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1818,7 +1818,8 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols, xdst->num_pols == num_pols && !xfrm_pol_dead(xdst) && memcmp(xdst->pols, pols, - sizeof(struct xfrm_policy *) * num_pols) == 0) { + sizeof(struct xfrm_policy *) * num_pols) == 0 && + xfrm_bundle_ok(xdst)) { dst_hold(&xdst->u.dst); return xdst; } -- 2.30.2