From: Steffen Klassert Subject: [PATCH 11/11] xfrm: Fix a race in the xdst pcpu cache. Date: Thu, 11 Jan 2018 12:37:46 +0100 Message-ID: <20180111113746.28186-12-steffen.klassert@secunet.com> References: <20180111113746.28186-1-steffen.klassert@secunet.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Herbert Xu , Steffen Klassert , To: David Miller Return-path: Received: from a.mx.secunet.com ([62.96.220.36]:50906 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933905AbeAKLh4 (ORCPT ); Thu, 11 Jan 2018 06:37:56 -0500 In-Reply-To: <20180111113746.28186-1-steffen.klassert@secunet.com> Sender: netdev-owner@vger.kernel.org List-ID: We need to run xfrm_resolve_and_create_bundle() with bottom halves off. Otherwise we may reuse an already released dst_enty when the xfrm lookup functions are called from process context. Fixes: c30d78c14a813db39a647b6a348b428 ("xfrm: add xdst pcpu cache") Reported-by: Darius Ski Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_policy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index bc5eae12fb09..bd6b0e7a0ee4 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2063,8 +2063,11 @@ xfrm_bundle_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir, if (num_xfrms <= 0) goto make_dummy_bundle; + local_bh_disable(); xdst = xfrm_resolve_and_create_bundle(pols, num_pols, fl, family, - xflo->dst_orig); + xflo->dst_orig); + local_bh_enable(); + if (IS_ERR(xdst)) { err = PTR_ERR(xdst); if (err != -EAGAIN) @@ -2151,9 +2154,12 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, goto no_transform; } + local_bh_disable(); xdst = xfrm_resolve_and_create_bundle( pols, num_pols, fl, family, dst_orig); + local_bh_enable(); + if (IS_ERR(xdst)) { xfrm_pols_put(pols, num_pols); err = PTR_ERR(xdst); -- 2.14.1