netdev - [PATCH] xfrm: do not assume that template resolving always returns xfrms

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 13 Jul 2010 10:29:42 +0300
From:	Timo Teräs <timo.teras@....fi>
To:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>,
	linux@...izon.com
Cc:	Timo Teräs <timo.teras@....fi>
Subject: [PATCH] xfrm: do not assume that template resolving always returns xfrms

xfrm_resolve_and_create_bundle() assumed that, if policies indicated
presence of xfrms, bundle template resolution would always return
some xfrms. This is not true for 'use' level policies which can
result in no xfrm's being applied if there is no suitable xfrm states.
This fixes a crash by this incorrect assumption.

Reported-by: George Spelvin <linux@...izon.com>
Bisected-by: George Spelvin <linux@...izon.com>
Tested-by: George Spelvin <linux@...izon.com>
Signed-off-by: Timo Teräs <timo.teras@....fi>
---
 net/xfrm/xfrm_policy.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index af1c173..a7ec5a8 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1594,8 +1594,8 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols,
 
 	/* Try to instantiate a bundle */
 	err = xfrm_tmpl_resolve(pols, num_pols, fl, xfrm, family);
-	if (err < 0) {
-		if (err != -EAGAIN)
+	if (err <= 0) {
+		if (err != 0 && err != -EAGAIN)
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
 		return ERR_PTR(err);
 	}
@@ -1678,6 +1678,13 @@ xfrm_bundle_lookup(struct net *net, struct flowi *fl, u16 family, u8 dir,
 			goto make_dummy_bundle;
 		dst_hold(&xdst->u.dst);
 		return oldflo;
+	} else if (new_xdst == NULL) {
+		num_xfrms = 0;
+		if (oldflo == NULL)
+			goto make_dummy_bundle;
+		xdst->num_xfrms = 0;
+		dst_hold(&xdst->u.dst);
+		return oldflo;
 	}
 
 	/* Kill the previous bundle */
@@ -1760,6 +1767,10 @@ restart:
 				xfrm_pols_put(pols, num_pols);
 				err = PTR_ERR(xdst);
 				goto dropdst;
+			} else if (xdst == NULL) {
+				num_xfrms = 0;
+				drop_pols = num_pols;
+				goto no_transform;
 			}
 
 			spin_lock_bh(&xfrm_policy_sk_bundle_lock);
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html