netdev - [PATCH 2/2] xfrm Fix potential error pointer dereference in xfrm_bundle

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Message-ID: <20180531102326.5728-3-steffen.klassert@secunet.com>
Date:   Thu, 31 May 2018 12:23:26 +0200
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     David Miller <davem@...emloft.net>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        <netdev@...r.kernel.org>
Subject: [PATCH 2/2] xfrm Fix potential error pointer dereference in xfrm_bundle_create.

We may derference an invalid pointer in the error path of
xfrm_bundle_create(). Fix this by returning this error
pointer directly instead of assigning it to xdst0.

Fixes: 45b018beddb6 ("ipsec: Create and use new helpers for dst child access.")
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/xfrm/xfrm_policy.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 40b54cc64243..5f48251c1319 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1658,7 +1658,6 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
 		trailer_len -= xdst_prev->u.dst.xfrm->props.trailer_len;
 	}
 
-out:
 	return &xdst0->u.dst;
 
 put_states:
@@ -1667,8 +1666,8 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
 free_dst:
 	if (xdst0)
 		dst_release_immediate(&xdst0->u.dst);
-	xdst0 = ERR_PTR(err);
-	goto out;
+
+	return ERR_PTR(err);
 }
 
 static int xfrm_expand_policies(const struct flowi *fl, u16 family,
-- 
2.14.1