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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 091/167] ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions
Date:   Mon, 26 Jul 2021 17:38:44 +0200
Message-Id: <20210726153842.454700281@linuxfoundation.org>
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From: Paolo Abeni <pabeni@redhat.com>

[ Upstream commit 8fb4792f091e608a0a1d353dfdf07ef55a719db5 ]

While running the self-tests on a KASAN enabled kernel, I observed a
slab-out-of-bounds splat very similar to the one reported in
commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in
 fib6_nh_flush_exceptions").

We additionally need to take care of fib6_metrics initialization
failure when the caller provides an nh.

The fix is similar, explicitly free the route instead of calling
fib6_info_release on a half-initialized object.

Fixes: f88d8ea67fbdb ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv6/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ccff4738313c..62db3c98424b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3640,7 +3640,7 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 		err = PTR_ERR(rt->fib6_metrics);
 		/* Do not leave garbage there. */
 		rt->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
-		goto out;
+		goto out_free;
 	}
 
 	if (cfg->fc_flags & RTF_ADDRCONF)
-- 
2.30.2