[PATCH 5.4 059/108] ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions

Greg Kroah-Hartman
2021-07-26T16:15:29Z

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 b903fe28ce50..d6fc22f7d7a6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3655,7 +3655,7 @@ 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