[PATCH 5.13 118/223] ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions

From: Greg Kroah-Hartman
Date: Mon Jul 26 2021 - 12:33:00 EST

From: Paolo Abeni <pabeni@xxxxxxxxxx>

[ 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

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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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 d417e514bd52..09e84161b731 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3642,7 +3642,7 @@ 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)