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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, Johannes Berg <johannes.berg@intel.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.8 14/16] netlink: fix state reallocation in policy export
Date:   Wed, 26 Aug 2020 14:02:51 +0200
Message-Id: <20200826114911.918676140@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit d1fb55592909ea249af70170c7a52e637009564d ]

Evidently, when I did this previously, we didn't have more than
10 policies and didn't run into the reallocation path, because
it's missing a memset() for the unused policies. Fix that.

Fixes: d07dcf9aadd6 ("netlink: add infrastructure to expose policies to userspace")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netlink/policy.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/netlink/policy.c
+++ b/net/netlink/policy.c
@@ -51,6 +51,9 @@ static int add_policy(struct nl_policy_d
 	if (!state)
 		return -ENOMEM;
 
+	memset(&state->policies[state->n_alloc], 0,
+	       flex_array_size(state, policies, n_alloc - state->n_alloc));
+
 	state->policies[state->n_alloc].policy = policy;
 	state->policies[state->n_alloc].maxtype = maxtype;
 	state->n_alloc = n_alloc;