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From:   Nathan Chancellor <nathan@kernel.org>
To:     Pablo Neira Ayuso <pablo@netfilter.org>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Florian Westphal <fw@strlen.de>
Cc:     netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>,
        kernel test robot <lkp@intel.com>
Subject: [PATCH] netfilter: ipset: Fix maximal range check in hash_ipportnet4_uadt()
Date:   Tue,  3 Aug 2021 12:18:13 -0700
Message-Id: <20210803191813.282980-1-nathan@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Clang warns:

net/netfilter/ipset/ip_set_hash_ipportnet.c:249:29: warning: variable
'port_to' is uninitialized when used here [-Wuninitialized]
        if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
                                   ^~~~~~~
net/netfilter/ipset/ip_set_hash_ipportnet.c:167:45: note: initialize the
variable 'port_to' to silence this warning
        u32 ip = 0, ip_to = 0, p = 0, port, port_to;
                                                   ^
                                                    = 0
net/netfilter/ipset/ip_set_hash_ipportnet.c:249:39: warning: variable
'port' is uninitialized when used here [-Wuninitialized]
        if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
                                             ^~~~
net/netfilter/ipset/ip_set_hash_ipportnet.c:167:36: note: initialize the
variable 'port' to silence this warning
        u32 ip = 0, ip_to = 0, p = 0, port, port_to;
                                          ^
                                           = 0
2 warnings generated.

The range check was added before port and port_to are initialized.
Shuffle the check after the initialization so that the check works
properly.

Fixes: 7fb6c63025ff ("netfilter: ipset: Limit the maximal range of consecutive elements to add/delete")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 net/netfilter/ipset/ip_set_hash_ipportnet.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_ipportnet.c b/net/netfilter/ipset/ip_set_hash_ipportnet.c
index b293aa1ff258..7df94f437f60 100644
--- a/net/netfilter/ipset/ip_set_hash_ipportnet.c
+++ b/net/netfilter/ipset/ip_set_hash_ipportnet.c
@@ -246,9 +246,6 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
 		ip_set_mask_from_to(ip, ip_to, cidr);
 	}
 
-	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
-		return -ERANGE;
-
 	port_to = port = ntohs(e.port);
 	if (tb[IPSET_ATTR_PORT_TO]) {
 		port_to = ip_set_get_h16(tb[IPSET_ATTR_PORT_TO]);
@@ -256,6 +253,9 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
 			swap(port, port_to);
 	}
 
+	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
+		return -ERANGE;
+
 	ip2_to = ip2_from;
 	if (tb[IPSET_ATTR_IP2_TO]) {
 		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP2_TO], &ip2_to);

base-commit: 4d3fc8ead710a06c98d36f382777c6a843a83b7c
-- 
2.33.0.rc0