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From:   Azeem Shaikh <azeemshaikh38@gmail.com>
To:     Pablo Neira Ayuso <pablo@netfilter.org>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Florian Westphal <fw@strlen.de>
Cc:     linux-hardening@vger.kernel.org,
        Azeem Shaikh <azeemshaikh38@gmail.com>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org
Subject: [PATCH] netfilter: ipset: Replace strlcpy with strscpy
Date:   Tue, 13 Jun 2023 00:34:37 +0000
Message-ID: <20230613003437.3538694-1-azeemshaikh38@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().

Direct replacement is safe here since return value from all
callers of STRLCPY macro were ignored.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 net/netfilter/ipset/ip_set_hash_netiface.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_netiface.c b/net/netfilter/ipset/ip_set_hash_netiface.c
index 031073286236..95aeb31c60e0 100644
--- a/net/netfilter/ipset/ip_set_hash_netiface.c
+++ b/net/netfilter/ipset/ip_set_hash_netiface.c
@@ -40,7 +40,7 @@ MODULE_ALIAS("ip_set_hash:net,iface");
 #define IP_SET_HASH_WITH_MULTI
 #define IP_SET_HASH_WITH_NET0
 
-#define STRLCPY(a, b)	strlcpy(a, b, IFNAMSIZ)
+#define STRSCPY(a, b)	strscpy(a, b, IFNAMSIZ)
 
 /* IPv4 variant */
 
@@ -182,11 +182,11 @@ hash_netiface4_kadt(struct ip_set *set, const struct sk_buff *skb,
 
 		if (!eiface)
 			return -EINVAL;
-		STRLCPY(e.iface, eiface);
+		STRSCPY(e.iface, eiface);
 		e.physdev = 1;
 #endif
 	} else {
-		STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+		STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
 	}
 
 	if (strlen(e.iface) == 0)
@@ -400,11 +400,11 @@ hash_netiface6_kadt(struct ip_set *set, const struct sk_buff *skb,
 
 		if (!eiface)
 			return -EINVAL;
-		STRLCPY(e.iface, eiface);
+		STRSCPY(e.iface, eiface);
 		e.physdev = 1;
 #endif
 	} else {
-		STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+		STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
 	}
 
 	if (strlen(e.iface) == 0)
-- 
2.41.0.162.gfafddb0af9-goog