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Date: Thu, 18 Aug 2022 17:59:46 +0100
From: Dmitry Safonov <dima@...sta.com>
To: Eric Dumazet <edumazet@...gle.com>,
"David S. Miller" <davem@...emloft.net>,
linux-kernel@...r.kernel.org
Cc: Dmitry Safonov <dima@...sta.com>,
Andy Lutomirski <luto@...capital.net>,
Ard Biesheuvel <ardb@...nel.org>,
Bob Gilligan <gilligan@...sta.com>,
David Ahern <dsahern@...nel.org>,
Dmitry Safonov <0x7f454c46@...il.com>,
Eric Biggers <ebiggers@...nel.org>,
Francesco Ruggeri <fruggeri@...sta.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Ivan Delalande <colona@...sta.com>,
Jakub Kicinski <kuba@...nel.org>,
Leonard Crestez <cdleonard@...il.com>,
Paolo Abeni <pabeni@...hat.com>,
Salam Noureddine <noureddine@...sta.com>,
Shuah Khan <shuah@...nel.org>, netdev@...r.kernel.org,
linux-crypto@...r.kernel.org
Subject: [PATCH 12/31] net/tcp: Add tcp_parse_auth_options()
Introduce a helper that:
(1) shares the common code with TCP-MD5 header options parsing
(2) looks for hash signature only once for both TCP-MD5 and TCP-AO
(3) fails with -EEXIST if any TCP sign option is present twice, see
RFC5925 (2.2):
">> A single TCP segment MUST NOT have more than one TCP-AO in its
options sequence. When multiple TCP-AOs appear, TCP MUST discard
the segment."
Co-developed-by: Francesco Ruggeri <fruggeri@...sta.com>
Signed-off-by: Francesco Ruggeri <fruggeri@...sta.com>
Co-developed-by: Salam Noureddine <noureddine@...sta.com>
Signed-off-by: Salam Noureddine <noureddine@...sta.com>
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
include/net/tcp.h | 24 +++++++++++++++++++++++-
include/net/tcp_ao.h | 3 +++
net/ipv4/tcp.c | 3 ++-
net/ipv4/tcp_input.c | 39 +++++++++++++++++++++++++++++----------
net/ipv4/tcp_ipv4.c | 21 ++++++++++++++-------
net/ipv6/tcp_ipv6.c | 17 +++++++++++------
6 files changed, 82 insertions(+), 25 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d91a963f430d..061fe8471bfc 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -428,7 +428,6 @@ int tcp_mmap(struct file *file, struct socket *sock,
void tcp_parse_options(const struct net *net, const struct sk_buff *skb,
struct tcp_options_received *opt_rx,
int estab, struct tcp_fastopen_cookie *foc);
-const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
/*
* BPF SKB-less helpers
@@ -2467,4 +2466,27 @@ static inline u64 tcp_transmit_time(const struct sock *sk)
return 0;
}
+static inline int tcp_parse_auth_options(const struct tcphdr *th,
+ const u8 **md5_hash, const struct tcp_ao_hdr **aoh)
+{
+ const u8 *md5_tmp, *ao_tmp;
+ int ret;
+
+ ret = tcp_do_parse_auth_options(th, &md5_tmp, &ao_tmp);
+ if (ret)
+ return ret;
+
+ if (md5_hash)
+ *md5_hash = md5_tmp;
+
+ if (aoh) {
+ if (!ao_tmp)
+ *aoh = NULL;
+ else
+ *aoh = (struct tcp_ao_hdr *)(ao_tmp - 2);
+ }
+
+ return 0;
+}
+
#endif /* _TCP_H */
diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h
index f840b693d038..b5516c83e489 100644
--- a/include/net/tcp_ao.h
+++ b/include/net/tcp_ao.h
@@ -87,6 +87,9 @@ struct tcp_ao_info {
u32 rcv_sne_seq;
};
+int tcp_do_parse_auth_options(const struct tcphdr *th,
+ const u8 **md5_hash, const u8 **ao_hash);
+
#ifdef CONFIG_TCP_AO
/* TCP-AO structures and functions */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 85854b8afc47..a5e94d8e8450 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4526,7 +4526,8 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
l3index = sdif ? dif : 0;
hash_expected = tcp_md5_do_lookup(sk, l3index, saddr, family);
- hash_location = tcp_parse_md5sig_option(th);
+ if (tcp_parse_auth_options(th, &hash_location, NULL))
+ return true;
/* We've parsed the options - do we have a hash? */
if (!hash_expected && !hash_location)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a5d6c7f1ead3..27e95876cba1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4188,39 +4188,58 @@ static bool tcp_fast_parse_options(const struct net *net,
return true;
}
-#ifdef CONFIG_TCP_MD5SIG
+#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
/*
- * Parse MD5 Signature option
+ * Parse Signature options
*/
-const u8 *tcp_parse_md5sig_option(const struct tcphdr *th)
+int tcp_do_parse_auth_options(const struct tcphdr *th,
+ const u8 **md5_hash, const u8 **ao_hash)
{
int length = (th->doff << 2) - sizeof(*th);
const u8 *ptr = (const u8 *)(th + 1);
+ unsigned int minlen = TCPOLEN_MD5SIG;
+
+ if (IS_ENABLED(CONFIG_TCP_AO))
+ minlen = sizeof(struct tcp_ao_hdr) + 1;
+
+ *md5_hash = NULL;
+ *ao_hash = NULL;
/* If not enough data remaining, we can short cut */
- while (length >= TCPOLEN_MD5SIG) {
+ while (length >= minlen) {
int opcode = *ptr++;
int opsize;
switch (opcode) {
case TCPOPT_EOL:
- return NULL;
+ return 0;
case TCPOPT_NOP:
length--;
continue;
default:
opsize = *ptr++;
if (opsize < 2 || opsize > length)
- return NULL;
- if (opcode == TCPOPT_MD5SIG)
- return opsize == TCPOLEN_MD5SIG ? ptr : NULL;
+ return -EINVAL;
+ if (opcode == TCPOPT_MD5SIG) {
+ if (opsize != TCPOLEN_MD5SIG)
+ return -EINVAL;
+ if (unlikely(*md5_hash || *ao_hash))
+ return -EEXIST;
+ *md5_hash = ptr;
+ } else if (opcode == TCPOPT_AO) {
+ if (opsize <= sizeof(struct tcp_ao_hdr))
+ return -EINVAL;
+ if (unlikely(*md5_hash || *ao_hash))
+ return -EEXIST;
+ *ao_hash = ptr;
+ }
}
ptr += opsize - 2;
length -= opsize;
}
- return NULL;
+ return 0;
}
-EXPORT_SYMBOL(tcp_parse_md5sig_option);
+EXPORT_SYMBOL(tcp_do_parse_auth_options);
#endif
/* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index f6fe9ec1c99d..034549c73beb 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -660,7 +660,9 @@ EXPORT_SYMBOL(tcp_v4_send_check);
* Exception: precedence violation. We do not implement it in any case.
*/
-#ifdef CONFIG_TCP_MD5SIG
+#ifdef CONFIG_TCP_AO
+#define OPTION_BYTES MAX_TCP_OPTION_SPACE
+#elif CONFIG_TCP_MD5SIG
#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
#else
#define OPTION_BYTES sizeof(__be32)
@@ -676,7 +678,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
struct ip_reply_arg arg;
#ifdef CONFIG_TCP_MD5SIG
struct tcp_md5sig_key *key = NULL;
- const __u8 *hash_location = NULL;
+ const __u8 *md5_hash_location = NULL;
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
@@ -715,9 +717,14 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
arg.iov[0].iov_len = sizeof(rep.th);
net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
-#ifdef CONFIG_TCP_MD5SIG
+#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
+ /* Invalid TCP option size or twice included auth */
+ if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, NULL))
+ return;
+
rcu_read_lock();
- hash_location = tcp_parse_md5sig_option(th);
+#endif
+#ifdef CONFIG_TCP_MD5SIG
if (sk && sk_fullsock(sk)) {
const union tcp_md5_addr *addr;
int l3index;
@@ -728,7 +735,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
- } else if (hash_location) {
+ } else if (md5_hash_location) {
const union tcp_md5_addr *addr;
int sdif = tcp_v4_sdif(skb);
int dif = inet_iif(skb);
@@ -760,7 +767,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
- if (genhash || memcmp(hash_location, newhash, 16) != 0)
+ if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
goto out;
}
@@ -835,7 +842,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
local_bh_enable();
-#ifdef CONFIG_TCP_MD5SIG
+#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
out:
rcu_read_unlock();
#endif
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index b5fa5ae53a47..ba968e856ca9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -982,7 +982,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
u32 seq = 0, ack_seq = 0;
struct tcp_md5sig_key *key = NULL;
#ifdef CONFIG_TCP_MD5SIG
- const __u8 *hash_location = NULL;
+ const __u8 *md5_hash_location = NULL;
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
@@ -1002,9 +1002,14 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
return;
net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
-#ifdef CONFIG_TCP_MD5SIG
+#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
+ /* Invalid TCP option size or twice included auth */
+ if (tcp_parse_auth_options(th, &md5_hash_location, NULL))
+ return;
+
rcu_read_lock();
- hash_location = tcp_parse_md5sig_option(th);
+#endif
+#ifdef CONFIG_TCP_MD5SIG
if (sk && sk_fullsock(sk)) {
int l3index;
@@ -1013,7 +1018,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
*/
l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
- } else if (hash_location) {
+ } else if (md5_hash_location) {
int dif = tcp_v6_iif_l3_slave(skb);
int sdif = tcp_v6_sdif(skb);
int l3index;
@@ -1043,7 +1048,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
goto out;
genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
- if (genhash || memcmp(hash_location, newhash, 16) != 0)
+ if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
goto out;
}
#endif
@@ -1076,7 +1081,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1,
ipv6_get_dsfield(ipv6h), label, priority);
-#ifdef CONFIG_TCP_MD5SIG
+#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
out:
rcu_read_unlock();
#endif
--
2.37.2
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