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tcp: Move TCP-AO bits from cookie_v[46]_check() to tcp_ao_syncookie().
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We initialise treq->af_specific in cookie_tcp_reqsk_alloc() so that
we can look up a key later in tcp_create_openreq_child().

Initially, that change was added for MD5 by commit ba5a4fd ("tcp:
make sure treq->af_specific is initialized"), but it has not been used
since commit d0f2b7a ("tcp: Disable header prediction for MD5
flow.").

Now, treq->af_specific is used only by TCP-AO, so, we can move that
initialisation into tcp_ao_syncookie().

In addition to that, l3index in cookie_v[46]_check() is only used for
tcp_ao_syncookie(), so let's move it as well.

While at it, we move down tcp_ao_syncookie() in cookie_v4_check() so
that it will be called after security_inet_conn_request() to make
functions order consistent with cookie_v6_check().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231129022924.96156-7-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Kuniyuki Iwashima authored and Jakub Kicinski committed Nov 30, 2023
1 parent efce3d1 commit 7b0f570
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Showing 5 changed files with 22 additions and 24 deletions.
1 change: 0 additions & 1 deletion include/net/tcp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -494,7 +494,6 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th);
struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb);
struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
const struct tcp_request_sock_ops *af_ops,
struct sock *sk, struct sk_buff *skb);
#ifdef CONFIG_SYN_COOKIES

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6 changes: 2 additions & 4 deletions include/net/tcp_ao.h
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Original file line number Diff line number Diff line change
Expand Up @@ -265,8 +265,7 @@ void tcp_ao_established(struct sock *sk);
void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb);
void tcp_ao_connect_init(struct sock *sk);
void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
struct tcp_request_sock *treq,
unsigned short int family, int l3index);
struct request_sock *req, unsigned short int family);
#else /* CONFIG_TCP_AO */

static inline int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
Expand All @@ -277,8 +276,7 @@ static inline int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
}

static inline void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
struct tcp_request_sock *treq,
unsigned short int family, int l3index)
struct request_sock *req, unsigned short int family)
{
}

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16 changes: 4 additions & 12 deletions net/ipv4/syncookies.c
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Original file line number Diff line number Diff line change
Expand Up @@ -286,9 +286,7 @@ bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt,
EXPORT_SYMBOL(cookie_ecn_ok);

struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
const struct tcp_request_sock_ops *af_ops,
struct sock *sk,
struct sk_buff *skb)
struct sock *sk, struct sk_buff *skb)
{
struct tcp_request_sock *treq;
struct request_sock *req;
Expand All @@ -303,9 +301,6 @@ struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,

treq = tcp_rsk(req);

/* treq->af_specific might be used to perform TCP_MD5 lookup */
treq->af_specific = af_ops;

treq->syn_tos = TCP_SKB_CB(skb)->ip_dsfield;
treq->req_usec_ts = false;

Expand Down Expand Up @@ -345,7 +340,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
struct rtable *rt;
__u8 rcv_wscale;
u32 tsoff = 0;
int l3index;

if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||
!th->ack || th->rst)
Expand Down Expand Up @@ -376,8 +370,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
if (!cookie_timestamp_decode(net, &tcp_opt))
goto out;

req = cookie_tcp_reqsk_alloc(&tcp_request_sock_ops,
&tcp_request_sock_ipv4_ops, sk, skb);
req = cookie_tcp_reqsk_alloc(&tcp_request_sock_ops, sk, skb);
if (!req)
goto out_drop;

Expand Down Expand Up @@ -406,9 +399,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)

ireq->ir_iif = inet_request_bound_dev_if(sk, skb);

l3index = l3mdev_master_ifindex_by_index(net, ireq->ir_iif);
tcp_ao_syncookie(sk, skb, treq, AF_INET, l3index);

/* We throwed the options of the initial SYN away, so we hope
* the ACK carries the same options again (see RFC1122 4.2.3.8)
*/
Expand All @@ -417,6 +407,8 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
if (security_inet_conn_request(sk, skb, req))
goto out_free;

tcp_ao_syncookie(sk, skb, req, AF_INET);

req->num_retrans = 0;

/*
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16 changes: 14 additions & 2 deletions net/ipv4/tcp_ao.c
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Original file line number Diff line number Diff line change
Expand Up @@ -844,18 +844,30 @@ static struct tcp_ao_key *tcp_ao_inbound_lookup(unsigned short int family,
}

void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
struct tcp_request_sock *treq,
unsigned short int family, int l3index)
struct request_sock *req, unsigned short int family)
{
struct tcp_request_sock *treq = tcp_rsk(req);
const struct tcphdr *th = tcp_hdr(skb);
const struct tcp_ao_hdr *aoh;
struct tcp_ao_key *key;
int l3index;

/* treq->af_specific is used to perform TCP_AO lookup
* in tcp_create_openreq_child().
*/
#if IS_ENABLED(CONFIG_IPV6)
if (family == AF_INET6)
treq->af_specific = &tcp_request_sock_ipv6_ops;
else
#endif
treq->af_specific = &tcp_request_sock_ipv4_ops;

treq->maclen = 0;

if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh)
return;

l3index = l3mdev_master_ifindex_by_index(sock_net(sk), inet_rsk(req)->ir_iif);
key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid, l3index);
if (!key)
/* Key not found, continue without TCP-AO */
Expand Down
7 changes: 2 additions & 5 deletions net/ipv6/syncookies.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -142,7 +142,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
int full_space, mss;
__u8 rcv_wscale;
u32 tsoff = 0;
int l3index;

if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||
!th->ack || th->rst)
Expand Down Expand Up @@ -173,8 +172,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
if (!cookie_timestamp_decode(net, &tcp_opt))
goto out;

req = cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops,
&tcp_request_sock_ipv6_ops, sk, skb);
req = cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops, sk, skb);
if (!req)
goto out_drop;

Expand Down Expand Up @@ -218,8 +216,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
treq->ts_off = tsoff;
treq->txhash = net_tx_rndhash();

l3index = l3mdev_master_ifindex_by_index(net, ireq->ir_iif);
tcp_ao_syncookie(sk, skb, treq, AF_INET6, l3index);
tcp_ao_syncookie(sk, skb, req, AF_INET6);

if (IS_ENABLED(CONFIG_SMC))
ireq->smc_ok = 0;
Expand Down

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