This fixes a crash where we assign tcp_prot to IPv6 sockets instead
of tcpv6_prot.

Previously we overwrote the sk->prot field with tcp_prot even in the
AF_INET6 case. This patch ensures the correct tcp_prot and tcpv6_prot
are used.

Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support")
Reported-by: [email protected]
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Wei Wang <[email protected]>
---
 kernel/bpf/sockmap.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 95a84b2..d16b5a3 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -41,6 +41,7 @@
 #include <linux/mm.h>
 #include <net/strparser.h>
 #include <net/tcp.h>
+#include <net/transp_v6.h>
 #include <linux/ptr_ring.h>
 #include <net/inet_common.h>
 #include <linux/sched/signal.h>
@@ -134,6 +135,8 @@ static bool bpf_tcp_stream_read(const struct sock *sk)
 }
 
 static struct proto tcp_bpf_proto;
+static struct proto tcpv6_bpf_proto;
+
 static int bpf_tcp_init(struct sock *sk)
 {
        struct smap_psock *psock;
@@ -154,13 +157,21 @@ static int bpf_tcp_init(struct sock *sk)
        psock->sk_proto = sk->sk_prot;
 
        if (psock->bpf_tx_msg) {
+               tcpv6_bpf_proto.sendmsg = bpf_tcp_sendmsg;
+               tcpv6_bpf_proto.sendpage = bpf_tcp_sendpage;
+               tcpv6_bpf_proto.recvmsg = bpf_tcp_recvmsg;
+               tcpv6_bpf_proto.stream_memory_read = bpf_tcp_stream_read;
                tcp_bpf_proto.sendmsg = bpf_tcp_sendmsg;
                tcp_bpf_proto.sendpage = bpf_tcp_sendpage;
                tcp_bpf_proto.recvmsg = bpf_tcp_recvmsg;
                tcp_bpf_proto.stream_memory_read = bpf_tcp_stream_read;
        }
 
-       sk->sk_prot = &tcp_bpf_proto;
+       if (sk->sk_family == AF_INET6)
+               sk->sk_prot = &tcpv6_bpf_proto;
+       else
+               sk->sk_prot = &tcp_bpf_proto;
+
        rcu_read_unlock();
        return 0;
 }
@@ -1072,6 +1083,8 @@ static int bpf_tcp_ulp_register(void)
 {
        tcp_bpf_proto = tcp_prot;
        tcp_bpf_proto.close = bpf_tcp_close;
+       tcpv6_bpf_proto = tcpv6_prot;
+       tcpv6_bpf_proto.close = bpf_tcp_close;
        /* Once BPF TX ULP is registered it is never unregistered. It
         * will be in the ULP list for the lifetime of the system. Doing
         * duplicate registers is not a problem.

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