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sctp: process sk_reuseport in sctp_get_port_local
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When socks' sk_reuseport is set, the same port and address are allowed
to be bound into these socks who have the same uid.

Note that the difference from sk_reuse is that it allows multiple socks
to listen on the same port and address.

Acked-by: Neil Horman <[email protected]>
Signed-off-by: Xin Long <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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lxin authored and davem330 committed Nov 12, 2018
1 parent 76c6d98 commit 6ba8457
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Showing 2 changed files with 36 additions and 14 deletions.
4 changes: 3 additions & 1 deletion include/net/sctp/structs.h
Original file line number Diff line number Diff line change
Expand Up @@ -96,7 +96,9 @@ struct sctp_stream;

struct sctp_bind_bucket {
unsigned short port;
unsigned short fastreuse;
signed char fastreuse;
signed char fastreuseport;
kuid_t fastuid;
struct hlist_node node;
struct hlist_head owner;
struct net *net;
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46 changes: 33 additions & 13 deletions net/sctp/socket.c
Original file line number Diff line number Diff line change
Expand Up @@ -7644,8 +7644,10 @@ static struct sctp_bind_bucket *sctp_bucket_create(

static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
{
bool reuse = (sk->sk_reuse || sctp_sk(sk)->reuse);
struct sctp_sock *sp = sctp_sk(sk);
bool reuse = (sk->sk_reuse || sp->reuse);
struct sctp_bind_hashbucket *head; /* hash list */
kuid_t uid = sock_i_uid(sk);
struct sctp_bind_bucket *pp;
unsigned short snum;
int ret;
Expand Down Expand Up @@ -7721,7 +7723,10 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)

pr_debug("%s: found a possible match\n", __func__);

if (pp->fastreuse && reuse && sk->sk_state != SCTP_SS_LISTENING)
if ((pp->fastreuse && reuse &&
sk->sk_state != SCTP_SS_LISTENING) ||
(pp->fastreuseport && sk->sk_reuseport &&
uid_eq(pp->fastuid, uid)))
goto success;

/* Run through the list of sockets bound to the port
Expand All @@ -7735,16 +7740,18 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
* in an endpoint.
*/
sk_for_each_bound(sk2, &pp->owner) {
struct sctp_endpoint *ep2;
ep2 = sctp_sk(sk2)->ep;
struct sctp_sock *sp2 = sctp_sk(sk2);
struct sctp_endpoint *ep2 = sp2->ep;

if (sk == sk2 ||
(reuse && (sk2->sk_reuse || sctp_sk(sk2)->reuse) &&
sk2->sk_state != SCTP_SS_LISTENING))
(reuse && (sk2->sk_reuse || sp2->reuse) &&
sk2->sk_state != SCTP_SS_LISTENING) ||
(sk->sk_reuseport && sk2->sk_reuseport &&
uid_eq(uid, sock_i_uid(sk2))))
continue;

if (sctp_bind_addr_conflict(&ep2->base.bind_addr, addr,
sctp_sk(sk2), sctp_sk(sk))) {
if (sctp_bind_addr_conflict(&ep2->base.bind_addr,
addr, sp2, sp)) {
ret = (long)sk2;
goto fail_unlock;
}
Expand All @@ -7767,19 +7774,32 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
pp->fastreuse = 1;
else
pp->fastreuse = 0;
} else if (pp->fastreuse &&
(!reuse || sk->sk_state == SCTP_SS_LISTENING))
pp->fastreuse = 0;

if (sk->sk_reuseport) {
pp->fastreuseport = 1;
pp->fastuid = uid;
} else {
pp->fastreuseport = 0;
}
} else {
if (pp->fastreuse &&
(!reuse || sk->sk_state == SCTP_SS_LISTENING))
pp->fastreuse = 0;

if (pp->fastreuseport &&
(!sk->sk_reuseport || !uid_eq(pp->fastuid, uid)))
pp->fastreuseport = 0;
}

/* We are set, so fill up all the data in the hash table
* entry, tie the socket list information with the rest of the
* sockets FIXME: Blurry, NPI (ipg).
*/
success:
if (!sctp_sk(sk)->bind_hash) {
if (!sp->bind_hash) {
inet_sk(sk)->inet_num = snum;
sk_add_bind_node(sk, &pp->owner);
sctp_sk(sk)->bind_hash = pp;
sp->bind_hash = pp;
}
ret = 0;

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