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inpcb: Factor out parts of in6_pcbbind() and in_pcbbind_setup()

Browse source 
A large portion of these functions just determines whether the inpcb can
bind to the address/port.  This portion has no side effects, so is a
good candidate to move into its own helper function.  This patch does
so, making the callers less complicated and reducing indentation.

While moving this code, also make some changes:
- Load socket options (SO_REUSEADDR etc.) only once.  There is nothing
  preventing another thread from toggling the socket options, so make
  this function easier to reason about by avoiding races.
- When checking whether the bind address is an interface address, make a
  separate sockaddr rather than temporarily modifying the one passed to
  in_pcbbind().

Reviewed by:	ae, glebius
MFC after:	1 month
Sponsored by:	Klara, Inc.
Sponsored by:	Stormshield
Differential Revision:	https://reviews.freebsd.org/D47590
This commit is contained in:
Mark Johnston 2024-12-05 15:00:13 +00:00
parent fcb5e8d0c1
commit 01f8ce8324
2 changed files with 242 additions and 192 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

172
sys/netinet/in_pcb.c
View file

@ -861,6 +861,93 @@ in_pcb_lport(struct inpcb *inp, struct in_addr *laddrp, u_short *lportp,
#endif /* INET || INET6 */
#ifdef INET
/*
* Determine whether the inpcb can be bound to the specified address/port tuple.
*/
static int
in_pcbbind_avail(struct inpcb *inp, const struct in_addr laddr,
const u_short lport, int sooptions, int lookupflags, struct ucred *cred)
{
int reuseport, reuseport_lb;
INP_LOCK_ASSERT(inp);
INP_HASH_LOCK_ASSERT(inp->inp_pcbinfo);
reuseport = (sooptions & SO_REUSEPORT);
reuseport_lb = (sooptions & SO_REUSEPORT_LB);
if (IN_MULTICAST(ntohl(laddr.s_addr))) {
/*
* Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
* allow complete duplication of binding if
* SO_REUSEPORT is set, or if SO_REUSEADDR is set
* and a multicast address is bound on both
* new and duplicated sockets.
*/
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT)) != 0)
reuseport = SO_REUSEADDR | SO_REUSEPORT;
/*
* XXX: How to deal with SO_REUSEPORT_LB here?
* Treat same as SO_REUSEPORT for now.
*/
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT_LB)) != 0)
reuseport_lb = SO_REUSEADDR | SO_REUSEPORT_LB;
} else if (!in_nullhost(laddr)) {
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_len = sizeof(sin);
sin.sin_addr = laddr;
/*
* Is the address a local IP address?
* If INP_BINDANY is set, then the socket may be bound
* to any endpoint address, local or not.
*/
if ((inp->inp_flags & INP_BINDANY) == 0 &&
ifa_ifwithaddr_check((const struct sockaddr *)&sin) == 0)
return (EADDRNOTAVAIL);
}
if (lport != 0) {
struct inpcb *t;
if (ntohs(lport) <= V_ipport_reservedhigh &&
ntohs(lport) >= V_ipport_reservedlow &&
priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT))
return (EACCES);
if (!IN_MULTICAST(ntohl(laddr.s_addr)) &&
priv_check_cred(inp->inp_cred, PRIV_NETINET_REUSEPORT) != 0) {
t = in_pcblookup_local(inp->inp_pcbinfo, laddr, lport,
INPLOOKUP_WILDCARD, cred);
if (t != NULL &&
(inp->inp_socket->so_type != SOCK_STREAM ||
in_nullhost(t->inp_faddr)) &&
(!in_nullhost(laddr) ||
!in_nullhost(t->inp_laddr) ||
(t->inp_socket->so_options & SO_REUSEPORT) ||
(t->inp_socket->so_options & SO_REUSEPORT_LB) == 0) &&
(inp->inp_cred->cr_uid != t->inp_cred->cr_uid))
return (EADDRINUSE);
}
t = in_pcblookup_local(inp->inp_pcbinfo, laddr, lport,
lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0) {
#ifdef INET6
if (!in_nullhost(laddr) ||
!in_nullhost(t->inp_laddr) ||
(inp->inp_vflag & INP_IPV6PROTO) == 0 ||
(t->inp_vflag & INP_IPV6PROTO) == 0)
#endif
return (EADDRINUSE);
}
}
return (0);
}
/*
* Set up a bind operation on a PCB, performing port allocation
* as required, but do not actually modify the PCB. Callers can
@ -878,15 +965,9 @@ in_pcbbind_setup(struct inpcb *inp, struct sockaddr_in *sin, in_addr_t *laddrp,
struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
struct in_addr laddr;
u_short lport = 0;
int lookupflags = 0, reuseport = (so->so_options & SO_REUSEPORT);
int lookupflags, sooptions;
int error;
/*
* XXX: Maybe we could let SO_REUSEPORT_LB set SO_REUSEPORT bit here
* so that we don't have to add to the (already messy) code below.
*/
int reuseport_lb = (so->so_options & SO_REUSEPORT_LB);
/*
* No state changes, so read locks are sufficient here.
*/
@ -896,7 +977,10 @@ in_pcbbind_setup(struct inpcb *inp, struct sockaddr_in *sin, in_addr_t *laddrp,
laddr.s_addr = *laddrp;
if (sin != NULL && laddr.s_addr != INADDR_ANY)
return (EINVAL);
if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT|SO_REUSEPORT_LB)) == 0)
lookupflags = 0;
sooptions = atomic_load_int(&so->so_options);
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT | SO_REUSEPORT_LB)) == 0)
lookupflags = INPLOOKUP_WILDCARD;
if (sin == NULL) {
if ((error = prison_local_ip4(cred, &laddr)) != 0)
@ -918,73 +1002,11 @@ in_pcbbind_setup(struct inpcb *inp, struct sockaddr_in *sin, in_addr_t *laddrp,
}
laddr = sin->sin_addr;
/* NB: lport is left as 0 if the port isn't being changed. */
if (IN_MULTICAST(ntohl(laddr.s_addr))) {
/*
* Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
* allow complete duplication of binding if
* SO_REUSEPORT is set, or if SO_REUSEADDR is set
* and a multicast address is bound on both
* new and duplicated sockets.
*/
if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) != 0)
reuseport = SO_REUSEADDR|SO_REUSEPORT;
/*
* XXX: How to deal with SO_REUSEPORT_LB here?
* Treat same as SO_REUSEPORT for now.
*/
if ((so->so_options &
(SO_REUSEADDR|SO_REUSEPORT_LB)) != 0)
reuseport_lb = SO_REUSEADDR|SO_REUSEPORT_LB;
} else if (!in_nullhost(laddr)) {
sin->sin_port = 0; /* yech... */
bzero(&sin->sin_zero, sizeof(sin->sin_zero));
/*
* Is the address a local IP address?
* If INP_BINDANY is set, then the socket may be bound
* to any endpoint address, local or not.
*/
if ((inp->inp_flags & INP_BINDANY) == 0 &&
ifa_ifwithaddr_check(
(const struct sockaddr *)sin) == 0)
return (EADDRNOTAVAIL);
}
if (lport) {
struct inpcb *t;
if (ntohs(lport) <= V_ipport_reservedhigh &&
ntohs(lport) >= V_ipport_reservedlow &&
priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT))
return (EACCES);
if (!IN_MULTICAST(ntohl(laddr.s_addr)) &&
priv_check_cred(inp->inp_cred, PRIV_NETINET_REUSEPORT) != 0) {
t = in_pcblookup_local(pcbinfo, laddr, lport,
INPLOOKUP_WILDCARD, cred);
if (t != NULL &&
(so->so_type != SOCK_STREAM ||
in_nullhost(t->inp_faddr)) &&
(!in_nullhost(laddr) ||
!in_nullhost(t->inp_laddr) ||
(t->inp_socket->so_options & SO_REUSEPORT) ||
(t->inp_socket->so_options & SO_REUSEPORT_LB) == 0) &&
(inp->inp_cred->cr_uid !=
t->inp_cred->cr_uid))
return (EADDRINUSE);
}
t = in_pcblookup_local(pcbinfo, laddr, lport,
lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0) {
#ifdef INET6
if (!in_nullhost(laddr) ||
!in_nullhost(t->inp_laddr) ||
(inp->inp_vflag & INP_IPV6PROTO) == 0 ||
(t->inp_vflag & INP_IPV6PROTO) == 0)
#endif
return (EADDRINUSE);
}
}
/* See if this address/port combo is available. */
error = in_pcbbind_avail(inp, laddr, lport, sooptions,
lookupflags, cred);
if (error != 0)
return (error);
}
if (*lportp != 0)
lport = *lportp;

262
sys/netinet6/in6_pcb.c
View file

@ -160,27 +160,157 @@ in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct ucred *cred)
return (0);
}
/*
* Determine whether the inpcb can be bound to the specified address/port tuple.
*/
static int
in6_pcbbind_avail(struct inpcb *inp, const struct sockaddr_in6 *sin6,
int sooptions, int lookupflags, struct ucred *cred)
{
const struct in6_addr *laddr;
int reuseport, reuseport_lb;
u_short lport;
INP_LOCK_ASSERT(inp);
INP_HASH_LOCK_ASSERT(inp->inp_pcbinfo);
laddr = &sin6->sin6_addr;
lport = sin6->sin6_port;
reuseport = (sooptions & SO_REUSEPORT);
reuseport_lb = (sooptions & SO_REUSEPORT_LB);
if (IN6_IS_ADDR_MULTICAST(laddr)) {
/*
* Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
* allow compepte duplication of binding if
* SO_REUSEPORT is set, or if SO_REUSEADDR is set
* and a multicast address is bound on both
* new and duplicated sockets.
*/
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT)) != 0)
reuseport = SO_REUSEADDR | SO_REUSEPORT;
/*
* XXX: How to deal with SO_REUSEPORT_LB here?
* Treat same as SO_REUSEPORT for now.
*/
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT_LB)) != 0)
reuseport_lb = SO_REUSEADDR | SO_REUSEPORT_LB;
} else if (!IN6_IS_ADDR_UNSPECIFIED(laddr)) {
struct sockaddr_in6 sin6;
struct epoch_tracker et;
struct ifaddr *ifa;
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
sin6.sin6_len = sizeof(sin6);
sin6.sin6_addr = *laddr;
NET_EPOCH_ENTER(et);
if ((ifa = ifa_ifwithaddr((const struct sockaddr *)&sin6)) ==
NULL && (inp->inp_flags & INP_BINDANY) == 0) {
NET_EPOCH_EXIT(et);
return (EADDRNOTAVAIL);
}
/*
* XXX: bind to an anycast address might accidentally
* cause sending a packet with anycast source address.
* We should allow to bind to a deprecated address, since
* the application dares to use it.
*/
if (ifa != NULL &&
((struct in6_ifaddr *)ifa)->ia6_flags &
(IN6_IFF_ANYCAST | IN6_IFF_NOTREADY | IN6_IFF_DETACHED)) {
NET_EPOCH_EXIT(et);
return (EADDRNOTAVAIL);
}
NET_EPOCH_EXIT(et);
}
if (lport != 0) {
struct inpcb *t;
if (ntohs(lport) <= V_ipport_reservedhigh &&
ntohs(lport) >= V_ipport_reservedlow &&
priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT))
return (EACCES);
if (!IN6_IS_ADDR_MULTICAST(laddr) &&
priv_check_cred(inp->inp_cred, PRIV_NETINET_REUSEPORT) !=
0) {
t = in6_pcblookup_local(inp->inp_pcbinfo, laddr, lport,
INPLOOKUP_WILDCARD, cred);
if (t != NULL &&
(inp->inp_socket->so_type != SOCK_STREAM ||
IN6_IS_ADDR_UNSPECIFIED(&t->in6p_faddr)) &&
(!IN6_IS_ADDR_UNSPECIFIED(laddr) ||
!IN6_IS_ADDR_UNSPECIFIED(&t->in6p_laddr) ||
(t->inp_socket->so_options & SO_REUSEPORT) ||
(t->inp_socket->so_options & SO_REUSEPORT_LB) == 0) &&
(inp->inp_cred->cr_uid != t->inp_cred->cr_uid))
return (EADDRINUSE);
#ifdef INET
if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0 &&
IN6_IS_ADDR_UNSPECIFIED(laddr)) {
struct sockaddr_in sin;
in6_sin6_2_sin(&sin, sin6);
t = in_pcblookup_local(inp->inp_pcbinfo,
sin.sin_addr, lport, INPLOOKUP_WILDCARD,
cred);
if (t != NULL &&
(inp->inp_socket->so_type != SOCK_STREAM ||
in_nullhost(t->inp_faddr)) &&
(inp->inp_cred->cr_uid !=
t->inp_cred->cr_uid))
return (EADDRINUSE);
}
#endif
}
t = in6_pcblookup_local(inp->inp_pcbinfo, laddr, lport,
lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0)
return (EADDRINUSE);
#ifdef INET
if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0 &&
IN6_IS_ADDR_UNSPECIFIED(laddr)) {
struct sockaddr_in sin;
in6_sin6_2_sin(&sin, sin6);
t = in_pcblookup_local(inp->inp_pcbinfo, sin.sin_addr,
lport, lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0 &&
(!in_nullhost(t->inp_laddr) ||
(t->inp_vflag & INP_IPV6PROTO) != 0)) {
return (EADDRINUSE);
}
}
#endif
}
return (0);
}
int
in6_pcbbind(struct inpcb *inp, struct sockaddr_in6 *sin6, struct ucred *cred)
{
struct socket *so = inp->inp_socket;
struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
u_short lport = 0;
int error, lookupflags = 0;
int reuseport = (so->so_options & SO_REUSEPORT);
/*
* XXX: Maybe we could let SO_REUSEPORT_LB set SO_REUSEPORT bit here
* so that we don't have to add to the (already messy) code below.
*/
int reuseport_lb = (so->so_options & SO_REUSEPORT_LB);
int error, lookupflags, sooptions;
INP_WLOCK_ASSERT(inp);
INP_HASH_WLOCK_ASSERT(pcbinfo);
if (inp->inp_lport || !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
return (EINVAL);
if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT|SO_REUSEPORT_LB)) == 0)
lookupflags = 0;
sooptions = atomic_load_int(&so->so_options);
if ((sooptions & (SO_REUSEADDR | SO_REUSEPORT | SO_REUSEPORT_LB)) == 0)
lookupflags = INPLOOKUP_WILDCARD;
if (sin6 == NULL) {
if ((error = prison_local_ip6(cred, &inp->in6p_laddr,
@ -199,115 +329,13 @@ in6_pcbbind(struct inpcb *inp, struct sockaddr_in6 *sin6, struct ucred *cred)
((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
return (error);
/* See if this address/port combo is available. */
error = in6_pcbbind_avail(inp, sin6, sooptions, lookupflags,
cred);
if (error != 0)
return (error);
lport = sin6->sin6_port;
if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
/*
* Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
* allow compepte duplication of binding if
* SO_REUSEPORT is set, or if SO_REUSEADDR is set
* and a multicast address is bound on both
* new and duplicated sockets.
*/
if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) != 0)
reuseport = SO_REUSEADDR|SO_REUSEPORT;
/*
* XXX: How to deal with SO_REUSEPORT_LB here?
* Treat same as SO_REUSEPORT for now.
*/
if ((so->so_options &
(SO_REUSEADDR|SO_REUSEPORT_LB)) != 0)
reuseport_lb = SO_REUSEADDR|SO_REUSEPORT_LB;
} else if (!IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
struct epoch_tracker et;
struct ifaddr *ifa;
sin6->sin6_port = 0; /* yech... */
NET_EPOCH_ENTER(et);
if ((ifa = ifa_ifwithaddr((struct sockaddr *)sin6)) ==
NULL &&
(inp->inp_flags & INP_BINDANY) == 0) {
NET_EPOCH_EXIT(et);
return (EADDRNOTAVAIL);
}
/*
* XXX: bind to an anycast address might accidentally
* cause sending a packet with anycast source address.
* We should allow to bind to a deprecated address, since
* the application dares to use it.
*/
if (ifa != NULL &&
((struct in6_ifaddr *)ifa)->ia6_flags &
(IN6_IFF_ANYCAST|IN6_IFF_NOTREADY|IN6_IFF_DETACHED)) {
NET_EPOCH_EXIT(et);
return (EADDRNOTAVAIL);
}
NET_EPOCH_EXIT(et);
}
if (lport) {
struct inpcb *t;
if (ntohs(lport) <= V_ipport_reservedhigh &&
ntohs(lport) >= V_ipport_reservedlow &&
priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT))
return (EACCES);
if (!IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr) &&
priv_check_cred(inp->inp_cred, PRIV_NETINET_REUSEPORT) != 0) {
t = in6_pcblookup_local(pcbinfo,
&sin6->sin6_addr, lport,
INPLOOKUP_WILDCARD, cred);
if (t != NULL &&
(so->so_type != SOCK_STREAM ||
IN6_IS_ADDR_UNSPECIFIED(&t->in6p_faddr)) &&
(!IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) ||
!IN6_IS_ADDR_UNSPECIFIED(&t->in6p_laddr) ||
(t->inp_socket->so_options & SO_REUSEPORT) ||
(t->inp_socket->so_options & SO_REUSEPORT_LB) == 0) &&
(inp->inp_cred->cr_uid !=
t->inp_cred->cr_uid))
return (EADDRINUSE);
#ifdef INET
if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0 &&
IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
struct sockaddr_in sin;
in6_sin6_2_sin(&sin, sin6);
t = in_pcblookup_local(pcbinfo,
sin.sin_addr, lport,
INPLOOKUP_WILDCARD, cred);
if (t != NULL &&
(so->so_type != SOCK_STREAM ||
in_nullhost(t->inp_faddr)) &&
(inp->inp_cred->cr_uid !=
t->inp_cred->cr_uid))
return (EADDRINUSE);
}
#endif
}
t = in6_pcblookup_local(pcbinfo, &sin6->sin6_addr,
lport, lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0)
return (EADDRINUSE);
#ifdef INET
if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0 &&
IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
struct sockaddr_in sin;
in6_sin6_2_sin(&sin, sin6);
t = in_pcblookup_local(pcbinfo, sin.sin_addr,
lport, lookupflags, cred);
if (t != NULL && ((reuseport | reuseport_lb) &
t->inp_socket->so_options) == 0 &&
(!in_nullhost(t->inp_laddr) ||
(t->inp_vflag & INP_IPV6PROTO) != 0)) {
return (EADDRINUSE);
}
}
#endif
}
inp->in6p_laddr = sin6->sin6_addr;
}
if (lport == 0) {