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socket: Implement SO_RERROR

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SO_RERROR indicates that receive buffer overflows should be handled as
errors. Historically receive buffer overflows have been ignored and
programs could not tell if they missed messages or messages had been
truncated because of overflows. Since programs historically do not
expect to get receive overflow errors, this behavior is not the
default.

This is really really important for programs that use route(4) to keep
in sync with the system. If we loose a message then we need to reload
the full system state, otherwise the behaviour from that point is
undefined and can lead to chasing bogus bug reports.

Reviewed by:	philip (network), kbowling (transport), gbe (manpages)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D26652
This commit is contained in:
Roy Marples 2021-07-28 08:46:59 -07:00 committed by Kevin Bowling
parent 33ff39796f
commit 7045b1603b
21 changed files with 100 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lib/libc/sys/getsockopt.2
View File

@ -28,7 +28,7 @@
.\" @(#)getsockopt.2 8.4 (Berkeley) 5/2/95
.\" $FreeBSD$
.\"
.Dd June 3, 2020
.Dd February 8, 2021
.Dt GETSOCKOPT 2
.Os
.Sh NAME
@ -177,6 +177,7 @@ for the socket
.It Dv SO_PROTOCOL Ta "get the protocol number for the socket (get only)"
.It Dv SO_PROTOTYPE Ta "SunOS alias for the Linux SO_PROTOCOL (get only)"
.It Dv SO_ERROR Ta "get and clear error on the socket (get only)"
.It Dv SO_RERROR Ta "enables receive error reporting"
.It Dv SO_SETFIB Ta "set the associated FIB (routing table) for the socket (set only)"
.El
.Pp
@ -514,6 +515,13 @@ returns any pending error on the socket and clears
the error status.
It may be used to check for asynchronous errors on connected
datagram sockets or for other asynchronous errors.
.Dv SO_RERROR
indicates that receive buffer overflows should be handled as errors.
Historically receive buffer overflows have been ignored and programs
could not tell if they missed messages or messages had been truncated
because of overflows.
Since programs historically do not expect to get receive overflow errors,
this behavior is not the default.
.Pp
.Dv SO_LABEL
returns the MAC label of the socket.

13
sbin/route/route.c
View File

@ -1444,9 +1444,20 @@ monitor(int argc, char *argv[])
interfaces();
exit(0);
}
#ifdef SO_RERROR
n = 1;
if (setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)) == -1)
warn("SO_RERROR");
#endif
for (;;) {
time_t now;
n = read(s, msg, 2048);
n = read(s, msg, sizeof(msg));
if (n == -1) {
warn("read");
continue;
}
now = time(NULL);
(void)printf("\ngot message of size %d on %s", n, ctime(&now));
print_rtmsg((struct rt_msghdr *)(void *)msg, n);

24
sys/kern/uipc_sockbuf.c
View File

@ -436,6 +436,30 @@ socantrcvmore(struct socket *so)
mtx_assert(SOCKBUF_MTX(&so->so_rcv), MA_NOTOWNED);
}
void
soroverflow_locked(struct socket *so)
{
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (so->so_options & SO_RERROR) {
so->so_rerror = ENOBUFS;
sorwakeup_locked(so);
} else
SOCKBUF_UNLOCK(&so->so_rcv);
mtx_assert(SOCKBUF_MTX(&so->so_rcv), MA_NOTOWNED);
}
void
soroverflow(struct socket *so)
{
SOCKBUF_LOCK(&so->so_rcv);
soroverflow_locked(so);
mtx_assert(SOCKBUF_MTX(&so->so_rcv), MA_NOTOWNED);
}
/*
* Wait for data to arrive at/drain from a socket buffer.
*/

30
sys/kern/uipc_socket.c
View File

@ -1952,12 +1952,19 @@ soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
KASSERT(m != NULL || !sbavail(&so->so_rcv),
("receive: m == %p sbavail == %u",
m, sbavail(&so->so_rcv)));
if (so->so_error) {
if (so->so_error || so->so_rerror) {
if (m != NULL)
goto dontblock;
error = so->so_error;
if ((flags & MSG_PEEK) == 0)
so->so_error = 0;
if (so->so_error)
error = so->so_error;
else
error = so->so_rerror;
if ((flags & MSG_PEEK) == 0) {
if (so->so_error)
so->so_error = 0;
else
so->so_rerror = 0;
}
SOCKBUF_UNLOCK(&so->so_rcv);
goto release;
}
@ -2302,7 +2309,7 @@ soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
!sosendallatonce(so) && nextrecord == NULL) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (so->so_error ||
if (so->so_error || so->so_rerror ||
so->so_rcv.sb_state & SBS_CANTRCVMORE)
break;
/*
@ -3043,6 +3050,7 @@ sosetopt(struct socket *so, struct sockopt *sopt)
case SO_NOSIGPIPE:
case SO_NO_DDP:
case SO_NO_OFFLOAD:
case SO_RERROR:
error = sooptcopyin(sopt, &optval, sizeof optval,
sizeof optval);
if (error)
@ -3264,6 +3272,7 @@ sogetopt(struct socket *so, struct sockopt *sopt)
case SO_NOSIGPIPE:
case SO_NO_DDP:
case SO_NO_OFFLOAD:
case SO_RERROR:
optval = so->so_options & sopt->sopt_name;
integer:
error = sooptcopyout(sopt, &optval, sizeof optval);
@ -3283,8 +3292,13 @@ sogetopt(struct socket *so, struct sockopt *sopt)
case SO_ERROR:
SOCK_LOCK(so);
optval = so->so_error;
so->so_error = 0;
if (so->so_error) {
optval = so->so_error;
so->so_error = 0;
} else {
optval = so->so_rerror;
so->so_rerror = 0;
}
SOCK_UNLOCK(so);
goto integer;
@ -3839,7 +3853,7 @@ filt_soread(struct knote *kn, long hint)
kn->kn_flags |= EV_EOF;
kn->kn_fflags = so->so_error;
return (1);
} else if (so->so_error) /* temporary udp error */
} else if (so->so_error || so->so_rerror)
return (1);
if (kn->kn_sfflags & NOTE_LOWAT) {

2
sys/kern/uipc_usrreq.c
View File

@ -1060,7 +1060,7 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
m = NULL;
control = NULL;
} else {
SOCKBUF_UNLOCK(&so2->so_rcv);
soroverflow_locked(so2);
error = ENOBUFS;
}
if (nam != NULL)

11
sys/net/raw_usrreq.c
View File

@ -100,10 +100,10 @@ raw_input_ext(struct mbuf *m0, struct sockproto *proto, struct sockaddr *src,
n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
if (n) {
if (sbappendaddr(&last->so_rcv, src,
n, (struct mbuf *)0) == 0)
/* should notify about lost packet */
n, (struct mbuf *)0) == 0) {
soroverflow(last);
m_freem(n);
else
} else
sorwakeup(last);
}
}
@ -111,9 +111,10 @@ raw_input_ext(struct mbuf *m0, struct sockproto *proto, struct sockaddr *src,
}
if (last) {
if (sbappendaddr(&last->so_rcv, src,
m, (struct mbuf *)0) == 0)
m, (struct mbuf *)0) == 0) {
soroverflow(last);
m_freem(m);
else
} else
sorwakeup(last);
} else
m_freem(m);

1
sys/netgraph/bluetooth/socket/ng_btsocket_hci_raw.c
View File

@ -539,6 +539,7 @@ ng_btsocket_hci_raw_data_input(struct mbuf *nam)
NG_FREE_M(m);
NG_FREE_M(ctl);
soroverflow(pcb->so);
}
}
next:

2
sys/netgraph/ng_socket.c
View File

@ -993,7 +993,7 @@ ngs_rcvmsg(node_p node, item_p item, hook_p lasthook)
/* Send it up to the socket. */
if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)&addr, m,
NULL) == 0) {
SOCKBUF_UNLOCK(&so->so_rcv);
soroverflow_locked(so);
TRAP_ERROR;
m_freem(m);
return (ENOBUFS);

2
sys/netinet/ip_divert.c
View File

@ -295,7 +295,7 @@ divert_packet(struct mbuf *m, bool incoming)
if (sbappendaddr_locked(&sa->so_rcv,
(struct sockaddr *)&divsrc, m,
(struct mbuf *)0) == 0) {
SOCKBUF_UNLOCK(&sa->so_rcv);
soroverflow_locked(sa);
sa = NULL; /* force mbuf reclaim below */
} else
sorwakeup_locked(sa);

2
sys/netinet/ip_mroute.c
View File

@ -1257,7 +1257,7 @@ socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in *src)
sorwakeup_locked(s);
return 0;
}
SOCKBUF_UNLOCK(&s->so_rcv);
soroverflow_locked(s);
}
m_freem(mm);
return -1;

3
sys/netinet/raw_ip.c
View File

@ -263,11 +263,10 @@ rip_append(struct inpcb *last, struct ip *ip, struct mbuf *n,
SOCKBUF_LOCK(&so->so_rcv);
if (sbappendaddr_locked(&so->so_rcv,
(struct sockaddr *)ripsrc, n, opts) == 0) {
/* should notify about lost packet */
soroverflow_locked(so);
m_freem(n);
if (opts)
m_freem(opts);
SOCKBUF_UNLOCK(&so->so_rcv);
} else
sorwakeup_locked(so);
} else

2
sys/netinet/udp_usrreq.c
View File

@ -379,7 +379,7 @@ udp_append(struct inpcb *inp, struct ip *ip, struct mbuf *n, int off,
so = inp->inp_socket;
SOCKBUF_LOCK(&so->so_rcv);
if (sbappendaddr_locked(&so->so_rcv, append_sa, n, opts) == 0) {
SOCKBUF_UNLOCK(&so->so_rcv);
soroverflow(so);
m_freem(n);
if (opts)
m_freem(opts);

6
sys/netinet6/icmp6.c
View File

@ -1974,13 +1974,11 @@ icmp6_rip6_input(struct mbuf **mp, int off)
&last->inp_socket->so_rcv,
(struct sockaddr *)&fromsa, n, opts)
== 0) {
/* should notify about lost packet */
soroverflow_locked(last->inp_socket);
m_freem(n);
if (opts) {
m_freem(opts);
}
SOCKBUF_UNLOCK(
&last->inp_socket->so_rcv);
} else
sorwakeup_locked(last->inp_socket);
opts = NULL;
@ -2020,7 +2018,7 @@ icmp6_rip6_input(struct mbuf **mp, int off)
m_freem(m);
if (opts)
m_freem(opts);
SOCKBUF_UNLOCK(&last->inp_socket->so_rcv);
soroverflow_locked(last->inp_socket);
} else
sorwakeup_locked(last->inp_socket);
INP_RUNLOCK(last);

1
sys/netinet6/ip6_input.c
View File

@ -1575,6 +1575,7 @@ ip6_notify_pmtu(struct inpcb *inp, struct sockaddr_in6 *dst, u_int32_t mtu)
so = inp->inp_socket;
if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
== 0) {
soroverflow(so);
m_freem(m_mtu);
/* XXX: should count statistics */
} else

3
sys/netinet6/ip6_mroute.c
View File

@ -1038,7 +1038,8 @@ socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in6 *src)
mm, (struct mbuf *)0) != 0) {
sorwakeup(s);
return (0);
}
} else
soroverflow(s);
}
m_freem(mm);
return (-1);

2
sys/netinet6/raw_ip6.c
View File

@ -214,6 +214,7 @@ rip6_input(struct mbuf **mp, int *offp, int proto)
if (sbappendaddr(&last->inp_socket->so_rcv,
(struct sockaddr *)&fromsa,
n, opts) == 0) {
soroverflow(last->inp_socket);
m_freem(n);
if (opts)
m_freem(opts);
@ -325,6 +326,7 @@ rip6_input(struct mbuf **mp, int *offp, int proto)
m_adj(m, *offp);
if (sbappendaddr(&last->inp_socket->so_rcv,
(struct sockaddr *)&fromsa, m, opts) == 0) {
soroverflow(last->inp_socket);
m_freem(m);
if (opts)
m_freem(opts);

2
sys/netinet6/send.c
View File

@ -307,7 +307,7 @@ send_input(struct mbuf *m, struct ifnet *ifp, int direction, int msglen __unused
SOCKBUF_LOCK(&V_send_so->so_rcv);
if (sbappendaddr_locked(&V_send_so->so_rcv,
(struct sockaddr *)&sendsrc, m, NULL) == 0) {
SOCKBUF_UNLOCK(&V_send_so->so_rcv);
soroverflow_locked(V_send_so);
/* XXX stats. */
m_freem(m);
} else {

2
sys/netinet6/udp6_usrreq.c
View File

@ -197,7 +197,7 @@ udp6_append(struct inpcb *inp, struct mbuf *n, int off,
SOCKBUF_LOCK(&so->so_rcv);
if (sbappendaddr_locked(&so->so_rcv, (struct sockaddr *)&fromsa[0], n,
opts) == 0) {
SOCKBUF_UNLOCK(&so->so_rcv);
soroverflow_locked(so);
m_freem(n);
if (opts)
m_freem(opts);

10
sys/netipsec/keysock.c
View File

@ -141,7 +141,6 @@ key_output(struct mbuf *m, struct socket *so, ...)
static int
key_sendup0(struct rawcb *rp, struct mbuf *m, int promisc)
{
int error;
if (promisc) {
struct sadb_msg *pmsg;
@ -165,11 +164,12 @@ key_sendup0(struct rawcb *rp, struct mbuf *m, int promisc)
m, NULL)) {
PFKEYSTAT_INC(in_nomem);
m_freem(m);
error = ENOBUFS;
} else
error = 0;
soroverflow(rp->rcb_socket);
return ENOBUFS;
}
sorwakeup(rp->rcb_socket);
return error;
return 0;
}
/* so can be NULL if target != KEY_SENDUP_ONE */

1
sys/sys/socket.h
View File

@ -147,6 +147,7 @@ typedef __uintptr_t uintptr_t;
#define SO_NO_OFFLOAD 0x00004000 /* socket cannot be offloaded */
#define SO_NO_DDP 0x00008000 /* disable direct data placement */
#define SO_REUSEPORT_LB 0x00010000 /* reuse with load balancing */
#define SO_RERROR 0x00020000 /* keep track of receive errors */
/*
* Additional options, not kept in so_options.

6
sys/sys/socketvar.h
View File

@ -100,6 +100,7 @@ struct socket {
struct protosw *so_proto; /* (a) protocol handle */
short so_timeo; /* (g) connection timeout */
u_short so_error; /* (f) error affecting connection */
u_short so_rerror; /* (f) error affecting connection */
struct sigio *so_sigio; /* [sg] information for async I/O or
out of band data (SIGURG) */
struct ucred *so_cred; /* (a) user credentials */
@ -266,7 +267,8 @@ struct socket {
/* can we read something from so? */
#define soreadabledata(so) \
(sbavail(&(so)->so_rcv) >= (so)->so_rcv.sb_lowat || (so)->so_error)
(sbavail(&(so)->so_rcv) >= (so)->so_rcv.sb_lowat || \
(so)->so_error || (so)->so_rerror)
#define soreadable(so) \
(soreadabledata(so) || ((so)->so_rcv.sb_state & SBS_CANTRCVMORE))
@ -480,6 +482,8 @@ void socantrcvmore(struct socket *so);
void socantrcvmore_locked(struct socket *so);
void socantsendmore(struct socket *so);
void socantsendmore_locked(struct socket *so);
void soroverflow(struct socket *so);
void soroverflow_locked(struct socket *so);
/*
* Accept filter functions (duh).