void smtpd_peer_init(SMTPD_STATE *state)
{
const char *myname = "smtpd_peer_init";
SOCKADDR_SIZE sa_length;
struct sockaddr *sa;
INET_PROTO_INFO *proto_info = inet_proto_info();
sa = (struct sockaddr *) & (state->sockaddr);
sa_length = sizeof(state->sockaddr);
/*
* Look up the peer address information.
*
* XXX If we make local endpoint (getsockname) information available to
* Milter applications as {if_name} and {if_addr}, then we also must be
* able to provide this via the XCLIENT command for Milter testing.
*
* XXX If we make local or remote port information available to policy
* servers or Milter applications, then we must also make this testable
* with the XCLIENT command, otherwise there will be confusion.
*
* XXX If we make local or remote port information available via logging,
* then we must also support these attributes with the XFORWARD command.
*
* XXX If support were to be added for Milter applications in down-stream
* MTAs, then consistency demands that we propagate a lot of Sendmail
* macro information via the XFORWARD command. Otherwise we could end up
* with a very confusing situation.
*/
if (getpeername(vstream_fileno(state->client), sa, &sa_length) >= 0) {
errno = 0;
}
/*
* If peer went away, give up.
*/
if (errno != 0 && errno != ENOTSOCK) {
state->name = mystrdup(CLIENT_NAME_UNKNOWN);
state->reverse_name = mystrdup(CLIENT_NAME_UNKNOWN);
state->addr = mystrdup(CLIENT_ADDR_UNKNOWN);
state->rfc_addr = mystrdup(CLIENT_ADDR_UNKNOWN);
state->addr_family = AF_UNSPEC;
state->name_status = SMTPD_PEER_CODE_PERM;
state->reverse_name_status = SMTPD_PEER_CODE_PERM;
state->port = mystrdup(CLIENT_PORT_UNKNOWN);
}
/*
* Convert the client address to printable address and hostname.
*
* XXX If we're given an IPv6 (or IPv4) connection from, e.g., inetd, while
* Postfix IPv6 (or IPv4) support is turned off, don't (skip to the final
* else clause, pretend the origin is localhost[127.0.0.1], and become an
* open relay).
*/
else if (errno == 0
&& (sa->sa_family == AF_INET
#ifdef AF_INET6
|| sa->sa_family == AF_INET6
#endif
)) {
MAI_HOSTNAME_STR client_name;
MAI_HOSTADDR_STR client_addr;
MAI_SERVPORT_STR client_port;
int aierr;
char *colonp;
/*
* Sanity check: we can't use sockets that we're not configured for.
*/
if (strchr((char *) proto_info->sa_family_list, sa->sa_family) == 0)
msg_fatal("cannot handle socket type %s with \"%s = %s\"",
#ifdef AF_INET6
sa->sa_family == AF_INET6 ? "AF_INET6" :
#endif
sa->sa_family == AF_INET ? "AF_INET" :
"other", VAR_INET_PROTOCOLS, var_inet_protocols);
/*
* Sorry, but there are some things that we just cannot do while
* connected to the network.
*/
if (geteuid() != var_owner_uid || getuid() != var_owner_uid) {
msg_error("incorrect SMTP server privileges: uid=%lu euid=%lu",
(unsigned long) getuid(), (unsigned long) geteuid());
msg_fatal("the Postfix SMTP server must run with $%s privileges",
VAR_MAIL_OWNER);
}
/*
* Convert the client address to printable form.
*/
if ((aierr = sockaddr_to_hostaddr(sa, sa_length, &client_addr,
&client_port, 0)) != 0)
msg_fatal("%s: cannot convert client address/port to string: %s",
myname, MAI_STRERROR(aierr));
state->port = mystrdup(client_port.buf);
/*
* XXX Strip off the IPv6 datalink suffix to avoid false alarms with
* strict address syntax checks.
*/
#ifdef HAS_IPV6
(void) split_at(client_addr.buf, '%');
#endif
/*
* We convert IPv4-in-IPv6 address to 'true' IPv4 address early on,
* but only if IPv4 support is enabled (why would anyone want to turn
* it off)? With IPv4 support enabled we have no need for the IPv6
* form in logging, hostname verification and access checks.
*/
#ifdef HAS_IPV6
if (sa->sa_family == AF_INET6) {
if (strchr((char *) proto_info->sa_family_list, AF_INET) != 0
&& IN6_IS_ADDR_V4MAPPED(&SOCK_ADDR_IN6_ADDR(sa))
&& (colonp = strrchr(client_addr.buf, ':')) != 0) {
struct addrinfo *res0;
if (msg_verbose > 1)
msg_info("%s: rewriting V4-mapped address \"%s\" to \"%s\"",
myname, client_addr.buf, colonp + 1);
state->addr = mystrdup(colonp + 1);
state->rfc_addr = mystrdup(colonp + 1);
state->addr_family = AF_INET;
aierr = hostaddr_to_sockaddr(state->addr, (char *) 0, 0, &res0);
if (aierr)
msg_fatal("%s: cannot convert %s from string to binary: %s",
myname, state->addr, MAI_STRERROR(aierr));
sa_length = res0->ai_addrlen;
if (sa_length > sizeof(state->sockaddr))
sa_length = sizeof(state->sockaddr);
memcpy((char *) sa, res0->ai_addr, sa_length);
freeaddrinfo(res0); /* 200412 */
}
/*
* Following RFC 2821 section 4.1.3, an IPv6 address literal gets
* a prefix of 'IPv6:'. We do this consistently for all IPv6
* addresses that that appear in headers or envelopes. The fact
* that valid_mailhost_addr() enforces the form helps of course.
* We use the form without IPV6: prefix when doing access
* control, or when accessing the connection cache.
*/
else {
state->addr = mystrdup(client_addr.buf);
state->rfc_addr =
concatenate(IPV6_COL, client_addr.buf, (char *) 0);
state->addr_family = sa->sa_family;
}
}
/*
* An IPv4 address is in dotted quad decimal form.
*/
else
#endif
{
state->addr = mystrdup(client_addr.buf);
state->rfc_addr = mystrdup(client_addr.buf);
state->addr_family = sa->sa_family;
}
/*
* Look up and sanity check the client hostname.
*
* It is unsafe to allow numeric hostnames, especially because there
* exists pressure to turn off the name->addr double check. In that
* case an attacker could trivally bypass access restrictions.
*
* sockaddr_to_hostname() already rejects malformed or numeric names.
*/
#define TEMP_AI_ERROR(e) \
((e) == EAI_AGAIN || (e) == EAI_MEMORY || (e) == EAI_SYSTEM)
#define REJECT_PEER_NAME(state, code) { \
myfree(state->name); \
state->name = mystrdup(CLIENT_NAME_UNKNOWN); \
state->name_status = code; \
}
if (var_smtpd_peername_lookup == 0) {
state->name = mystrdup(CLIENT_NAME_UNKNOWN);
state->reverse_name = mystrdup(CLIENT_NAME_UNKNOWN);
state->name_status = SMTPD_PEER_CODE_PERM;
state->reverse_name_status = SMTPD_PEER_CODE_PERM;
} else if ((aierr = sockaddr_to_hostname(sa, sa_length, &client_name,
(MAI_SERVNAME_STR *) 0, 0)) != 0) {
state->name = mystrdup(CLIENT_NAME_UNKNOWN);
state->reverse_name = mystrdup(CLIENT_NAME_UNKNOWN);
state->name_status = (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_PERM);
state->reverse_name_status = (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_PERM);
} else {
struct addrinfo *res0;
struct addrinfo *res;
state->name = mystrdup(client_name.buf);
state->reverse_name = mystrdup(client_name.buf);
state->name_status = SMTPD_PEER_CODE_OK;
state->reverse_name_status = SMTPD_PEER_CODE_OK;
/*
* Reject the hostname if it does not list the peer address.
* Without further validation or qualification, such information
* must not be allowed to enter the audit trail, as people would
* draw false conclusions.
*/
aierr = hostname_to_sockaddr_pf(state->name, state->addr_family,
(char *) 0, 0, &res0);
if (aierr) {
msg_warn("%s: hostname %s verification failed: %s",
state->addr, state->name, MAI_STRERROR(aierr));
REJECT_PEER_NAME(state, (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_FORGED));
} else {
for (res = res0; /* void */ ; res = res->ai_next) {
if (res == 0) {
msg_warn("%s: address not listed for hostname %s",
state->addr, state->name);
REJECT_PEER_NAME(state, SMTPD_PEER_CODE_FORGED);
break;
}
if (strchr((char *) proto_info->sa_family_list, res->ai_family) == 0) {
msg_info("skipping address family %d for host %s",
res->ai_family, state->name);
continue;
}
if (sock_addr_cmp_addr(res->ai_addr, sa) == 0)
break; /* keep peer name */
}
freeaddrinfo(res0);
}
}
}
/*
* If it's not Internet, assume the client is local, and avoid using the
* naming service because that can hang when the machine is disconnected.
*/
else {
state->name = mystrdup("localhost");
state->reverse_name = mystrdup("localhost");
state->addr = mystrdup("127.0.0.1"); /* XXX bogus. */
state->rfc_addr = mystrdup("127.0.0.1");/* XXX bogus. */
state->addr_family = AF_UNSPEC;
state->name_status = SMTPD_PEER_CODE_OK;
state->reverse_name_status = SMTPD_PEER_CODE_OK;
state->port = mystrdup("0"); /* XXX bogus. */
}
/*
* Do the name[addr]:port formatting for pretty reports.
*/
state->namaddr = SMTPD_BUILD_NAMADDRPORT(state->name, state->addr,
state->port);
}
static void smtpd_peer_sockaddr_to_hostname(SMTPD_STATE *state)
{
struct sockaddr *sa = (struct sockaddr *) &(state->sockaddr);
SOCKADDR_SIZE sa_length = state->sockaddr_len;
MAI_HOSTNAME_STR client_name;
int aierr;
/*
* Look up and sanity check the client hostname.
*
* It is unsafe to allow numeric hostnames, especially because there exists
* pressure to turn off the name->addr double check. In that case an
* attacker could trivally bypass access restrictions.
*
* sockaddr_to_hostname() already rejects malformed or numeric names.
*/
#define TEMP_AI_ERROR(e) \
((e) == EAI_AGAIN || (e) == EAI_MEMORY || (e) == EAI_SYSTEM)
#define REJECT_PEER_NAME(state, code) { \
myfree(state->name); \
state->name = mystrdup(CLIENT_NAME_UNKNOWN); \
state->name_status = code; \
}
if (var_smtpd_peername_lookup == 0) {
state->name = mystrdup(CLIENT_NAME_UNKNOWN);
state->reverse_name = mystrdup(CLIENT_NAME_UNKNOWN);
state->name_status = SMTPD_PEER_CODE_PERM;
state->reverse_name_status = SMTPD_PEER_CODE_PERM;
} else if ((aierr = sockaddr_to_hostname(sa, sa_length, &client_name,
(MAI_SERVNAME_STR *) 0, 0)) != 0) {
state->name = mystrdup(CLIENT_NAME_UNKNOWN);
state->reverse_name = mystrdup(CLIENT_NAME_UNKNOWN);
state->name_status = (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_PERM);
state->reverse_name_status = (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_PERM);
} else {
struct addrinfo *res0;
struct addrinfo *res;
state->name = mystrdup(client_name.buf);
state->reverse_name = mystrdup(client_name.buf);
state->name_status = SMTPD_PEER_CODE_OK;
state->reverse_name_status = SMTPD_PEER_CODE_OK;
/*
* Reject the hostname if it does not list the peer address. Without
* further validation or qualification, such information must not be
* allowed to enter the audit trail, as people would draw false
* conclusions.
*/
aierr = hostname_to_sockaddr_pf(state->name, state->addr_family,
(char *) 0, 0, &res0);
if (aierr) {
msg_warn("hostname %s does not resolve to address %s: %s",
state->name, state->addr, MAI_STRERROR(aierr));
REJECT_PEER_NAME(state, (TEMP_AI_ERROR(aierr) ?
SMTPD_PEER_CODE_TEMP : SMTPD_PEER_CODE_FORGED));
} else {
for (res = res0; /* void */ ; res = res->ai_next) {
if (res == 0) {
msg_warn("hostname %s does not resolve to address %s",
state->name, state->addr);
REJECT_PEER_NAME(state, SMTPD_PEER_CODE_FORGED);
break;
}
if (strchr((char *) proto_info->sa_family_list, res->ai_family) == 0) {
msg_info("skipping address family %d for host %s",
res->ai_family, state->name);
continue;
}
if (sock_addr_cmp_addr(res->ai_addr, sa) == 0)
break; /* keep peer name */
}
freeaddrinfo(res0);
}
}
}