/*
** Copyright (C) 2001-2025 Zabbix SIA
**
** This program is free software: you can redistribute it and/or modify it under the terms of
** the GNU Affero General Public License as published by the Free Software Foundation, version 3.
**
** This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
** without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
** See the GNU Affero General Public License for more details.
**
** You should have received a copy of the GNU Affero General Public License along with this program.
** If not, see <https://www.gnu.org/licenses/>.
**/
#include "zbxmedia.h"
#include "zbxstr.h"
#include "zbxcomms.h"
#include "zbxcrypto.h"
#include "zbxalgo.h"
#include "zbxcurl.h"
/* number of characters per line when wrapping Base64 data in Email */
#define ZBX_EMAIL_B64_MAXLINE 76
/* number of characters per "encoded-word" in RFC-2047 message header */
#define ZBX_EMAIL_B64_MAXWORD_RFC2047 75
/* multiple 'encoded-word's should be separated by <CR><LF><SPACE> */
#define ZBX_EMAIL_ENCODED_WORD_SEPARATOR "\r\n "
/* separator for multipart mixed messages */
#define ZBX_MULTIPART_MIXED_BOUNDARY "MULTIPART-MIXED-BOUNDARY"
#define OK_250 "250"
/******************************************************************************
* *
* Purpose: Encode a string into a base64 string as required by rfc2047. *
* Used for encoding e-mail headers. *
* *
* Parameters: src - [IN] a null-terminated UTF-8 string to encode *
* p_base64 - [OUT] a pointer to the encoded string *
* *
* Comments: Based on the patch submitted by *
* Jairo Eduardo Lopez Fuentes Nacarino *
* *
******************************************************************************/
static void str_base64_encode_rfc2047(const char *src, char **p_base64)
{
const char *p0; /* pointer in src to start encoding from */
const char *p1; /* pointer in src: 1st byte of UTF-8 character */
size_t c_len; /* length of UTF-8 character sequence */
size_t p_base64_alloc; /* allocated memory size for subject */
size_t p_base64_offset = 0; /* offset for writing into subject */
assert(src);
assert(NULL == *p_base64); /* do not accept already allocated memory */
p_base64_alloc = ZBX_EMAIL_B64_MAXWORD_RFC2047 + sizeof(ZBX_EMAIL_ENCODED_WORD_SEPARATOR);
*p_base64 = (char *)zbx_malloc(NULL, p_base64_alloc);
**p_base64 = '\0';
for (p0 = src; '\0' != *p0; p0 = p1)
{
/* Max length of line is 76 characters (without line separator). */
/* Max length of "encoded-word" is 75 characters (without word separator). */
/* 3 characters are taken by word separator "<CR><LF><Space>" which also includes the line separator. */
/* 12 characters are taken by header "=?UTF-8?B?" and trailer "?=". */
/* So, one "encoded-word" can hold up to 63 characters of Base64-encoded string. */
/* Encoding 45 bytes produces a 61 byte long Base64-encoded string which meets the limit. */
/* Encoding 46 bytes produces a 65 byte long Base64-encoded string which exceeds the limit. */
for (p1 = p0; '\0' != *p1; p1 += c_len)
{
/* an invalid UTF-8 character or length of a string more than 45 bytes */
if (0 == (c_len = zbx_utf8_char_len(p1)) || 45 < p1 - p0 + c_len)
break;
}
if (0 < p1 - p0)
{
/* 12 characters are taken by header "=?UTF-8?B?" and trailer "?=" plus '\0' */
char b64_buf[ZBX_EMAIL_B64_MAXWORD_RFC2047 - 12 + 1];
zbx_base64_encode(p0, b64_buf, p1 - p0);
if (0 != p_base64_offset) /* not the first "encoded-word" ? */
{
zbx_strcpy_alloc(p_base64, &p_base64_alloc, &p_base64_offset,
ZBX_EMAIL_ENCODED_WORD_SEPARATOR);
}
zbx_snprintf_alloc(p_base64, &p_base64_alloc, &p_base64_offset, "=?UTF-8?B?%s?=", b64_buf);
}
else
break;
}
}
/******************************************************************************
* *
* Comments: reads until '\n' *
* *
******************************************************************************/
static int smtp_readln(zbx_socket_t *s, const char **buf)
{
while (NULL != (*buf = zbx_tcp_recv_line(s)) &&
4 <= strlen(*buf) &&
0 != isdigit((*buf)[0]) &&
0 != isdigit((*buf)[1]) &&
0 != isdigit((*buf)[2]) &&
'-' == (*buf)[3])
;
return NULL == *buf ? FAIL : SUCCEED;
}
/********************************************************************************
* *
* Purpose: 1. Extract a display name and an angle address from mailbox string *
* for using in "MAIL FROM:", "RCPT TO:", "From:" and "To:" fields. *
* 2. If the display name contains multibyte UTF-8 characters encode *
* it into a base64 string as required by rfc2047. The encoding is *
* also applied if the display name looks like a base64-encoded *
* word. *
* *
* Parameters: mailbox - [IN] a null-terminated UTF-8 string *
* error - [IN] pointer to string for reporting errors *
* mailaddrs - [OUT] array of mail addresses *
* *
* Comments: The function is very much simplified in comparison with full *
* RFC 5322-compliant parser. It does not recognize: *
* - comments, *
* - quoted strings and quoted pairs, *
* - folding whitespace. *
* For example, '<' and '@' are not supported in the display name *
* and the local part of email address. *
* *
********************************************************************************/
static int smtp_parse_mailbox(const char *mailbox, char **error, zbx_vector_ptr_t *mailaddrs)
{
const char *p, *pstart, *angle_addr_start, *domain_start, *utf8_end;
const char *base64_like_start, *base64_like_end, *token;
char *base64_buf, *tmp_mailbox;
size_t size_angle_addr = 0, offset_angle_addr = 0, len, i;
int ret = FAIL;
zbx_mailaddr_t *mailaddr = NULL;
tmp_mailbox = zbx_strdup(NULL, mailbox);
token = strtok(tmp_mailbox, "\n");
while (token != NULL)
{
angle_addr_start = NULL;
domain_start = NULL;
utf8_end = NULL;
base64_like_start = NULL;
base64_like_end = NULL;
base64_buf = NULL;
p = token;
while (' ' == *p || '\t' == *p)
p++;
pstart = p;
while ('\0' != *p)
{
len = zbx_utf8_char_len(p);
if (1 == len) /* ASCII character */
{
switch (*p)
{
case '<':
angle_addr_start = p;
break;
case '@':
domain_start = p;
break;
/* if mailbox contains a sequence '=?'.*'?=' which looks like a Base64-encoded word */
case '=':
if ('?' == *(p + 1))
base64_like_start = p++;
break;
case '?':
if (NULL != base64_like_start && '=' == *(p + 1))
base64_like_end = p++;
}
p++;
}
else if (1 < len) /* multibyte UTF-8 character */
{
for (i = 1; i < len; i++)
{
if ('\0' == *(p + i))
{
*error = zbx_dsprintf(*error, "invalid UTF-8 character in email"
" address: %s", token);
goto out;
}
}
utf8_end = p + len - 1;
p += len;
}
else if (0 == len) /* invalid UTF-8 character */
{
*error = zbx_dsprintf(*error, "invalid UTF-8 character in email address: %s", token);
goto out;
}
}
if (NULL == domain_start)
{
*error = zbx_dsprintf(*error, "no '@' in email address: %s", token);
goto out;
}
if (utf8_end > angle_addr_start)
{
*error = zbx_dsprintf(*error, "email address local or domain part contains UTF-8 character: %s",
token);
goto out;
}
mailaddr = (zbx_mailaddr_t *)zbx_malloc(NULL, sizeof(zbx_mailaddr_t));
memset(mailaddr, 0, sizeof(zbx_mailaddr_t));
if (NULL != angle_addr_start)
{
zbx_snprintf_alloc(&mailaddr->addr, &size_angle_addr, &offset_angle_addr, "%s",
angle_addr_start);
if (pstart < angle_addr_start) /* display name */
{
mailaddr->disp_name = (char *)zbx_malloc(mailaddr->disp_name,
(size_t)(angle_addr_start - pstart + 1));
memcpy(mailaddr->disp_name, pstart, (size_t)(angle_addr_start - pstart));
*(mailaddr->disp_name + (angle_addr_start - pstart)) = '\0';
/* UTF-8 or Base64-looking display name */
if (NULL != utf8_end || (NULL != base64_like_end &&
angle_addr_start - 1 > base64_like_end))
{
str_base64_encode_rfc2047(mailaddr->disp_name, &base64_buf);
zbx_free(mailaddr->disp_name);
mailaddr->disp_name = base64_buf;
}
}
}
else
{
zbx_snprintf_alloc(&mailaddr->addr, &size_angle_addr, &offset_angle_addr, "<%s>", pstart);
}
zbx_vector_ptr_append(mailaddrs, mailaddr);
token = strtok(NULL, "\n");
}
ret = SUCCEED;
out:
zbx_free(tmp_mailbox);
return ret;
}
static char *email_encode_part(const char *data, size_t data_size)
{
char *base64 = NULL, *part;
zbx_base64_encode_dyn(data, &base64, data_size);
part = zbx_str_linefeed(base64, ZBX_EMAIL_B64_MAXLINE, "\r\n");
zbx_free(base64);
return part;
}
static char *smtp_prepare_payload(zbx_vector_ptr_t *from_mails, zbx_vector_ptr_t *to_mails, const char *inreplyto,
const char *mailsubject, const char *mailbody, unsigned char message_format)
{
char *tmp = NULL, *base64 = NULL;
char *localsubject = NULL, *localbody = NULL, *from = NULL, *to = NULL;
char str_time[MAX_STRING_LEN];
struct tm *local_time;
time_t email_time;
int i;
size_t from_alloc = 0, from_offset = 0, to_alloc = 0, to_offset = 0, tmp_alloc = 0, tmp_offset = 0;
/* prepare subject */
tmp = zbx_string_replace(mailsubject, "\r\n", " ");
localsubject = zbx_string_replace(tmp, "\n", " ");
zbx_free(tmp);
if (FAIL == zbx_is_ascii_string(localsubject))
{
/* split subject into multiple RFC 2047 "encoded-words" */
str_base64_encode_rfc2047(localsubject, &base64);
zbx_free(localsubject);
localsubject = base64;
base64 = NULL;
}
/* prepare body */
if (ZBX_MEDIA_MESSAGE_FORMAT_MULTI != message_format)
{
char *tmp_body;
tmp = zbx_string_replace(mailbody, "\r\n", "\n");
tmp_body = zbx_string_replace(tmp, "\n", "\r\n");
localbody = email_encode_part(tmp_body, strlen(tmp_body));
zbx_free(tmp_body);
zbx_free(tmp);
}
else
localbody = (char *)mailbody;
/* prepare date */
time(&email_time);
local_time = localtime(&email_time);
strftime(str_time, MAX_STRING_LEN, "%a, %d %b %Y %H:%M:%S %z", local_time);
for (i = 0; i < from_mails->values_num; i++)
{
zbx_snprintf_alloc(&from, &from_alloc, &from_offset, "%s%s",
ZBX_NULL2EMPTY_STR(((zbx_mailaddr_t *)from_mails->values[i])->disp_name),
((zbx_mailaddr_t *)from_mails->values[i])->addr);
if (from_mails->values_num - 1 > i)
zbx_strcpy_alloc(&from, &from_alloc, &from_offset, ",");
}
for (i = 0; i < to_mails->values_num; i++)
{
zbx_snprintf_alloc(&to, &to_alloc, &to_offset, "%s%s",
ZBX_NULL2EMPTY_STR(((zbx_mailaddr_t *)to_mails->values[i])->disp_name),
((zbx_mailaddr_t *)to_mails->values[i])->addr);
if (to_mails->values_num - 1 > i)
zbx_strcpy_alloc(&to, &to_alloc, &to_offset, ",");
}
/* e-mails are sent in 'SMTP/MIME e-mail' format because UTF-8 is used both in mailsubject and mailbody */
/* =?charset?encoding?encoded text?= format must be used for subject field */
zbx_snprintf_alloc(&tmp, &tmp_alloc, &tmp_offset,
"From: %s\r\n"
"To: %s\r\n"
"In-Reply-To: %s\r\n"
"Date: %s\r\n"
"Subject: %s\r\n"
"MIME-Version: 1.0\r\n",
from, to, inreplyto, str_time, localsubject);
if (ZBX_MEDIA_MESSAGE_FORMAT_MULTI == message_format)
{
zbx_strcpy_alloc(&tmp, &tmp_alloc, &tmp_offset,
"Content-Type: multipart/mixed; boundary=" ZBX_MULTIPART_MIXED_BOUNDARY "\r\n");
}
else
{
zbx_snprintf_alloc(&tmp, &tmp_alloc, &tmp_offset,
"Content-Type: %s; charset=\"UTF-8\"\r\n"
"Content-Transfer-Encoding: base64\r\n",
ZBX_MEDIA_MESSAGE_FORMAT_HTML == message_format ? "text/html" : "text/plain");
}
zbx_snprintf_alloc(&tmp, &tmp_alloc, &tmp_offset,
"\r\n"
"%s",
localbody);
zbx_free(localsubject);
if (localbody != mailbody)
zbx_free(localbody);
zbx_free(from);
zbx_free(to);
return tmp;
}
#ifdef HAVE_LIBCURL
typedef struct
{
char *payload;
size_t payload_len;
size_t provided_len;
}
smtp_payload_status_t;
static size_t smtp_provide_payload(void *buffer, size_t size, size_t nmemb, void *instream)
{
size_t current_len;
smtp_payload_status_t *payload_status = (smtp_payload_status_t *)instream;
current_len = MIN(size * nmemb, payload_status->payload_len - payload_status->provided_len);
memcpy(buffer, payload_status->payload + payload_status->provided_len, current_len);
payload_status->provided_len += current_len;
return current_len;
}
static int smtp_debug_function(CURL *easyhandle, curl_infotype type, char *data, size_t size, void *userptr)
{
const char labels[3] = {'*', '<', '>'};
ZBX_UNUSED(easyhandle);
ZBX_UNUSED(userptr);
if (CURLINFO_TEXT != type && CURLINFO_HEADER_IN != type && CURLINFO_HEADER_OUT != type)
goto out;
while (0 < size && ('\r' == data[size - 1] || '\n' == data[size - 1]))
size--;
zabbix_log(LOG_LEVEL_TRACE, "%c %.*s", labels[type], (int)size, data);
out:
return 0;
}
#endif
static char *smtp_get_helo_from_system(void)
{
struct utsname name;
if (-1 == uname(&name))
return NULL;
return zbx_strdup(NULL, name.nodename);
}
static char *smtp_get_helo_from_addr(const char *addr)
{
const char *domain;
char *helo_addr;
size_t addr_len;
if (NULL == addr || '\0' == *addr || NULL == (domain = strrchr(addr, '@')))
return NULL;
addr_len = strlen(domain + 1);
if (1 == addr_len && '>' == *(domain + 1))
return NULL;
helo_addr = zbx_strdup(NULL, domain + 1);
helo_addr[addr_len - 1] = '\0';
return helo_addr;
}
static int send_smtp_helo_plain(const char *addr, const char *helo, zbx_socket_t *s, char **error)
{
char cmd[MAX_STRING_LEN], *helo_parsed = NULL;
const char *response;
int ret = SUCCEED;
if ('\0' != *helo)
{
zbx_snprintf(cmd, sizeof(cmd), "HELO %s\r\n", helo);
}
else
{
if (NULL == (helo_parsed = smtp_get_helo_from_addr(addr)))
{
zabbix_log(LOG_LEVEL_DEBUG, "%s() HELO is not specified and failed to parse HELO from email "
"address, trying to form HELO command using system's hostname", __func__);
if (NULL == (helo_parsed = smtp_get_helo_from_system()))
{
*error = zbx_strdup(*error, "failed to retrieve domain name for HELO command");
ret = FAIL;
goto out;
}
}
zbx_snprintf(cmd, sizeof(cmd), "HELO %s\r\n", helo_parsed);
}
if (-1 == zbx_tcp_send_raw(s, cmd))
{
*error = zbx_dsprintf(*error, "error sending HELO to mailserver: %s", zbx_strerror(errno));
ret = FAIL;
goto out;
}
if (FAIL == smtp_readln(s, &response))
{
*error = zbx_dsprintf(*error, "error receiving answer on HELO request: %s", zbx_strerror(errno));
ret = FAIL;
goto out;
}
if (0 != strncmp(response, OK_250, ZBX_CONST_STRLEN(OK_250)))
{
*error = zbx_dsprintf(*error, "wrong answer on HELO \"%s\"", response);
ret = FAIL;
goto out;
}
out:
zbx_free(helo_parsed);
return ret;
}
static const char *socket_error(zbx_socket_t *s, int socket_errno)
{
if (SUCCEED != zbx_socket_check_deadline(s))
return "timeout error";
return zbx_strerror(socket_errno);
}
static int send_email_plain(const char *smtp_server, unsigned short smtp_port, const char *smtp_helo,
zbx_vector_ptr_t *from_mails, zbx_vector_ptr_t *to_mails, const char *inreplyto,
const char *mailsubject, const char *mailbody, unsigned char message_format, int timeout,
const char *config_source_ip, char **error)
{
#define OK_220 "220"
#define OK_251 "251"
#define OK_354 "354"
zbx_socket_t s;
int err, ret = FAIL, i;
char cmd[MAX_STRING_LEN], *cmdp = NULL, *helo_addr = NULL;
const char *response;
/* connect to and receive an initial greeting from SMTP server */
if (FAIL == zbx_tcp_connect(&s, config_source_ip, smtp_server, smtp_port, timeout, ZBX_TCP_SEC_UNENCRYPTED,
NULL, NULL))
{
*error = zbx_dsprintf(*error, "cannot connect to SMTP server \"%s\": %s",
smtp_server, zbx_socket_strerror());
goto out;
}
if (FAIL == smtp_readln(&s, &response))
{
*error = zbx_dsprintf(*error, "error receiving initial string from SMTP server: %s",
socket_error(&s, errno));
goto close;
}
if (0 != strncmp(response, OK_220, ZBX_CONST_STRLEN(OK_220)))
{
*error = zbx_dsprintf(*error, "no welcome message 220* from SMTP server \"%s\"", response);
goto close;
}
/* send HELO */
if (0 != from_mails->values_num)
helo_addr = ((zbx_mailaddr_t *)from_mails->values[0])->addr;
if (FAIL == send_smtp_helo_plain(helo_addr, smtp_helo, &s, error))
goto close;
/* send MAIL FROM */
for (i = 0; i < from_mails->values_num; i++)
{
zbx_snprintf(cmd, sizeof(cmd), "MAIL FROM:%s\r\n", ((zbx_mailaddr_t *)from_mails->values[i])->addr);
if (-1 == zbx_tcp_send_raw(&s, cmd))
{
*error = zbx_dsprintf(*error, "error sending MAIL FROM to mailserver: %s",
socket_error(&s, errno));
goto close;
}
if (FAIL == smtp_readln(&s, &response))
{
*error = zbx_dsprintf(*error, "error receiving answer on MAIL FROM request: %s",
socket_error(&s, errno));
goto close;
}
if (0 != strncmp(response, OK_250, ZBX_CONST_STRLEN(OK_250)))
{
*error = zbx_dsprintf(*error, "wrong answer on MAIL FROM \"%s\"", response);
goto close;
}
}
/* send RCPT TO */
for (i = 0; i < to_mails->values_num; i++)
{
zbx_snprintf(cmd, sizeof(cmd), "RCPT TO:%s\r\n", ((zbx_mailaddr_t *)to_mails->values[i])->addr);
if (-1 == zbx_tcp_send_raw(&s, cmd))
{
*error = zbx_dsprintf(*error, "error sending RCPT TO to mailserver: %s",
socket_error(&s, errno));
goto close;
}
if (FAIL == smtp_readln(&s, &response))
{
*error = zbx_dsprintf(*error, "error receiving answer on RCPT TO request: %s",
socket_error(&s, errno));
goto close;
}
/* May return 251 as well: User not local; will forward to <forward-path>. See RFC825. */
if (0 != strncmp(response, OK_250, ZBX_CONST_STRLEN(OK_250)) &&
0 != strncmp(response, OK_251, ZBX_CONST_STRLEN(OK_251)))
{
*error = zbx_dsprintf(*error, "wrong answer on RCPT TO \"%s\"", response);
goto close;
}
}
/* send DATA */
zbx_snprintf(cmd, sizeof(cmd), "DATA\r\n");
if (-1 == zbx_tcp_send_raw(&s, cmd))
{
*error = zbx_dsprintf(*error, "error sending DATA to mailserver: %s",
socket_error(&s, errno));
goto close;
}
if (FAIL == smtp_readln(&s, &response))
{
*error = zbx_dsprintf(*error, "error receiving answer on DATA request: %s",
socket_error(&s, errno));
goto close;
}
if (0 != strncmp(response, OK_354, ZBX_CONST_STRLEN(OK_354)))
{
*error = zbx_dsprintf(*error, "wrong answer on DATA \"%s\"", response);
goto close;
}
cmdp = smtp_prepare_payload(from_mails, to_mails, inreplyto, mailsubject, mailbody, message_format);
err = zbx_tcp_send_raw(&s, cmdp);
zbx_free(cmdp);
if (-1 == err)
{
*error = zbx_dsprintf(*error, "error sending headers and mail body to mailserver: %s",
socket_error(&s, errno));
goto close;
}
/* send . */
zbx_snprintf(cmd, sizeof(cmd), "\r\n.\r\n");
if (-1 == zbx_tcp_send_raw(&s, cmd))
{
*error = zbx_dsprintf(*error, "error sending . to mailserver: %s",
socket_error(&s, errno));
goto close;
}
if (FAIL == smtp_readln(&s, &response))
{
*error = zbx_dsprintf(*error, "error receiving answer on . request: %s",
socket_error(&s, errno));
goto close;
}
if (0 != strncmp(response, OK_250, ZBX_CONST_STRLEN(OK_250)))
{
*error = zbx_dsprintf(*error, "wrong answer on end of data \"%s\"", response);
goto close;
}
/* send QUIT */
zbx_snprintf(cmd, sizeof(cmd), "QUIT\r\n");
if (-1 == zbx_tcp_send_raw(&s, cmd))
{
*error = zbx_dsprintf(*error, "error sending QUIT to mailserver: %s",
socket_error(&s, errno));
goto close;
}
ret = SUCCEED;
close:
zbx_tcp_close(&s);
out:
return ret;
#undef OK_220
#undef OK_251
#undef OK_354
}
/* SMTP security options */
#define SMTP_SECURITY_NONE 0
#define SMTP_SECURITY_STARTTLS 1
#define SMTP_SECURITY_SSL 2
static int send_email_curl(const char *smtp_server, unsigned short smtp_port, const char *smtp_helo,
zbx_vector_ptr_t *from_mails, zbx_vector_ptr_t *to_mails, const char *inreplyto,
const char *mailsubject, const char *mailbody, unsigned char smtp_security, unsigned char
smtp_verify_peer, unsigned char smtp_verify_host, unsigned char smtp_authentication,
const char *username, const char *password, unsigned char message_format, int timeout,
const char *config_source_ip, const char *config_ssl_ca_location, char **error)
{
#ifdef HAVE_LIBCURL
int ret = FAIL, i;
CURL *easyhandle;
CURLcode err;
char url[MAX_STRING_LEN], errbuf[CURL_ERROR_SIZE] = "";
size_t url_offset= 0;
struct curl_slist *recipients = NULL;
smtp_payload_status_t payload_status;
if (SMTP_SECURITY_NONE != smtp_security && SUCCEED != zbx_curl_has_ssl(error))
goto out;
if (SMTP_AUTHENTICATION_NONE != smtp_authentication && SUCCEED != zbx_curl_has_smtp_auth(error))
goto out;
if (NULL == (easyhandle = curl_easy_init()))
{
*error = zbx_strdup(*error, "cannot initialize cURL library");
goto out;
}
memset(&payload_status, 0, sizeof(payload_status));
if (SMTP_SECURITY_SSL == smtp_security)
{
if (SUCCEED != zbx_curl_protocol("smtps", error))
goto clean;
url_offset += zbx_snprintf(url + url_offset, sizeof(url) - url_offset, "smtps://");
}
else
url_offset += zbx_snprintf(url + url_offset, sizeof(url) - url_offset, "smtp://");
url_offset += zbx_snprintf(url + url_offset, sizeof(url) - url_offset, "%s:%hu", smtp_server, smtp_port);
if ('\0' != *smtp_helo)
{
zbx_snprintf(url + url_offset, sizeof(url) - url_offset, "/%s", smtp_helo);
}
else
{
char *helo_domain = NULL;
if (0 != from_mails->values_num)
{
if (NULL == (helo_domain =
smtp_get_helo_from_addr(((zbx_mailaddr_t *)from_mails->values[0])->addr)))
{
zabbix_log(LOG_LEVEL_DEBUG, "%s() HELO is not specified and failed to parse HELO "
"from email address, trying to form HELO command using system's "
"hostname", __func__);
}
}
if (NULL == helo_domain)
{
if (NULL == (helo_domain = smtp_get_helo_from_system()))
{
*error = zbx_strdup(*error, "failed to retrieve domain name for HELO command");
goto clean;
}
}
zbx_snprintf(url + url_offset, sizeof(url) - url_offset, "/%s", helo_domain);
zbx_free(helo_domain);
}
if (SUCCEED != zbx_curl_setopt_smtps(easyhandle, error))
goto clean;
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_URL, url)))
goto error;
if (SMTP_SECURITY_NONE != smtp_security)
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_SSL_VERIFYPEER,
0 == smtp_verify_peer ? 0L : 1L)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_SSL_VERIFYHOST,
0 == smtp_verify_host ? 0L : 2L)))
{
goto error;
}
if (0 != smtp_verify_peer && NULL != config_ssl_ca_location)
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_CAPATH, config_ssl_ca_location)))
goto error;
}
if (SMTP_SECURITY_STARTTLS == smtp_security)
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL)))
goto error;
}
}
if (SMTP_AUTHENTICATION_NORMAL_PASSWORD == smtp_authentication)
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_USERNAME, username)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_PASSWORD, password)))
{
goto error;
}
/* Don't specify preferred authentication mechanism implying AUTH=* and let libcurl choose the best */
/* one (in its mind) among supported by SMTP server. If someday we decide to let user choose their */
/* preferred authentication mechanism one should know that: */
/* - versions 7.20.0 to 7.30.0 do not support specifying login options */
/* - versions 7.31.0 to 7.33.0 support login options in CURLOPT_USERPWD */
/* - versions 7.34.0 and above support explicit CURLOPT_LOGIN_OPTIONS */
}
if (0 >= from_mails->values_num)
{
zabbix_log(LOG_LEVEL_DEBUG, "%s() sender's address is not specified", __func__);
}
else if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_MAIL_FROM,
((zbx_mailaddr_t *)from_mails->values[0])->addr)))
{
goto error;
}
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_ACCEPT_ENCODING, "")))
goto error;
for (i = 0; i < to_mails->values_num; i++)
recipients = curl_slist_append(recipients, ((zbx_mailaddr_t *)to_mails->values[i])->addr);
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_MAIL_RCPT, recipients)))
goto error;
payload_status.payload = smtp_prepare_payload(from_mails, to_mails, inreplyto, mailsubject, mailbody,
message_format);
payload_status.payload_len = strlen(payload_status.payload);
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_UPLOAD, 1L)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_READFUNCTION, smtp_provide_payload)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_READDATA, &payload_status)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_TIMEOUT, (long)timeout)) ||
CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_ERRORBUFFER, errbuf)))
{
goto error;
}
if (NULL != config_source_ip)
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_INTERFACE, config_source_ip)))
goto error;
}
if (SUCCEED == ZBX_CHECK_LOG_LEVEL(LOG_LEVEL_TRACE))
{
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_VERBOSE, 1L)))
goto error;
if (CURLE_OK != (err = curl_easy_setopt(easyhandle, CURLOPT_DEBUGFUNCTION, smtp_debug_function)))
goto error;
}
if (CURLE_OK != (err = curl_easy_perform(easyhandle)))
{
*error = zbx_dsprintf(*error, "%s%s%s", curl_easy_strerror(err), ('\0' != *errbuf ? ": " : ""),
errbuf);
goto clean;
}
ret = SUCCEED;
goto clean;
error:
*error = zbx_strdup(*error, curl_easy_strerror(err));
clean:
zbx_free(payload_status.payload);
curl_slist_free_all(recipients);
curl_easy_cleanup(easyhandle);
out:
return ret;
#else
ZBX_UNUSED(smtp_server);
ZBX_UNUSED(smtp_port);
ZBX_UNUSED(smtp_helo);
ZBX_UNUSED(from_mails);
ZBX_UNUSED(to_mails);
ZBX_UNUSED(inreplyto);
ZBX_UNUSED(mailsubject);
ZBX_UNUSED(mailbody);
ZBX_UNUSED(smtp_security);
ZBX_UNUSED(smtp_verify_peer);
ZBX_UNUSED(smtp_verify_host);
ZBX_UNUSED(smtp_authentication);
ZBX_UNUSED(username);
ZBX_UNUSED(password);
ZBX_UNUSED(message_format);
ZBX_UNUSED(timeout);
ZBX_UNUSED(config_source_ip);
ZBX_UNUSED(config_ssl_ca_location);
*error = zbx_strdup(*error, "Zabbix server was compiled without cURL library required for SMTP authentication");
return FAIL;
#endif
}
/******************************************************************************
* *
* Purpose: frees the mail address object *
* *
* Parameters: mailaddr - [IN] the mail address *
* *
******************************************************************************/
static void zbx_mailaddr_free(zbx_mailaddr_t *mailaddr)
{
zbx_free(mailaddr->addr);
zbx_free(mailaddr->disp_name);
zbx_free(mailaddr);
}
int send_email(const char *smtp_server, unsigned short smtp_port, const char *smtp_helo, const char *smtp_email,
const char *mailto, const char *inreplyto, const char *mailsubject, const char *mailbody,
unsigned char smtp_security, unsigned char smtp_verify_peer, unsigned char smtp_verify_host,
unsigned char smtp_authentication, const char *username, const char *password,
unsigned char message_format, int timeout, const char *config_source_ip,
const char *config_ssl_ca_location, char **error)
{
int ret = FAIL;
zbx_vector_ptr_t from_mails, to_mails;
zabbix_log(LOG_LEVEL_DEBUG, "In %s() smtp_server:'%s' smtp_port:%hu smtp_security:%d smtp_authentication:%d",
__func__, smtp_server, smtp_port, (int)smtp_security, (int)smtp_authentication);
zbx_vector_ptr_create(&from_mails);
zbx_vector_ptr_create(&to_mails);
/* validate addresses before connecting to the server */
if (SUCCEED != smtp_parse_mailbox(smtp_email, error, &from_mails))
goto clean;
if (SUCCEED != smtp_parse_mailbox(mailto, error, &to_mails))
goto clean;
/* choose appropriate method for sending the email */
if (SMTP_SECURITY_NONE == smtp_security && SMTP_AUTHENTICATION_NONE == smtp_authentication)
{
ret = send_email_plain(smtp_server, smtp_port, smtp_helo, &from_mails, &to_mails, inreplyto,
mailsubject, mailbody, message_format, timeout, config_source_ip, error);
}
else
{
ret = send_email_curl(smtp_server, smtp_port, smtp_helo, &from_mails, &to_mails, inreplyto, mailsubject,
mailbody, smtp_security, smtp_verify_peer, smtp_verify_host, smtp_authentication,
username, password, message_format, timeout, config_source_ip, config_ssl_ca_location,
error);
}
clean:
zbx_vector_ptr_clear_ext(&from_mails, (zbx_clean_func_t)zbx_mailaddr_free);
zbx_vector_ptr_destroy(&from_mails);
zbx_vector_ptr_clear_ext(&to_mails, (zbx_clean_func_t)zbx_mailaddr_free);
zbx_vector_ptr_destroy(&to_mails);
if (FAIL == ret)
zabbix_log(LOG_LEVEL_WARNING, "failed to send email: %s", *error);
zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __func__, zbx_result_string(ret));
return ret;
}
#undef SMTP_SECURITY_NONE
#undef SMTP_SECURITY_STARTTLS
#undef SMTP_SECURITY_SSL
char *zbx_email_make_body(const char *message, unsigned char message_format, const char *attachment_name,
const char *attachment_type, const char *attachment, size_t attachment_size)
{
size_t body_alloc = 0, body_offset = 0;
char *body = NULL, *localbody, *tmp, *tmp_body, *localattachment;
tmp = zbx_string_replace(message, "\r\n", "\n");
tmp_body = zbx_string_replace(tmp, "\n", "\r\n");
localbody = email_encode_part(tmp_body, strlen(tmp_body));
zbx_free(tmp_body);
zbx_free(tmp);
zbx_snprintf_alloc(&body, &body_alloc, &body_offset,
"--" ZBX_MULTIPART_MIXED_BOUNDARY "\r\n"
"Content-Type: %s; charset=\"UTF-8\"\r\n"
"Content-Transfer-Encoding: base64\r\n"
"\r\n"
"%s\r\n"
"\r\n",
ZBX_MEDIA_MESSAGE_FORMAT_HTML == message_format ? "text/html" : "text/plain",
localbody);
zbx_free(localbody);
localattachment = email_encode_part(attachment, attachment_size);
zbx_snprintf_alloc(&body, &body_alloc, &body_offset,
"--" ZBX_MULTIPART_MIXED_BOUNDARY "\r\n"
"Content-Type: %s\r\n"
"Content-Transfer-Encoding: base64\r\n"
"Content-Disposition: attachment; filename=\"%s\"\r\n"
"\r\n"
"%s\r\n"
"\r\n"
"--" ZBX_MULTIPART_MIXED_BOUNDARY "--\r\n",
attachment_type, attachment_name, localattachment);
zbx_free(localattachment);
return body;
}