smtp.c File Reference

Send email to an SMTP server. More...

#include "config.h"
#include <netdb.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include "mutt/lib.h"
#include "address/lib.h"
#include "config/lib.h"
#include "email/lib.h"
#include "conn/lib.h"
#include "smtp.h"
#include "lib.h"
#include "progress/lib.h"
#include "question/lib.h"
#include "mutt_account.h"
#include "mutt_globals.h"
#include "mutt_socket.h"
#include <sasl/sasl.h>
#include <sasl/saslutil.h>
#include "options.h"

Include dependency graph for smtp.c:

Go to the source code of this file.

Data Structures
struct	SmtpAccountData
	Server connection data. More...
struct	SmtpAuth
	SMTP authentication multiplexor. More...

Macros
#define	smtp_success(x)   ((x) / 100 == 2)
#define	SMTP_READY   334
#define	SMTP_CONTINUE   354
#define	SMTP_ERR_READ   -2
#define	SMTP_ERR_WRITE   -3
#define	SMTP_ERR_CODE   -4
#define	SMTP_PORT   25
#define	SMTPS_PORT   465
#define	SMTP_AUTH_SUCCESS   0
#define	SMTP_AUTH_UNAVAIL   1
#define	SMTP_AUTH_FAIL   -1
#define	SMTP_CAP_NO_FLAGS   0
	No flags are set. More...
#define	SMTP_CAP_STARTTLS   (1 << 0)
	Server supports STARTTLS command. More...
#define	SMTP_CAP_AUTH   (1 << 1)
	Server supports AUTH command. More...
#define	SMTP_CAP_DSN   (1 << 2)
	Server supports Delivery Status Notification. More...
#define	SMTP_CAP_EIGHTBITMIME   (1 << 3)
	Server supports 8-bit MIME content. More...
#define	SMTP_CAP_SMTPUTF8   (1 << 4)
	Server accepts UTF-8 strings. More...
#define	SMTP_CAP_ALL   ((1 << 5) - 1)

Typedefs
typedef uint8_t	SmtpCapFlags
	SMTP server capabilities. More...

Functions
static bool	valid_smtp_code (char *buf, size_t buflen, int *n)
	Is the is a valid SMTP return code? More...
static int	smtp_get_resp (struct SmtpAccountData *adata)
	Read a command response from the SMTP server. More...
static int	smtp_rcpt_to (struct SmtpAccountData *adata, const struct AddressList *al)
	Set the recipient to an Address. More...
static int	smtp_data (struct SmtpAccountData *adata, const char *msgfile)
	Send data to an SMTP server. More...
static const char *	smtp_get_field (enum ConnAccountField field, void *gf_data)
	Get connection login credentials - Implements ConnAccount::get_field() More...
static int	smtp_fill_account (struct SmtpAccountData *adata, struct ConnAccount *cac)
	Create ConnAccount object from SMTP Url. More...
static int	smtp_helo (struct SmtpAccountData *adata, bool esmtp)
	Say hello to an SMTP Server. More...
static int	smtp_auth_sasl (struct SmtpAccountData *adata, const char *mechlist)
	Authenticate using SASL. More...
static int	smtp_auth_oauth (struct SmtpAccountData *adata, const char *method)
	Authenticate an SMTP connection using OAUTHBEARER. More...
static int	smtp_auth_plain (struct SmtpAccountData *adata, const char *method)
	Authenticate using plain text. More...
static int	smtp_auth_login (struct SmtpAccountData *adata, const char *method)
	Authenticate using plain text. More...
bool	smtp_auth_is_valid (const char *authenticator)
	Check if string is a valid smtp authentication method. More...
static int	smtp_authenticate (struct SmtpAccountData *adata)
	Authenticate to an SMTP server. More...
static int	smtp_open (struct SmtpAccountData *adata, bool esmtp)
	Open an SMTP Connection. More...
int	mutt_smtp_send (const struct AddressList *from, const struct AddressList *to, const struct AddressList *cc, const struct AddressList *bcc, const char *msgfile, bool eightbit, struct ConfigSubset *sub)
	Send a message using SMTP. More...

Variables
static const struct SmtpAuth	smtp_authenticators []
	Accepted authentication methods. More...

Detailed Description

Send email to an SMTP server.

Authors

• Michael R. Elkins
• Brendan Cully
• Pietro Cerutti

Copyright

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version.

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 General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file smtp.c.

Macro Definition Documentation

smtp_success

#define smtp_success

(

x

)

((x) / 100 == 2)

Definition at line 60 of file smtp.c.

SMTP_READY

#define SMTP_READY   334

Definition at line 61 of file smtp.c.

SMTP_CONTINUE

#define SMTP_CONTINUE   354

Definition at line 62 of file smtp.c.

SMTP_ERR_READ

#define SMTP_ERR_READ   -2

Definition at line 64 of file smtp.c.

SMTP_ERR_WRITE

#define SMTP_ERR_WRITE   -3

Definition at line 65 of file smtp.c.

SMTP_ERR_CODE

#define SMTP_ERR_CODE   -4

Definition at line 66 of file smtp.c.

SMTP_PORT

#define SMTP_PORT   25

Definition at line 68 of file smtp.c.

SMTPS_PORT

#define SMTPS_PORT   465

Definition at line 69 of file smtp.c.

SMTP_AUTH_SUCCESS

#define SMTP_AUTH_SUCCESS   0

Definition at line 71 of file smtp.c.

SMTP_AUTH_UNAVAIL

#define SMTP_AUTH_UNAVAIL   1

Definition at line 72 of file smtp.c.

SMTP_AUTH_FAIL

#define SMTP_AUTH_FAIL   -1

Definition at line 73 of file smtp.c.

SMTP_CAP_NO_FLAGS

#define SMTP_CAP_NO_FLAGS   0

No flags are set.

Definition at line 80 of file smtp.c.

SMTP_CAP_STARTTLS

#define SMTP_CAP_STARTTLS   (1 << 0)

Server supports STARTTLS command.

Definition at line 81 of file smtp.c.

SMTP_CAP_AUTH

#define SMTP_CAP_AUTH   (1 << 1)

Server supports AUTH command.

Definition at line 82 of file smtp.c.

SMTP_CAP_DSN

#define SMTP_CAP_DSN   (1 << 2)

Server supports Delivery Status Notification.

Definition at line 83 of file smtp.c.

SMTP_CAP_EIGHTBITMIME

#define SMTP_CAP_EIGHTBITMIME   (1 << 3)

Server supports 8-bit MIME content.

Definition at line 84 of file smtp.c.

SMTP_CAP_SMTPUTF8

#define SMTP_CAP_SMTPUTF8   (1 << 4)

Server accepts UTF-8 strings.

Definition at line 85 of file smtp.c.

SMTP_CAP_ALL

#define SMTP_CAP_ALL   ((1 << 5) - 1)

Definition at line 87 of file smtp.c.

Typedef Documentation

SmtpCapFlags

typedef uint8_t SmtpCapFlags

SMTP server capabilities.

Flags, e.g. SMTP_CAP_STARTTLS

Definition at line 79 of file smtp.c.

Function Documentation

valid_smtp_code()

static bool valid_smtp_code ( char *  buf, size_t  buflen, int *  n  )

static

Is the is a valid SMTP return code?

Parameters

[in]	buf	String to check
[in]	buflen	Length of string
[out]	n	Numeric value of code

Return values

true	Valid number

Definition at line 126 of file smtp.c.

{
  char code[4];

  if (buflen < 4)
    return false;
  code[0] = buf[0];
  code[1] = buf[1];
  code[2] = buf[2];
  code[3] = '\0';
  if (mutt_str_atoi(code, n) < 0)
    return false;
  return true;
}

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smtp_get_resp()

static int smtp_get_resp ( struct SmtpAccountData *  adata )

static

Read a command response from the SMTP server.

Parameters

adata

SMTP Account data

Return values

0	Success (2xx code) or continue (354 code)
-1	Write error, or any other response code

Definition at line 147 of file smtp.c.

{
  int n;
  char buf[1024];

  do
  {
    n = mutt_socket_readln(buf, sizeof(buf), adata->conn);
    if (n < 4)
    {
      /* read error, or no response code */
      return SMTP_ERR_READ;
    }
    const char *s = buf + 4; /* Skip the response code and the space/dash */
    size_t plen;

    if (mutt_istr_startswith(s, "8BITMIME"))
      adata->capabilities |= SMTP_CAP_EIGHTBITMIME;
    else if ((plen = mutt_istr_startswith(s, "AUTH ")))
    {
      adata->capabilities |= SMTP_CAP_AUTH;
      FREE(&adata->auth_mechs);
      adata->auth_mechs = mutt_str_dup(s + plen);
    }
    else if (mutt_istr_startswith(s, "DSN"))
      adata->capabilities |= SMTP_CAP_DSN;
    else if (mutt_istr_startswith(s, "STARTTLS"))
      adata->capabilities |= SMTP_CAP_STARTTLS;
    else if (mutt_istr_startswith(s, "SMTPUTF8"))
      adata->capabilities |= SMTP_CAP_SMTPUTF8;

    if (!valid_smtp_code(buf, n, &n))
      return SMTP_ERR_CODE;

  } while (buf[3] == '-');

  if (smtp_success(n) || (n == SMTP_CONTINUE))
    return 0;

  mutt_error(_("SMTP session failed: %s"), buf);
  return -1;
}

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smtp_rcpt_to()

static int smtp_rcpt_to ( struct SmtpAccountData *  adata, const struct AddressList *  al  )

static

Set the recipient to an Address.

Parameters

adata	SMTP Account data
al	AddressList to use

Return values

0	Success
<0	Error, e.g. SMTP_ERR_WRITE

Definition at line 197 of file smtp.c.

{
  if (!al)
    return 0;

  const char *const c_dsn_notify = cs_subset_string(adata->sub, "dsn_notify");

  struct Address *a = NULL;
  TAILQ_FOREACH(a, al, entries)
  {
    /* weed out group mailboxes, since those are for display only */
    if (!a->mailbox || a->group)
    {
      continue;
    }
    char buf[1024];
    if ((adata->capabilities & SMTP_CAP_DSN) && c_dsn_notify)
      snprintf(buf, sizeof(buf), "RCPT TO:<%s> NOTIFY=%s\r\n", a->mailbox, c_dsn_notify);
    else
      snprintf(buf, sizeof(buf), "RCPT TO:<%s>\r\n", a->mailbox);
    if (mutt_socket_send(adata->conn, buf) == -1)
      return SMTP_ERR_WRITE;
    int rc = smtp_get_resp(adata);
    if (rc != 0)
      return rc;
  }

  return 0;
}

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smtp_data()

static int smtp_data ( struct SmtpAccountData *  adata, const char *  msgfile  )

static

Send data to an SMTP server.

Parameters

adata	SMTP Account data
msgfile	Filename containing data

Return values

0	Success
<0	Error, e.g. SMTP_ERR_WRITE

Definition at line 234 of file smtp.c.

{
  char buf[1024];
  struct Progress *progress = NULL;
  struct stat st;
  int rc = SMTP_ERR_WRITE;
  int term = 0;
  size_t buflen = 0;

  FILE *fp = fopen(msgfile, "r");
  if (!fp)
  {
    mutt_error(_("SMTP session failed: unable to open %s"), msgfile);
    return -1;
  }
  stat(msgfile, &st);
  unlink(msgfile);
  progress = progress_new(_("Sending message..."), MUTT_PROGRESS_NET, st.st_size);

  snprintf(buf, sizeof(buf), "DATA\r\n");
  if (mutt_socket_send(adata->conn, buf) == -1)
  {
    mutt_file_fclose(&fp);
    goto done;
  }
  rc = smtp_get_resp(adata);
  if (rc != 0)
  {
    mutt_file_fclose(&fp);
    goto done;
  }

  rc = SMTP_ERR_WRITE;
  while (fgets(buf, sizeof(buf) - 1, fp))
  {
    buflen = mutt_str_len(buf);
    term = buflen && buf[buflen - 1] == '\n';
    if (term && ((buflen == 1) || (buf[buflen - 2] != '\r')))
      snprintf(buf + buflen - 1, sizeof(buf) - buflen + 1, "\r\n");
    if (buf[0] == '.')
    {
      if (mutt_socket_send_d(adata->conn, ".", MUTT_SOCK_LOG_FULL) == -1)
      {
        mutt_file_fclose(&fp);
        goto done;
      }
    }
    if (mutt_socket_send_d(adata->conn, buf, MUTT_SOCK_LOG_FULL) == -1)
    {
      mutt_file_fclose(&fp);
      goto done;
    }
    progress_update(progress, ftell(fp), -1);
  }
  if (!term && buflen &&
      (mutt_socket_send_d(adata->conn, "\r\n", MUTT_SOCK_LOG_FULL) == -1))
  {
    mutt_file_fclose(&fp);
    goto done;
  }
  mutt_file_fclose(&fp);

  /* terminate the message body */
  if (mutt_socket_send(adata->conn, ".\r\n") == -1)
    goto done;

  rc = smtp_get_resp(adata);

done:
  progress_free(&progress);
  return rc;
}

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smtp_get_field()

static const char* smtp_get_field ( enum ConnAccountField  field, void *  gf_data  )

static

Get connection login credentials - Implements ConnAccount::get_field()

Definition at line 310 of file smtp.c.

{
  struct SmtpAccountData *adata = gf_data;
  if (!adata)
    return NULL;

  switch (field)
  {
    case MUTT_CA_LOGIN:
    case MUTT_CA_USER:
    {
      const char *const c_smtp_user = cs_subset_string(adata->sub, "smtp_user");
      return c_smtp_user;
    }
    case MUTT_CA_PASS:
    {
      const char *const c_smtp_pass = cs_subset_string(adata->sub, "smtp_pass");
      return c_smtp_pass;
    }
    case MUTT_CA_OAUTH_CMD:
    {
      const char *const c_smtp_oauth_refresh_command =
          cs_subset_string(adata->sub, "smtp_oauth_refresh_command");
      return c_smtp_oauth_refresh_command;
    }
    case MUTT_CA_HOST:
    default:
      return NULL;
  }
}

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smtp_fill_account()

static int smtp_fill_account ( struct SmtpAccountData *  adata, struct ConnAccount *  cac  )

static

Create ConnAccount object from SMTP Url.

Parameters

adata	SMTP Account data
cac	ConnAccount to populate

Return values

0	Success
-1	Error

Definition at line 348 of file smtp.c.

{
  cac->flags = 0;
  cac->port = 0;
  cac->type = MUTT_ACCT_TYPE_SMTP;
  cac->service = "smtp";
  cac->get_field = smtp_get_field;
  cac->gf_data = adata;

  const char *const c_smtp_url = cs_subset_string(adata->sub, "smtp_url");

  struct Url *url = url_parse(c_smtp_url);
  if (!url || ((url->scheme != U_SMTP) && (url->scheme != U_SMTPS)) ||
      !url->host || (mutt_account_fromurl(cac, url) < 0))
  {
    url_free(&url);
    mutt_error(_("Invalid SMTP URL: %s"), c_smtp_url);
    return -1;
  }

  if (url->scheme == U_SMTPS)
    cac->flags |= MUTT_ACCT_SSL;

  if (cac->port == 0)
  {
    if (cac->flags & MUTT_ACCT_SSL)
      cac->port = SMTPS_PORT;
    else
    {
      static unsigned short SmtpPort = 0;
      if (SmtpPort == 0)
      {
        struct servent *service = getservbyname("smtp", "tcp");
        if (service)
          SmtpPort = ntohs(service->s_port);
        else
          SmtpPort = SMTP_PORT;
        mutt_debug(LL_DEBUG3, "Using default SMTP port %d\n", SmtpPort);
      }
      cac->port = SmtpPort;
    }
  }

  url_free(&url);
  return 0;
}

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smtp_helo()

static int smtp_helo ( struct SmtpAccountData *  adata, bool  esmtp  )

static

Say hello to an SMTP Server.

Parameters

adata	SMTP Account data
esmtp	If true, use ESMTP

Return values

0	Success
<0	Error, e.g. SMTP_ERR_WRITE

Definition at line 402 of file smtp.c.

{
  adata->capabilities = SMTP_CAP_NO_FLAGS;

  if (!esmtp)
  {
    /* if TLS or AUTH are requested, use EHLO */
    if (adata->conn->account.flags & MUTT_ACCT_USER)
      esmtp = true;
#ifdef USE_SSL
    const bool c_ssl_force_tls = cs_subset_bool(adata->sub, "ssl_force_tls");
    const enum QuadOption c_ssl_starttls =
        cs_subset_quad(adata->sub, "ssl_starttls");

    if (c_ssl_force_tls || (c_ssl_starttls != MUTT_NO))
      esmtp = true;
#endif
  }

  char buf[1024];
  snprintf(buf, sizeof(buf), "%s %s\r\n", esmtp ? "EHLO" : "HELO", adata->fqdn);
  /* XXX there should probably be a wrapper in mutt_socket.c that
   * repeatedly calls adata->conn->write until all data is sent.  This
   * currently doesn't check for a short write.  */
  if (mutt_socket_send(adata->conn, buf) == -1)
    return SMTP_ERR_WRITE;
  return smtp_get_resp(adata);
}

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smtp_auth_sasl()

static int smtp_auth_sasl ( struct SmtpAccountData *  adata, const char *  mechlist  )

static

Authenticate using SASL.

Parameters

adata	SMTP Account data
mechlist	List of mechanisms to use

Return values

0	Success
<0	Error, e.g. SMTP_AUTH_FAIL

Definition at line 439 of file smtp.c.

{
  sasl_conn_t *saslconn = NULL;
  sasl_interact_t *interaction = NULL;
  const char *mech = NULL;
  const char *data = NULL;
  unsigned int len;
  char *buf = NULL;
  size_t bufsize = 0;
  int rc, saslrc;

  if (mutt_sasl_client_new(adata->conn, &saslconn) < 0)
    return SMTP_AUTH_FAIL;

  do
  {
    rc = sasl_client_start(saslconn, mechlist, &interaction, &data, &len, &mech);
    if (rc == SASL_INTERACT)
      mutt_sasl_interact(interaction);
  } while (rc == SASL_INTERACT);

  if ((rc != SASL_OK) && (rc != SASL_CONTINUE))
  {
    mutt_debug(LL_DEBUG2, "%s unavailable\n", NONULL(mech));
    sasl_dispose(&saslconn);
    return SMTP_AUTH_UNAVAIL;
  }

  if (!OptNoCurses)
  {
    // L10N: (%s) is the method name, e.g. Anonymous, CRAM-MD5, GSSAPI, SASL
    mutt_message(_("Authenticating (%s)..."), mech);
  }

  bufsize = MAX((len * 2), 1024);
  buf = mutt_mem_malloc(bufsize);

  snprintf(buf, bufsize, "AUTH %s", mech);
  if (len)
  {
    mutt_str_cat(buf, bufsize, " ");
    if (sasl_encode64(data, len, buf + mutt_str_len(buf),
                      bufsize - mutt_str_len(buf), &len) != SASL_OK)
    {
      mutt_debug(LL_DEBUG1, "#1 error base64-encoding client response\n");
      goto fail;
    }
  }
  mutt_str_cat(buf, bufsize, "\r\n");

  do
  {
    if (mutt_socket_send(adata->conn, buf) < 0)
      goto fail;
    rc = mutt_socket_readln_d(buf, bufsize, adata->conn, MUTT_SOCK_LOG_FULL);
    if (rc < 0)
      goto fail;
    if (!valid_smtp_code(buf, rc, &rc))
      goto fail;

    if (rc != SMTP_READY)
      break;

    if (sasl_decode64(buf + 4, strlen(buf + 4), buf, bufsize - 1, &len) != SASL_OK)
    {
      mutt_debug(LL_DEBUG1, "error base64-decoding server response\n");
      goto fail;
    }

    do
    {
      saslrc = sasl_client_step(saslconn, buf, len, &interaction, &data, &len);
      if (saslrc == SASL_INTERACT)
        mutt_sasl_interact(interaction);
    } while (saslrc == SASL_INTERACT);

    if (len)
    {
      if ((len * 2) > bufsize)
      {
        bufsize = len * 2;
        mutt_mem_realloc(&buf, bufsize);
      }
      if (sasl_encode64(data, len, buf, bufsize, &len) != SASL_OK)
      {
        mutt_debug(LL_DEBUG1, "#2 error base64-encoding client response\n");
        goto fail;
      }
    }
    mutt_str_copy(buf + len, "\r\n", bufsize - len);
  } while (rc == SMTP_READY && saslrc != SASL_FAIL);

  if (smtp_success(rc))
  {
    mutt_sasl_setup_conn(adata->conn, saslconn);
    FREE(&buf);
    return SMTP_AUTH_SUCCESS;
  }

fail:
  sasl_dispose(&saslconn);
  FREE(&buf);
  return SMTP_AUTH_FAIL;
}

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smtp_auth_oauth()

static int smtp_auth_oauth ( struct SmtpAccountData *  adata, const char *  method  )

static

Authenticate an SMTP connection using OAUTHBEARER.

Parameters

adata	SMTP Account data
method	Authentication method (not used)

Return values

num	Result, e.g. SMTP_AUTH_SUCCESS

Definition at line 551 of file smtp.c.

{
  (void) method; // This is OAUTHBEARER

  // L10N: (%s) is the method name, e.g. Anonymous, CRAM-MD5, GSSAPI, SASL
  mutt_message(_("Authenticating (%s)..."), "OAUTHBEARER");

  /* We get the access token from the smtp_oauth_refresh_command */
  char *oauthbearer = mutt_account_getoauthbearer(&adata->conn->account);
  if (!oauthbearer)
    return SMTP_AUTH_FAIL;

  size_t ilen = strlen(oauthbearer) + 30;
  char *ibuf = mutt_mem_malloc(ilen);
  snprintf(ibuf, ilen, "AUTH OAUTHBEARER %s\r\n", oauthbearer);

  int rc = mutt_socket_send(adata->conn, ibuf);
  FREE(&oauthbearer);
  FREE(&ibuf);

  if (rc == -1)
    return SMTP_AUTH_FAIL;
  if (smtp_get_resp(adata) != 0)
    return SMTP_AUTH_FAIL;

  return SMTP_AUTH_SUCCESS;
}

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smtp_auth_plain()

static int smtp_auth_plain ( struct SmtpAccountData *  adata, const char *  method  )

static

Authenticate using plain text.

Parameters

adata	SMTP Account data
method	Authentication method (not used)

Return values

0	Success
<0	Error, e.g. SMTP_AUTH_FAIL

Definition at line 586 of file smtp.c.

{
  (void) method; // This is PLAIN

  char buf[1024];

  /* Get username and password. Bail out of any can't be retrieved. */
  if ((mutt_account_getuser(&adata->conn->account) < 0) ||
      (mutt_account_getpass(&adata->conn->account) < 0))
  {
    goto error;
  }

  /* Build the initial client response. */
  size_t len =
      mutt_sasl_plain_msg(buf, sizeof(buf), "AUTH PLAIN", adata->conn->account.user,
                          adata->conn->account.user, adata->conn->account.pass);

  /* Terminate as per SMTP protocol. Bail out if there's no room left. */
  if (snprintf(buf + len, sizeof(buf) - len, "\r\n") != 2)
  {
    goto error;
  }

  /* Send request, receive response (with a check for OK code). */
  if ((mutt_socket_send(adata->conn, buf) < 0) || smtp_get_resp(adata))
  {
    goto error;
  }

  /* If we got here, auth was successful. */
  return 0;

error:
  // L10N: %s is the method name, e.g. Anonymous, CRAM-MD5, GSSAPI, SASL
  mutt_error(_("%s authentication failed"), "SASL");
  return -1;
}

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smtp_auth_login()

static int smtp_auth_login ( struct SmtpAccountData *  adata, const char *  method  )

static

Authenticate using plain text.

Parameters

adata	SMTP Account data
method	Authentication method (not used)

Return values

0	Success
<0	Error, e.g. SMTP_AUTH_FAIL

Definition at line 632 of file smtp.c.

{
  (void) method; // This is LOGIN

  char b64[1024] = { 0 };
  char buf[1024] = { 0 };

  /* Get username and password. Bail out of any can't be retrieved. */
  if ((mutt_account_getuser(&adata->conn->account) < 0) ||
      (mutt_account_getpass(&adata->conn->account) < 0))
  {
    goto error;
  }

  /* Send the AUTH LOGIN request. */
  if (mutt_socket_send(adata->conn, "AUTH LOGIN\r\n") < 0)
  {
    goto error;
  }

  /* Read the 334 VXNlcm5hbWU6 challenge ("Username:" base64-encoded) */
  mutt_socket_readln_d(buf, sizeof(buf), adata->conn, MUTT_SOCK_LOG_FULL);
  if (!mutt_str_equal(buf, "334 VXNlcm5hbWU6"))
  {
    goto error;
  }

  /* Send the username */
  size_t len = snprintf(buf, sizeof(buf), "%s", adata->conn->account.user);
  mutt_b64_encode(buf, len, b64, sizeof(b64));
  snprintf(buf, sizeof(buf), "%s\r\n", b64);
  if (mutt_socket_send(adata->conn, buf) < 0)
  {
    goto error;
  }

  /* Read the 334 UGFzc3dvcmQ6 challenge ("Password:" base64-encoded) */
  mutt_socket_readln_d(buf, sizeof(buf), adata->conn, MUTT_SOCK_LOG_FULL);
  if (!mutt_str_equal(buf, "334 UGFzc3dvcmQ6"))
  {
    goto error;
  }

  /* Send the password */
  len = snprintf(buf, sizeof(buf), "%s", adata->conn->account.pass);
  mutt_b64_encode(buf, len, b64, sizeof(b64));
  snprintf(buf, sizeof(buf), "%s\r\n", b64);
  if (mutt_socket_send(adata->conn, buf) < 0)
  {
    goto error;
  }

  /* Check the final response */
  if (smtp_get_resp(adata) < 0)
  {
    goto error;
  }

  /* If we got here, auth was successful. */
  return 0;

error:
  // L10N: %s is the method name, e.g. Anonymous, CRAM-MD5, GSSAPI, SASL
  mutt_error(_("%s authentication failed"), "LOGIN");
  return -1;
}

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smtp_auth_is_valid()

bool smtp_auth_is_valid

(

const char *

authenticator

)

Check if string is a valid smtp authentication method.

Parameters

authenticator

Authenticator string to check

Return values

true	Argument is a valid auth method

Validate whether an input string is an accepted smtp authentication method as defined by smtp_authenticators.

Definition at line 719 of file smtp.c.

{
  for (size_t i = 0; i < mutt_array_size(smtp_authenticators); i++)
  {
    const struct SmtpAuth *auth = &smtp_authenticators[i];
    if (auth->method && mutt_istr_equal(auth->method, authenticator))
      return true;
  }

  return false;
}

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smtp_authenticate()

static int smtp_authenticate ( struct SmtpAccountData *  adata )

static

Authenticate to an SMTP server.

Parameters

adata

SMTP Account data

Return values

0	Success
<0	Error, e.g. SMTP_AUTH_FAIL

Definition at line 737 of file smtp.c.

{
  int r = SMTP_AUTH_UNAVAIL;

  const struct Slist *c_smtp_authenticators =
      cs_subset_slist(adata->sub, "smtp_authenticators");
  if (c_smtp_authenticators && (c_smtp_authenticators->count > 0))
  {
    mutt_debug(LL_DEBUG2, "Trying user-defined smtp_authenticators\n");

    /* Try user-specified list of authentication methods */
    struct ListNode *np = NULL;
    STAILQ_FOREACH(np, &c_smtp_authenticators->head, entries)
    {
      mutt_debug(LL_DEBUG2, "Trying method %s\n", np->data);

      for (size_t i = 0; i < mutt_array_size(smtp_authenticators); i++)
      {
        const struct SmtpAuth *auth = &smtp_authenticators[i];
        if (!auth->method || mutt_istr_equal(auth->method, np->data))
        {
          r = auth->authenticate(adata, np->data);
          if (r == SMTP_AUTH_SUCCESS)
            return r;
        }
      }
    }
  }
  else
  {
    /* Fall back to default: any authenticator */
    mutt_debug(LL_DEBUG2, "Falling back to smtp_auth_sasl, if using sasl.\n");

#ifdef USE_SASL
    r = smtp_auth_sasl(adata, adata->auth_mechs);
#else
    mutt_error(_("SMTP authentication requires SASL"));
    r = SMTP_AUTH_UNAVAIL;
#endif
  }

  if (r != SMTP_AUTH_SUCCESS)
    mutt_account_unsetpass(&adata->conn->account);

  if (r == SMTP_AUTH_FAIL)
  {
    // L10N: %s is the method name, e.g. Anonymous, CRAM-MD5, GSSAPI, SASL
    mutt_error(_("%s authentication failed"), "SASL");
  }
  else if (r == SMTP_AUTH_UNAVAIL)
  {
    mutt_error(_("No authenticators available"));
  }

  return (r == SMTP_AUTH_SUCCESS) ? 0 : -1;
}

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smtp_open()

static int smtp_open ( struct SmtpAccountData *  adata, bool  esmtp  )

static

Open an SMTP Connection.

Parameters

adata	SMTP Account data
esmtp	If true, use ESMTP

Return values

0	Success
-1	Error

Definition at line 801 of file smtp.c.

{
  int rc;

  if (mutt_socket_open(adata->conn))
    return -1;

  /* get greeting string */
  rc = smtp_get_resp(adata);
  if (rc != 0)
    return rc;

  rc = smtp_helo(adata, esmtp);
  if (rc != 0)
    return rc;

#ifdef USE_SSL
  const bool c_ssl_force_tls = cs_subset_bool(adata->sub, "ssl_force_tls");
  const enum QuadOption c_ssl_starttls =
      cs_subset_quad(adata->sub, "ssl_starttls");
  enum QuadOption ans = MUTT_NO;
  if (adata->conn->ssf != 0)
    ans = MUTT_NO;
  else if (c_ssl_force_tls)
    ans = MUTT_YES;
  else if ((adata->capabilities & SMTP_CAP_STARTTLS) &&
           ((ans = query_quadoption(c_ssl_starttls,
                                    _("Secure connection with TLS?"))) == MUTT_ABORT))
  {
    return -1;
  }

  if (ans == MUTT_YES)
  {
    if (mutt_socket_send(adata->conn, "STARTTLS\r\n") < 0)
      return SMTP_ERR_WRITE;
    rc = smtp_get_resp(adata);
    // Clear any data after the STARTTLS acknowledgement
    mutt_socket_empty(adata->conn);
    if (rc != 0)
      return rc;

    if (mutt_ssl_starttls(adata->conn))
    {
      mutt_error(_("Could not negotiate TLS connection"));
      return -1;
    }

    /* re-EHLO to get authentication mechanisms */
    rc = smtp_helo(adata, esmtp);
    if (rc != 0)
      return rc;
  }
#endif

  if (adata->conn->account.flags & MUTT_ACCT_USER)
  {
    if (!(adata->capabilities & SMTP_CAP_AUTH))
    {
      mutt_error(_("SMTP server does not support authentication"));
      return -1;
    }

    return smtp_authenticate(adata);
  }

  return 0;
}

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mutt_smtp_send()

int mutt_smtp_send	(	const struct AddressList *	from,
		const struct AddressList *	to,
		const struct AddressList *	cc,
		const struct AddressList *	bcc,
		const char *	msgfile,
		bool	eightbit,
		struct ConfigSubset *	sub
	)

Send a message using SMTP.

Parameters

from	From Address
to	To Address
cc	Cc Address
bcc	Bcc Address
msgfile	Message to send to the server
eightbit	If true, try for an 8-bit friendly connection
sub	Config Subset

Return values

0	Success
-1	Error

Definition at line 882 of file smtp.c.

{
  struct SmtpAccountData adata = { 0 };
  struct ConnAccount cac = { { 0 } };
  const char *envfrom = NULL;
  char buf[1024];
  int rc = -1;

  adata.sub = sub;
  adata.fqdn = mutt_fqdn(false, adata.sub);
  if (!adata.fqdn)
    adata.fqdn = NONULL(ShortHostname);

  const struct Address *c_envelope_from_address =
      cs_subset_address(adata.sub, "envelope_from_address");

  /* it might be better to synthesize an envelope from from user and host
   * but this condition is most likely arrived at accidentally */
  if (c_envelope_from_address)
    envfrom = c_envelope_from_address->mailbox;
  else if (from && !TAILQ_EMPTY(from))
    envfrom = TAILQ_FIRST(from)->mailbox;
  else
  {
    mutt_error(_("No from address given"));
    return -1;
  }

  if (smtp_fill_account(&adata, &cac) < 0)
    return rc;

  adata.conn = mutt_conn_find(&cac);
  if (!adata.conn)
    return -1;

  const char *const c_dsn_return = cs_subset_string(adata.sub, "dsn_return");

  do
  {
    /* send our greeting */
    rc = smtp_open(&adata, eightbit);
    if (rc != 0)
      break;
    FREE(&adata.auth_mechs);

    /* send the sender's address */
    int len = snprintf(buf, sizeof(buf), "MAIL FROM:<%s>", envfrom);
    if (eightbit && (adata.capabilities & SMTP_CAP_EIGHTBITMIME))
    {
      mutt_strn_cat(buf, sizeof(buf), " BODY=8BITMIME", 15);
      len += 14;
    }
    if (c_dsn_return && (adata.capabilities & SMTP_CAP_DSN))
      len += snprintf(buf + len, sizeof(buf) - len, " RET=%s", c_dsn_return);
    if ((adata.capabilities & SMTP_CAP_SMTPUTF8) &&
        (mutt_addr_uses_unicode(envfrom) || mutt_addrlist_uses_unicode(to) ||
         mutt_addrlist_uses_unicode(cc) || mutt_addrlist_uses_unicode(bcc)))
    {
      snprintf(buf + len, sizeof(buf) - len, " SMTPUTF8");
    }
    mutt_strn_cat(buf, sizeof(buf), "\r\n", 3);
    if (mutt_socket_send(adata.conn, buf) == -1)
    {
      rc = SMTP_ERR_WRITE;
      break;
    }
    rc = smtp_get_resp(&adata);
    if (rc != 0)
      break;

    /* send the recipient list */
    if ((rc = smtp_rcpt_to(&adata, to)) || (rc = smtp_rcpt_to(&adata, cc)) ||
        (rc = smtp_rcpt_to(&adata, bcc)))
    {
      break;
    }

    /* send the message data */
    rc = smtp_data(&adata, msgfile);
    if (rc != 0)
      break;

    mutt_socket_send(adata.conn, "QUIT\r\n");

    rc = 0;
  } while (false);

  mutt_socket_close(adata.conn);
  FREE(&adata.conn);

  if (rc == SMTP_ERR_READ)
    mutt_error(_("SMTP session failed: read error"));
  else if (rc == SMTP_ERR_WRITE)
    mutt_error(_("SMTP session failed: write error"));
  else if (rc == SMTP_ERR_CODE)
    mutt_error(_("Invalid server response"));

  return rc;
}

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Variable Documentation

smtp_authenticators

const struct SmtpAuth smtp_authenticators[]

static

Initial value:

= {
  { smtp_auth_oauth, "oauthbearer" },
  { smtp_auth_plain, "plain" },
  { smtp_auth_login, "login" },

  { smtp_auth_sasl, NULL },

}

Accepted authentication methods.

Definition at line 702 of file smtp.c.