-/* $Cambridge: exim/src/src/auths/dovecot.c,v 1.3 2006/10/16 15:44:36 ph10 Exp $ */
-
/*
* Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
+ * Copyright (c) 2006-2017 The Exim Maintainers
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* (at your option) any later version.
*/
+/* A number of modifications have been made to the original code. Originally I
+commented them specially, but now they are getting quite extensive, so I have
+ceased doing that. The biggest change is to use unbuffered I/O on the socket
+because using C buffered I/O gives problems on some operating systems. PH */
+
+/* Protocol specifications:
+ * Dovecot 1, protocol version 1.1
+ * http://wiki.dovecot.org/Authentication%20Protocol
+ *
+ * Dovecot 2, protocol version 1.1
+ * http://wiki2.dovecot.org/Design/AuthProtocol
+ */
+
#include "../exim.h"
#include "dovecot.h"
#define VERSION_MAJOR 1
#define VERSION_MINOR 0
+/* http://wiki.dovecot.org/Authentication%20Protocol
+"The maximum line length isn't defined,
+ but it's currently expected to fit into 8192 bytes"
+*/
+#define DOVECOT_AUTH_MAXLINELEN 8192
+
+/* This was hard-coded as 8.
+AUTH req C->S sends {"AUTH", id, mechanism, service } + params, 5 defined for
+Dovecot 1; Dovecot 2 (same protocol version) defines 9.
+
+Master->Server sends {"USER", id, userid} + params, 6 defined.
+Server->Client only gives {"OK", id} + params, unspecified, only 1 guaranteed.
+
+We only define here to accept S->C; max seen is 3+<unspecified>, plus the two
+for the command and id, where unspecified might include _at least_ user=...
+
+So: allow for more fields than we ever expect to see, while aware that count
+can go up without changing protocol version.
+The cost is the length of an array of pointers on the stack.
+*/
+#define DOVECOT_AUTH_MAXFIELDCOUNT 16
+
/* Options specific to the authentication mechanism. */
optionlist auth_dovecot_options[] = {
{
- "server_socket",
- opt_stringptr,
- (void *)(offsetof(auth_dovecot_options_block, server_socket))
+ "server_socket",
+ opt_stringptr,
+ (void *)(offsetof(auth_dovecot_options_block, server_socket))
},
};
/* Size of the options list. An extern variable has to be used so that its
address can appear in the tables drtables.c. */
+
int auth_dovecot_options_count =
sizeof(auth_dovecot_options) / sizeof(optionlist);
/* Default private options block for the authentication method. */
+
auth_dovecot_options_block auth_dovecot_option_defaults = {
NULL, /* server_socket */
};
+
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+void auth_dovecot_init(auth_instance *ablock) {}
+int auth_dovecot_server(auth_instance *ablock, uschar *data) {return 0;}
+int auth_dovecot_client(auth_instance *ablock, void * sx,
+ int timeout, uschar *buffer, int buffsize) {return 0;}
+
+#else /*!MACRO_PREDEF*/
+
+
+/* Static variables for reading from the socket */
+
+static uschar sbuffer[256];
+static int socket_buffer_left;
+
+
+
/*************************************************
* Initialization entry point *
*************************************************/
/* Called for each instance, after its options have been read, to
enable consistency checks to be done, or anything else that needs
to be set up. */
+
void auth_dovecot_init(auth_instance *ablock)
{
auth_dovecot_options_block *ob =
ablock->client = FALSE;
}
-static int strcut(char *str, char **ptrs, int nptrs)
+/*************************************************
+ * "strcut" to split apart server lines *
+ *************************************************/
+
+/* Dovecot auth protocol uses TAB \t as delimiter; a line consists
+of a command-name, TAB, and then any parameters, each separated by a TAB.
+A parameter can be param=value or a bool, just param.
+
+This function modifies the original str in-place, inserting NUL characters.
+It initialises ptrs entries, setting all to NULL and only setting
+non-NULL N entries, where N is the return value, the number of fields seen
+(one more than the number of tabs).
+
+Note that the return value will always be at least 1, is the count of
+actual fields (so last valid offset into ptrs is one less).
+*/
+
+static int
+strcut(uschar *str, uschar **ptrs, int nptrs)
+{
+uschar *last_sub_start = str;
+int n;
+
+for (n = 0; n < nptrs; n++)
+ ptrs[n] = NULL;
+n = 1;
+
+while (*str)
+ {
+ if (*str == '\t')
+ {
+ if (n <= nptrs)
+ {
+ *ptrs++ = last_sub_start;
+ last_sub_start = str + 1;
+ *str = '\0';
+ }
+ n++;
+ }
+ str++;
+ }
+
+/* It's acceptable for the string to end with a tab character. We see
+this in AUTH PLAIN without an initial response from the client, which
+causing us to send "334 " and get the data from the client. */
+if (n <= nptrs)
+ *ptrs = last_sub_start;
+else
+ {
+ HDEBUG(D_auth) debug_printf("dovecot: warning: too many results from tab-splitting; saw %d fields, room for %d\n", n, nptrs);
+ n = nptrs;
+ }
+
+return n <= nptrs ? n : nptrs;
+}
+
+static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED;
+static void
+debug_strcut(uschar **ptrs, int nlen, int alen)
{
- char *tmp = str;
- int n;
-
- for (n = 0; n < nptrs; n++)
- ptrs[n] = NULL;
- n = 1;
-
- while (*str) {
- if (*str == '\t') {
- if (n <= nptrs) {
- *ptrs++ = tmp;
- tmp = str + 1;
- *str = 0;
- }
- n++;
- }
- str++;
- }
-
- if (n < nptrs)
- *ptrs = tmp;
-
- return n;
+int i;
+debug_printf("%d read but unreturned bytes; strcut() gave %d results: ",
+ socket_buffer_left, nlen);
+for (i = 0; i < nlen; i++)
+ debug_printf(" {%s}", ptrs[i]);
+if (nlen < alen)
+ debug_printf(" last is %s\n", ptrs[i] ? ptrs[i] : US"<null>");
+else
+ debug_printf(" (max for capacity)\n");
}
#define CHECK_COMMAND(str, arg_min, arg_max) do { \
- if (strcasecmp((str), args[0]) != 0) \
+ if (strcmpic(US(str), args[0]) != 0) \
goto out; \
if (nargs - 1 < (arg_min)) \
goto out; \
- if (nargs - 1 > (arg_max)) \
+ if ( (arg_max != -1) && (nargs - 1 > (arg_max)) ) \
goto out; \
} while (0)
/*************************************************
- * Server entry point *
- *************************************************/
+* "fgets" to read directly from socket *
+*************************************************/
+
+/* Added by PH after a suggestion by Steve Usher because the previous use of
+C-style buffered I/O gave trouble. */
-int auth_dovecot_server(auth_instance *ablock, uschar *data)
+static uschar *
+dc_gets(uschar *s, int n, int fd)
{
- auth_dovecot_options_block *ob =
- (auth_dovecot_options_block *)(ablock->options_block);
- struct sockaddr_un sa;
- char buffer[4096];
- char *args[8];
- uschar *auth_command;
- uschar *auth_extra_data = US"";
- int nargs, tmp;
- int cuid = 0, cont = 1, found = 0, fd, ret = DEFER;
- FILE *f;
-
- HDEBUG(D_auth) debug_printf("dovecot authentication\n");
-
- memset(&sa, 0, sizeof(sa));
- sa.sun_family = AF_UNIX;
-
- /* This was the original code here: it is nonsense because strncpy()
- does not return an integer. I have converted this to use the function
- that formats and checks length. PH */
-
- /*
- if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) {
- */
-
- if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s",
- ob->server_socket)) {
- auth_defer_msg = US"authentication socket path too long";
- return DEFER;
- }
-
- auth_defer_msg = US"authentication socket connection error";
-
- fd = socket(PF_UNIX, SOCK_STREAM, 0);
- if (fd < 0)
- return DEFER;
-
- if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
- goto out;
-
- f = fdopen(fd, "a+");
- if (f == NULL)
- goto out;
-
- auth_defer_msg = US"authentication socket protocol error";
-
- while (cont) {
- if (fgets(buffer, sizeof(buffer), f) == NULL)
- OUT("authentication socket read error or premature eof");
-
- buffer[strlen(buffer) - 1] = 0;
- HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
- nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
-
- switch (toupper(*args[0])) {
- case 'C':
- CHECK_COMMAND("CUID", 1, 1);
- cuid = atoi(args[1]);
- break;
-
- case 'D':
- CHECK_COMMAND("DONE", 0, 0);
- cont = 0;
- break;
-
- case 'M':
- CHECK_COMMAND("MECH", 1, INT_MAX);
- if (strcmpic(US args[1], ablock->public_name) == 0)
- found = 1;
- break;
-
- case 'S':
- CHECK_COMMAND("SPID", 1, 1);
- break;
-
- case 'V':
- CHECK_COMMAND("VERSION", 2, 2);
- if (atoi(args[1]) != VERSION_MAJOR)
- OUT("authentication socket protocol version mismatch");
- break;
-
- default:
- goto out;
- }
- }
-
- if (!found)
- goto out;
-
- /* Added by PH: data must not contain tab (as it is
- b64 it shouldn't, but check for safety). */
-
- if (Ustrchr(data, '\t') != NULL) {
- ret = FAIL;
- goto out;
- }
-
- /* Added by PH: extra fields when TLS is in use or if the TCP/IP
- connection is local. */
-
- if (tls_cipher != NULL)
- auth_extra_data = string_sprintf("secured\t%s%s",
- tls_certificate_verified? "valid-client-cert" : "",
- tls_certificate_verified? "\t" : "");
- else if (Ustrcmp(sender_host_address, interface_address) == 0)
- auth_extra_data = US"secured\t";
+int p = 0;
+int count = 0;
+
+for (;;)
+ {
+ if (socket_buffer_left == 0)
+ {
+ if ((socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer))) <= 0)
+ if (count == 0) return NULL; else break;
+ p = 0;
+ }
+
+ while (p < socket_buffer_left)
+ {
+ if (count >= n - 1) break;
+ s[count++] = sbuffer[p];
+ if (sbuffer[p++] == '\n') break;
+ }
+
+ memmove(sbuffer, sbuffer + p, socket_buffer_left - p);
+ socket_buffer_left -= p;
+
+ if (s[count-1] == '\n' || count >= n - 1) break;
+ }
+
+s[count] = '\0';
+return s;
+}
+
+
+
+
+/*************************************************
+* Server entry point *
+*************************************************/
+
+int
+auth_dovecot_server(auth_instance * ablock, uschar * data)
+{
+auth_dovecot_options_block *ob =
+ (auth_dovecot_options_block *) ablock->options_block;
+struct sockaddr_un sa;
+uschar buffer[DOVECOT_AUTH_MAXLINELEN];
+uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT];
+uschar *auth_command;
+uschar *auth_extra_data = US"";
+uschar *p;
+int nargs, tmp;
+int crequid = 1, cont = 1, fd = -1, ret = DEFER;
+BOOL found = FALSE, have_mech_line = FALSE;
+
+HDEBUG(D_auth) debug_printf("dovecot authentication\n");
+
+if (!data)
+ {
+ ret = FAIL;
+ goto out;
+ }
+
+memset(&sa, 0, sizeof(sa));
+sa.sun_family = AF_UNIX;
+
+/* This was the original code here: it is nonsense because strncpy()
+does not return an integer. I have converted this to use the function
+that formats and checks length. PH */
+
+/*
+if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) {
+}
+*/
+
+if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s",
+ ob->server_socket))
+ {
+ auth_defer_msg = US"authentication socket path too long";
+ return DEFER;
+ }
+
+auth_defer_msg = US"authentication socket connection error";
+
+if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+ return DEFER;
+
+if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
+ goto out;
+
+auth_defer_msg = US"authentication socket protocol error";
+
+socket_buffer_left = 0; /* Global, used to read more than a line but return by line */
+while (cont)
+ {
+ if (dc_gets(buffer, sizeof(buffer), fd) == NULL)
+ OUT("authentication socket read error or premature eof");
+ p = buffer + Ustrlen(buffer) - 1;
+ if (*p != '\n')
+ OUT("authentication socket protocol line too long");
+
+ *p = '\0';
+ HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
+
+ nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
+
+ /* HDEBUG(D_auth) debug_strcut(args, nargs, sizeof(args) / sizeof(args[0])); */
+
+ /* Code below rewritten by Kirill Miazine (km@krot.org). Only check commands that
+ Exim will need. Original code also failed if Dovecot server sent unknown
+ command. E.g. COOKIE in version 1.1 of the protocol would cause troubles. */
+ /* pdp: note that CUID is a per-connection identifier sent by the server,
+ which increments at server discretion.
+ By contrast, the "id" field of the protocol is a connection-specific request
+ identifier, which needs to be unique per request from the client and is not
+ connected to the CUID value, so we ignore CUID from server. It's purely for
+ diagnostics. */
+
+ if (Ustrcmp(args[0], US"VERSION") == 0)
+ {
+ CHECK_COMMAND("VERSION", 2, 2);
+ if (Uatoi(args[1]) != VERSION_MAJOR)
+ OUT("authentication socket protocol version mismatch");
+ }
+ else if (Ustrcmp(args[0], US"MECH") == 0)
+ {
+ CHECK_COMMAND("MECH", 1, INT_MAX);
+ have_mech_line = TRUE;
+ if (strcmpic(US args[1], ablock->public_name) == 0)
+ found = TRUE;
+ }
+ else if (Ustrcmp(args[0], US"SPID") == 0)
+ {
+ /* Unfortunately the auth protocol handshake wasn't designed well
+ to differentiate between auth-client/userdb/master. auth-userdb
+ and auth-master send VERSION + SPID lines only and nothing
+ afterwards, while auth-client sends VERSION + MECH + SPID +
+ CUID + more. The simplest way that we can determine if we've
+ connected to the correct socket is to see if MECH line exists or
+ not (alternatively we'd have to have a small timeout after SPID
+ to see if CUID is sent or not). */
+
+ if (!have_mech_line)
+ OUT("authentication socket type mismatch"
+ " (connected to auth-master instead of auth-client)");
+ }
+ else if (Ustrcmp(args[0], US"DONE") == 0)
+ {
+ CHECK_COMMAND("DONE", 0, 0);
+ cont = 0;
+ }
+ }
+
+if (!found)
+ {
+ auth_defer_msg = string_sprintf(
+ "Dovecot did not advertise mechanism \"%s\" to us", ablock->public_name);
+ goto out;
+ }
+
+/* Added by PH: data must not contain tab (as it is
+b64 it shouldn't, but check for safety). */
+
+if (Ustrchr(data, '\t') != NULL)
+ {
+ ret = FAIL;
+ goto out;
+ }
+
+/* Added by PH: extra fields when TLS is in use or if the TCP/IP
+connection is local. */
+
+if (tls_in.cipher != NULL)
+ auth_extra_data = string_sprintf("secured\t%s%s",
+ tls_in.certificate_verified? "valid-client-cert" : "",
+ tls_in.certificate_verified? "\t" : "");
+
+else if ( interface_address != NULL
+ && Ustrcmp(sender_host_address, interface_address) == 0)
+ auth_extra_data = US"secured\t";
/****************************************************************************
- The code below was the original code here. It didn't work. A reading of the
- file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that
- this was not right. Maybe something changed. I changed it to move the
- service indication into the AUTH command, and it seems to be better. PH
-
- fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n"
- "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n",
- VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
- ablock->public_name, sender_host_address, interface_address,
- data ? (char *) data : "");
-
- Subsequently, the command was modified to add "secured" and "valid-client-
- cert" when relevant.
+The code below was the original code here. It didn't work. A reading of the
+file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that
+this was not right. Maybe something changed. I changed it to move the
+service indication into the AUTH command, and it seems to be better. PH
+
+fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n"
+ "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n",
+ VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
+ ablock->public_name, sender_host_address, interface_address,
+ data ? CS data : "");
+
+Subsequently, the command was modified to add "secured" and "valid-client-
+cert" when relevant.
****************************************************************************/
- auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n"
- "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tresp=%s\n",
- VERSION_MAJOR, VERSION_MINOR, getpid(), cuid,
- ablock->public_name, auth_extra_data, sender_host_address,
- interface_address, data ? (char *) data : "");
-
- fprintf(f, "%s", auth_command);
- HDEBUG(D_auth) debug_printf("sent: %s", auth_command);
-
- while (1) {
- if (fgets(buffer, sizeof(buffer), f) == NULL) {
- auth_defer_msg = US"authentication socket read error or premature eof";
- goto out;
- }
-
- buffer[strlen(buffer) - 1] = 0;
- HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
- nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
-
- if (atoi(args[1]) != cuid)
- OUT("authentication socket connection id mismatch");
-
- switch (toupper(*args[0])) {
- case 'C':
- CHECK_COMMAND("CONT", 1, 2);
-
- tmp = auth_get_no64_data(&data, US args[2]);
- if (tmp != OK) {
- ret = tmp;
- goto out;
- }
-
- /* Added by PH: data must not contain tab (as it is
- b64 it shouldn't, but check for safety). */
-
- if (Ustrchr(data, '\t') != NULL) {
- ret = FAIL;
- goto out;
- }
-
- if (fprintf(f, "CONT\t%d\t%s\r\n", cuid, data) < 0)
- OUT("authentication socket write error");
-
- break;
-
- case 'F':
- CHECK_COMMAND("FAIL", 1, 2);
-
- /* FIXME: add proper response handling */
- if (args[2]) {
- uschar *p = US strchr(args[2], '=');
- if (p) {
- ++p;
- expand_nstring[1] = auth_vars[0] = p;
- expand_nlength[1] = Ustrlen(p);
- expand_nmax = 1;
- }
- }
-
- ret = FAIL;
- goto out;
-
- case 'O':
- CHECK_COMMAND("OK", 2, 2);
- {
- /* FIXME: add proper response handling */
- uschar *p = US strchr(args[2], '=');
- if (!p)
- OUT("authentication socket protocol error, username missing");
-
- p++;
- expand_nstring[1] = auth_vars[0] = p;
- expand_nlength[1] = Ustrlen(p);
- expand_nmax = 1;
- }
- ret = OK;
- /* fallthrough */
-
- default:
- goto out;
- }
- }
-
-out: close(fd);
-
- /* Expand server_condition as an authorization check */
- return (ret == OK)? auth_check_serv_cond(ablock) : ret;
+auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n"
+ "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tnologin\tresp=%s\n",
+ VERSION_MAJOR, VERSION_MINOR, getpid(), crequid,
+ ablock->public_name, auth_extra_data, sender_host_address,
+ interface_address, data);
+
+if (write(fd, auth_command, Ustrlen(auth_command)) < 0)
+ HDEBUG(D_auth) debug_printf("error sending auth_command: %s\n",
+ strerror(errno));
+
+HDEBUG(D_auth) debug_printf("sent: %s", auth_command);
+
+while (1)
+ {
+ uschar *temp;
+ uschar *auth_id_pre = NULL;
+ int i;
+
+ if (dc_gets(buffer, sizeof(buffer), fd) == NULL)
+ {
+ auth_defer_msg = US"authentication socket read error or premature eof";
+ goto out;
+ }
+
+ buffer[Ustrlen(buffer) - 1] = 0;
+ HDEBUG(D_auth) debug_printf("received: %s\n", buffer);
+ nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0]));
+
+ if (Uatoi(args[1]) != crequid)
+ OUT("authentication socket connection id mismatch");
+
+ switch (toupper(*args[0]))
+ {
+ case 'C':
+ CHECK_COMMAND("CONT", 1, 2);
+
+ if ((tmp = auth_get_no64_data(&data, US args[2])) != OK)
+ {
+ ret = tmp;
+ goto out;
+ }
+
+ /* Added by PH: data must not contain tab (as it is
+ b64 it shouldn't, but check for safety). */
+
+ if (Ustrchr(data, '\t') != NULL)
+ {
+ ret = FAIL;
+ goto out;
+ }
+
+ temp = string_sprintf("CONT\t%d\t%s\n", crequid, data);
+ if (write(fd, temp, Ustrlen(temp)) < 0)
+ OUT("authentication socket write error");
+ break;
+
+ case 'F':
+ CHECK_COMMAND("FAIL", 1, -1);
+
+ for (i=2; (i<nargs) && (auth_id_pre == NULL); i++)
+ {
+ if ( Ustrncmp(args[i], US"user=", 5) == 0 )
+ {
+ auth_id_pre = args[i]+5;
+ expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */
+ expand_nlength[1] = Ustrlen(auth_id_pre);
+ expand_nmax = 1;
+ }
+ }
+
+ ret = FAIL;
+ goto out;
+
+ case 'O':
+ CHECK_COMMAND("OK", 2, -1);
+
+ /* Search for the "user=$USER" string in the args array
+ and return the proper value. */
+
+ for (i=2; (i<nargs) && (auth_id_pre == NULL); i++)
+ {
+ if ( Ustrncmp(args[i], US"user=", 5) == 0 )
+ {
+ auth_id_pre = args[i]+5;
+ expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */
+ expand_nlength[1] = Ustrlen(auth_id_pre);
+ expand_nmax = 1;
+ }
+ }
+
+ if (auth_id_pre == NULL)
+ OUT("authentication socket protocol error, username missing");
+
+ ret = OK;
+ /* fallthrough */
+
+ default:
+ goto out;
+ }
+ }
+
+out:
+/* close the socket used by dovecot */
+if (fd >= 0)
+ close(fd);
+
+/* Expand server_condition as an authorization check */
+return ret == OK ? auth_check_serv_cond(ablock) : ret;
}
+
+
+#endif /*!MACRO_PREDEF*/
projects / exim.git / blobdiff