X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;ds=inline;f=src%2Fsrc%2Fauths%2Fdovecot.c;h=94b315209918dfc184fe8124903a418ff1a6a35d;hb=970ba64f07bf5523c7098235664f2ce02962a128;hp=421d5e793acf0a9c6c0495f01d719400b3f16a07;hpb=c75df3d220bfabed85b70752228bbb1c6e5fddc9;p=exim.git diff --git a/src/src/auths/dovecot.c b/src/src/auths/dovecot.c index 421d5e793..94b315209 100644 --- a/src/src/auths/dovecot.c +++ b/src/src/auths/dovecot.c @@ -1,5 +1,3 @@ -/* $Cambridge: exim/src/src/auths/dovecot.c,v 1.5 2007/01/24 17:14:27 magnus Exp $ */ - /* * Copyright (c) 2004 Andrey Panin * @@ -9,31 +7,76 @@ * (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+, 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 */ }; + +/* Static variables for reading from the socket */ + +static uschar sbuffer[256]; +static int socket_buffer_left; + + + /************************************************* * Initialization entry point * *************************************************/ @@ -41,6 +84,7 @@ auth_dovecot_options_block auth_dovecot_option_defaults = { /* 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 = @@ -53,9 +97,27 @@ void auth_dovecot_init(auth_instance *ablock) 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) { - char *tmp = str; + uschar *last_sub_start = str; int n; for (n = 0; n < nptrs; n++) @@ -65,27 +127,50 @@ static int strcut(char *str, char **ptrs, int nptrs) while (*str) { if (*str == '\t') { if (n <= nptrs) { - *ptrs++ = tmp; - tmp = str + 1; - *str = 0; + *ptrs++ = last_sub_start; + last_sub_start = str + 1; + *str = '\0'; } n++; } str++; } - if (n < nptrs) - *ptrs = tmp; + /* 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; +} - return n; +static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED; +static void +debug_strcut(uschar **ptrs, int nlen, int alen) +{ + 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""); + 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) @@ -97,21 +182,64 @@ static int strcut(char *str, char **ptrs, int nptrs) /************************************************* - * 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. */ + +static uschar * +dc_gets(uschar *s, int n, int fd) +{ +int p = 0; +int count = 0; + +for (;;) + { + if (socket_buffer_left == 0) + { + socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer)); + if (socket_buffer_left == 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; - char buffer[4096]; - char *args[8]; + uschar buffer[DOVECOT_AUTH_MAXLINELEN]; + uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT]; uschar *auth_command; uschar *auth_extra_data = US""; + uschar *p; int nargs, tmp; - int cuid = 0, cont = 1, found = 0, fd, ret = DEFER; - FILE *f; + int crequid = 1, cont = 1, fd, ret = DEFER; + BOOL found = FALSE; HDEBUG(D_auth) debug_printf("dovecot authentication\n"); @@ -141,54 +269,48 @@ int auth_dovecot_server(auth_instance *ablock, uschar *data) 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"; + socket_buffer_left = 0; /* Global, used to read more than a line but return by line */ while (cont) { - if (fgets(buffer, sizeof(buffer), f) == NULL) + if (dc_gets(buffer, sizeof(buffer), fd) == NULL) OUT("authentication socket read error or premature eof"); - - buffer[strlen(buffer) - 1] = 0; + 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])); - - 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': + /* 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 (atoi(args[1]) != VERSION_MAJOR) + if (Uatoi(args[1]) != VERSION_MAJOR) OUT("authentication socket protocol version mismatch"); - break; - - default: - goto out; + } else if (Ustrcmp(args[0], US"MECH") == 0) { + CHECK_COMMAND("MECH", 1, INT_MAX); + if (strcmpic(US args[1], ablock->public_name) == 0) + found = TRUE; + } else if (Ustrcmp(args[0], US"DONE") == 0) { + CHECK_COMMAND("DONE", 0, 0); + cont = 0; } } - if (!found) + 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). */ @@ -201,12 +323,12 @@ int auth_dovecot_server(auth_instance *ablock, uschar *data) /* Added by PH: extra fields when TLS is in use or if the TCP/IP connection is local. */ - if (tls_cipher != NULL) + if (tls_in.cipher != NULL) auth_extra_data = string_sprintf("secured\t%s%s", - tls_certificate_verified? "valid-client-cert" : "", - tls_certificate_verified? "\t" : ""); - else if (interface_address - && Ustrcmp(sender_host_address, interface_address) == 0) + 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"; @@ -227,25 +349,32 @@ int auth_dovecot_server(auth_instance *ablock, uschar *data) ****************************************************************************/ 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, + "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 ? (char *) data : ""); - fprintf(f, "%s", auth_command); + 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) { - if (fgets(buffer, sizeof(buffer), f) == NULL) { + 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[strlen(buffer) - 1] = 0; + buffer[Ustrlen(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) + if (Uatoi(args[1]) != crequid) OUT("authentication socket connection id mismatch"); switch (toupper(*args[0])) { @@ -266,22 +395,22 @@ int auth_dovecot_server(auth_instance *ablock, uschar *data) goto out; } - if (fprintf(f, "CONT\t%d\t%s\r\n", cuid, data) < 0) + 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, 2); + CHECK_COMMAND("FAIL", 1, -1); - /* FIXME: add proper response handling */ - if (args[2]) { - uschar *p = US strchr(args[2], '='); - if (p) { - ++p; + for (i=2; (i