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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
commit | e90fcc54809db2591dc083f43ef54c6ec8c60847 (patch) | |
tree | f20bc206c3c2d5d59d37c46c5cf5d53a20642556 /src/auths/spa.c | |
parent | Initial commit. (diff) | |
download | exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.tar.xz exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.zip |
Adding upstream version 4.96.upstream/4.96upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/auths/spa.c | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/src/auths/spa.c b/src/auths/spa.c new file mode 100644 index 0000000..ff90d33 --- /dev/null +++ b/src/auths/spa.c @@ -0,0 +1,376 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) University of Cambridge 1995 - 2018 */ +/* Copyright (c) The Exim Maintainers 2020 */ +/* See the file NOTICE for conditions of use and distribution. */ + +/* This file, which provides support for Microsoft's Secure Password +Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA +server support. I (PH) have only modified it in very trivial ways. + +References: + http://www.innovation.ch/java/ntlm.html + http://www.kuro5hin.org/story/2002/4/28/1436/66154 + http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf + + * It seems that some systems have existing but different definitions of some + * of the following types. I received a complaint about "int16" causing + * compilation problems. So I (PH) have renamed them all, to be on the safe + * side, by adding 'x' on the end. See auths/auth-spa.h. + + * typedef signed short int16; + * typedef unsigned short uint16; + * typedef unsigned uint32; + * typedef unsigned char uint8; + +07-August-2003: PH: Patched up the code to avoid assert bombouts for stupid + input data. Find appropriate comment by grepping for "PH". +16-October-2006: PH: Added a call to auth_check_serv_cond() at the end +05-June-2010: PP: handle SASL initial response +*/ + + +#include "../exim.h" +#include "spa.h" + +/* #define DEBUG_SPA */ + +#ifdef DEBUG_SPA +#define DSPA(x,y,z) debug_printf(x,y,z) +#else +#define DSPA(x,y,z) +#endif + +/* Options specific to the spa authentication mechanism. */ + +optionlist auth_spa_options[] = { + { "client_domain", opt_stringptr, + OPT_OFF(auth_spa_options_block, spa_domain) }, + { "client_password", opt_stringptr, + OPT_OFF(auth_spa_options_block, spa_password) }, + { "client_username", opt_stringptr, + OPT_OFF(auth_spa_options_block, spa_username) }, + { "server_password", opt_stringptr, + OPT_OFF(auth_spa_options_block, spa_serverpassword) } +}; + +/* 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_spa_options_count = + sizeof(auth_spa_options)/sizeof(optionlist); + +/* Default private options block for the condition authentication method. */ + +auth_spa_options_block auth_spa_option_defaults = { + NULL, /* spa_password */ + NULL, /* spa_username */ + NULL, /* spa_domain */ + NULL /* spa_serverpassword (for server side use) */ +}; + + +#ifdef MACRO_PREDEF + +/* Dummy values */ +void auth_spa_init(auth_instance *ablock) {} +int auth_spa_server(auth_instance *ablock, uschar *data) {return 0;} +int auth_spa_client(auth_instance *ablock, void * sx, int timeout, + uschar *buffer, int buffsize) {return 0;} + +#else /*!MACRO_PREDEF*/ + + + + +/************************************************* +* 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_spa_init(auth_instance *ablock) +{ +auth_spa_options_block *ob = + (auth_spa_options_block *)(ablock->options_block); + +/* The public name defaults to the authenticator name */ + +if (ablock->public_name == NULL) ablock->public_name = ablock->name; + +/* Both username and password must be set for a client */ + +if ((ob->spa_username == NULL) != (ob->spa_password == NULL)) + log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator:\n " + "one of client_username and client_password cannot be set without " + "the other", ablock->name); +ablock->client = ob->spa_username != NULL; + +/* For a server we have just one option */ + +ablock->server = ob->spa_serverpassword != NULL; +} + + + +/************************************************* +* Server entry point * +*************************************************/ + +/* For interface, see auths/README */ + +#define CVAL(buf,pos) ((US (buf))[pos]) +#define PVAL(buf,pos) ((unsigned)CVAL(buf,pos)) +#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) +#define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) + +int +auth_spa_server(auth_instance *ablock, uschar *data) +{ +auth_spa_options_block *ob = (auth_spa_options_block *)(ablock->options_block); +uint8x lmRespData[24]; +uint8x ntRespData[24]; +SPAAuthRequest request; +SPAAuthChallenge challenge; +SPAAuthResponse response; +SPAAuthResponse *responseptr = &response; +uschar msgbuf[2048]; +uschar *clearpass, *s; +unsigned off; + +/* send a 334, MS Exchange style, and grab the client's request, +unless we already have it via an initial response. */ + +if (!*data && auth_get_no64_data(&data, US"NTLM supported") != OK) + return FAIL; + +if (spa_base64_to_bits(CS &request, sizeof(request), CCS data) < 0) + { + DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " + "request: %s\n", data); + return FAIL; + } + +/* create a challenge and send it back */ + +spa_build_auth_challenge(&request, &challenge); +spa_bits_to_base64(msgbuf, US &challenge, spa_request_length(&challenge)); + +if (auth_get_no64_data(&data, msgbuf) != OK) + return FAIL; + +/* dump client response */ +if (spa_base64_to_bits(CS &response, sizeof(response), CCS data) < 0) + { + DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " + "response: %s\n", data); + return FAIL; + } + +/*************************************************************** +PH 07-Aug-2003: The original code here was this: + +Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) + + IVAL(&responseptr->uUser.offset,0), + SVAL(&responseptr->uUser.len,0)/2) ); + +However, if the response data is too long, unicodeToString bombs out on +an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good +idea. It's too messy to try to rework that function to return an error because +it is called from a number of other places in the auth-spa.c module. Instead, +since it is a very small function, I reproduce its code here, with a size check +that causes failure if the size of msgbuf is exceeded. ****/ + + { + int i; + char * p; + int len = SVAL(&responseptr->uUser.len,0)/2; + + if ( (off = IVAL(&responseptr->uUser.offset,0)) >= sizeof(SPAAuthResponse) + || len >= sizeof(responseptr->buffer)/2 + || (p = (CS responseptr) + off) + len*2 >= CS (responseptr+1) + ) + { + DEBUG(D_auth) + debug_printf("auth_spa_server(): bad uUser spec in response\n"); + return FAIL; + } + + if (len + 1 >= sizeof(msgbuf)) return FAIL; + for (i = 0; i < len; ++i) + { + msgbuf[i] = *p & 0x7f; + p += 2; + } + msgbuf[i] = 0; + } + +/***************************************************************/ + +/* Put the username in $auth1 and $1. The former is now the preferred variable; +the latter is the original variable. These have to be out of stack memory, and +need to be available once known even if not authenticated, for error messages +(server_set_id, which only makes it to authenticated_id if we return OK) */ + +auth_vars[0] = expand_nstring[1] = string_copy(msgbuf); +expand_nlength[1] = Ustrlen(msgbuf); +expand_nmax = 1; + +debug_print_string(ablock->server_debug_string); /* customized debug */ + +/* look up password */ + +if (!(clearpass = expand_string(ob->spa_serverpassword))) + if (f.expand_string_forcedfail) + { + DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while " + "expanding spa_serverpassword\n"); + return FAIL; + } + else + { + DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding " + "spa_serverpassword: %s\n", expand_string_message); + return DEFER; + } + +/* create local hash copy */ + +spa_smb_encrypt(clearpass, challenge.challengeData, lmRespData); +spa_smb_nt_encrypt(clearpass, challenge.challengeData, ntRespData); + +/* compare NT hash (LM may not be available) */ + +off = IVAL(&responseptr->ntResponse.offset,0); +if (off >= sizeof(SPAAuthResponse) - 24) + { + DEBUG(D_auth) + debug_printf("auth_spa_server(): bad ntRespData spec in response\n"); + return FAIL; + } +s = (US responseptr) + off; + +if (memcmp(ntRespData, s, 24) == 0) + return auth_check_serv_cond(ablock); /* success. we have a winner. */ + + /* Expand server_condition as an authorization check (PH) */ + +return FAIL; +} + + +/************************************************* +* Client entry point * +*************************************************/ + +/* For interface, see auths/README */ + +int +auth_spa_client( + auth_instance *ablock, /* authenticator block */ + void * sx, /* connection */ + int timeout, /* command timeout */ + uschar *buffer, /* buffer for reading response */ + int buffsize) /* size of buffer */ +{ +auth_spa_options_block *ob = + (auth_spa_options_block *)(ablock->options_block); +SPAAuthRequest request; +SPAAuthChallenge challenge; +SPAAuthResponse response; +char msgbuf[2048]; +char *domain = NULL; +char *username, *password; + +/* Code added by PH to expand the options */ + +*buffer = 0; /* Default no message when cancelled */ + +if (!(username = CS expand_string(ob->spa_username))) + { + if (f.expand_string_forcedfail) return CANCELLED; + string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " + "authenticator: %s", ob->spa_username, ablock->name, + expand_string_message); + return ERROR; + } + +if (!(password = CS expand_string(ob->spa_password))) + { + if (f.expand_string_forcedfail) return CANCELLED; + string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " + "authenticator: %s", ob->spa_password, ablock->name, + expand_string_message); + return ERROR; + } + +if (ob->spa_domain) + if (!(domain = CS expand_string(ob->spa_domain))) + { + if (f.expand_string_forcedfail) return CANCELLED; + string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " + "authenticator: %s", ob->spa_domain, ablock->name, + expand_string_message); + return ERROR; + } + +/* Original code */ + +if (smtp_write_command(sx, SCMD_FLUSH, "AUTH %s\r\n", ablock->public_name) < 0) + return FAIL_SEND; + +/* wait for the 3XX OK message */ +if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) + return FAIL; + +DSPA("\n\n%s authenticator: using domain %s\n\n", ablock->name, domain); + +spa_build_auth_request(&request, CS username, domain); +spa_bits_to_base64(US msgbuf, US &request, spa_request_length(&request)); + +DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name, msgbuf); + +/* send the encrypted password */ +if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) + return FAIL_SEND; + +/* wait for the auth challenge */ +if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) + return FAIL; + +/* convert the challenge into the challenge struct */ +DSPA("\n\n%s authenticator: challenge (%s)\n\n", ablock->name, buffer + 4); +spa_base64_to_bits(CS (&challenge), sizeof(challenge), CCS (buffer + 4)); + +spa_build_auth_response(&challenge, &response, CS username, CS password); +spa_bits_to_base64(US msgbuf, US &response, spa_request_length(&response)); +DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name, msgbuf); + +/* send the challenge response */ +if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) + return FAIL_SEND; + +/* If we receive a success response from the server, authentication +has succeeded. There may be more data to send, but is there any point +in provoking an error here? */ + +if (smtp_read_response(sx, US buffer, buffsize, '2', timeout)) + return OK; + +/* Not a success response. If errno != 0 there is some kind of transmission +error. Otherwise, check the response code in the buffer. If it starts with +'3', more data is expected. */ + +if (errno != 0 || buffer[0] != '3') + return FAIL; + +return FAIL; +} + +#endif /*!MACRO_PREDEF*/ +/* End of spa.c */ |