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904b27d18d
curl/lib/curl_sasl.c
Daniel Stenberg a9bc819c89
sasl: use 'unsigned short' to store mechanism 
... saves a few bytes of struct size in memory and it only uses
10 bits anyway.

Closes #7045
2021-05-12 00:16:52 +02:00

724 lines
23 KiB
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2012 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* RFC2195 CRAM-MD5 authentication
* RFC2617 Basic and Digest Access Authentication
* RFC2831 DIGEST-MD5 authentication
* RFC4422 Simple Authentication and Security Layer (SASL)
* RFC4616 PLAIN authentication
* RFC5802 SCRAM-SHA-1 authentication
* RFC7677 SCRAM-SHA-256 authentication
* RFC6749 OAuth 2.0 Authorization Framework
* RFC7628 A Set of SASL Mechanisms for OAuth
* Draft LOGIN SASL Mechanism <draft-murchison-sasl-login-00.txt>
*
***************************************************************************/
#include "curl_setup.h"
#if !defined(CURL_DISABLE_IMAP) || !defined(CURL_DISABLE_SMTP) || \
!defined(CURL_DISABLE_POP3)
#include <curl/curl.h>
#include "urldata.h"
#include "curl_base64.h"
#include "curl_md5.h"
#include "vauth/vauth.h"
#include "vtls/vtls.h"
#include "curl_hmac.h"
#include "curl_sasl.h"
#include "warnless.h"
#include "strtok.h"
#include "sendf.h"
#include "non-ascii.h" /* included for Curl_convert_... prototypes */
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
/* Supported mechanisms */
static const struct {
const char *name; /* Name */
size_t len; /* Name length */
unsigned short bit; /* Flag bit */
} mechtable[] = {
{ "LOGIN", 5, SASL_MECH_LOGIN },
{ "PLAIN", 5, SASL_MECH_PLAIN },
{ "CRAM-MD5", 8, SASL_MECH_CRAM_MD5 },
{ "DIGEST-MD5", 10, SASL_MECH_DIGEST_MD5 },
{ "GSSAPI", 6, SASL_MECH_GSSAPI },
{ "EXTERNAL", 8, SASL_MECH_EXTERNAL },
{ "NTLM", 4, SASL_MECH_NTLM },
{ "XOAUTH2", 7, SASL_MECH_XOAUTH2 },
{ "OAUTHBEARER", 11, SASL_MECH_OAUTHBEARER },
{ "SCRAM-SHA-1", 11, SASL_MECH_SCRAM_SHA_1 },
{ "SCRAM-SHA-256",13, SASL_MECH_SCRAM_SHA_256 },
{ ZERO_NULL, 0, 0 }
};
/*
* Curl_sasl_cleanup()
*
* This is used to cleanup any libraries or curl modules used by the sasl
* functions.
*
* Parameters:
*
* conn [in] - The connection data.
* authused [in] - The authentication mechanism used.
*/
void Curl_sasl_cleanup(struct connectdata *conn, unsigned int authused)
{
#if defined(USE_KERBEROS5)
/* Cleanup the gssapi structure */
if(authused == SASL_MECH_GSSAPI) {
Curl_auth_cleanup_gssapi(&conn->krb5);
}
#endif
#if defined(USE_GSASL)
/* Cleanup the GSASL structure */
if(authused & (SASL_MECH_SCRAM_SHA_1 | SASL_MECH_SCRAM_SHA_256)) {
Curl_auth_gsasl_cleanup(&conn->gsasl);
}
#endif
#if defined(USE_NTLM)
/* Cleanup the NTLM structure */
if(authused == SASL_MECH_NTLM) {
Curl_auth_cleanup_ntlm(&conn->ntlm);
}
#endif
#if !defined(USE_KERBEROS5) && !defined(USE_NTLM)
/* Reserved for future use */
(void)conn;
(void)authused;
#endif
}
/*
* Curl_sasl_decode_mech()
*
* Convert a SASL mechanism name into a token.
*
* Parameters:
*
* ptr [in] - The mechanism string.
* maxlen [in] - Maximum mechanism string length.
* len [out] - If not NULL, effective name length.
*
* Returns the SASL mechanism token or 0 if no match.
*/
unsigned short Curl_sasl_decode_mech(const char *ptr, size_t maxlen,
size_t *len)
{
unsigned int i;
char c;
for(i = 0; mechtable[i].name; i++) {
if(maxlen >= mechtable[i].len &&
!memcmp(ptr, mechtable[i].name, mechtable[i].len)) {
if(len)
*len = mechtable[i].len;
if(maxlen == mechtable[i].len)
return mechtable[i].bit;
c = ptr[mechtable[i].len];
if(!ISUPPER(c) && !ISDIGIT(c) && c != '-' && c != '_')
return mechtable[i].bit;
}
}
return 0;
}
/*
* Curl_sasl_parse_url_auth_option()
*
* Parse the URL login options.
*/
CURLcode Curl_sasl_parse_url_auth_option(struct SASL *sasl,
const char *value, size_t len)
{
CURLcode result = CURLE_OK;
size_t mechlen;
if(!len)
return CURLE_URL_MALFORMAT;
if(sasl->resetprefs) {
sasl->resetprefs = FALSE;
sasl->prefmech = SASL_AUTH_NONE;
}
if(!strncmp(value, "*", len))
sasl->prefmech = SASL_AUTH_DEFAULT;
else {
unsigned short mechbit = Curl_sasl_decode_mech(value, len, &mechlen);
if(mechbit && mechlen == len)
sasl->prefmech |= mechbit;
else
result = CURLE_URL_MALFORMAT;
}
return result;
}
/*
* Curl_sasl_init()
*
* Initializes the SASL structure.
*/
void Curl_sasl_init(struct SASL *sasl, const struct SASLproto *params)
{
sasl->params = params; /* Set protocol dependent parameters */
sasl->state = SASL_STOP; /* Not yet running */
sasl->authmechs = SASL_AUTH_NONE; /* No known authentication mechanism yet */
sasl->prefmech = SASL_AUTH_DEFAULT; /* Prefer all mechanisms */
sasl->authused = SASL_AUTH_NONE; /* No the authentication mechanism used */
sasl->resetprefs = TRUE; /* Reset prefmech upon AUTH parsing. */
sasl->mutual_auth = FALSE; /* No mutual authentication (GSSAPI only) */
sasl->force_ir = FALSE; /* Respect external option */
}
/*
* state()
*
* This is the ONLY way to change SASL state!
*/
static void state(struct SASL *sasl, struct Curl_easy *data,
saslstate newstate)
{
#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
/* for debug purposes */
static const char * const names[]={
"STOP",
"PLAIN",
"LOGIN",
"LOGIN_PASSWD",
"EXTERNAL",
"CRAMMD5",
"DIGESTMD5",
"DIGESTMD5_RESP",
"NTLM",
"NTLM_TYPE2MSG",
"GSSAPI",
"GSSAPI_TOKEN",
"GSSAPI_NO_DATA",
"OAUTH2",
"OAUTH2_RESP",
"GSASL",
"CANCEL",
"FINAL",
/* LAST */
};
if(sasl->state != newstate)
infof(data, "SASL %p state change from %s to %s\n",
(void *)sasl, names[sasl->state], names[newstate]);
#else
(void) data;
#endif
sasl->state = newstate;
}
/* Get the SASL server message and convert it to binary. */
static CURLcode get_server_message(struct SASL *sasl, struct Curl_easy *data,
struct bufref *out)
{
unsigned char *msg;
size_t msglen;
char *serverdata = NULL;
CURLcode result = CURLE_OK;
sasl->params->getmessage(data->state.buffer, &serverdata);
if(!serverdata)
result = CURLE_BAD_CONTENT_ENCODING;
else if(!*serverdata || *serverdata == '=')
Curl_bufref_set(out, NULL, 0, NULL);
else {
result = Curl_base64_decode(serverdata, &msg, &msglen);
if(!result)
Curl_bufref_set(out, msg, msglen, curl_free);
}
return result;
}
/* Encode the outgoing SASL message. */
static CURLcode build_message(struct Curl_easy *data, struct bufref *msg)
{
CURLcode result = CURLE_OK;
char *base64;
size_t base64len;
if(!Curl_bufref_ptr(msg)) /* Empty mesage. */
Curl_bufref_set(msg, "", 0, NULL);
else if(!Curl_bufref_len(msg)) /* Explicit empty response. */
Curl_bufref_set(msg, "=", 1, NULL);
else {
result = Curl_base64_encode(data, (const char *) Curl_bufref_ptr(msg),
Curl_bufref_len(msg), &base64, &base64len);
if(!result)
Curl_bufref_set(msg, base64, base64len, curl_free);
}
return result;
}
/*
* Curl_sasl_can_authenticate()
*
* Check if we have enough auth data and capabilities to authenticate.
*/
bool Curl_sasl_can_authenticate(struct SASL *sasl, struct connectdata *conn)
{
/* Have credentials been provided? */
if(conn->bits.user_passwd)
return TRUE;
/* EXTERNAL can authenticate without a user name and/or password */
if(sasl->authmechs & sasl->prefmech & SASL_MECH_EXTERNAL)
return TRUE;
return FALSE;
}
/*
* Curl_sasl_start()
*
* Calculate the required login details for SASL authentication.
*/
CURLcode Curl_sasl_start(struct SASL *sasl, struct Curl_easy *data,
struct connectdata *conn,
bool force_ir, saslprogress *progress)
{
CURLcode result = CURLE_OK;
unsigned int enabledmechs;
const char *mech = NULL;
struct bufref resp;
saslstate state1 = SASL_STOP;
saslstate state2 = SASL_FINAL;
const char * const hostname = SSL_HOST_NAME();
const long int port = SSL_HOST_PORT();
#if defined(USE_KERBEROS5) || defined(USE_NTLM)
const char *service = data->set.str[STRING_SERVICE_NAME] ?
data->set.str[STRING_SERVICE_NAME] :
sasl->params->service;
#endif
const char *oauth_bearer = data->set.str[STRING_BEARER];
struct bufref nullmsg;
Curl_bufref_init(&nullmsg);
Curl_bufref_init(&resp);
sasl->force_ir = force_ir; /* Latch for future use */
sasl->authused = 0; /* No mechanism used yet */
enabledmechs = sasl->authmechs & sasl->prefmech;
*progress = SASL_IDLE;
/* Calculate the supported authentication mechanism, by decreasing order of
security, as well as the initial response where appropriate */
if((enabledmechs & SASL_MECH_EXTERNAL) && !conn->passwd[0]) {
mech = SASL_MECH_STRING_EXTERNAL;
state1 = SASL_EXTERNAL;
sasl->authused = SASL_MECH_EXTERNAL;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_external_message(conn->user, &resp);
}
else if(conn->bits.user_passwd) {
#if defined(USE_KERBEROS5)
if((enabledmechs & SASL_MECH_GSSAPI) && Curl_auth_is_gssapi_supported() &&
Curl_auth_user_contains_domain(conn->user)) {
sasl->mutual_auth = FALSE;
mech = SASL_MECH_STRING_GSSAPI;
state1 = SASL_GSSAPI;
state2 = SASL_GSSAPI_TOKEN;
sasl->authused = SASL_MECH_GSSAPI;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_gssapi_user_message(data, conn->user,
conn->passwd,
service,
conn->host.name,
sasl->mutual_auth,
NULL, &conn->krb5,
&resp);
}
else
#endif
#ifdef USE_GSASL
if((enabledmechs & SASL_MECH_SCRAM_SHA_256) &&
Curl_auth_gsasl_is_supported(data, SASL_MECH_STRING_SCRAM_SHA_256,
&conn->gsasl)) {
mech = SASL_MECH_STRING_SCRAM_SHA_256;
sasl->authused = SASL_MECH_SCRAM_SHA_256;
state1 = SASL_GSASL;
state2 = SASL_GSASL;
result = Curl_auth_gsasl_start(data, conn->user,
conn->passwd, &conn->gsasl);
if(result == CURLE_OK && (force_ir || data->set.sasl_ir))
result = Curl_auth_gsasl_token(data, &nullmsg, &conn->gsasl, &resp);
}
else if((enabledmechs & SASL_MECH_SCRAM_SHA_1) &&
Curl_auth_gsasl_is_supported(data, SASL_MECH_STRING_SCRAM_SHA_1,
&conn->gsasl)) {
mech = SASL_MECH_STRING_SCRAM_SHA_1;
sasl->authused = SASL_MECH_SCRAM_SHA_1;
state1 = SASL_GSASL;
state2 = SASL_GSASL;
result = Curl_auth_gsasl_start(data, conn->user,
conn->passwd, &conn->gsasl);
if(result == CURLE_OK && (force_ir || data->set.sasl_ir))
result = Curl_auth_gsasl_token(data, &nullmsg, &conn->gsasl, &resp);
}
else
#endif
#ifndef CURL_DISABLE_CRYPTO_AUTH
if((enabledmechs & SASL_MECH_DIGEST_MD5) &&
Curl_auth_is_digest_supported()) {
mech = SASL_MECH_STRING_DIGEST_MD5;
state1 = SASL_DIGESTMD5;
sasl->authused = SASL_MECH_DIGEST_MD5;
}
else if(enabledmechs & SASL_MECH_CRAM_MD5) {
mech = SASL_MECH_STRING_CRAM_MD5;
state1 = SASL_CRAMMD5;
sasl->authused = SASL_MECH_CRAM_MD5;
}
else
#endif
#ifdef USE_NTLM
if((enabledmechs & SASL_MECH_NTLM) && Curl_auth_is_ntlm_supported()) {
mech = SASL_MECH_STRING_NTLM;
state1 = SASL_NTLM;
state2 = SASL_NTLM_TYPE2MSG;
sasl->authused = SASL_MECH_NTLM;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_ntlm_type1_message(data,
conn->user, conn->passwd,
service,
hostname,
&conn->ntlm, &resp);
}
else
#endif
if((enabledmechs & SASL_MECH_OAUTHBEARER) && oauth_bearer) {
mech = SASL_MECH_STRING_OAUTHBEARER;
state1 = SASL_OAUTH2;
state2 = SASL_OAUTH2_RESP;
sasl->authused = SASL_MECH_OAUTHBEARER;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_oauth_bearer_message(conn->user,
hostname,
port,
oauth_bearer,
&resp);
}
else if((enabledmechs & SASL_MECH_XOAUTH2) && oauth_bearer) {
mech = SASL_MECH_STRING_XOAUTH2;
state1 = SASL_OAUTH2;
sasl->authused = SASL_MECH_XOAUTH2;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_xoauth_bearer_message(conn->user,
oauth_bearer,
&resp);
}
else if(enabledmechs & SASL_MECH_PLAIN) {
mech = SASL_MECH_STRING_PLAIN;
state1 = SASL_PLAIN;
sasl->authused = SASL_MECH_PLAIN;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_plain_message(conn->sasl_authzid,
conn->user, conn->passwd,
&resp);
}
else if(enabledmechs & SASL_MECH_LOGIN) {
mech = SASL_MECH_STRING_LOGIN;
state1 = SASL_LOGIN;
state2 = SASL_LOGIN_PASSWD;
sasl->authused = SASL_MECH_LOGIN;
if(force_ir || data->set.sasl_ir)
result = Curl_auth_create_login_message(conn->user, &resp);
}
}
if(!result && mech) {
if(Curl_bufref_ptr(&resp))
result = build_message(data, &resp);
if(sasl->params->maxirlen &&
strlen(mech) + Curl_bufref_len(&resp) > sasl->params->maxirlen)
Curl_bufref_free(&resp);
if(!result)
result = sasl->params->sendauth(data, conn, mech,
(const char *) Curl_bufref_ptr(&resp));
if(!result) {
*progress = SASL_INPROGRESS;
state(sasl, data, Curl_bufref_ptr(&resp) ? state2 : state1);
}
}
Curl_bufref_free(&resp);
return result;
}
/*
* Curl_sasl_continue()
*
* Continue the authentication.
*/
CURLcode Curl_sasl_continue(struct SASL *sasl, struct Curl_easy *data,
struct connectdata *conn,
int code, saslprogress *progress)
{
CURLcode result = CURLE_OK;
saslstate newstate = SASL_FINAL;
struct bufref resp;
const char * const hostname = SSL_HOST_NAME();
const long int port = SSL_HOST_PORT();
#if !defined(CURL_DISABLE_CRYPTO_AUTH) || defined(USE_KERBEROS5) || \
defined(USE_NTLM)
const char *service = data->set.str[STRING_SERVICE_NAME] ?
data->set.str[STRING_SERVICE_NAME] :
sasl->params->service;
#endif
const char *oauth_bearer = data->set.str[STRING_BEARER];
struct bufref serverdata;
Curl_bufref_init(&serverdata);
Curl_bufref_init(&resp);
*progress = SASL_INPROGRESS;
if(sasl->state == SASL_FINAL) {
if(code != sasl->params->finalcode)
result = CURLE_LOGIN_DENIED;
*progress = SASL_DONE;
state(sasl, data, SASL_STOP);
return result;
}
if(sasl->state != SASL_CANCEL && sasl->state != SASL_OAUTH2_RESP &&
code != sasl->params->contcode) {
*progress = SASL_DONE;
state(sasl, data, SASL_STOP);
return CURLE_LOGIN_DENIED;
}
switch(sasl->state) {
case SASL_STOP:
*progress = SASL_DONE;
return result;
case SASL_PLAIN:
result = Curl_auth_create_plain_message(conn->sasl_authzid,
conn->user, conn->passwd, &resp);
break;
case SASL_LOGIN:
result = Curl_auth_create_login_message(conn->user, &resp);
newstate = SASL_LOGIN_PASSWD;
break;
case SASL_LOGIN_PASSWD:
result = Curl_auth_create_login_message(conn->passwd, &resp);
break;
case SASL_EXTERNAL:
result = Curl_auth_create_external_message(conn->user, &resp);
break;
#ifndef CURL_DISABLE_CRYPTO_AUTH
#ifdef USE_GSASL
case SASL_GSASL:
result = get_server_message(sasl, data, &serverdata);
if(!result)
result = Curl_auth_gsasl_token(data, &serverdata, &conn->gsasl, &resp);
if(!result && Curl_bufref_len(&resp) > 0)
newstate = SASL_GSASL;
break;
#endif
case SASL_CRAMMD5:
result = get_server_message(sasl, data, &serverdata);
if(!result)
result = Curl_auth_create_cram_md5_message(&serverdata, conn->user,
conn->passwd, &resp);
break;
case SASL_DIGESTMD5:
result = get_server_message(sasl, data, &serverdata);
if(!result)
result = Curl_auth_create_digest_md5_message(data, &serverdata,
conn->user, conn->passwd,
service, &resp);
newstate = SASL_DIGESTMD5_RESP;
break;
case SASL_DIGESTMD5_RESP:
/* Keep response NULL to output an empty line. */
break;
#endif
#ifdef USE_NTLM
case SASL_NTLM:
/* Create the type-1 message */
result = Curl_auth_create_ntlm_type1_message(data,
conn->user, conn->passwd,
service, hostname,
&conn->ntlm, &resp);
newstate = SASL_NTLM_TYPE2MSG;
break;
case SASL_NTLM_TYPE2MSG:
/* Decode the type-2 message */
result = get_server_message(sasl, data, &serverdata);
if(!result)
result = Curl_auth_decode_ntlm_type2_message(data, &serverdata,
&conn->ntlm);
if(!result)
result = Curl_auth_create_ntlm_type3_message(data, conn->user,
conn->passwd, &conn->ntlm,
&resp);
break;
#endif
#if defined(USE_KERBEROS5)
case SASL_GSSAPI:
result = Curl_auth_create_gssapi_user_message(data, conn->user,
conn->passwd,
service,
conn->host.name,
sasl->mutual_auth, NULL,
&conn->krb5,
&resp);
newstate = SASL_GSSAPI_TOKEN;
break;
case SASL_GSSAPI_TOKEN:
result = get_server_message(sasl, data, &serverdata);
if(!result) {
if(sasl->mutual_auth) {
/* Decode the user token challenge and create the optional response
message */
result = Curl_auth_create_gssapi_user_message(data, NULL, NULL,
NULL, NULL,
sasl->mutual_auth,
&serverdata,
&conn->krb5,
&resp);
newstate = SASL_GSSAPI_NO_DATA;
}
else
/* Decode the security challenge and create the response message */
result = Curl_auth_create_gssapi_security_message(data, &serverdata,
&conn->krb5,
&resp);
}
break;
case SASL_GSSAPI_NO_DATA:
/* Decode the security challenge and create the response message */
result = get_server_message(sasl, data, &serverdata);
if(!result)
result = Curl_auth_create_gssapi_security_message(data, &serverdata,
&conn->krb5,
&resp);
break;
#endif
case SASL_OAUTH2:
/* Create the authorisation message */
if(sasl->authused == SASL_MECH_OAUTHBEARER) {
result = Curl_auth_create_oauth_bearer_message(conn->user,
hostname,
port,
oauth_bearer,
&resp);
/* Failures maybe sent by the server as continuations for OAUTHBEARER */
newstate = SASL_OAUTH2_RESP;
}
else
result = Curl_auth_create_xoauth_bearer_message(conn->user,
oauth_bearer,
&resp);
break;
case SASL_OAUTH2_RESP:
/* The continuation is optional so check the response code */
if(code == sasl->params->finalcode) {
/* Final response was received so we are done */
*progress = SASL_DONE;
state(sasl, data, SASL_STOP);
return result;
}
else if(code == sasl->params->contcode) {
/* Acknowledge the continuation by sending a 0x01 response. */
Curl_bufref_set(&resp, "\x01", 1, NULL);
break;
}
else {
*progress = SASL_DONE;
state(sasl, data, SASL_STOP);
return CURLE_LOGIN_DENIED;
}
case SASL_CANCEL:
/* Remove the offending mechanism from the supported list */
sasl->authmechs ^= sasl->authused;
/* Start an alternative SASL authentication */
return Curl_sasl_start(sasl, data, conn, sasl->force_ir, progress);
default:
failf(data, "Unsupported SASL authentication mechanism");
result = CURLE_UNSUPPORTED_PROTOCOL; /* Should not happen */
break;
}
Curl_bufref_free(&serverdata);
switch(result) {
case CURLE_BAD_CONTENT_ENCODING:
/* Cancel dialog */
result = sasl->params->sendcont(data, conn, "*");
newstate = SASL_CANCEL;
break;
case CURLE_OK:
result = build_message(data, &resp);
if(!result)
result = sasl->params->sendcont(data, conn,
(const char *) Curl_bufref_ptr(&resp));
break;
default:
newstate = SASL_STOP; /* Stop on error */
*progress = SASL_DONE;
break;
}
Curl_bufref_free(&resp);
state(sasl, data, newstate);
return result;
}
#endif /* protocols are enabled that use SASL */
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