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Diffstat (limited to 'lib/vauth/krb5_sspi.c')
| -rw-r--r-- | lib/vauth/krb5_sspi.c | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/lib/vauth/krb5_sspi.c b/lib/vauth/krb5_sspi.c new file mode 100644 index 000000000..284fd98dd --- /dev/null +++ b/lib/vauth/krb5_sspi.c @@ -0,0 +1,485 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 2014 - 2016, Steve Holme, <steve_holme@hotmail.com>. + * + * 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 http://curl.haxx.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. + * + * RFC4752 The Kerberos V5 ("GSSAPI") SASL Mechanism + * + ***************************************************************************/ + +#include "curl_setup.h" + +#if defined(USE_WINDOWS_SSPI) && defined(USE_KERBEROS5) + +#include <curl/curl.h> + +#include "vauth/vauth.h" +#include "urldata.h" +#include "curl_base64.h" +#include "warnless.h" +#include "curl_multibyte.h" +#include "sendf.h" + +/* The last #include files should be: */ +#include "curl_memory.h" +#include "memdebug.h" + +/* + * Curl_sasl_create_gssapi_user_message() + * + * This is used to generate an already encoded GSSAPI (Kerberos V5) user token + * message ready for sending to the recipient. + * + * Parameters: + * + * data [in] - The session handle. + * userp [in] - The user name in the format User or Domain\User. + * passdwp [in] - The user's password. + * service [in] - The service type such as www, smtp, pop or imap. + * mutual_auth [in] - Flag specifing whether or not mutual authentication + * is enabled. + * chlg64 [in] - The optional base64 encoded challenge message. + * krb5 [in/out] - The Kerberos 5 data struct being used and modified. + * outptr [in/out] - The address where a pointer to newly allocated memory + * holding the result will be stored upon completion. + * outlen [out] - The length of the output message. + * + * Returns CURLE_OK on success. + */ +CURLcode Curl_sasl_create_gssapi_user_message(struct SessionHandle *data, + const char *userp, + const char *passwdp, + const char *service, + const bool mutual_auth, + const char *chlg64, + struct kerberos5data *krb5, + char **outptr, size_t *outlen) +{ + CURLcode result = CURLE_OK; + size_t chlglen = 0; + unsigned char *chlg = NULL; + CtxtHandle context; + PSecPkgInfo SecurityPackage; + SecBuffer chlg_buf; + SecBuffer resp_buf; + SecBufferDesc chlg_desc; + SecBufferDesc resp_desc; + SECURITY_STATUS status; + unsigned long attrs; + TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */ + + if(!krb5->credentials) { + /* Query the security package for Kerberos */ + status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *) + TEXT(SP_NAME_KERBEROS), + &SecurityPackage); + if(status != SEC_E_OK) { + return CURLE_NOT_BUILT_IN; + } + + krb5->token_max = SecurityPackage->cbMaxToken; + + /* Release the package buffer as it is not required anymore */ + s_pSecFn->FreeContextBuffer(SecurityPackage); + + /* Allocate our response buffer */ + krb5->output_token = malloc(krb5->token_max); + if(!krb5->output_token) + return CURLE_OUT_OF_MEMORY; + + /* Generate our SPN */ + krb5->spn = Curl_sasl_build_spn(service, data->easy_conn->host.name); + if(!krb5->spn) + return CURLE_OUT_OF_MEMORY; + + if(userp && *userp) { + /* Populate our identity structure */ + result = Curl_create_sspi_identity(userp, passwdp, &krb5->identity); + if(result) + return result; + + /* Allow proper cleanup of the identity structure */ + krb5->p_identity = &krb5->identity; + } + else + /* Use the current Windows user */ + krb5->p_identity = NULL; + + /* Allocate our credentials handle */ + krb5->credentials = malloc(sizeof(CredHandle)); + if(!krb5->credentials) + return CURLE_OUT_OF_MEMORY; + + memset(krb5->credentials, 0, sizeof(CredHandle)); + + /* Acquire our credentials handle */ + status = s_pSecFn->AcquireCredentialsHandle(NULL, + (TCHAR *) + TEXT(SP_NAME_KERBEROS), + SECPKG_CRED_OUTBOUND, NULL, + krb5->p_identity, NULL, NULL, + krb5->credentials, &expiry); + if(status != SEC_E_OK) + return CURLE_LOGIN_DENIED; + + /* Allocate our new context handle */ + krb5->context = malloc(sizeof(CtxtHandle)); + if(!krb5->context) + return CURLE_OUT_OF_MEMORY; + + memset(krb5->context, 0, sizeof(CtxtHandle)); + } + else { + /* Decode the base-64 encoded challenge message */ + if(strlen(chlg64) && *chlg64 != '=') { + result = Curl_base64_decode(chlg64, &chlg, &chlglen); + if(result) + return result; + } + + /* Ensure we have a valid challenge message */ + if(!chlg) { + infof(data, "GSSAPI handshake failure (empty challenge message)\n"); + + return CURLE_BAD_CONTENT_ENCODING; + } + + /* Setup the challenge "input" security buffer */ + chlg_desc.ulVersion = SECBUFFER_VERSION; + chlg_desc.cBuffers = 1; + chlg_desc.pBuffers = &chlg_buf; + chlg_buf.BufferType = SECBUFFER_TOKEN; + chlg_buf.pvBuffer = chlg; + chlg_buf.cbBuffer = curlx_uztoul(chlglen); + } + + /* Setup the response "output" security buffer */ + resp_desc.ulVersion = SECBUFFER_VERSION; + resp_desc.cBuffers = 1; + resp_desc.pBuffers = &resp_buf; + resp_buf.BufferType = SECBUFFER_TOKEN; + resp_buf.pvBuffer = krb5->output_token; + resp_buf.cbBuffer = curlx_uztoul(krb5->token_max); + + /* Generate our challenge-response message */ + status = s_pSecFn->InitializeSecurityContext(krb5->credentials, + chlg ? krb5->context : NULL, + krb5->spn, + (mutual_auth ? + ISC_REQ_MUTUAL_AUTH : 0), + 0, SECURITY_NATIVE_DREP, + chlg ? &chlg_desc : NULL, 0, + &context, + &resp_desc, &attrs, + &expiry); + + if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED) { + free(chlg); + + return CURLE_RECV_ERROR; + } + + if(memcmp(&context, krb5->context, sizeof(context))) { + s_pSecFn->DeleteSecurityContext(krb5->context); + + memcpy(krb5->context, &context, sizeof(context)); + } + + if(resp_buf.cbBuffer) { + /* Base64 encode the response */ + result = Curl_base64_encode(data, (char *) resp_buf.pvBuffer, + resp_buf.cbBuffer, outptr, outlen); + } + + /* Free the decoded challenge */ + free(chlg); + + return result; +} + +/* + * Curl_sasl_create_gssapi_security_message() + * + * This is used to generate an already encoded GSSAPI (Kerberos V5) security + * token message ready for sending to the recipient. + * + * Parameters: + * + * data [in] - The session handle. + * chlg64 [in] - The optional base64 encoded challenge message. + * krb5 [in/out] - The Kerberos 5 data struct being used and modified. + * outptr [in/out] - The address where a pointer to newly allocated memory + * holding the result will be stored upon completion. + * outlen [out] - The length of the output message. + * + * Returns CURLE_OK on success. + */ +CURLcode Curl_sasl_create_gssapi_security_message(struct SessionHandle *data, + const char *chlg64, + struct kerberos5data *krb5, + char **outptr, + size_t *outlen) +{ + CURLcode result = CURLE_OK; + size_t offset = 0; + size_t chlglen = 0; + size_t messagelen = 0; + size_t appdatalen = 0; + unsigned char *chlg = NULL; + unsigned char *trailer = NULL; + unsigned char *message = NULL; + unsigned char *padding = NULL; + unsigned char *appdata = NULL; + SecBuffer input_buf[2]; + SecBuffer wrap_buf[3]; + SecBufferDesc input_desc; + SecBufferDesc wrap_desc; + unsigned long indata = 0; + unsigned long outdata = 0; + unsigned long qop = 0; + unsigned long sec_layer = 0; + unsigned long max_size = 0; + SecPkgContext_Sizes sizes; + SecPkgCredentials_Names names; + SECURITY_STATUS status; + char *user_name; + + /* Decode the base-64 encoded input message */ + if(strlen(chlg64) && *chlg64 != '=') { + result = Curl_base64_decode(chlg64, &chlg, &chlglen); + if(result) + return result; + } + + /* Ensure we have a valid challenge message */ + if(!chlg) { + infof(data, "GSSAPI handshake failure (empty security message)\n"); + + return CURLE_BAD_CONTENT_ENCODING; + } + + /* Get our response size information */ + status = s_pSecFn->QueryContextAttributes(krb5->context, + SECPKG_ATTR_SIZES, + &sizes); + if(status != SEC_E_OK) { + free(chlg); + + return CURLE_OUT_OF_MEMORY; + } + + /* Get the fully qualified username back from the context */ + status = s_pSecFn->QueryCredentialsAttributes(krb5->credentials, + SECPKG_CRED_ATTR_NAMES, + &names); + if(status != SEC_E_OK) { + free(chlg); + + return CURLE_RECV_ERROR; + } + + /* Setup the "input" security buffer */ + input_desc.ulVersion = SECBUFFER_VERSION; + input_desc.cBuffers = 2; + input_desc.pBuffers = input_buf; + input_buf[0].BufferType = SECBUFFER_STREAM; + input_buf[0].pvBuffer = chlg; + input_buf[0].cbBuffer = curlx_uztoul(chlglen); + input_buf[1].BufferType = SECBUFFER_DATA; + input_buf[1].pvBuffer = NULL; + input_buf[1].cbBuffer = 0; + + /* Decrypt the inbound challenge and obtain the qop */ + status = s_pSecFn->DecryptMessage(krb5->context, &input_desc, 0, &qop); + if(status != SEC_E_OK) { + infof(data, "GSSAPI handshake failure (empty security message)\n"); + + free(chlg); + + return CURLE_BAD_CONTENT_ENCODING; + } + + /* Not 4 octets long so fail as per RFC4752 Section 3.1 */ + if(input_buf[1].cbBuffer != 4) { + infof(data, "GSSAPI handshake failure (invalid security data)\n"); + + free(chlg); + + return CURLE_BAD_CONTENT_ENCODING; + } + + /* Copy the data out and free the challenge as it is not required anymore */ + memcpy(&indata, input_buf[1].pvBuffer, 4); + s_pSecFn->FreeContextBuffer(input_buf[1].pvBuffer); + free(chlg); + + /* Extract the security layer */ + sec_layer = indata & 0x000000FF; + if(!(sec_layer & KERB_WRAP_NO_ENCRYPT)) { + infof(data, "GSSAPI handshake failure (invalid security layer)\n"); + + return CURLE_BAD_CONTENT_ENCODING; + } + + /* Extract the maximum message size the server can receive */ + max_size = ntohl(indata & 0xFFFFFF00); + if(max_size > 0) { + /* The server has told us it supports a maximum receive buffer, however, as + we don't require one unless we are encrypting data, we tell the server + our receive buffer is zero. */ + max_size = 0; + } + + /* Allocate the trailer */ + trailer = malloc(sizes.cbSecurityTrailer); + if(!trailer) + return CURLE_OUT_OF_MEMORY; + + /* Convert the user name to UTF8 when operating with Unicode */ + user_name = Curl_convert_tchar_to_UTF8(names.sUserName); + if(!user_name) { + free(trailer); + + return CURLE_OUT_OF_MEMORY; + } + + /* Allocate our message */ + messagelen = sizeof(outdata) + strlen(user_name) + 1; + message = malloc(messagelen); + if(!message) { + free(trailer); + Curl_unicodefree(user_name); + + return CURLE_OUT_OF_MEMORY; + } + + /* Populate the message with the security layer, client supported receive + message size and authorization identity including the 0x00 based + terminator. Note: Dispite RFC4752 Section 3.1 stating "The authorization + identity is not terminated with the zero-valued (%x00) octet." it seems + necessary to include it. */ + outdata = htonl(max_size) | sec_layer; + memcpy(message, &outdata, sizeof(outdata)); + strcpy((char *) message + sizeof(outdata), user_name); + Curl_unicodefree(user_name); + + /* Allocate the padding */ + padding = malloc(sizes.cbBlockSize); + if(!padding) { + free(message); + free(trailer); + + return CURLE_OUT_OF_MEMORY; + } + + /* Setup the "authentication data" security buffer */ + wrap_desc.ulVersion = SECBUFFER_VERSION; + wrap_desc.cBuffers = 3; + wrap_desc.pBuffers = wrap_buf; + wrap_buf[0].BufferType = SECBUFFER_TOKEN; + wrap_buf[0].pvBuffer = trailer; + wrap_buf[0].cbBuffer = sizes.cbSecurityTrailer; + wrap_buf[1].BufferType = SECBUFFER_DATA; + wrap_buf[1].pvBuffer = message; + wrap_buf[1].cbBuffer = curlx_uztoul(messagelen); + wrap_buf[2].BufferType = SECBUFFER_PADDING; + wrap_buf[2].pvBuffer = padding; + wrap_buf[2].cbBuffer = sizes.cbBlockSize; + + /* Encrypt the data */ + status = s_pSecFn->EncryptMessage(krb5->context, KERB_WRAP_NO_ENCRYPT, + &wrap_desc, 0); + if(status != SEC_E_OK) { + free(padding); + free(message); + free(trailer); + + return CURLE_OUT_OF_MEMORY; + } + + /* Allocate the encryption (wrap) buffer */ + appdatalen = wrap_buf[0].cbBuffer + wrap_buf[1].cbBuffer + + wrap_buf[2].cbBuffer; + appdata = malloc(appdatalen); + if(!appdata) { + free(padding); + free(message); + free(trailer); + + return CURLE_OUT_OF_MEMORY; + } + + /* Populate the encryption buffer */ + memcpy(appdata, wrap_buf[0].pvBuffer, wrap_buf[0].cbBuffer); + offset += wrap_buf[0].cbBuffer; + memcpy(appdata + offset, wrap_buf[1].pvBuffer, wrap_buf[1].cbBuffer); + offset += wrap_buf[1].cbBuffer; + memcpy(appdata + offset, wrap_buf[2].pvBuffer, wrap_buf[2].cbBuffer); + + /* Base64 encode the response */ + result = Curl_base64_encode(data, (char *) appdata, appdatalen, outptr, + outlen); + + /* Free all of our local buffers */ + free(appdata); + free(padding); + free(message); + free(trailer); + + return result; +} + +/* + * Curl_sasl_gssapi_cleanup() + * + * This is used to clean up the GSSAPI (Kerberos V5) specific data. + * + * Parameters: + * + * krb5 [in/out] - The Kerberos 5 data struct being cleaned up. + * + */ +void Curl_sasl_gssapi_cleanup(struct kerberos5data *krb5) +{ + /* Free our security context */ + if(krb5->context) { + s_pSecFn->DeleteSecurityContext(krb5->context); + free(krb5->context); + krb5->context = NULL; + } + + /* Free our credentials handle */ + if(krb5->credentials) { + s_pSecFn->FreeCredentialsHandle(krb5->credentials); + free(krb5->credentials); + krb5->credentials = NULL; + } + + /* Free our identity */ + Curl_sspi_free_identity(krb5->p_identity); + krb5->p_identity = NULL; + + /* Free the SPN and output token */ + Curl_safefree(krb5->spn); + Curl_safefree(krb5->output_token); + + /* Reset any variables */ + krb5->token_max = 0; +} + +#endif /* USE_WINDOWS_SSPI && USE_KERBEROS5*/ |