lib/krb5.c - third_party/curl - Git at Google

 /* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
  *
  * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
  * (Royal Institute of Technology, Stockholm, Sweden).
  * Copyright (c) 2004 - 2019 Daniel Stenberg
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * 3. Neither the name of the Institute nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.  */

 #include "curl_setup.h"

 #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP)

 #ifdef HAVE_NETDB_H
 #include <netdb.h>
 #endif

 #include "urldata.h"
 #include "curl_base64.h"
 #include "ftp.h"
 #include "curl_gssapi.h"
 #include "sendf.h"
 #include "curl_sec.h"
 #include "warnless.h"

 /* The last 3 #include files should be in this order */
 #include "curl_printf.h"
 #include "curl_memory.h"
 #include "memdebug.h"

 static int
 krb5_init(void *app_data)
 {
   gss_ctx_id_t *context = app_data;
   /* Make sure our context is initialized for krb5_end. */
   *context = GSS_C_NO_CONTEXT;
   return 0;
 }

 static int
 krb5_check_prot(void *app_data, int level)
 {
   (void)app_data; /* unused */
   if(level == PROT_CONFIDENTIAL)
     return -1;
   return 0;
 }

 static int
 krb5_decode(void *app_data, void *buf, int len,
             int level UNUSED_PARAM,
             struct connectdata *conn UNUSED_PARAM)
 {
   gss_ctx_id_t *context = app_data;
   OM_uint32 maj, min;
   gss_buffer_desc enc, dec;

   (void)level;
   (void)conn;

   enc.value = buf;
   enc.length = len;
   maj = gss_unwrap(&min, *context, &enc, &dec, NULL, NULL);
   if(maj != GSS_S_COMPLETE) {
     if(len >= 4)
       strcpy(buf, "599 ");
     return -1;
   }

   memcpy(buf, dec.value, dec.length);
   len = curlx_uztosi(dec.length);
   gss_release_buffer(&min, &dec);

   return len;
 }

 static int
 krb5_overhead(void *app_data, int level, int len)
 {
   /* no arguments are used */
   (void)app_data;
   (void)level;
   (void)len;
   return 0;
 }

 static int
 krb5_encode(void *app_data, const void *from, int length, int level, void **to)
 {
   gss_ctx_id_t *context = app_data;
   gss_buffer_desc dec, enc;
   OM_uint32 maj, min;
   int state;
   int len;

   /* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
    * libraries modify the input buffer in gss_wrap()
    */
   dec.value = (void *)from;
   dec.length = length;
   maj = gss_wrap(&min, *context,
                  level == PROT_PRIVATE,
                  GSS_C_QOP_DEFAULT,
                  &dec, &state, &enc);

   if(maj != GSS_S_COMPLETE)
     return -1;

   /* malloc a new buffer, in case gss_release_buffer doesn't work as
      expected */
   *to = malloc(enc.length);
   if(!*to)
     return -1;
   memcpy(*to, enc.value, enc.length);
   len = curlx_uztosi(enc.length);
   gss_release_buffer(&min, &enc);
   return len;
 }

 static int
 krb5_auth(void *app_data, struct connectdata *conn)
 {
   int ret = AUTH_OK;
   char *p;
   const char *host = conn->host.name;
   ssize_t nread;
   curl_socklen_t l = sizeof(conn->local_addr);
   struct Curl_easy *data = conn->data;
   CURLcode result;
   const char *service = data->set.str[STRING_SERVICE_NAME] ?
                         data->set.str[STRING_SERVICE_NAME] :
                         "ftp";
   const char *srv_host = "host";
   gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp;
   OM_uint32 maj, min;
   gss_name_t gssname;
   gss_ctx_id_t *context = app_data;
   struct gss_channel_bindings_struct chan;
   size_t base64_sz = 0;
   struct sockaddr_in **remote_addr =
     (struct sockaddr_in **)&conn->ip_addr->ai_addr;
   char *stringp;

   if(getsockname(conn->sock[FIRSTSOCKET],
                  (struct sockaddr *)&conn->local_addr, &l) < 0)
     perror("getsockname()");

   chan.initiator_addrtype = GSS_C_AF_INET;
   chan.initiator_address.length = l - 4;
   chan.initiator_address.value = &conn->local_addr.sin_addr.s_addr;
   chan.acceptor_addrtype = GSS_C_AF_INET;
   chan.acceptor_address.length = l - 4;
   chan.acceptor_address.value = &(*remote_addr)->sin_addr.s_addr;
   chan.application_data.length = 0;
   chan.application_data.value = NULL;

   /* this loop will execute twice (once for service, once for host) */
   for(;;) {
     /* this really shouldn't be repeated here, but can't help it */
     if(service == srv_host) {
       result = Curl_ftpsend(conn, "AUTH GSSAPI");
       if(result)
         return -2;

       if(Curl_GetFTPResponse(&nread, conn, NULL))
         return -1;

       if(data->state.buffer[0] != '3')
         return -1;
     }

     stringp = aprintf("%s@%s", service, host);
     if(!stringp)
       return -2;

     input_buffer.value = stringp;
     input_buffer.length = strlen(stringp);
     maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
                           &gssname);
     free(stringp);
     if(maj != GSS_S_COMPLETE) {
       gss_release_name(&min, &gssname);
       if(service == srv_host) {
         failf(data, "Error importing service name %s@%s", service, host);
         return AUTH_ERROR;
       }
       service = srv_host;
       continue;
     }
     /* We pass NULL as |output_name_type| to avoid a leak. */
     gss_display_name(&min, gssname, &output_buffer, NULL);
     Curl_infof(data, "Trying against %s\n", output_buffer.value);
     gssresp = GSS_C_NO_BUFFER;
     *context = GSS_C_NO_CONTEXT;

     do {
       /* Release the buffer at each iteration to avoid leaking: the first time
          we are releasing the memory from gss_display_name. The last item is
          taken care by a final gss_release_buffer. */
       gss_release_buffer(&min, &output_buffer);
       ret = AUTH_OK;
       maj = Curl_gss_init_sec_context(data,
                                       &min,
                                       context,
                                       gssname,
                                       &Curl_krb5_mech_oid,
                                       &chan,
                                       gssresp,
                                       &output_buffer,
                                       TRUE,
                                       NULL);

       if(gssresp) {
         free(_gssresp.value);
         gssresp = NULL;
       }

       if(GSS_ERROR(maj)) {
         Curl_infof(data, "Error creating security context\n");
         ret = AUTH_ERROR;
         break;
       }

       if(output_buffer.length != 0) {
         char *cmd;

         result = Curl_base64_encode(data, (char *)output_buffer.value,
                                     output_buffer.length, &p, &base64_sz);
         if(result) {
           Curl_infof(data, "base64-encoding: %s\n",
                      curl_easy_strerror(result));
           ret = AUTH_ERROR;
           break;
         }

         cmd = aprintf("ADAT %s", p);
         if(cmd)
           result = Curl_ftpsend(conn, cmd);
         else
           result = CURLE_OUT_OF_MEMORY;

         free(p);
         free(cmd);

         if(result) {
           ret = -2;
           break;
         }

         if(Curl_GetFTPResponse(&nread, conn, NULL)) {
           ret = -1;
           break;
         }

         if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') {
           Curl_infof(data, "Server didn't accept auth data\n");
           ret = AUTH_ERROR;
           break;
         }

         _gssresp.value = NULL; /* make sure it is initialized */
         p = data->state.buffer + 4;
         p = strstr(p, "ADAT=");
         if(p) {
           result = Curl_base64_decode(p + 5,
                                       (unsigned char **)&_gssresp.value,
                                       &_gssresp.length);
           if(result) {
             failf(data, "base64-decoding: %s", curl_easy_strerror(result));
             ret = AUTH_CONTINUE;
             break;
           }
         }

         gssresp = &_gssresp;
       }
     } while(maj == GSS_S_CONTINUE_NEEDED);

     gss_release_name(&min, &gssname);
     gss_release_buffer(&min, &output_buffer);

     if(gssresp)
       free(_gssresp.value);

     if(ret == AUTH_OK || service == srv_host)
       return ret;

     service = srv_host;
   }
   return ret;
 }

 static void krb5_end(void *app_data)
 {
     OM_uint32 min;
     gss_ctx_id_t *context = app_data;
     if(*context != GSS_C_NO_CONTEXT) {
       OM_uint32 maj = gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
       (void)maj;
       DEBUGASSERT(maj == GSS_S_COMPLETE);
     }
 }

 struct Curl_sec_client_mech Curl_krb5_client_mech = {
     "GSSAPI",
     sizeof(gss_ctx_id_t),
     krb5_init,
     krb5_auth,
     krb5_end,
     krb5_check_prot,
     krb5_overhead,
     krb5_encode,
     krb5_decode
 };

 #endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */
	/* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
	*
	* Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
	* (Royal Institute of Technology, Stockholm, Sweden).
	* Copyright (c) 2004 - 2019 Daniel Stenberg
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* 3. Neither the name of the Institute nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE. */

	#include "curl_setup.h"

	#if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP)

	#ifdef HAVE_NETDB_H
	#include <netdb.h>
	#endif

	#include "urldata.h"
	#include "curl_base64.h"
	#include "ftp.h"
	#include "curl_gssapi.h"
	#include "sendf.h"
	#include "curl_sec.h"
	#include "warnless.h"

	/* The last 3 #include files should be in this order */
	#include "curl_printf.h"
	#include "curl_memory.h"
	#include "memdebug.h"

	static int
	krb5_init(void *app_data)
	{
	gss_ctx_id_t *context = app_data;
	/* Make sure our context is initialized for krb5_end. */
	*context = GSS_C_NO_CONTEXT;
	return 0;
	}

	static int
	krb5_check_prot(void *app_data, int level)
	{
	(void)app_data; /* unused */
	if(level == PROT_CONFIDENTIAL)
	return -1;
	return 0;
	}

	static int
	krb5_decode(void app_data, void buf, int len,
	int level UNUSED_PARAM,
	struct connectdata *conn UNUSED_PARAM)
	{
	gss_ctx_id_t *context = app_data;
	OM_uint32 maj, min;
	gss_buffer_desc enc, dec;

	(void)level;
	(void)conn;

	enc.value = buf;
	enc.length = len;
	maj = gss_unwrap(&min, *context, &enc, &dec, NULL, NULL);
	if(maj != GSS_S_COMPLETE) {
	if(len >= 4)
	strcpy(buf, "599 ");
	return -1;
	}

	memcpy(buf, dec.value, dec.length);
	len = curlx_uztosi(dec.length);
	gss_release_buffer(&min, &dec);

	return len;
	}

	static int
	krb5_overhead(void *app_data, int level, int len)
	{
	/* no arguments are used */
	(void)app_data;
	(void)level;
	(void)len;
	return 0;
	}

	static int
	krb5_encode(void app_data, const void from, int length, int level, void **to)
	{
	gss_ctx_id_t *context = app_data;
	gss_buffer_desc dec, enc;
	OM_uint32 maj, min;
	int state;
	int len;

	/* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
	* libraries modify the input buffer in gss_wrap()
	*/
	dec.value = (void *)from;
	dec.length = length;
	maj = gss_wrap(&min, *context,
	level == PROT_PRIVATE,
	GSS_C_QOP_DEFAULT,
	&dec, &state, &enc);

	if(maj != GSS_S_COMPLETE)
	return -1;

	/* malloc a new buffer, in case gss_release_buffer doesn't work as
	expected */
	*to = malloc(enc.length);
	if(!*to)
	return -1;
	memcpy(*to, enc.value, enc.length);
	len = curlx_uztosi(enc.length);
	gss_release_buffer(&min, &enc);
	return len;
	}

	static int
	krb5_auth(void app_data, struct connectdata conn)
	{
	int ret = AUTH_OK;
	char *p;
	const char *host = conn->host.name;
	ssize_t nread;
	curl_socklen_t l = sizeof(conn->local_addr);
	struct Curl_easy *data = conn->data;
	CURLcode result;
	const char *service = data->set.str[STRING_SERVICE_NAME] ?
	data->set.str[STRING_SERVICE_NAME] :
	"ftp";
	const char *srv_host = "host";
	gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp;
	OM_uint32 maj, min;
	gss_name_t gssname;
	gss_ctx_id_t *context = app_data;
	struct gss_channel_bindings_struct chan;
	size_t base64_sz = 0;
	struct sockaddr_in **remote_addr =
	(struct sockaddr_in **)&conn->ip_addr->ai_addr;
	char *stringp;

	if(getsockname(conn->sock[FIRSTSOCKET],
	(struct sockaddr *)&conn->local_addr, &l) < 0)
	perror("getsockname()");

	chan.initiator_addrtype = GSS_C_AF_INET;
	chan.initiator_address.length = l - 4;
	chan.initiator_address.value = &conn->local_addr.sin_addr.s_addr;
	chan.acceptor_addrtype = GSS_C_AF_INET;
	chan.acceptor_address.length = l - 4;
	chan.acceptor_address.value = &(*remote_addr)->sin_addr.s_addr;
	chan.application_data.length = 0;
	chan.application_data.value = NULL;

	/* this loop will execute twice (once for service, once for host) */
	for(;;) {
	/* this really shouldn't be repeated here, but can't help it */
	if(service == srv_host) {
	result = Curl_ftpsend(conn, "AUTH GSSAPI");
	if(result)
	return -2;

	if(Curl_GetFTPResponse(&nread, conn, NULL))
	return -1;

	if(data->state.buffer[0] != '3')
	return -1;
	}

	stringp = aprintf("%s@%s", service, host);
	if(!stringp)
	return -2;

	input_buffer.value = stringp;
	input_buffer.length = strlen(stringp);
	maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
	&gssname);
	free(stringp);
	if(maj != GSS_S_COMPLETE) {
	gss_release_name(&min, &gssname);
	if(service == srv_host) {
	failf(data, "Error importing service name %s@%s", service, host);
	return AUTH_ERROR;
	}
	service = srv_host;
	continue;
	}
	/* We pass NULL as \|output_name_type\| to avoid a leak. */
	gss_display_name(&min, gssname, &output_buffer, NULL);
	Curl_infof(data, "Trying against %s\n", output_buffer.value);
	gssresp = GSS_C_NO_BUFFER;
	*context = GSS_C_NO_CONTEXT;

	do {
	/* Release the buffer at each iteration to avoid leaking: the first time
	we are releasing the memory from gss_display_name. The last item is
	taken care by a final gss_release_buffer. */
	gss_release_buffer(&min, &output_buffer);
	ret = AUTH_OK;
	maj = Curl_gss_init_sec_context(data,
	&min,
	context,
	gssname,
	&Curl_krb5_mech_oid,
	&chan,
	gssresp,
	&output_buffer,
	TRUE,
	NULL);

	if(gssresp) {
	free(_gssresp.value);
	gssresp = NULL;
	}

	if(GSS_ERROR(maj)) {
	Curl_infof(data, "Error creating security context\n");
	ret = AUTH_ERROR;
	break;
	}

	if(output_buffer.length != 0) {
	char *cmd;

	result = Curl_base64_encode(data, (char *)output_buffer.value,
	output_buffer.length, &p, &base64_sz);
	if(result) {
	Curl_infof(data, "base64-encoding: %s\n",
	curl_easy_strerror(result));
	ret = AUTH_ERROR;
	break;
	}

	cmd = aprintf("ADAT %s", p);
	if(cmd)
	result = Curl_ftpsend(conn, cmd);
	else
	result = CURLE_OUT_OF_MEMORY;

	free(p);
	free(cmd);

	if(result) {
	ret = -2;
	break;
	}

	if(Curl_GetFTPResponse(&nread, conn, NULL)) {
	ret = -1;
	break;
	}

	if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') {
	Curl_infof(data, "Server didn't accept auth data\n");
	ret = AUTH_ERROR;
	break;
	}

	_gssresp.value = NULL; /* make sure it is initialized */
	p = data->state.buffer + 4;
	p = strstr(p, "ADAT=");
	if(p) {
	result = Curl_base64_decode(p + 5,
	(unsigned char **)&_gssresp.value,
	&_gssresp.length);
	if(result) {
	failf(data, "base64-decoding: %s", curl_easy_strerror(result));
	ret = AUTH_CONTINUE;
	break;
	}
	}

	gssresp = &_gssresp;
	}
	} while(maj == GSS_S_CONTINUE_NEEDED);

	gss_release_name(&min, &gssname);
	gss_release_buffer(&min, &output_buffer);

	if(gssresp)
	free(_gssresp.value);

	if(ret == AUTH_OK \|\| service == srv_host)
	return ret;

	service = srv_host;
	}
	return ret;
	}

	static void krb5_end(void *app_data)
	{
	OM_uint32 min;
	gss_ctx_id_t *context = app_data;
	if(*context != GSS_C_NO_CONTEXT) {
	OM_uint32 maj = gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
	(void)maj;
	DEBUGASSERT(maj == GSS_S_COMPLETE);
	}
	}

	struct Curl_sec_client_mech Curl_krb5_client_mech = {
	"GSSAPI",
	sizeof(gss_ctx_id_t),
	krb5_init,
	krb5_auth,
	krb5_end,
	krb5_check_prot,
	krb5_overhead,
	krb5_encode,
	krb5_decode
	};

	#endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */