/src/cups/cups/auth.c

Source
/*
 * Authentication functions for CUPS.
 *
 * Copyright © 2020-2025 by OpenPrinting.
 * Copyright © 2007-2019 by Apple Inc.
 * Copyright © 1997-2007 by Easy Software Products.
 *
 * This file contains Kerberos support code, copyright 2006 by
 * Jelmer Vernooij.
 *
 * Licensed under Apache License v2.0.  See the file "LICENSE" for more
 * information.
 */

#include "cups-private.h"
#include "debug-internal.h"
#include <fcntl.h>
#include <sys/stat.h>
#if defined(_WIN32) || defined(__EMX__)
#  include <io.h>
#else
#  include <unistd.h>
#endif /* _WIN32 || __EMX__ */

#if HAVE_AUTHORIZATION_H
#  include <Security/Authorization.h>
#endif /* HAVE_AUTHORIZATION_H */

#if defined(SO_PEERCRED) && defined(AF_LOCAL)
#  include <pwd.h>
#endif /* SO_PEERCRED && AF_LOCAL */


/*
 * Local functions...
 */

static const char *cups_auth_find(const char *www_authenticate, const char *scheme);
static const char *cups_auth_param(const char *scheme, const char *name, char *value, size_t valsize);
static const char *cups_auth_scheme(const char *www_authenticate, char *scheme, size_t schemesize);

#ifdef HAVE_GSSAPI
#  define CUPS_GSS_OK 0   /* Successfully set credentials */
#  define CUPS_GSS_NONE -1    /* No credentials */
#  define CUPS_GSS_FAIL -2    /* Failed credentials/authentication */
#  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
#    ifdef HAVE_GSS_GSSAPI_SPI_H
#      include <GSS/gssapi_spi.h>
#    else
#      define GSS_AUTH_IDENTITY_TYPE_1 1
#      define gss_acquire_cred_ex_f __ApplePrivate_gss_acquire_cred_ex_f
typedef struct gss_auth_identity /* @private@ */
{
  uint32_t type;
  uint32_t flags;
  char *username;
  char *realm;
  char *password;
  gss_buffer_t *credentialsRef;
} gss_auth_identity_desc;
extern OM_uint32 gss_acquire_cred_ex_f(gss_status_id_t, const gss_name_t,
               OM_uint32, OM_uint32, const gss_OID,
               gss_cred_usage_t, gss_auth_identity_t,
               void *, void (*)(void *, OM_uint32,
                                gss_status_id_t,
              gss_cred_id_t,
              gss_OID_set,
              OM_uint32));
#    endif /* HAVE_GSS_GSSAPI_SPI_H */
#    include <dispatch/dispatch.h>
typedef struct _cups_gss_acquire_s  /* Acquire callback data */
{
  dispatch_semaphore_t  sem;    /* Synchronization semaphore */
  OM_uint32   major;    /* Returned status code */
  gss_cred_id_t   creds;    /* Returned credentials */
} _cups_gss_acquire_t;

static void cups_gss_acquire(void *ctx, OM_uint32 major,
                     gss_status_id_t status,
         gss_cred_id_t creds, gss_OID_set oids,
         OM_uint32 time_rec);
#  endif /* HAVE_GSS_ACQUIRE_CRED_EX_F */
static gss_name_t cups_gss_getname(http_t *http, const char *service_name);
#  ifdef DEBUG
static void cups_gss_printf(OM_uint32 major_status, OM_uint32 minor_status,
        const char *message);
#  else
#    define cups_gss_printf(major, minor, message)
#  endif /* DEBUG */
#endif /* HAVE_GSSAPI */
static int  cups_is_local_connection(http_t *http);
static int  cups_local_auth(http_t *http);


/*
 * 'cupsDoAuthentication()' - Authenticate a request.
 *
 * This function should be called in response to a @code HTTP_STATUS_UNAUTHORIZED@
 * status, prior to resubmitting your request.
 *
 * @since CUPS 1.1.20@
 */

int         /* O - 0 on success, -1 on error */
cupsDoAuthentication(
    http_t     *http,     /* I - Connection to server or @code CUPS_HTTP_DEFAULT@ */
    const char *method,     /* I - Request method ("GET", "POST", "PUT") */
    const char *resource)   /* I - Resource path */
{
  const char  *password,    /* Password string */
    *www_auth,    /* WWW-Authenticate header */
    *schemedata;    /* Scheme-specific data */
  char    scheme[256],    /* Scheme name */
    prompt[1024];   /* Prompt for user */
  int   localauth;    /* Local authentication result */
  _cups_globals_t *cg = _cupsGlobals(); /* Global data */


  DEBUG_printf("cupsDoAuthentication(http=%p, method=\"%s\", resource=\"%s\")", (void *)http, method, resource);

  if (!http)
    http = _cupsConnect();

  if (!http || !method || !resource)
    return (-1);

  DEBUG_printf("2cupsDoAuthentication: digest_tries=%d, userpass=\"%s\"", http->digest_tries, http->userpass);
  DEBUG_printf("2cupsDoAuthentication: WWW-Authenticate=\"%s\"", httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE));

 /*
  * Clear the current authentication string...
  */

  httpSetAuthString(http, NULL, NULL);

 /*
  * See if we can do local authentication...
  */

  if (http->digest_tries < 3)
  {
    if ((localauth = cups_local_auth(http)) == 0)
    {
      DEBUG_printf("2cupsDoAuthentication: authstring=\"%s\"", http->authstring);

      if (http->status == HTTP_STATUS_UNAUTHORIZED)
  http->digest_tries ++;

      return (0);
    }
    else if (localauth == -1)
    {
      http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
      return (-1);      /* Error or canceled */
    }
  }

 /*
  * Nope, loop through the authentication schemes to find the first we support.
  */

  www_auth = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);

  for (schemedata = cups_auth_scheme(www_auth, scheme, sizeof(scheme)); schemedata; schemedata = cups_auth_scheme(schemedata + strlen(scheme), scheme, sizeof(scheme)))
  {
   /*
    * Check the scheme name...
    */

    DEBUG_printf("2cupsDoAuthentication: Trying scheme \"%s\"...", scheme);

#ifdef HAVE_GSSAPI
    if (!_cups_strcasecmp(scheme, "Negotiate") && !cups_is_local_connection(http))
    {
     /*
      * Kerberos authentication to remote server...
      */

      int gss_status;     /* Auth status */

      if ((gss_status = _cupsSetNegotiateAuthString(http, method, resource)) == CUPS_GSS_FAIL)
      {
        DEBUG_puts("1cupsDoAuthentication: Negotiate failed.");
  http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
  return (-1);
      }
      else if (gss_status == CUPS_GSS_NONE)
      {
        DEBUG_puts("2cupsDoAuthentication: No credentials for Negotiate.");
        continue;
      }
      else
      {
        DEBUG_puts("2cupsDoAuthentication: Using Negotiate.");
        break;
      }
    }
    else
#endif /* HAVE_GSSAPI */
    if (!_cups_strcasecmp(scheme, "Bearer"))
    {
      // OAuth 2.0 (Bearer) authentication...
      const char  *bearer = NULL; /* Bearer token string, if any */

      if (cg->oauth_cb)
      {
        // Try callback...
  char  scope[HTTP_MAX_VALUE];  /* scope="xyz" string */

  cups_auth_param(schemedata, "realm", http->realm, sizeof(http->realm));

  if (cups_auth_param(schemedata, "scope", scope, sizeof(scope)))
    bearer = (cg->oauth_cb)(http, http->realm, scope, resource, cg->oauth_data);
  else
    bearer = (cg->oauth_cb)(http, http->realm, NULL, resource, cg->oauth_data);
      }

      if (bearer)
      {
        // Use this access token...
        httpSetAuthString(http, "Bearer", bearer);
        break;
      }
      else
      {
        // No access token, try the next scheme...
        DEBUG_puts("2cupsDoAuthentication: No OAuth access token to provide.");
        continue;
      }
    }
    else if (_cups_strcasecmp(scheme, "Basic") && _cups_strcasecmp(scheme, "Digest") && _cups_strcasecmp(scheme, "Negotiate"))
    {
     /*
      * Other schemes not yet supported...
      */

      DEBUG_printf("2cupsDoAuthentication: Scheme \"%s\" not yet supported.", scheme);
      continue;
    }

   /*
    * See if we should retry the current username:password...
    */

    if (http->digest_tries > 1 || !http->userpass[0])
    {
     /*
      * Nope - get a new password from the user...
      */

      char default_username[HTTP_MAX_VALUE];
          /* Default username */

      if (!cg->lang_default)
  cg->lang_default = cupsLangDefault();

      if (cups_auth_param(schemedata, "username", default_username, sizeof(default_username)))
  cupsSetUser(default_username);

      snprintf(prompt, sizeof(prompt), _cupsLangString(cg->lang_default, _("Password for %s on %s? ")), cupsGetUser(), http->hostname[0] == '/' ? "localhost" : http->hostname);

      http->digest_tries  = _cups_strncasecmp(scheme, "Digest", 6) != 0;
      http->userpass[0]   = '\0';

      if ((password = cupsGetPassword2(prompt, http, method, resource)) == NULL)
      {
        DEBUG_puts("1cupsDoAuthentication: User canceled password request.");
  http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
  return (-1);
      }

      snprintf(http->userpass, sizeof(http->userpass), "%s:%s", cupsGetUser(), password);
    }
    else if (http->status == HTTP_STATUS_UNAUTHORIZED)
      http->digest_tries ++;

    if (http->status == HTTP_STATUS_UNAUTHORIZED && http->digest_tries >= 3)
    {
      DEBUG_printf("1cupsDoAuthentication: Too many authentication tries (%d)", http->digest_tries);

      http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;
      return (-1);
    }

   /*
    * Got a password; encode it for the server...
    */

    if (!_cups_strcasecmp(scheme, "Basic"))
    {
     /*
      * Basic authentication...
      */

      char  encode[256];    /* Base64 buffer */

      DEBUG_puts("2cupsDoAuthentication: Using Basic.");
      httpEncode64_2(encode, sizeof(encode), http->userpass, (int)strlen(http->userpass));
      httpSetAuthString(http, "Basic", encode);
      break;
    }
    else if (!_cups_strcasecmp(scheme, "Digest"))
    {
     /*
      * Digest authentication...
      */

      char nonce[HTTP_MAX_VALUE]; /* nonce="xyz" string */

      cups_auth_param(schemedata, "algorithm", http->algorithm, sizeof(http->algorithm));
      cups_auth_param(schemedata, "nonce", nonce, sizeof(nonce));
      cups_auth_param(schemedata, "opaque", http->opaque, sizeof(http->opaque));
      cups_auth_param(schemedata, "qop", http->qop, sizeof(http->qop));
      cups_auth_param(schemedata, "realm", http->realm, sizeof(http->realm));

      if (_httpSetDigestAuthString(http, nonce, method, resource))
      {
  DEBUG_puts("2cupsDoAuthentication: Using Digest.");
        break;
      }
    }
  }

  if (http->authstring && http->authstring[0])
  {
    DEBUG_printf("1cupsDoAuthentication: authstring=\"%s\".", http->authstring);

    return (0);
  }
  else
  {
    DEBUG_puts("1cupsDoAuthentication: No supported schemes.");
    http->status = HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED;

    return (-1);
  }
}


#ifdef HAVE_GSSAPI
/*
 * '_cupsSetNegotiateAuthString()' - Set the Kerberos authentication string.
 */

int         /* O - 0 on success, negative on error */
_cupsSetNegotiateAuthString(
    http_t     *http,     /* I - Connection to server */
    const char *method,     /* I - Request method ("GET", "POST", "PUT") */
    const char *resource)   /* I - Resource path */
{
  OM_uint32 minor_status,   /* Minor status code */
    major_status;   /* Major status code */
  gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
          /* Output token */

#  ifdef __APPLE__
 /*
  * If the weak-linked GSSAPI/Kerberos library is not present, don't try
  * to use it...
  */

  if (&gss_init_sec_context == NULL)
  {
    DEBUG_puts("1_cupsSetNegotiateAuthString: Weak-linked GSSAPI/Kerberos "
               "framework is not present");
    return (CUPS_GSS_NONE);
  }
#  endif /* __APPLE__ */

  if (!strcmp(http->hostname, "localhost") || http->hostname[0] == '/' || isdigit(http->hostname[0] & 255) || !strchr(http->hostname, '.'))
  {
    DEBUG_printf("1_cupsSetNegotiateAuthString: Kerberos not available for host \"%s\".", http->hostname);
    return (CUPS_GSS_NONE);
  }

  if (http->gssname == GSS_C_NO_NAME)
  {
    http->gssname = cups_gss_getname(http, _cupsGSSServiceName());
  }

  if (http->gssctx != GSS_C_NO_CONTEXT)
  {
    gss_delete_sec_context(&minor_status, &http->gssctx, GSS_C_NO_BUFFER);
    http->gssctx = GSS_C_NO_CONTEXT;
  }

  major_status = gss_init_sec_context(&minor_status, GSS_C_NO_CREDENTIAL,
              &http->gssctx,
              http->gssname, http->gssmech,
              GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG,
              GSS_C_INDEFINITE,
              GSS_C_NO_CHANNEL_BINDINGS,
              GSS_C_NO_BUFFER, &http->gssmech,
              &output_token, NULL, NULL);

#  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
  if (major_status == GSS_S_NO_CRED)
  {
   /*
    * Ask the user for credentials...
    */

    char    prompt[1024], /* Prompt for user */
      userbuf[256]; /* Kerberos username */
    const char    *username,  /* Username string */
      *password;  /* Password string */
    _cups_gss_acquire_t data;   /* Callback data */
    gss_auth_identity_desc identity;  /* Kerberos user identity */
    _cups_globals_t *cg = _cupsGlobals();
          /* Per-thread global data */

    if (!cg->lang_default)
      cg->lang_default = cupsLangDefault();

    snprintf(prompt, sizeof(prompt),
             _cupsLangString(cg->lang_default, _("Password for %s on %s? ")),
       cupsGetUser(), http->gsshost);

    if ((password = cupsGetPassword2(prompt, http, method, resource)) == NULL)
      return (CUPS_GSS_FAIL);

   /*
    * Try to acquire credentials...
    */

    username = cupsGetUser();
    if (!strchr(username, '@'))
    {
      snprintf(userbuf, sizeof(userbuf), "%s@%s", username, http->gsshost);
      username = userbuf;
    }

    identity.type           = GSS_AUTH_IDENTITY_TYPE_1;
    identity.flags          = 0;
    identity.username       = (char *)username;
    identity.realm          = (char *)"";
    identity.password       = (char *)password;
    identity.credentialsRef = NULL;

    data.sem   = dispatch_semaphore_create(0);
    data.major = 0;
    data.creds = NULL;

    if (data.sem)
    {
      major_status = gss_acquire_cred_ex_f(NULL, GSS_C_NO_NAME, 0, GSS_C_INDEFINITE, GSS_KRB5_MECHANISM, GSS_C_INITIATE, (gss_auth_identity_t)&identity, &data, cups_gss_acquire);

      if (major_status == GSS_S_COMPLETE)
      {
  dispatch_semaphore_wait(data.sem, DISPATCH_TIME_FOREVER);
  major_status = data.major;
      }

      dispatch_release(data.sem);

      if (major_status == GSS_S_COMPLETE)
      {
        OM_uint32 release_minor;  /* Minor status from releasing creds */

  major_status = gss_init_sec_context(&minor_status, data.creds,
              &http->gssctx,
              http->gssname, http->gssmech,
              GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG,
              GSS_C_INDEFINITE,
              GSS_C_NO_CHANNEL_BINDINGS,
              GSS_C_NO_BUFFER, &http->gssmech,
              &output_token, NULL, NULL);
        gss_release_cred(&release_minor, &data.creds);
      }
    }
  }
#  else
  (void)method;
  (void)resource;
#  endif /* HAVE_GSS_ACQUIRED_CRED_EX_F */

  if (major_status == GSS_S_NO_CRED)
  {
    cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: No credentials");
    return (CUPS_GSS_NONE);
  }
  else if (GSS_ERROR(major_status))
  {
    cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: Unable to initialize security context");
    return (CUPS_GSS_FAIL);
  }

#  ifdef DEBUG
  else if (major_status == GSS_S_CONTINUE_NEEDED)
    cups_gss_printf(major_status, minor_status, "_cupsSetNegotiateAuthString: Continuation needed");
#  endif /* DEBUG */

  if (output_token.length > 0 && output_token.length <= 65536)
  {
   /*
    * Allocate the authorization string since Windows KDCs can have
    * arbitrarily large credentials...
    */

    int authsize = 10 +     /* "Negotiate " */
       (((int)output_token.length * 4 / 3 + 3) & ~3) + 1;
            /* Base64 + nul */

    httpSetAuthString(http, NULL, NULL);

    if ((http->authstring = malloc((size_t)authsize)) == NULL)
    {
      http->authstring = http->_authstring;
      authsize         = sizeof(http->_authstring);
    }

    cupsCopyString(http->authstring, "Negotiate ", (size_t)authsize);
    httpEncode64_2(http->authstring + 10, authsize - 10, output_token.value,
       (int)output_token.length);

    gss_release_buffer(&minor_status, &output_token);
  }
  else
  {
    DEBUG_printf("1_cupsSetNegotiateAuthString: Kerberos credentials too large - %d bytes!", (int)output_token.length);
    gss_release_buffer(&minor_status, &output_token);

    return (CUPS_GSS_FAIL);
  }

  return (CUPS_GSS_OK);
}
#endif /* HAVE_GSSAPI */


/*
 * 'cups_auth_find()' - Find the named WWW-Authenticate scheme.
 *
 * The "www_authenticate" parameter points to the current position in the header.
 *
 * Returns @code NULL@ if the auth scheme is not present.
 */

static const char *       /* O - Start of matching scheme or @code NULL@ if not found */
cups_auth_find(const char *www_authenticate,  /* I - Pointer into WWW-Authenticate header */
               const char *scheme)    /* I - Authentication scheme */
{
  size_t  schemelen = strlen(scheme); /* Length of scheme */


  DEBUG_printf("8cups_auth_find(www_authenticate=\"%s\", scheme=\"%s\"(%d))", www_authenticate, scheme, (int)schemelen);

  while (*www_authenticate)
  {
   /*
    * Skip leading whitespace and commas...
    */

    DEBUG_printf("9cups_auth_find: Before whitespace: \"%s\"", www_authenticate);
    while (isspace(*www_authenticate & 255) || *www_authenticate == ',')
      www_authenticate ++;
    DEBUG_printf("9cups_auth_find: After whitespace: \"%s\"", www_authenticate);

   /*
    * See if this is "Scheme" followed by whitespace or the end of the string.
    */

    if (!strncmp(www_authenticate, scheme, schemelen) && (isspace(www_authenticate[schemelen] & 255) || www_authenticate[schemelen] == ',' || !www_authenticate[schemelen]))
    {
     /*
      * Yes, this is the start of the scheme-specific information...
      */

      DEBUG_printf("9cups_auth_find: Returning \"%s\".", www_authenticate);

      return (www_authenticate);
    }

   /*
    * Skip the scheme name or param="value" string...
    */

    while (!isspace(*www_authenticate & 255) && *www_authenticate)
    {
      if (*www_authenticate == '\"')
      {
       /*
        * Skip quoted value...
        */

        www_authenticate ++;
        while (*www_authenticate && *www_authenticate != '\"')
          www_authenticate ++;

        DEBUG_printf("9cups_auth_find: After quoted: \"%s\"", www_authenticate);
      }

      www_authenticate ++;
    }

    DEBUG_printf("9cups_auth_find: After skip: \"%s\"", www_authenticate);
  }

  DEBUG_puts("9cups_auth_find: Returning NULL.");

  return (NULL);
}


/*
 * 'cups_auth_param()' - Copy the value for the named authentication parameter,
 *                       if present.
 */

static const char *       /* O - Parameter value or @code NULL@ if not present */
cups_auth_param(const char *scheme,   /* I - Pointer to auth data */
                const char *name,   /* I - Name of parameter */
                char       *value,    /* I - Value buffer */
                size_t     valsize)   /* I - Size of value buffer */
{
  char    *valptr = value,    /* Pointer into value buffer */
          *valend = value + valsize - 1;  /* Pointer to end of buffer */
  size_t  namelen = strlen(name);   /* Name length */
  int   param;        /* Is this a parameter? */


  DEBUG_printf("8cups_auth_param(scheme=\"%s\", name=\"%s\", value=%p, valsize=%d)", scheme, name, (void *)value, (int)valsize);

  while (!isspace(*scheme & 255) && *scheme)
    scheme ++;

  while (*scheme)
  {
    while (isspace(*scheme & 255) || *scheme == ',')
      scheme ++;

    if (!strncmp(scheme, name, namelen) && scheme[namelen] == '=')
    {
     /*
      * Found the parameter, copy the value...
      */

      scheme += namelen + 1;
      if (*scheme == '\"')
      {
        scheme ++;

  while (*scheme && *scheme != '\"')
  {
    if (valptr < valend)
      *valptr++ = *scheme;

    scheme ++;
  }
      }
      else
      {
  while (*scheme && strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~+/=", *scheme))
  {
    if (valptr < valend)
      *valptr++ = *scheme;

    scheme ++;
  }
      }

      *valptr = '\0';

      DEBUG_printf("9cups_auth_param: Returning \"%s\".", value);

      return (value);
    }

   /*
    * Skip the param=value string...
    */

    param = 0;

    while (!isspace(*scheme & 255) && *scheme)
    {
      if (*scheme == '=')
        param = 1;
      else if (*scheme == '\"')
      {
       /*
        * Skip quoted value...
        */

        scheme ++;
        while (*scheme && *scheme != '\"')
          scheme ++;
      }

      scheme ++;
    }

   /*
    * If this wasn't a parameter, we are at the end of this scheme's
    * parameters...
    */

    if (!param)
      break;
  }

  *value = '\0';

  DEBUG_puts("9cups_auth_param: Returning NULL.");

  return (NULL);
}


/*
 * 'cups_auth_scheme()' - Get the (next) WWW-Authenticate scheme.
 *
 * The "www_authenticate" parameter points to the current position in the header.
 *
 * Returns @code NULL@ if there are no (more) auth schemes present.
 */

static const char *       /* O - Start of scheme or @code NULL@ if not found */
cups_auth_scheme(const char *www_authenticate,  /* I - Pointer into WWW-Authenticate header */
     char       *scheme,    /* I - Scheme name buffer */
     size_t     schemesize)   /* I - Size of buffer */
{
  const char  *start;       /* Start of scheme data */
  char    *sptr = scheme,     /* Pointer into scheme buffer */
    *send = scheme + schemesize - 1;/* End of scheme buffer */
  int   param;        /* Is this a parameter? */


  DEBUG_printf("8cups_auth_scheme(www_authenticate=\"%s\", scheme=%p, schemesize=%u)", www_authenticate, (void *)scheme, (unsigned)schemesize);

  while (*www_authenticate)
  {
   /*
    * Skip leading whitespace and commas...
    */

    while (isspace(*www_authenticate & 255) || *www_authenticate == ',')
      www_authenticate ++;

   /*
    * Parse the scheme name or param="value" string...
    */

    for (sptr = scheme, start = www_authenticate, param = 0; *www_authenticate && *www_authenticate != ',' && !isspace(*www_authenticate & 255); www_authenticate ++)
    {
      if (*www_authenticate == '=')
        param = 1;
      else if (!param && sptr < send)
        *sptr++ = *www_authenticate;
      else if (*www_authenticate == '\"')
      {
       /*
        * Skip quoted value...
        */


        do
          www_authenticate ++;
        while (*www_authenticate && *www_authenticate != '\"');
      }
    }

    if (sptr > scheme && !param)
    {
      *sptr = '\0';

      DEBUG_printf("9cups_auth_scheme: Returning \"%s\".", start);

      return (start);
    }
  }

  *scheme = '\0';

  DEBUG_puts("9cups_auth_scheme: Returning NULL.");

  return (NULL);
}


#ifdef HAVE_GSSAPI
#  ifdef HAVE_GSS_ACQUIRE_CRED_EX_F
/*
 * 'cups_gss_acquire()' - Kerberos credentials callback.
 */
static void
cups_gss_acquire(
    void            *ctx,   /* I - Caller context */
    OM_uint32       major,    /* I - Major error code */
    gss_status_id_t status,   /* I - Status (unused) */
    gss_cred_id_t   creds,    /* I - Credentials (if any) */
    gss_OID_set     oids,   /* I - Mechanism OIDs (unused) */
    OM_uint32       time_rec)   /* I - Timestamp (unused) */
{
  uint32_t    min;    /* Minor error code */
  _cups_gss_acquire_t *data;    /* Callback data */


  (void)status;
  (void)time_rec;

  data        = (_cups_gss_acquire_t *)ctx;
  data->major = major;
  data->creds = creds;

  gss_release_oid_set(&min, &oids);
  dispatch_semaphore_signal(data->sem);
}
#  endif /* HAVE_GSS_ACQUIRE_CRED_EX_F */


/*
 * 'cups_gss_getname()' - Get CUPS service credentials for authentication.
 */

static gss_name_t     /* O - Server name */
cups_gss_getname(
    http_t     *http,     /* I - Connection to server */
    const char *service_name)   /* I - Service name */
{
  gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
          /* Service token */
  OM_uint32   major_status,   /* Major status code */
      minor_status;   /* Minor status code */
  gss_name_t    server_name;    /* Server name */
  char      buf[1024];    /* Name buffer */


  DEBUG_printf("7cups_gss_getname(http=%p, service_name=\"%s\")", (void *)http, service_name);

 /*
  * Get the hostname...
  */

  if (!http->gsshost[0])
  {
    httpGetHostname(http, http->gsshost, sizeof(http->gsshost));

    if (!strcmp(http->gsshost, "localhost"))
    {
      if (gethostname(http->gsshost, sizeof(http->gsshost)) < 0)
      {
  DEBUG_printf("1cups_gss_getname: gethostname() failed: %s", strerror(errno));
  http->gsshost[0] = '\0';
  return (NULL);
      }

      if (!strchr(http->gsshost, '.'))
      {
       /*
  * The hostname is not a FQDN, so look it up...
  */

  struct hostent  *host;    /* Host entry to get FQDN */

  if ((host = gethostbyname(http->gsshost)) != NULL && host->h_name)
  {
   /*
    * Use the resolved hostname...
    */

    cupsCopyString(http->gsshost, host->h_name, sizeof(http->gsshost));
  }
  else
  {
    DEBUG_printf("1cups_gss_getname: gethostbyname(\"%s\") failed.", http->gsshost);
    http->gsshost[0] = '\0';
    return (NULL);
  }
      }
    }
  }

 /*
  * Get a service name we can use for authentication purposes...
  */

  snprintf(buf, sizeof(buf), "%s@%s", service_name, http->gsshost);

  DEBUG_printf("8cups_gss_getname: Looking up \"%s\".", buf);

  token.value  = buf;
  token.length = strlen(buf);
  server_name  = GSS_C_NO_NAME;
  major_status = gss_import_name(&minor_status, &token,
         GSS_C_NT_HOSTBASED_SERVICE,
         &server_name);

  if (GSS_ERROR(major_status))
  {
    cups_gss_printf(major_status, minor_status,
                    "cups_gss_getname: gss_import_name() failed");
    return (NULL);
  }

  return (server_name);
}


#  ifdef DEBUG
/*
 * 'cups_gss_printf()' - Show debug error messages from GSSAPI.
 */

static void
cups_gss_printf(OM_uint32  major_status,/* I - Major status code */
    OM_uint32  minor_status,/* I - Minor status code */
    const char *message)  /* I - Prefix for error message */
{
  OM_uint32 err_major_status, /* Major status code for display */
    err_minor_status; /* Minor status code for display */
  OM_uint32 msg_ctx;    /* Message context */
  gss_buffer_desc major_status_string = GSS_C_EMPTY_BUFFER,
          /* Major status message */
    minor_status_string = GSS_C_EMPTY_BUFFER;
          /* Minor status message */


  msg_ctx          = 0;
  err_major_status = gss_display_status(&err_minor_status,
                            major_status,
          GSS_C_GSS_CODE,
          GSS_C_NO_OID,
          &msg_ctx,
          &major_status_string);

  if (!GSS_ERROR(err_major_status))
    gss_display_status(&err_minor_status, minor_status, GSS_C_MECH_CODE,
           GSS_C_NULL_OID, &msg_ctx, &minor_status_string);

  DEBUG_printf("1%s: %s, %s", message, (char *)major_status_string.value, (char *)minor_status_string.value);

  gss_release_buffer(&err_minor_status, &major_status_string);
  gss_release_buffer(&err_minor_status, &minor_status_string);
}
#  endif /* DEBUG */
#endif /* HAVE_GSSAPI */

static int        /* O - 0 if not a local connection */
          /*     1  if local connection */
cups_is_local_connection(http_t *http)  /* I - HTTP connection to server */
{
  if (!httpAddrLocalhost(http->hostaddr) && _cups_strcasecmp(http->hostname, "localhost") != 0)
    return 0;
  return 1;
}

/*
 * 'cups_local_auth()' - Get the local authorization certificate if
 *                       available/applicable.
 */

static int        /* O - 0 if available */
          /*     1 if not available */
          /*    -1 error */
cups_local_auth(http_t *http)   /* I - HTTP connection to server */
{
#if defined(_WIN32) || defined(__EMX__)
 /*
  * Currently _WIN32 and OS-2 do not support the CUPS server...
  */

  return (1);
#else
  int     pid;    /* Current process ID */
  FILE      *fp;    /* Certificate file */
  char      trc[16],  /* Try Root Certificate parameter */
      filename[1024]; /* Certificate filename */
  const char    *www_auth,  /* WWW-Authenticate header */
      *schemedata;  /* Data for the named auth scheme */
  _cups_globals_t *cg = _cupsGlobals(); /* Global data */
#  if defined(HAVE_AUTHORIZATION_H)
  OSStatus    status;   /* Status */
  AuthorizationItem auth_right; /* Authorization right */
  AuthorizationRights auth_rights;  /* Authorization rights */
  AuthorizationFlags  auth_flags; /* Authorization flags */
  AuthorizationExternalForm auth_extrn; /* Authorization ref external */
  char      auth_key[1024]; /* Buffer */
  char      buffer[1024]; /* Buffer */
#  endif /* HAVE_AUTHORIZATION_H */


  DEBUG_printf("7cups_local_auth(http=%p) hostaddr=%s, hostname=\"%s\"", (void *)http, httpAddrString(http->hostaddr, filename, sizeof(filename)), http->hostname);

 /*
  * See if we are accessing localhost...
  */

  if (!cups_is_local_connection(http))
  {
    DEBUG_puts("8cups_local_auth: Not a local connection!");
    return (1);
  }

  www_auth = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);

#  if defined(HAVE_AUTHORIZATION_H)
 /*
  * Delete any previous authorization reference...
  */

  if (http->auth_ref)
  {
    AuthorizationFree(http->auth_ref, kAuthorizationFlagDefaults);
    http->auth_ref = NULL;
  }

  if (!getenv("GATEWAY_INTERFACE") && (schemedata = cups_auth_find(www_auth, "AuthRef")) != NULL && cups_auth_param(schemedata, "key", auth_key, sizeof(auth_key)))
  {
    status = AuthorizationCreate(NULL, kAuthorizationEmptyEnvironment, kAuthorizationFlagDefaults, &http->auth_ref);
    if (status != errAuthorizationSuccess)
    {
      DEBUG_printf("8cups_local_auth: AuthorizationCreate() returned %d", (int)status);
      return (-1);
    }

    auth_right.name        = auth_key;
    auth_right.valueLength = 0;
    auth_right.value       = NULL;
    auth_right.flags       = 0;

    auth_rights.count = 1;
    auth_rights.items = &auth_right;

    auth_flags = kAuthorizationFlagDefaults |
     kAuthorizationFlagPreAuthorize |
     kAuthorizationFlagInteractionAllowed |
     kAuthorizationFlagExtendRights;

    status = AuthorizationCopyRights(http->auth_ref, &auth_rights,
             kAuthorizationEmptyEnvironment,
             auth_flags, NULL);
    if (status == errAuthorizationSuccess)
      status = AuthorizationMakeExternalForm(http->auth_ref, &auth_extrn);

    if (status == errAuthorizationSuccess)
    {
     /*
      * Set the authorization string and return...
      */

      httpEncode64_2(buffer, sizeof(buffer), (void *)&auth_extrn,
         sizeof(auth_extrn));

      httpSetAuthString(http, "AuthRef", buffer);

      DEBUG_printf("8cups_local_auth: Returning authstring=\"%s\"", http->authstring);
      return (0);
    }
    else if (status == errAuthorizationCanceled)
      return (-1);

    DEBUG_printf("9cups_local_auth: AuthorizationCopyRights() returned %d", (int)status);

  /*
   * Fall through to try certificates...
   */
  }
#  endif /* HAVE_AUTHORIZATION_H */

#  if defined(SO_PEERCRED) && defined(AF_LOCAL)
 /*
  * See if we can authenticate using the peer credentials provided over a
  * domain socket; if so, specify "PeerCred username" as the authentication
  * information...
  */

  if (http->hostaddr->addr.sa_family == AF_LOCAL &&
      !getenv("GATEWAY_INTERFACE") && /* Not via CGI programs... */
      cups_auth_find(www_auth, "PeerCred"))
  {
   /*
    * Verify that the current cupsGetUser() matches the current UID...
    */

    struct passwd pwd;    /* Password information */
    struct passwd *result;  /* Auxiliary pointer */
    const char    *username;  /* Current username */

    username = cupsGetUser();

    getpwnam_r(username, &pwd, cg->pw_buf, PW_BUF_SIZE, &result);
    if (result && pwd.pw_uid == getuid())
    {
      httpSetAuthString(http, "PeerCred", username);

      DEBUG_printf("8cups_local_auth: Returning authstring=\"%s\"", http->authstring);

      return (0);
    }
  }
#  endif /* SO_PEERCRED && AF_LOCAL */

  if ((schemedata = cups_auth_find(www_auth, "Local")) == NULL)
    return (1);

 /*
  * Try opening a certificate file for this PID.  If that fails,
  * try the root certificate...
  */

  pid = getpid();
  snprintf(filename, sizeof(filename), "%s/certs/%d", cg->cups_statedir, pid);
  if ((fp = fopen(filename, "r")) == NULL && pid > 0)
  {
   /*
    * No certificate for this PID; see if we can get the root certificate...
    */

    DEBUG_printf("9cups_local_auth: Unable to open file \"%s\": %s", filename, strerror(errno));

    if (!cups_auth_param(schemedata, "trc", trc, sizeof(trc)))
    {
     /*
      * Scheduler doesn't want us to use the root certificate...
      */

      return (1);
    }

    snprintf(filename, sizeof(filename), "%s/certs/0", cg->cups_statedir);
    if ((fp = fopen(filename, "r")) == NULL)
      DEBUG_printf("9cups_local_auth: Unable to open file \"%s\": %s", filename, strerror(errno));
  }

  if (fp)
  {
   /*
    * Read the certificate from the file...
    */

    char  certificate[33],  /* Certificate string */
    *certptr;   /* Pointer to certificate string */

    certptr = fgets(certificate, sizeof(certificate), fp);
    fclose(fp);

    if (certptr)
    {
     /*
      * Set the authorization string and return...
      */

      httpSetAuthString(http, "Local", certificate);

      DEBUG_printf("8cups_local_auth: Returning authstring=\"%s\"", http->authstring);

      return (0);
    }
  }

  return (1);
#endif /* _WIN32 || __EMX__ */
}

Coverage Report

Created: 2025-10-08 06:06