src/swtpm/capabilities.c

   1 /*
   2  * capabilities.c -- capabilities
   3  *
   4  * (c) Copyright IBM Corporation 2019.
   5  *
   6  * Author: Stefan Berger <stefanb@us.ibm.com>
   7  *
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions are
  12  * met:
  13  *
  14  * Redistributions of source code must retain the above copyright notice,
  15  * this list of conditions and the following disclaimer.
  16  *
  17  * Redistributions in binary form must reproduce the above copyright
  18  * notice, this list of conditions and the following disclaimer in the
  19  * documentation and/or other materials provided with the distribution.
  20  *
  21  * Neither the names of the IBM Corporation nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "config.h"
  39
  40 #define _GNU_SOURCE
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 #include <libtpms/tpm_library.h>
  46 #include <libtpms/tpm_error.h>
  47
  48 #include "capabilities.h"
  49 #include "logging.h"
  50 #include "swtpm_nvstore.h"
  51
  52 /* Convert the RSA key size indicators supported by libtpms into capability
  53  * strings.
  54  * libtpms may return us something like this here:
  55  * "TPMAttributes":{"manufacturer":"id:00001014",\
  56  * "version":"id:20191023","model":"swtpm","RSAKeySizes":[1024,2048,3072]}}
  57  *
  58  * or an older version may not report RSA keysizes:
  59  * "TPMAttributes":{"manufacturer":"id:00001014",\
  60  * "version":"id:20191023","model":"swtpm"}}
  61  */
  62 static int get_rsa_keysize_caps(char **keysizecaps)
  63 {
  64     int ret = 0;
  65     char *start, *endptr;
  66     const char *needle = "\"RSAKeySizes\":[";
  67     char *info_data = TPMLIB_GetInfo(4 /*TPMLIB_INFO_TPMFEATURES*/);
  68     char buffer[128];
  69     off_t offset = 0;
  70     int n;
  71
  72     if (!info_data)
  73         goto cleanup;
  74
  75     start = strstr(info_data, needle);
  76     if (start) {
  77         start += strlen(needle);
  78         while (1) {
  79             unsigned long int keysize = strtoul(start, &endptr, 10);
  80
  81             if (*endptr != ',' && *endptr != ']') {
  82                 logprintf(STDERR_FILENO, "Malformed TPMLIB_GetInfo() string\n");
  83                 ret = -1;
  84                 goto cleanup;
  85             }
  86
  87             n = snprintf(buffer + offset, sizeof(buffer) - offset,
  88                          ", \"rsa-keysize-%lu\"",
  89                           keysize);
  90             if (n < 0 || (unsigned)n >= sizeof(buffer) - offset) {
  91                 logprintf(STDERR_FILENO, "%s: buffer is too small\n", __func__);
  92                 ret = -1;
  93                 goto cleanup;
  94             }
  95             if (*endptr == ']')
  96                 break;
  97
  98             offset += n;
  99             start = endptr + 1;
 100         }
 101
 102         *keysizecaps = strndup(buffer, sizeof(buffer) - 1);
 103         if (*keysizecaps == NULL)
 104             goto oom;
 105     }
 106
 107 cleanup:
 108     free(info_data);
 109     return ret;
 110
 111 oom:
 112     logprintf(STDERR_FILENO, "Out of memory\n");
 113     ret = -1;
 114     goto cleanup;
 115 }
 116
 117 int capabilities_print_json(bool cusetpm)
 118 {
 119     char *string = NULL;
 120     int ret = -1;
 121     int n;
 122 #ifdef WITH_SECCOMP
 123     const char *cmdarg_seccomp = "\"cmdarg-seccomp\", ";
 124 #else
 125     const char *cmdarg_seccomp = "";
 126 #endif
 127     const char *with_tpm1 = "";
 128     const char *with_tpm2 = "";
 129     char *keysizecaps = NULL;
 130     const char *nvram_backend_dir = "\"nvram-backend-dir\", ";
 131     const char *nvram_backend_file = "\"nvram-backend-file\"";
 132
 133     ret = get_rsa_keysize_caps(&keysizecaps);
 134     if (ret < 0)
 135         goto cleanup;
 136
 137     if (TPMLIB_ChooseTPMVersion(TPMLIB_TPM_VERSION_1_2) == TPM_SUCCESS)
 138         with_tpm1 = "\"tpm-1.2\", ";
 139     if (TPMLIB_ChooseTPMVersion(TPMLIB_TPM_VERSION_2) == TPM_SUCCESS)
 140         with_tpm2 = "\"tpm-2.0\", ";
 141
 142     n =  asprintf(&string,
 143          "{ "
 144          "\"type\": \"swtpm\", "
 145          "\"features\": [ "
 146              "%s%s%s%s%s%s%s%s%s%s"
 147           " ], "
 148          "\"version\": \"" VERSION "\" "
 149          "}",
 150          with_tpm1,
 151          with_tpm2,
 152          !cusetpm     ? "\"tpm-send-command-header\", ": "",
 153          !cusetpm     ? "\"flags-opt-startup\", "      : "",
 154          cmdarg_seccomp,
 155          true         ? "\"cmdarg-key-fd\", "          : "",
 156          true         ? "\"cmdarg-pwd-fd\", "          : "",
 157          nvram_backend_dir,
 158          nvram_backend_file,
 159          keysizecaps  ? keysizecaps                    : ""
 160     );
 161
 162     if (n < 0) {
 163         logprintf(STDERR_FILENO, "Out of memory\n");
 164         goto cleanup;
 165     }
 166
 167     ret = 0;
 168
 169     fprintf(stdout, "%s\n", string);
 170
 171 cleanup:
 172     free(keysizecaps);
 173     free(string);
 174
 175     return ret;
 176 }