src/native_client/src/trusted/desc_cacheability/desc_cacheability.c

   1 /*
   2  * Copyright (c) 2013 The Native Client Authors. All rights reserved.
   3  * Use of this source code is governed by a BSD-style license that can be
   4  * found in the LICENSE file.
   5  */
   6
   7 #include "native_client/src/trusted/desc_cacheability/desc_cacheability.h"
   8
   9 #include "native_client/src/include/portability.h"
  10 #include "native_client/src/public/desc_metadata_types.h"
  11 #include "native_client/src/shared/platform/nacl_log.h"
  12 #include "native_client/src/trusted/desc/nacl_desc_base.h"
  13 #include "native_client/src/trusted/desc/nacl_desc_io.h"
  14 #include "native_client/src/trusted/service_runtime/include/sys/fcntl.h"
  15 #include "native_client/src/trusted/validator/nacl_file_info.h"
  16 #include "native_client/src/trusted/validator/rich_file_info.h"
  17 #include "native_client/src/trusted/validator/validation_cache.h"
  18
  19 int NaClDescSetFileToken(struct NaClDesc *desc,
  20                          struct NaClFileToken const *token) {
  21   int error;
  22   error = (*NACL_VTBL(NaClDesc, desc)->
  23            SetMetadata)(desc,
  24                         NACL_DESC_METADATA_FILE_TOKEN_TYPE,
  25                         sizeof *token, (uint8_t const *) token);
  26   if (0 != error) {
  27     NaClLog(4, "NaClDescSetFileToken: failed, errno %d\n", -error);
  28     return 0;
  29   }
  30   return 1;
  31 }
  32
  33 int NaClDescGetFileToken(struct NaClDesc *desc,
  34                          struct NaClFileToken *out_token) {
  35   int32_t metadata_type;
  36   uint32_t metadata_bytes;
  37
  38   metadata_bytes = (uint32_t) sizeof *out_token;
  39   metadata_type = (*NACL_VTBL(NaClDesc, desc)->
  40                    GetMetadata)(desc, &metadata_bytes,
  41                                 (uint8_t *) out_token);
  42   if (NACL_DESC_METADATA_NONE_TYPE == metadata_type) {
  43     NaClLog(4, "NaClDescGetFileToken: no meta data, cannot map\n");
  44     return 0;
  45   } else if (NACL_DESC_METADATA_FILE_TOKEN_TYPE != metadata_type) {
  46     return 0;
  47   } else if (metadata_bytes != (uint32_t) sizeof *out_token) {
  48     /* there is supposed to be a file token, but wrong size? */
  49     NaClLog(LOG_WARNING,
  50             "NaClDescGetFileToken: purported file token present,"
  51             " but token size is incorrect.\n");
  52     return 0;
  53   }
  54   NaClLog(4,
  55           "NaClDescGetFileToken: got token 0x%"NACL_PRIx64":%"NACL_PRIx64"\n",
  56           out_token->hi, out_token->lo);
  57   return 1;
  58 }
  59
  60 struct NaClDesc *NaClExchangeFileTokenForMappableDesc(
  61     struct NaClFileToken *file_token,
  62     struct NaClValidationCache *validation_cache) {
  63   int32_t new_fd;
  64   char *file_path;
  65   uint32_t file_path_length;
  66   struct NaClDesc *desc = NULL;
  67
  68   /*
  69    * Not all file loading paths will produce a valid token.  Zero is
  70    * an invalid token value that indicates there is nothing to
  71    * resolve.  In this case, assume nothing about the providence of
  72    * the file.
  73    */
  74   if (!(file_token->lo == 0 && file_token->hi == 0) &&
  75       validation_cache->ResolveFileToken != NULL &&
  76       validation_cache->ResolveFileToken(validation_cache->handle,
  77                                          file_token,
  78                                          &new_fd,
  79                                          &file_path,
  80                                          &file_path_length)) {
  81     struct NaClRichFileInfo info;
  82
  83     desc = NaClDescIoDescFromHandleAllocCtor((NaClHandle) new_fd,
  84                                              NACL_ABI_O_RDONLY);
  85
  86     /* Mark the desc as OK for mmapping. */
  87     NaClDescMarkSafeForMmap(desc);
  88
  89     /* Provide metadata for validation. */
  90     NaClRichFileInfoCtor(&info);
  91     info.known_file = 1;
  92     info.file_path = file_path;  /* Takes ownership. */
  93     info.file_path_length = file_path_length;
  94     NaClSetFileOriginInfo(desc, &info);
  95     NaClRichFileInfoDtor(&info);
  96   }
  97   return desc;
  98 }
  99
 100 void NaClReplaceDescIfValidationCacheAssertsMappable(
 101     struct NaClDesc **desc_in_out,
 102     struct NaClValidationCache *validation_cache) {
 103   struct NaClDesc *desc = *desc_in_out;
 104   struct NaClDesc *replacement;
 105   struct NaClFileToken file_token;
 106
 107   if (!NaClDescGetFileToken(desc, &file_token)) {
 108     NaClLog(4,
 109             "NaClReplaceDescIfValidationCacheAssertsMappable: no valid"
 110             " file token\n");
 111   } else {
 112     replacement = NaClExchangeFileTokenForMappableDesc(&file_token,
 113                                                        validation_cache);
 114     if (NULL != replacement) {
 115       NaClDescUnref(desc);
 116       *desc_in_out = replacement;
 117     }
 118   }
 119 }