src/hotspot/share/memory/filemap.cpp

rev 52787 : 8226406: JVM fails to detect mismatched or corrupt CDS archive
Summary: Check important archive header fields such as _jvm_ident before processing other fields.
Reviewed-by: iklam, jiangli

*** 134,143 ****
--- 134,145 ----
    assert(N == JVM_IDENT_MAX, "Bad header_version size");
  
    const char *vm_version = VM_Version::internal_vm_info_string();
    const int version_len = (int)strlen(vm_version);
  
+   memset(header_version, 0, JVM_IDENT_MAX);
+ 
    if (version_len < (JVM_IDENT_MAX-1)) {
      strcpy(header_version, vm_version);
  
    } else {
      // Get the hash value.  Use a static seed because the hash needs to return the same
*** 149,158 ****
--- 151,162 ----
  
      // Append the hash code as eight hex digits.
      sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash);
      header_version[JVM_IDENT_MAX-1] = 0;  // Null terminate.
    }
+ 
+   assert(header_version[JVM_IDENT_MAX-1] == 0, "must be");
  }
  
  FileMapInfo::FileMapInfo() {
    assert(_current_info == NULL, "must be singleton"); // not thread safe
    _current_info = this;
*** 497,510 ****
--- 501,563 ----
    size_t n = os::read(fd, _header, (unsigned int)sz);
    if (n != sz) {
      fail_continue("Unable to read the file header.");
      return false;
    }
+ 
+   if (!Arguments::has_jimage()) {
+     FileMapInfo::fail_continue("The shared archive file cannot be used with an exploded module build.");
+     return false;
+   }
+ 
+   unsigned int expected_magic = CDS_ARCHIVE_MAGIC; // is_static ? CDS_ARCHIVE_MAGIC : CDS_DYNAMIC_ARCHIVE_MAGIC;
+   if (_header->_magic != expected_magic) {
+     log_info(cds)("_magic expected: 0x%08x", expected_magic);
+     log_info(cds)("         actual: 0x%08x", _header->_magic);
+     FileMapInfo::fail_continue("The shared archive file has a bad magic number.");
+     return false;
+   }
+ 
    if (_header->_version != CURRENT_CDS_ARCHIVE_VERSION) {
+     log_info(cds)("_version expected: %d", CURRENT_CDS_ARCHIVE_VERSION);
+     log_info(cds)("           actual: %d", _header->_version);
      fail_continue("The shared archive file has the wrong version.");
      return false;
    }
+ 
+   //if (_header->_header_size != sz) {
+   //  log_info(cds)("_header_size expected: " SIZE_FORMAT, sz);
+   //  log_info(cds)("               actual: " SIZE_FORMAT, _header->_header_size);
+   //  FileMapInfo::fail_continue("The shared archive file has an incorrect header size.");
+   //  return false;
+   // }
+ 
+   if (_header->_jvm_ident[JVM_IDENT_MAX-1] != 0) {
+     FileMapInfo::fail_continue("JVM version identifier is corrupted.");
+     return false;
+   }
+ 
+   char header_version[JVM_IDENT_MAX];
+   get_header_version(header_version);
+   if (strncmp(_header->_jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) {
+     log_info(cds)("_jvm_ident expected: %s", header_version);
+     log_info(cds)("             actual: %s", _header->_jvm_ident);
+     FileMapInfo::fail_continue("The shared archive file was created by a different"
+                   " version or build of HotSpot");
+     return false;
+   }
+ 
+   if (VerifySharedSpaces) {
+     int expected_crc = _header->compute_crc();
+     if (expected_crc != _header->_crc) {
+       log_info(cds)("_crc expected: %d", expected_crc);
+       log_info(cds)("       actual: %d", _header->_crc);
+       FileMapInfo::fail_continue("Header checksum verification failed.");
+       return false;
+     }
+   }
+ 
    _file_offset = (long)n;
  
    size_t info_size = _header->_paths_misc_info_size;
    _paths_misc_info = NEW_C_HEAP_ARRAY_RETURN_NULL(char, info_size, mtClass);
    if (_paths_misc_info == NULL) {
*** 526,535 ****
--- 579,589 ----
      fail_continue("The shared archive file has been truncated.");
      return false;
    }
  
    _file_offset += (long)n;
+ 
    return true;
  }
  
  
  // Read the FileMapInfo information from the file.
*** 1126,1162 ****
    return crc;
  }
  
  // This function should only be called during run time with UseSharedSpaces enabled.
  bool FileMapHeader::validate() {
-   if (VerifySharedSpaces && compute_crc() != _crc) {
-     FileMapInfo::fail_continue("Header checksum verification failed.");
-     return false;
-   }
- 
-   if (!Arguments::has_jimage()) {
-     FileMapInfo::fail_continue("The shared archive file cannot be used with an exploded module build.");
-     return false;
-   }
- 
-   if (_version != CURRENT_CDS_ARCHIVE_VERSION) {
-     FileMapInfo::fail_continue("The shared archive file is the wrong version.");
-     return false;
-   }
-   if (_magic != CDS_ARCHIVE_MAGIC) {
-     FileMapInfo::fail_continue("The shared archive file has a bad magic number.");
-     return false;
-   }
-   char header_version[JVM_IDENT_MAX];
-   get_header_version(header_version);
-   if (strncmp(_jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) {
-     log_info(class, path)("expected: %s", header_version);
-     log_info(class, path)("actual:   %s", _jvm_ident);
-     FileMapInfo::fail_continue("The shared archive file was created by a different"
-                   " version or build of HotSpot");
-     return false;
-   }
    if (_obj_alignment != ObjectAlignmentInBytes) {
      FileMapInfo::fail_continue("The shared archive file's ObjectAlignmentInBytes of %d"
                    " does not equal the current ObjectAlignmentInBytes of " INTX_FORMAT ".",
                    _obj_alignment, ObjectAlignmentInBytes);
      return false;
--- 1180,1189 ----