toolkit/xre/nsWindowsDllBlocklist.cpp

   1 /* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  *   Mozilla Corp
  19  * Portions created by the Initial Developer are Copyright (C) 2009
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *  Vladimir Vukicevic <vladimir@pobox.com>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
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  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include <windows.h>
  40 #include <winternl.h>
  41
  42 #include <stdio.h>
  43
  44 #include "nsAutoPtr.h"
  45
  46 #include "prlog.h"
  47
  48 #include "nsWindowsDllInterceptor.h"
  49
  50 #define IN_WINDOWS_DLL_BLOCKLIST
  51 #include "nsWindowsDllBlocklist.h"
  52
  53 #ifndef STATUS_DLL_NOT_FOUND
  54 #define STATUS_DLL_NOT_FOUND ((DWORD)0xC0000135L)
  55 #endif
  56
  57 // define this for very verbose dll load debug spew
  58 #undef DEBUG_very_verbose
  59
  60 // The signature for LdrLoadDll changed at some point, with the second arg
  61 // becoming a PULONG instead of a ULONG.  This should only matter on 64-bit
  62 // systems, for which there was no support earlier -- on 32-bit systems,
  63 // they should be the same size.
  64 PR_STATIC_ASSERT(sizeof(PULONG) == sizeof(ULONG));
  65
  66 typedef NTSTATUS (NTAPI *LdrLoadDll_func) (PWCHAR filePath, PULONG flags, PUNICODE_STRING moduleFileName, PHANDLE handle);
  67
  68 static LdrLoadDll_func stub_LdrLoadDll = 0;
  69
  70 static NTSTATUS NTAPI
  71 patched_LdrLoadDll (PWCHAR filePath, PULONG flags, PUNICODE_STRING moduleFileName, PHANDLE handle)
  72 {
  73   // We have UCS2 (UTF16?), we want ASCII, but we also just want the filename portion
  74 #define DLLNAME_MAX 128
  75   char dllName[DLLNAME_MAX+1];
  76
  77   int len = moduleFileName->Length / 2;
  78   wchar_t *fname = moduleFileName->Buffer;
  79
  80   // The filename isn't guaranteed to be null terminated, but in practice
  81   // it always will be; ensure that this is so, and bail if not.
  82   // This is done instead of the more robust approach because of bug 527122,
  83   // where lots of weird things were happening when we tried to make a copy.
  84   if (moduleFileName->MaximumLength < moduleFileName->Length+2 ||
  85       fname[len] != 0)
  86   {
  87 #ifdef DEBUG
  88     printf_stderr("LdrLoadDll: non-null terminated string found!\n");
  89 #endif
  90     goto continue_loading;
  91   }
  92
  93   wchar_t *dll_part = wcsrchr(fname, L'\\');
  94   if (dll_part) {
  95     dll_part = dll_part + 1;
  96     len -= dll_part - fname;
  97   } else {
  98     dll_part = fname;
  99   }
 100
 101 #ifdef DEBUG_very_verbose
 102   printf_stderr("LdrLoadDll: dll_part '%S' %d\n", dll_part, len);
 103 #endif
 104
 105   // if it's too long, then, we assume we won't want to block it,
 106   // since DLLNAME_MAX should be at least long enough to hold the longest
 107   // entry in our blocklist.
 108   if (len > DLLNAME_MAX) {
 109 #ifdef DEBUG
 110     printf_stderr("LdrLoadDll: len too long! %d\n", len);
 111 #endif
 112     goto continue_loading;
 113   }
 114
 115   // copy over to our char byte buffer, lowercasing ASCII as we go
 116   for (int i = 0; i < len; i++) {
 117     wchar_t c = dll_part[i];
 118
 119     if (c > 0x7f) {
 120       // welp, it's not ascii; if we need to add non-ascii things to
 121       // our blocklist, we'll have to remove this limitation.
 122       goto continue_loading;
 123     }
 124
 125     // ensure that dll name is all lowercase
 126     if (c >= 'A' && c <= 'Z')
 127       c += 'a' - 'A';
 128
 129     dllName[i] = (char) c;
 130   }
 131
 132   dllName[len] = 0;
 133
 134 #ifdef DEBUG_very_verbose
 135   printf_stderr("LdrLoadDll: dll name '%s'\n", dllName);
 136 #endif
 137
 138   // then compare to everything on the blocklist
 139   DllBlockInfo *info = &sWindowsDllBlocklist[0];
 140   while (info->name) {
 141     if (strcmp(info->name, dllName) == 0)
 142       break;
 143
 144     info++;
 145   }
 146
 147   if (info->name) {
 148     bool load_ok = false;
 149
 150 #ifdef DEBUG_very_verbose
 151     printf_stderr("LdrLoadDll: info->name: '%s'\n", info->name);
 152 #endif
 153
 154     if (info->maxVersion != ALL_VERSIONS) {
 155       // figure out the length of the string that we need
 156       DWORD pathlen = SearchPathW(filePath, fname, L".dll", 0, NULL, NULL);
 157       if (pathlen == 0) {
 158         // uh, we couldn't find the DLL at all, so...
 159         printf_stderr("LdrLoadDll: Blocking load of '%s' (SearchPathW didn't find it?)\n", dllName);
 160         return STATUS_DLL_NOT_FOUND;
 161       }
 162
 163       wchar_t *full_fname = (wchar_t*) malloc(sizeof(wchar_t)*(pathlen+1));
 164       if (!full_fname) {
 165         // couldn't allocate memory?
 166         return STATUS_DLL_NOT_FOUND;
 167       }
 168
 169       // now actually grab it
 170       SearchPathW(filePath, fname, L".dll", pathlen+1, full_fname, NULL);
 171
 172       DWORD zero;
 173       DWORD infoSize = GetFileVersionInfoSizeW(full_fname, &zero);
 174
 175       // If we failed to get the version information, we block.
 176
 177       if (infoSize != 0) {
 178         nsAutoArrayPtr<unsigned char> infoData = new unsigned char[infoSize];
 179         VS_FIXEDFILEINFO *vInfo;
 180         UINT vInfoLen;
 181
 182         if (GetFileVersionInfoW(full_fname, 0, infoSize, infoData) &&
 183             VerQueryValueW(infoData, L"\\", (LPVOID*) &vInfo, &vInfoLen))
 184         {
 185           unsigned long long fVersion =
 186             ((unsigned long long)vInfo->dwFileVersionMS) << 32 |
 187             ((unsigned long long)vInfo->dwFileVersionLS);
 188
 189           // finally do the version check, and if it's greater than our block
 190           // version, keep loading
 191           if (fVersion > info->maxVersion)
 192             load_ok = true;
 193         }
 194       }
 195
 196       free(full_fname);
 197     }
 198
 199     if (!load_ok) {
 200       printf_stderr("LdrLoadDll: Blocking load of '%s' -- see http://www.mozilla.com/en-US/blocklist/\n", dllName);
 201       return STATUS_DLL_NOT_FOUND;
 202     }
 203   }
 204
 205 continue_loading:
 206 #ifdef DEBUG_very_verbose
 207   printf_stderr("LdrLoadDll: continuing load... ('%S')\n", moduleFileName->Buffer);
 208 #endif
 209
 210   NS_SetHasLoadedNewDLLs();
 211
 212   return stub_LdrLoadDll(filePath, flags, moduleFileName, handle);
 213 }
 214
 215 WindowsDllInterceptor NtDllIntercept;
 216
 217 void
 218 SetupDllBlocklist()
 219 {
 220   NtDllIntercept.Init("ntdll.dll");
 221
 222   bool ok = NtDllIntercept.AddHook("LdrLoadDll", patched_LdrLoadDll, (void**) &stub_LdrLoadDll);
 223
 224 #ifdef DEBUG
 225   if (!ok)
 226     printf_stderr ("LdrLoadDll hook failed, no dll blocklisting active\n");
 227 #endif
 228 }