summaryrefslogtreecommitdiffstats
path: root/security/sandbox/chromium/sandbox/win/src/policy_target.cc
blob: 1727d622f837a3ad40db2be8adb909f1fd4dc40a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "sandbox/win/src/policy_target.h"

#include <stddef.h>

#include "sandbox/win/src/crosscall_client.h"
#include "sandbox/win/src/ipc_tags.h"
#include "sandbox/win/src/policy_engine_processor.h"
#include "sandbox/win/src/policy_low_level.h"
#include "sandbox/win/src/policy_params.h"
#include "sandbox/win/src/sandbox_factory.h"
#include "sandbox/win/src/sandbox_nt_util.h"
#include "sandbox/win/src/sharedmem_ipc_client.h"
#include "sandbox/win/src/target_services.h"

namespace sandbox {

// Handle for our private heap.
extern void* g_heap;

// This is the list of all imported symbols from ntdll.dll.
SANDBOX_INTERCEPT NtExports g_nt;

// Policy data.
extern void* volatile g_shared_policy_memory;
SANDBOX_INTERCEPT size_t g_shared_policy_size;

bool QueryBroker(IpcTag ipc_id, CountedParameterSetBase* params) {
  DCHECK_NT(static_cast<size_t>(ipc_id) < kMaxServiceCount);
  DCHECK_NT(g_shared_policy_memory);
  DCHECK_NT(g_shared_policy_size > 0);

  if (static_cast<size_t>(ipc_id) >= kMaxServiceCount)
    return false;

  PolicyGlobal* global_policy =
      reinterpret_cast<PolicyGlobal*>(g_shared_policy_memory);

  if (!global_policy->entry[static_cast<size_t>(ipc_id)])
    return false;

  PolicyBuffer* policy = reinterpret_cast<PolicyBuffer*>(
      reinterpret_cast<char*>(g_shared_policy_memory) +
      reinterpret_cast<size_t>(
          global_policy->entry[static_cast<size_t>(ipc_id)]));

  if ((reinterpret_cast<size_t>(
           global_policy->entry[static_cast<size_t>(ipc_id)]) >
       global_policy->data_size) ||
      (g_shared_policy_size < global_policy->data_size)) {
    NOTREACHED_NT();
    return false;
  }

  for (size_t i = 0; i < params->count; i++) {
    if (!params->parameters[i].IsValid()) {
      NOTREACHED_NT();
      return false;
    }
  }

  PolicyProcessor processor(policy);
  PolicyResult result =
      processor.Evaluate(kShortEval, params->parameters, params->count);
  DCHECK_NT(POLICY_ERROR != result);

  return POLICY_MATCH == result && ASK_BROKER == processor.GetAction();
}

// -----------------------------------------------------------------------

// Hooks NtSetInformationThread to block RevertToSelf from being
// called before the actual call to LowerToken.
NTSTATUS WINAPI TargetNtSetInformationThread(
    NtSetInformationThreadFunction orig_SetInformationThread,
    HANDLE thread,
    NT_THREAD_INFORMATION_CLASS thread_info_class,
    PVOID thread_information,
    ULONG thread_information_bytes) {
  do {
    if (SandboxFactory::GetTargetServices()->GetState()->RevertedToSelf())
      break;
    if (ThreadImpersonationToken != thread_info_class)
      break;
    if (!thread_information)
      break;
    HANDLE token;
    if (sizeof(token) > thread_information_bytes)
      break;

    NTSTATUS ret = CopyData(&token, thread_information, sizeof(token));
    if (!NT_SUCCESS(ret) || NULL != token)
      break;

    // This is a revert to self.
    return STATUS_SUCCESS;
  } while (false);

  return orig_SetInformationThread(
      thread, thread_info_class, thread_information, thread_information_bytes);
}

// Hooks NtOpenThreadToken to force the open_as_self parameter to be set to
// false if we are still running with the impersonation token. open_as_self set
// to true means that the token will be open using the process token instead of
// the impersonation token. This is bad because the process token does not have
// access to open the thread token.
NTSTATUS WINAPI
TargetNtOpenThreadToken(NtOpenThreadTokenFunction orig_OpenThreadToken,
                        HANDLE thread,
                        ACCESS_MASK desired_access,
                        BOOLEAN open_as_self,
                        PHANDLE token) {
  if (!SandboxFactory::GetTargetServices()->GetState()->RevertedToSelf())
    open_as_self = false;

  return orig_OpenThreadToken(thread, desired_access, open_as_self, token);
}

// See comment for TargetNtOpenThreadToken
NTSTATUS WINAPI
TargetNtOpenThreadTokenEx(NtOpenThreadTokenExFunction orig_OpenThreadTokenEx,
                          HANDLE thread,
                          ACCESS_MASK desired_access,
                          BOOLEAN open_as_self,
                          ULONG handle_attributes,
                          PHANDLE token) {
  if (!SandboxFactory::GetTargetServices()->GetState()->RevertedToSelf())
    open_as_self = false;

  return orig_OpenThreadTokenEx(thread, desired_access, open_as_self,
                                handle_attributes, token);
}

}  // namespace sandbox