1 files changed, 355 insertions, 0 deletions

diff --git a/security/sandbox/chromium/sandbox/win/src/policy_low_level.cc b/security/sandbox/chromium/sandbox/win/src/policy_low_level.cc
new file mode 100644
index 0000000000..d987211c8b
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+++ b/security/sandbox/chromium/sandbox/win/src/policy_low_level.cc
@@ -0,0 +1,355 @@
+// 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_low_level.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <string>
+
+namespace {
+
+// A single rule can use at most this amount of memory.
+const size_t kRuleBufferSize = 1024 * 4;
+
+// The possible states of the string matching opcode generator.
+enum {
+  PENDING_NONE,
+  PENDING_ASTERISK,  // Have seen an '*' but have not generated an opcode.
+  PENDING_QMARK,     // Have seen an '?' but have not generated an opcode.
+};
+
+// The category of the last character seen by the string matching opcode
+// generator.
+const uint32_t kLastCharIsNone = 0;
+const uint32_t kLastCharIsAlpha = 1;
+const uint32_t kLastCharIsWild = 2;
+const uint32_t kLastCharIsAsterisk = kLastCharIsWild + 4;
+const uint32_t kLastCharIsQuestionM = kLastCharIsWild + 8;
+
+}  // namespace
+
+namespace sandbox {
+
+LowLevelPolicy::LowLevelPolicy(PolicyGlobal* policy_store)
+    : policy_store_(policy_store) {}
+
+// Adding a rule is nothing more than pushing it into an stl container. Done()
+// is called for the rule in case the code that made the rule in the first
+// place has not done it.
+bool LowLevelPolicy::AddRule(IpcTag service, PolicyRule* rule) {
+  if (!rule->Done()) {
+    return false;
+  }
+
+  PolicyRule* local_rule = new PolicyRule(*rule);
+  RuleNode node = {local_rule, service};
+  rules_.push_back(node);
+  return true;
+}
+
+LowLevelPolicy::~LowLevelPolicy() {
+  // Delete all the rules.
+  typedef std::list<RuleNode> RuleNodes;
+  for (RuleNodes::iterator it = rules_.begin(); it != rules_.end(); ++it) {
+    delete it->rule;
+  }
+}
+
+// Here is where the heavy byte shuffling is done. We take all the rules and
+// 'compile' them into a single memory region. Now, the rules are in random
+// order so the first step is to reorganize them into a stl map that is keyed
+// by the service id and as a value contains a list with all the rules that
+// belong to that service. Then we enter the big for-loop where we carve a
+// memory zone for the opcodes and the data and call RebindCopy on each rule
+// so they all end up nicely packed in the policy_store_.
+bool LowLevelPolicy::Done() {
+  typedef std::list<RuleNode> RuleNodes;
+  typedef std::list<const PolicyRule*> RuleList;
+  typedef std::map<IpcTag, RuleList> Mmap;
+  Mmap mmap;
+
+  for (RuleNodes::iterator it = rules_.begin(); it != rules_.end(); ++it) {
+    mmap[it->service].push_back(it->rule);
+  }
+
+  PolicyBuffer* current_buffer = &policy_store_->data[0];
+  char* buffer_end =
+      reinterpret_cast<char*>(current_buffer) + policy_store_->data_size;
+  size_t avail_size = policy_store_->data_size;
+
+  for (Mmap::iterator it = mmap.begin(); it != mmap.end(); ++it) {
+    IpcTag service = (*it).first;
+    if (static_cast<size_t>(service) >= kMaxServiceCount) {
+      return false;
+    }
+    policy_store_->entry[static_cast<size_t>(service)] = current_buffer;
+
+    RuleList::iterator rules_it = (*it).second.begin();
+    RuleList::iterator rules_it_end = (*it).second.end();
+
+    size_t svc_opcode_count = 0;
+
+    for (; rules_it != rules_it_end; ++rules_it) {
+      const PolicyRule* rule = (*rules_it);
+      size_t op_count = rule->GetOpcodeCount();
+
+      size_t opcodes_size = op_count * sizeof(PolicyOpcode);
+      if (avail_size < opcodes_size) {
+        return false;
+      }
+      size_t data_size = avail_size - opcodes_size;
+      PolicyOpcode* opcodes_start = &current_buffer->opcodes[svc_opcode_count];
+      if (!rule->RebindCopy(opcodes_start, opcodes_size, buffer_end,
+                            &data_size)) {
+        return false;
+      }
+      size_t used = avail_size - data_size;
+      buffer_end -= used;
+      avail_size -= used;
+      svc_opcode_count += op_count;
+    }
+
+    current_buffer->opcode_count = svc_opcode_count;
+    size_t policy_buffers_occupied =
+        (svc_opcode_count * sizeof(PolicyOpcode)) / sizeof(current_buffer[0]);
+    current_buffer = &current_buffer[policy_buffers_occupied + 1];
+  }
+
+  return true;
+}
+
+PolicyRule::PolicyRule(EvalResult action) : action_(action), done_(false) {
+  char* memory = new char[sizeof(PolicyBuffer) + kRuleBufferSize];
+  buffer_ = reinterpret_cast<PolicyBuffer*>(memory);
+  buffer_->opcode_count = 0;
+  opcode_factory_ =
+      new OpcodeFactory(buffer_, kRuleBufferSize + sizeof(PolicyOpcode));
+}
+
+PolicyRule::PolicyRule(const PolicyRule& other) {
+  if (this == &other)
+    return;
+  action_ = other.action_;
+  done_ = other.done_;
+  size_t buffer_size = sizeof(PolicyBuffer) + kRuleBufferSize;
+  char* memory = new char[buffer_size];
+  buffer_ = reinterpret_cast<PolicyBuffer*>(memory);
+  memcpy(buffer_, other.buffer_, buffer_size);
+
+  char* opcode_buffer = reinterpret_cast<char*>(&buffer_->opcodes[0]);
+  char* next_opcode = &opcode_buffer[GetOpcodeCount() * sizeof(PolicyOpcode)];
+  opcode_factory_ =
+      new OpcodeFactory(next_opcode, other.opcode_factory_->memory_size());
+}
+
+// This function get called from a simple state machine implemented in
+// AddStringMatch() which passes the current state (in state) and it passes
+// true in last_call if AddStringMatch() has finished processing the input
+// pattern string and this would be the last call to generate any pending
+// opcode. The skip_count is the currently accumulated number of '?' seen so
+// far and once the associated opcode is generated this function sets it back
+// to zero.
+bool PolicyRule::GenStringOpcode(RuleType rule_type,
+                                 StringMatchOptions match_opts,
+                                 uint16_t parameter,
+                                 int state,
+                                 bool last_call,
+                                 int* skip_count,
+                                 std::wstring* fragment) {
+  // The last opcode must:
+  //   1) Always clear the context.
+  //   2) Preserve the negation.
+  //   3) Remove the 'OR' mode flag.
+  uint32_t options = kPolNone;
+  if (last_call) {
+    if (IF_NOT == rule_type) {
+      options = kPolClearContext | kPolNegateEval;
+    } else {
+      options = kPolClearContext;
+    }
+  } else if (IF_NOT == rule_type) {
+    options = kPolUseOREval | kPolNegateEval;
+  }
+
+  PolicyOpcode* op = nullptr;
+
+  // The fragment string contains the accumulated characters to match with, it
+  // never contains wildcards (unless they have been escaped) and while there
+  // is no fragment there is no new string match opcode to generate.
+  if (fragment->empty()) {
+    // There is no new opcode to generate but in the last call we have to fix
+    // the previous opcode because it was really the last but we did not know
+    // it at that time.
+    if (last_call && (buffer_->opcode_count > 0)) {
+      op = &buffer_->opcodes[buffer_->opcode_count - 1];
+      op->SetOptions(options);
+    }
+    return true;
+  }
+
+  if (PENDING_ASTERISK == state) {
+    if (last_call) {
+      op = opcode_factory_->MakeOpWStringMatch(parameter, fragment->c_str(),
+                                               kSeekToEnd, match_opts, options);
+    } else {
+      op = opcode_factory_->MakeOpWStringMatch(
+          parameter, fragment->c_str(), kSeekForward, match_opts, options);
+    }
+
+  } else if (PENDING_QMARK == state) {
+    op = opcode_factory_->MakeOpWStringMatch(parameter, fragment->c_str(),
+                                             *skip_count, match_opts, options);
+    *skip_count = 0;
+  } else {
+    if (last_call) {
+      match_opts = static_cast<StringMatchOptions>(EXACT_LENGTH | match_opts);
+    }
+    op = opcode_factory_->MakeOpWStringMatch(parameter, fragment->c_str(), 0,
+                                             match_opts, options);
+  }
+  if (!op)
+    return false;
+  ++buffer_->opcode_count;
+  fragment->clear();
+  return true;
+}
+
+bool PolicyRule::AddStringMatch(RuleType rule_type,
+                                int16_t parameter,
+                                const wchar_t* string,
+                                StringMatchOptions match_opts) {
+  if (done_) {
+    // Do not allow to add more rules after generating the action opcode.
+    return false;
+  }
+
+  const wchar_t* current_char = string;
+  uint32_t last_char = kLastCharIsNone;
+  int state = PENDING_NONE;
+  int skip_count = 0;       // counts how many '?' we have seen in a row.
+  std::wstring fragment;    // accumulates the non-wildcard part.
+
+  while (L'\0' != *current_char) {
+    switch (*current_char) {
+      case L'*':
+        if (kLastCharIsWild & last_char) {
+          // '**' and '&*' is an error.
+          return false;
+        }
+        if (!GenStringOpcode(rule_type, match_opts, parameter, state, false,
+                             &skip_count, &fragment)) {
+          return false;
+        }
+        last_char = kLastCharIsAsterisk;
+        state = PENDING_ASTERISK;
+        break;
+      case L'?':
+        if (kLastCharIsAsterisk == last_char) {
+          // '*?' is an error.
+          return false;
+        }
+        if (!GenStringOpcode(rule_type, match_opts, parameter, state, false,
+                             &skip_count, &fragment)) {
+          return false;
+        }
+        ++skip_count;
+        last_char = kLastCharIsQuestionM;
+        state = PENDING_QMARK;
+        break;
+      case L'/':
+        // Note: "/?" is an escaped '?'. Eat the slash and fall through.
+        if (L'?' == current_char[1]) {
+          ++current_char;
+        }
+        FALLTHROUGH;
+      default:
+        fragment += *current_char;
+        last_char = kLastCharIsAlpha;
+    }
+    ++current_char;
+  }
+
+  if (!GenStringOpcode(rule_type, match_opts, parameter, state, true,
+                       &skip_count, &fragment)) {
+    return false;
+  }
+  return true;
+}
+
+bool PolicyRule::AddNumberMatch(RuleType rule_type,
+                                int16_t parameter,
+                                uint32_t number,
+                                RuleOp comparison_op) {
+  if (done_) {
+    // Do not allow to add more rules after generating the action opcode.
+    return false;
+  }
+  uint32_t opts = (rule_type == IF_NOT) ? kPolNegateEval : kPolNone;
+
+  if (EQUAL == comparison_op) {
+    if (!opcode_factory_->MakeOpNumberMatch(parameter, number, opts))
+      return false;
+  } else if (AND == comparison_op) {
+    if (!opcode_factory_->MakeOpNumberAndMatch(parameter, number, opts))
+      return false;
+  }
+  ++buffer_->opcode_count;
+  return true;
+}
+
+bool PolicyRule::Done() {
+  if (done_) {
+    return true;
+  }
+  if (!opcode_factory_->MakeOpAction(action_, kPolNone))
+    return false;
+  ++buffer_->opcode_count;
+  done_ = true;
+  return true;
+}
+
+bool PolicyRule::RebindCopy(PolicyOpcode* opcode_start,
+                            size_t opcode_size,
+                            char* data_start,
+                            size_t* data_size) const {
+  size_t count = buffer_->opcode_count;
+  for (size_t ix = 0; ix != count; ++ix) {
+    if (opcode_size < sizeof(PolicyOpcode)) {
+      return false;
+    }
+    PolicyOpcode& opcode = buffer_->opcodes[ix];
+    *opcode_start = opcode;
+    if (OP_WSTRING_MATCH == opcode.GetID()) {
+      // For this opcode argument 0 is a delta to the string and argument 1
+      // is the length (in chars) of the string.
+      const wchar_t* str = opcode.GetRelativeString(0);
+      size_t str_len;
+      opcode.GetArgument(1, &str_len);
+      str_len = str_len * sizeof(wchar_t);
+      if ((*data_size) < str_len) {
+        return false;
+      }
+      *data_size -= str_len;
+      data_start -= str_len;
+      memcpy(data_start, str, str_len);
+      // Recompute the string displacement
+      ptrdiff_t delta = data_start - reinterpret_cast<char*>(opcode_start);
+      opcode_start->SetArgument(0, delta);
+    }
+    ++opcode_start;
+    opcode_size -= sizeof(PolicyOpcode);
+  }
+
+  return true;
+}
+
+PolicyRule::~PolicyRule() {
+  delete[] reinterpret_cast<char*>(buffer_);
+  delete opcode_factory_;
+}
+
+}  // namespace sandbox