michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef SANDBOX_SRC_POLICY_LOW_LEVEL_H__
michael@0: #define SANDBOX_SRC_POLICY_LOW_LEVEL_H__
michael@0: 
michael@0: #include <list>
michael@0: 
michael@0: #include "base/basictypes.h"
michael@0: #include "sandbox/win/src/ipc_tags.h"
michael@0: #include "sandbox/win/src/policy_engine_params.h"
michael@0: #include "sandbox/win/src/policy_engine_opcodes.h"
michael@0: 
michael@0: // Low level policy classes.
michael@0: // Built on top of the PolicyOpcode and OpcodeFatory, the low level policy
michael@0: // provides a way to define rules on strings and numbers but it is unaware
michael@0: // of Windows specific details or how the Interceptions must be set up.
michael@0: // To use these classes you construct one or more rules and add them to the
michael@0: // LowLevelPolicy object like this:
michael@0: //
michael@0: //   PolicyRule rule1(ASK_BROKER);
michael@0: //   rule1.AddStringMatch(IF, 0, L"\\\\/?/?\\c:\\*Microsoft*\\*.exe", true);
michael@0: //   rule1.AddNumberMatch(IF_NOT, 1, CREATE_ALWAYS, EQUAL);
michael@0: //   rule1.AddNumberMatch(IF, 2, FILE_ATTRIBUTE_NORMAL, EQUAL);
michael@0: //
michael@0: //   PolicyRule rule2(FAKE_SUCCESS);
michael@0: //   rule2.AddStringMatch(IF, 0, L"\\\\/?/?\\Pipe\\Chrome.*", false));
michael@0: //   rule2.AddNumberMatch(IF, 1, OPEN_EXISTING, EQUAL));
michael@0: //
michael@0: //   LowLevelPolicy policyGen(*policy_memory);
michael@0: //   policyGen.AddRule(kNtCreateFileSvc, &rule1);
michael@0: //   policyGen.AddRule(kNtCreateFileSvc, &rule2);
michael@0: //   policyGen.Done();
michael@0: //
michael@0: // At this point (error checking omitted) the policy_memory can be copied
michael@0: // to the target process where it can be evaluated.
michael@0: 
michael@0: namespace sandbox {
michael@0: 
michael@0: // TODO(cpu): Move this constant to crosscall_client.h.
michael@0: const size_t kMaxServiceCount = 32;
michael@0: COMPILE_ASSERT(IPC_LAST_TAG <= kMaxServiceCount, kMaxServiceCount_is_too_low);
michael@0: 
michael@0: // Defines the memory layout of the policy. This memory is filled by
michael@0: // LowLevelPolicy object.
michael@0: // For example:
michael@0: //
michael@0: //  [Service 0] --points to---\
michael@0: //  [Service 1] --------------|-----\
michael@0: //   ......                   |     |
michael@0: //  [Service N]               |     |
michael@0: //  [data_size]               |     |
michael@0: //  [Policy Buffer 0] <-------/     |
michael@0: //  [opcodes of]                    |
michael@0: //  .......                         |
michael@0: //  [Policy Buffer 1] <-------------/
michael@0: //  [opcodes]
michael@0: //  .......
michael@0: //  .......
michael@0: //  [Policy Buffer N]
michael@0: //  [opcodes]
michael@0: //  .......
michael@0: //   <possibly unused space here>
michael@0: //  .......
michael@0: //  [opcode string ]
michael@0: //  [opcode string ]
michael@0: //  .......
michael@0: //  [opcode string ]
michael@0: struct PolicyGlobal {
michael@0:   PolicyBuffer* entry[kMaxServiceCount];
michael@0:   size_t data_size;
michael@0:   PolicyBuffer data[1];
michael@0: };
michael@0: 
michael@0: class PolicyRule;
michael@0: 
michael@0: // Provides the means to collect rules into a policy store (memory)
michael@0: class LowLevelPolicy {
michael@0:  public:
michael@0:   // policy_store: must contain allocated memory and the internal
michael@0:   // size fields set to correct values.
michael@0:   explicit LowLevelPolicy(PolicyGlobal* policy_store)
michael@0:       : policy_store_(policy_store) {
michael@0:   }
michael@0: 
michael@0:   // Destroys all the policy rules.
michael@0:   ~LowLevelPolicy();
michael@0: 
michael@0:   // Adds a rule to be generated when Done() is called.
michael@0:   // service: The id of the service that this rule is associated with,
michael@0:   // for example the 'Open Thread' service or the "Create File" service.
michael@0:   // returns false on error.
michael@0:   bool AddRule(int service, PolicyRule* rule);
michael@0: 
michael@0:   // Generates all the rules added with AddRule() into the memory area
michael@0:   // passed on the constructor. Returns false on error.
michael@0:   bool Done();
michael@0: 
michael@0:  private:
michael@0:   struct RuleNode {
michael@0:     const PolicyRule* rule;
michael@0:     int service;
michael@0:   };
michael@0:   std::list<RuleNode> rules_;
michael@0:   PolicyGlobal* policy_store_;
michael@0:   DISALLOW_IMPLICIT_CONSTRUCTORS(LowLevelPolicy);
michael@0: };
michael@0: 
michael@0: // There are 'if' rules and 'if not' comparisons
michael@0: enum RuleType {
michael@0:   IF = 0,
michael@0:   IF_NOT = 1,
michael@0: };
michael@0: 
michael@0: // Possible comparisons for numbers
michael@0: enum RuleOp {
michael@0:   EQUAL,
michael@0:   AND,
michael@0:   RANGE   // TODO(cpu): Implement this option.
michael@0: };
michael@0: 
michael@0: // Provides the means to collect a set of comparisons into a single
michael@0: // rule and its associated action.
michael@0: class PolicyRule {
michael@0:   friend class LowLevelPolicy;
michael@0: 
michael@0:  public:
michael@0:   explicit PolicyRule(EvalResult action);
michael@0:   PolicyRule(const PolicyRule& other);
michael@0:   ~PolicyRule();
michael@0: 
michael@0:   // Adds a string comparison to the rule.
michael@0:   // rule_type: possible values are IF and IF_NOT.
michael@0:   // parameter: the expected index of the argument for this rule. For example
michael@0:   // in a 'create file' service the file name argument can be at index 0.
michael@0:   // string: is the desired matching pattern.
michael@0:   // match_opts: if the pattern matching is case sensitive or not.
michael@0:   bool AddStringMatch(RuleType rule_type, int16 parameter,
michael@0:                       const wchar_t* string, StringMatchOptions match_opts);
michael@0: 
michael@0:   // Adds a number match comparison to the rule.
michael@0:   // rule_type: possible values are IF and IF_NOT.
michael@0:   // parameter: the expected index of the argument for this rule.
michael@0:   // number: the value to compare the input to.
michael@0:   // comparison_op: the comparison kind (equal, logical and, etc).
michael@0:   bool AddNumberMatch(RuleType rule_type, int16 parameter,
michael@0:                       unsigned long number, RuleOp comparison_op);
michael@0: 
michael@0:   // Returns the number of opcodes generated so far.
michael@0:   size_t GetOpcodeCount() const {
michael@0:     return buffer_->opcode_count;
michael@0:   }
michael@0: 
michael@0:   // Called when there is no more comparisons to add. Internally it generates
michael@0:   // the last opcode (the action opcode). Returns false if this operation fails.
michael@0:   bool Done();
michael@0: 
michael@0:  private:
michael@0:   void operator=(const PolicyRule&);
michael@0:   // Called in a loop from AddStringMatch to generate the required string
michael@0:   // match opcodes. rule_type, match_opts and parameter are the same as
michael@0:   // in AddStringMatch.
michael@0:   bool GenStringOpcode(RuleType rule_type, StringMatchOptions match_opts,
michael@0:                        uint16 parameter, int state, bool last_call,
michael@0:                        int* skip_count, std::wstring* fragment);
michael@0: 
michael@0:   // Loop over all generated opcodes and copy them to increasing memory
michael@0:   // addresses from opcode_start and copy the extra data (strings usually) into
michael@0:   // decreasing addresses from data_start. Extra data is only present in the
michael@0:   // string evaluation opcodes.
michael@0:   bool RebindCopy(PolicyOpcode* opcode_start, size_t opcode_size,
michael@0:                   char* data_start, size_t* data_size) const;
michael@0:   PolicyBuffer* buffer_;
michael@0:   OpcodeFactory* opcode_factory_;
michael@0:   EvalResult action_;
michael@0:   bool done_;
michael@0: };
michael@0: 
michael@0: }  // namespace sandbox
michael@0: 
michael@0: #endif  // SANDBOX_SRC_POLICY_LOW_LEVEL_H__