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Diffstat (limited to 'sandbox/src/policy_low_level.h')
| -rw-r--r-- | sandbox/src/policy_low_level.h | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/sandbox/src/policy_low_level.h b/sandbox/src/policy_low_level.h new file mode 100644 index 0000000..0adaf11 --- /dev/null +++ b/sandbox/src/policy_low_level.h @@ -0,0 +1,207 @@ +// Copyright 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#ifndef SANDBOX_SRC_POLICY_LOW_LEVEL_H__ +#define SANDBOX_SRC_POLICY_LOW_LEVEL_H__ + +#include <list> + +#include "base/basictypes.h" +#include "sandbox/src/ipc_tags.h" +#include "sandbox/src/policy_engine_params.h" +#include "sandbox/src/policy_engine_opcodes.h" + +// Low level policy classes. +// Built on top of the PolicyOpcode and OpcodeFatory, the low level policy +// provides a way to define rules on strings and numbers but it is unaware +// of Windows specific details or how the Interceptions must be set up. +// To use these classes you construct one or more rules and add them to the +// LowLevelPolicy object like this: +// +// PolicyRule rule1(ASK_BROKER); +// rule1.AddStringMatch(IF, 0, L"\\\\/?/?\\c:\\*Microsoft*\\*.exe", true); +// rule1.AddNumberMatch(IF_NOT, 1, CREATE_ALWAYS, EQUAL); +// rule1.AddNumberMatch(IF, 2, FILE_ATTRIBUTE_NORMAL, EQUAL); +// +// PolicyRule rule2(FAKE_SUCCESS); +// rule2.AddStringMatch(IF, 0, L"\\\\/?/?\\Pipe\\Chrome.*", false)); +// rule2.AddNumberMatch(IF, 1, OPEN_EXISTING, EQUAL)); +// +// LowLevelPolicy policyGen(*policy_memory); +// policyGen.AddRule(kNtCreateFileSvc, &rule1); +// policyGen.AddRule(kNtCreateFileSvc, &rule2); +// policyGen.Done(); +// +// At this point (error checking omitted) the policy_memory can be copied +// to the target process where it can be evaluated. + +namespace sandbox { + +// TODO(cpu): Move this constant to crosscall_client.h. +const size_t kMaxServiceCount = 32; +COMPILE_ASSERT(IPC_LAST_TAG <= kMaxServiceCount, kMaxServiceCount_is_too_low); + +// Defines the memory layout of the policy. This memory is filled by +// LowLevelPolicy object. +// For example: +// +// [Service 0] --points to---\ +// [Service 1] --------------|-----\ +// ...... | | +// [Service N] | | +// [data_size] | | +// [Policy Buffer 0] <-------/ | +// [opcodes of] | +// ....... | +// [Policy Buffer 1] <-------------/ +// [opcodes] +// ....... +// ....... +// [Policy Buffer N] +// [opcodes] +// ....... +// <possibly unused space here> +// ....... +// [opcode string ] +// [opcode string ] +// ....... +// [opcode string ] +struct PolicyGlobal { + PolicyBuffer* entry[kMaxServiceCount]; + size_t data_size; + PolicyBuffer data[1]; +}; + +class PolicyRule; + +// Provides the means to collect rules into a policy store (memory) +class LowLevelPolicy { + public: + // policy_store: must contain allocated memory and the internal + // size fields set to correct values. + explicit LowLevelPolicy(PolicyGlobal* policy_store) + : policy_store_(policy_store) { + } + + // Destroys all the policy rules. + ~LowLevelPolicy(); + + // Adds a rule to be generated when Done() is called. + // service: The id of the service that this rule is associated with, + // for example the 'Open Thread' service or the "Create File" service. + // returns false on error. + bool AddRule(int service, PolicyRule* rule); + + // Generates all the rules added with AddRule() into the memory area + // passed on the constructor. Returns false on error. + bool Done(); + + private: + struct RuleNode { + const PolicyRule* rule; + int service; + }; + std::list<RuleNode> rules_; + PolicyGlobal* policy_store_; + DISALLOW_IMPLICIT_CONSTRUCTORS(LowLevelPolicy); +}; + +// There are 'if' rules and 'if not' comparisons +enum RuleType { + IF = 0, + IF_NOT = 1, +}; + +// Possible comparisons for numbers +enum RuleOp { + EQUAL, + AND, + RANGE // TODO(cpu): Implement this option. +}; + +// Provides the means to collect a set of comparisons into a single +// rule and its associated action. +class PolicyRule { + friend class LowLevelPolicy; + + public: + explicit PolicyRule(EvalResult action); + PolicyRule(const PolicyRule& other); + ~PolicyRule(); + + // Adds a string comparison to the rule. + // rule_type: possible values are IF and IF_NOT. + // parameter: the expected index of the argument for this rule. For example + // in a 'create file' service the file name argument can be at index 0. + // string: is the desired matching pattern. + // match_opts: if the pattern matching is case sensitive or not. + bool AddStringMatch(RuleType rule_type, int16 parameter, + const wchar_t* string, StringMatchOptions match_opts); + + // Adds a number match comparison to the rule. + // rule_type: possible values are IF and IF_NOT. + // parameter: the expected index of the argument for this rule. + // number: the value to compare the input to. + // comparison_op: the comparison kind (equal, logical and, etc). + bool AddNumberMatch(RuleType rule_type, int16 parameter, + unsigned long number, RuleOp comparison_op); + + // Returns the number of opcodes generated so far. + size_t GetOpcodeCount() const { + return buffer_->opcode_count; + } + + // Called when there is no more comparisons to add. Internally it generates + // the last opcode (the action opcode). Returns false if this operation fails. + bool Done(); + + private: + void operator=(const PolicyRule&); + // Called in a loop from AddStringMatch to generate the required string + // match opcodes. rule_type, match_opts and parameter are the same as + // in AddStringMatch. + bool GenStringOpcode(RuleType rule_type, StringMatchOptions match_opts, + uint16 parameter, int state, bool last_call, + int* skip_count, std::wstring* fragment); + + // Loop over all generated opcodes and copy them to increasing memory + // addresses from opcode_start and copy the extra data (strings usually) into + // decreasing addresses from data_start. Extra data is only present in the + // string evaluation opcodes. + bool RebindCopy(PolicyOpcode* opcode_start, size_t opcode_size, + char* data_start, size_t* data_size) const; + PolicyBuffer* buffer_; + OpcodeFactory* opcode_factory_; + EvalResult action_; + bool done_; +}; + +} // namespace sandbox + +#endif // SANDBOX_SRC_POLICY_LOW_LEVEL_H__ |