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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "sandbox/mac/seatbelt_extension.h"
#include <ostream>
#include "base/check.h"
#include "base/memory/ptr_util.h"
#include "base/notreached.h"
#include "sandbox/mac/seatbelt_extension_token.h"
// libsandbox private API.
extern "C" {
extern const char* APP_SANDBOX_READ;
extern const char* APP_SANDBOX_READ_WRITE;
int64_t sandbox_extension_consume(const char* token);
int sandbox_extension_release(int64_t handle);
char* sandbox_extension_issue_file(const char* type,
const char* path,
uint32_t flags);
}
namespace sandbox {
SeatbeltExtension::~SeatbeltExtension() {
DCHECK(token_.empty() && handle_ == 0)
<< "A SeatbeltExtension must be consumed permanently or revoked.";
}
// static
std::unique_ptr<SeatbeltExtensionToken> SeatbeltExtension::Issue(
SeatbeltExtension::Type type,
const std::string& resource) {
char* token = IssueToken(type, resource);
if (!token)
return nullptr;
return base::WrapUnique(new SeatbeltExtensionToken(token));
}
// static
std::unique_ptr<SeatbeltExtension> SeatbeltExtension::FromToken(
SeatbeltExtensionToken token) {
if (token.token_.empty())
return nullptr;
return base::WrapUnique(new SeatbeltExtension(token.token_));
}
bool SeatbeltExtension::Consume() {
DCHECK(!token_.empty());
handle_ = sandbox_extension_consume(token_.c_str());
return handle_ > 0;
}
bool SeatbeltExtension::ConsumePermanently() {
bool rv = Consume();
handle_ = 0;
token_.clear();
return rv;
}
bool SeatbeltExtension::Revoke() {
int rv = sandbox_extension_release(handle_);
handle_ = 0;
token_.clear();
return rv == 0;
}
SeatbeltExtension::SeatbeltExtension(const std::string& token)
: token_(token), handle_(0) {}
// static
// The token returned by libsandbox is an opaque string generated by the kernel.
// The string contains all the information about the extension (class and
// resource), which is then SHA1 hashed with a salt only known to the kernel.
// In this way, the kernel does not track issued tokens, it merely validates
// them on consumption.
char* SeatbeltExtension::IssueToken(SeatbeltExtension::Type type,
const std::string& resource) {
switch (type) {
case FILE_READ:
return sandbox_extension_issue_file(APP_SANDBOX_READ, resource.c_str(),
0);
case FILE_READ_WRITE:
return sandbox_extension_issue_file(APP_SANDBOX_READ_WRITE,
resource.c_str(), 0);
default:
NOTREACHED();
}
}
} // namespace sandbox
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