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This also transitions exception_port_tool to use TaskForPID(), so that it can be safely used as a setuid executable without giving permission to operate on any process on the system. It is difficult to provide a test for this function, because it must be running setuid root in order to do anything interesting. R=rsesek@chromium.org Review URL: https://codereview.chromium.org/728973002
60 lines
2.7 KiB
C++
60 lines
2.7 KiB
C++
// Copyright 2014 The Crashpad Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef CRASHPAD_UTIL_MACH_TASK_FOR_PID_H_
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#define CRASHPAD_UTIL_MACH_TASK_FOR_PID_H_
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#include <mach/mach.h>
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#include <sys/types.h>
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namespace crashpad {
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//! \brief Wraps `task_for_pid()`.
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//!
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//! This function exists to support `task_for_pid()` access checks in a setuid
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//! environment. Normally, `task_for_pid()` can only return an arbitrary task’s
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//! port when running as root or when taskgated(8) approves. When not running as
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//! root, a series of access checks are perfomed to ensure that the running
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//! process has permission to obtain the other process’ task port.
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//!
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//! It is possible to make an executable setuid root to give it broader
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//! `task_for_pid()` access by bypassing taskgated(8) checks, but this also has
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//! the effect of bypassing the access checks, allowing any process’ task port
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//! to be obtained. In most situations, these access checks are desirable to
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//! prevent security and privacy breaches.
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//!
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//! When running as setuid root, this function wraps `task_for_pid()`,
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//! reimplementing those access checks. A process whose effective user ID is 0
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//! and whose real user ID is nonzero is understood to be running setuid root.
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//! In this case, the requested task’s real, effective, and saved set-user IDs
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//! must all equal the running process’ real user ID, the requested task must
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//! not have changed privileges, and the requested task’s set of all group IDs
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//! (including its real, effective, and saved set-group IDs and supplementary
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//! group list) must be a subset of the running process’ set of all group IDs.
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//! These access checks mimic those that the kernel performs.
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//!
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//! When not running as setuid root, `task_for_pid()` is called directly,
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//! without imposing any additional checks beyond what the kernel does.
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//!
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//! \param[in] pid The process ID of the task whose task port is desired.
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//!
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//! \return A send right to the task port if it could be obtained, or
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//! `TASK_NULL` otherwise, with an error message logged. If a send right is
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//! returned, the caller takes ownership of it.
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task_t TaskForPID(pid_t pid);
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} // namespace crashpad
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#endif // CRASHPAD_UTIL_MACH_TASK_FOR_PID_H_
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