mirror of
https://github.com/RGBCube/serenity
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e87eac9273
This achieves two things: - Programs can now intentionally perform arbitrary syscalls by calling syscall(). This allows us to work on things like syscall fuzzing. - It restricts the ability of userspace to make syscalls to a single 4KB page of code. In order to call the kernel directly, an attacker must now locate this page and call through it.
69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
/*
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* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/LogStream.h>
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#include <errno.h>
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#include <sys/ptrace.h>
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#include <syscall.h>
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extern "C" {
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int ptrace(int request, pid_t tid, void* addr, int data)
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{
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// PT_PEEK needs special handling since the syscall wrapper
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// returns the peeked value as an int, which can be negative because of the cast.
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// When using PT_PEEK, the user can check if an error occurred
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// by looking at errno rather than the return value.
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u32 out_data;
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Syscall::SC_ptrace_peek_params peek_params;
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if (request == PT_PEEK) {
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peek_params.address = reinterpret_cast<u32*>(addr);
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peek_params.out_data = &out_data;
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addr = &peek_params;
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}
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Syscall::SC_ptrace_params params {
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request,
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tid,
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reinterpret_cast<u8*>(addr),
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data
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};
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int rc = syscall(SC_ptrace, ¶ms);
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if (request == PT_PEEK) {
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if (rc < 0) {
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errno = -rc;
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return -1;
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}
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errno = 0;
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return static_cast<int>(out_data);
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}
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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}
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