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Kernel: Reorganize ptrace implementation a bit

Browse source 
The generic parts of ptrace now live in Kernel/Syscalls/ptrace.cpp
and the i386 specific parts are moved to Arch/i386/CPU.cpp
This commit is contained in:
Andreas Kling 2021-02-08 19:34:41 +01:00
parent 45231051e6
commit f39c2b653e
8 changed files with 169 additions and 246 deletions
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34
Kernel/Arch/i386/CPU.cpp
View file

@ -2264,6 +2264,40 @@ void Processor::set_thread_specific(u8* data, size_t len)
descriptor.set_limit(len);
}
void copy_kernel_registers_into_ptrace_registers(PtraceRegisters& ptrace_regs, const RegisterState& kernel_regs)
{
ptrace_regs.eax = kernel_regs.eax,
ptrace_regs.ecx = kernel_regs.ecx,
ptrace_regs.edx = kernel_regs.edx,
ptrace_regs.ebx = kernel_regs.ebx,
ptrace_regs.esp = kernel_regs.userspace_esp,
ptrace_regs.ebp = kernel_regs.ebp,
ptrace_regs.esi = kernel_regs.esi,
ptrace_regs.edi = kernel_regs.edi,
ptrace_regs.eip = kernel_regs.eip,
ptrace_regs.eflags = kernel_regs.eflags,
ptrace_regs.cs = 0;
ptrace_regs.ss = 0;
ptrace_regs.ds = 0;
ptrace_regs.es = 0;
ptrace_regs.fs = 0;
ptrace_regs.gs = 0;
}
void copy_ptrace_registers_into_kernel_registers(RegisterState& kernel_regs, const PtraceRegisters& ptrace_regs)
{
kernel_regs.eax = ptrace_regs.eax;
kernel_regs.ecx = ptrace_regs.ecx;
kernel_regs.edx = ptrace_regs.edx;
kernel_regs.ebx = ptrace_regs.ebx;
kernel_regs.esp = ptrace_regs.esp;
kernel_regs.ebp = ptrace_regs.ebp;
kernel_regs.esi = ptrace_regs.esi;
kernel_regs.edi = ptrace_regs.edi;
kernel_regs.eip = ptrace_regs.eip;
kernel_regs.eflags = (kernel_regs.eflags & ~safe_eflags_mask) | (ptrace_regs.eflags & safe_eflags_mask);
}
}
#ifdef DEBUG

6
Kernel/Arch/i386/CPU.h
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -32,6 +32,7 @@
#include <AK/Vector.h>
#include <Kernel/PhysicalAddress.h>
#include <Kernel/VirtualAddress.h>
#include <LibC/sys/arch/i386/regs.h>
#define PAGE_SIZE 4096
#define GENERIC_INTERRUPT_HANDLERS_COUNT (256 - IRQ_VECTOR_BASE)
@ -494,6 +495,9 @@ struct [[gnu::packed]] RegisterState {
#define REGISTER_STATE_SIZE (19 * 4)
static_assert(REGISTER_STATE_SIZE == sizeof(RegisterState));
void copy_kernel_registers_into_ptrace_registers(PtraceRegisters&, const RegisterState&);
void copy_ptrace_registers_into_kernel_registers(RegisterState&, const PtraceRegisters&);
struct [[gnu::aligned(16)]] FPUState
{
u8 buffer[512];

1
Kernel/CMakeLists.txt
View file

@ -104,7 +104,6 @@ set(KERNEL_SOURCES
PerformanceEventBuffer.cpp
Process.cpp
ProcessGroup.cpp
Ptrace.cpp
RTC.cpp
Random.cpp
Scheduler.cpp

3
Kernel/CoreDump.cpp
View file

@ -34,7 +34,6 @@
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
#include <Kernel/Ptrace.h>
#include <Kernel/RTC.h>
#include <Kernel/SpinLock.h>
#include <Kernel/VM/ProcessPagingScope.h>
@ -246,7 +245,7 @@ ByteBuffer CoreDump::create_notes_threads_data() const
ELF::Core::ThreadInfo info {};
info.header.type = ELF::Core::NotesEntryHeader::Type::ThreadInfo;
info.tid = thread.tid().value();
Ptrace::copy_kernel_registers_into_ptrace_registers(info.regs, thread.get_register_dump_from_stack());
copy_kernel_registers_into_ptrace_registers(info.regs, thread.get_register_dump_from_stack());
entry_buff.append((void*)&info, sizeof(info));

194
Kernel/Ptrace.cpp
View file

@ -1,194 +0,0 @@
/*
* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. 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.
*
* 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 HOLDER 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.
*/
#include <Kernel/Process.h>
#include <Kernel/Ptrace.h>
#include <Kernel/Thread.h>
#include <Kernel/ThreadTracer.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/ProcessPagingScope.h>
namespace Ptrace {
KResultOr<u32> handle_syscall(const Kernel::Syscall::SC_ptrace_params& params, Process& caller)
{
ScopedSpinLock scheduler_lock(g_scheduler_lock);
if (params.request == PT_TRACE_ME) {
if (Process::current()->tracer())
return EBUSY;
caller.set_wait_for_tracer_at_next_execve(true);
return KSuccess;
}
// FIXME: PID/TID BUG
// This bug allows to request PT_ATTACH (or anything else) the same process, as
// long it is not the main thread. Alternatively, if this is desired, then the
// bug is that this prevents PT_ATTACH to the main thread from another thread.
if (params.tid == caller.pid().value())
return EINVAL;
auto peer = Thread::from_tid(params.tid);
if (!peer)
return ESRCH;
if ((peer->process().uid() != caller.euid())
|| (peer->process().uid() != peer->process().euid())) // Disallow tracing setuid processes
return EACCES;
if (!peer->process().is_dumpable())
return EACCES;
auto& peer_process = peer->process();
if (params.request == PT_ATTACH) {
if (peer_process.tracer()) {
return EBUSY;
}
peer_process.start_tracing_from(caller.pid());
ScopedSpinLock lock(peer->get_lock());
if (peer->state() != Thread::State::Stopped) {
peer->send_signal(SIGSTOP, &caller);
}
return KSuccess;
}
auto* tracer = peer_process.tracer();
if (!tracer)
return EPERM;
if (tracer->tracer_pid() != caller.pid())
return EBUSY;
if (peer->state() == Thread::State::Running)
return EBUSY;
scheduler_lock.unlock();
switch (params.request) {
case PT_CONTINUE:
peer->send_signal(SIGCONT, &caller);
break;
case PT_DETACH:
peer_process.stop_tracing();
peer->send_signal(SIGCONT, &caller);
break;
case PT_SYSCALL:
tracer->set_trace_syscalls(true);
peer->send_signal(SIGCONT, &caller);
break;
case PT_GETREGS: {
if (!tracer->has_regs())
return EINVAL;
auto* regs = reinterpret_cast<PtraceRegisters*>(params.addr);
if (!copy_to_user(regs, &tracer->regs()))
return EFAULT;
break;
}
case PT_SETREGS: {
if (!tracer->has_regs())
return EINVAL;
PtraceRegisters regs;
if (!copy_from_user(&regs, (const PtraceRegisters*)params.addr))
return EFAULT;
auto& peer_saved_registers = peer->get_register_dump_from_stack();
// Verify that the saved registers are in usermode context
if ((peer_saved_registers.cs & 0x03) != 3)
return EFAULT;
tracer->set_regs(regs);
copy_ptrace_registers_into_kernel_registers(peer_saved_registers, regs);
break;
}
case PT_PEEK: {
Kernel::Syscall::SC_ptrace_peek_params peek_params;
if (!copy_from_user(&peek_params, reinterpret_cast<Kernel::Syscall::SC_ptrace_peek_params*>(params.addr)))
return EFAULT;
if (!is_user_address(VirtualAddress { peek_params.address }))
return EFAULT;
auto result = peer->process().peek_user_data(Userspace<const u32*> { (FlatPtr)peek_params.address });
if (result.is_error())
return result.error();
if (!copy_to_user(peek_params.out_data, &result.value()))
return EFAULT;
break;
}
case PT_POKE:
if (!is_user_address(VirtualAddress { params.addr }))
return EFAULT;
return peer->process().poke_user_data(Userspace<u32*> { (FlatPtr)params.addr }, params.data);
default:
return EINVAL;
}
return KSuccess;
}
void copy_kernel_registers_into_ptrace_registers(PtraceRegisters& ptrace_regs, const RegisterState& kernel_regs)
{
ptrace_regs.eax = kernel_regs.eax,
ptrace_regs.ecx = kernel_regs.ecx,
ptrace_regs.edx = kernel_regs.edx,
ptrace_regs.ebx = kernel_regs.ebx,
ptrace_regs.esp = kernel_regs.userspace_esp,
ptrace_regs.ebp = kernel_regs.ebp,
ptrace_regs.esi = kernel_regs.esi,
ptrace_regs.edi = kernel_regs.edi,
ptrace_regs.eip = kernel_regs.eip,
ptrace_regs.eflags = kernel_regs.eflags,
ptrace_regs.cs = 0;
ptrace_regs.ss = 0;
ptrace_regs.ds = 0;
ptrace_regs.es = 0;
ptrace_regs.fs = 0;
ptrace_regs.gs = 0;
}
void copy_ptrace_registers_into_kernel_registers(RegisterState& kernel_regs, const PtraceRegisters& ptrace_regs)
{
kernel_regs.eax = ptrace_regs.eax;
kernel_regs.ecx = ptrace_regs.ecx;
kernel_regs.edx = ptrace_regs.edx;
kernel_regs.ebx = ptrace_regs.ebx;
kernel_regs.esp = ptrace_regs.esp;
kernel_regs.ebp = ptrace_regs.ebp;
kernel_regs.esi = ptrace_regs.esi;
kernel_regs.edi = ptrace_regs.edi;
kernel_regs.eip = ptrace_regs.eip;
kernel_regs.eflags = (kernel_regs.eflags & ~safe_eflags_mask) | (ptrace_regs.eflags & safe_eflags_mask);
}
}

41
Kernel/Ptrace.h
View file

@ -1,41 +0,0 @@
/*
* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. 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.
*
* 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 HOLDER 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.
*/
#pragma once
#include <Kernel/API/Syscall.h>
#include <Kernel/KResult.h>
#include <Kernel/Process.h>
#include <LibC/sys/arch/i386/regs.h>
namespace Ptrace {
KResultOr<u32> handle_syscall(const Kernel::Syscall::SC_ptrace_params& params, Process& caller);
void copy_kernel_registers_into_ptrace_registers(PtraceRegisters&, const RegisterState&);
void copy_ptrace_registers_into_kernel_registers(RegisterState&, const PtraceRegisters&);
}

131
Kernel/Syscalls/ptrace.cpp
View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -26,7 +27,6 @@
#include <AK/ScopeGuard.h>
#include <Kernel/Process.h>
#include <Kernel/Ptrace.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/PrivateInodeVMObject.h>
#include <Kernel/VM/ProcessPagingScope.h>
@ -35,13 +35,136 @@
namespace Kernel {
static KResultOr<u32> handle_ptrace(const Kernel::Syscall::SC_ptrace_params& params, Process& caller)
{
ScopedSpinLock scheduler_lock(g_scheduler_lock);
if (params.request == PT_TRACE_ME) {
if (Process::current()->tracer())
return EBUSY;
caller.set_wait_for_tracer_at_next_execve(true);
return KSuccess;
}
// FIXME: PID/TID BUG
// This bug allows to request PT_ATTACH (or anything else) the same process, as
// long it is not the main thread. Alternatively, if this is desired, then the
// bug is that this prevents PT_ATTACH to the main thread from another thread.
if (params.tid == caller.pid().value())
return EINVAL;
auto peer = Thread::from_tid(params.tid);
if (!peer)
return ESRCH;
if ((peer->process().uid() != caller.euid())
|| (peer->process().uid() != peer->process().euid())) // Disallow tracing setuid processes
return EACCES;
if (!peer->process().is_dumpable())
return EACCES;
auto& peer_process = peer->process();
if (params.request == PT_ATTACH) {
if (peer_process.tracer()) {
return EBUSY;
}
peer_process.start_tracing_from(caller.pid());
ScopedSpinLock lock(peer->get_lock());
if (peer->state() != Thread::State::Stopped) {
peer->send_signal(SIGSTOP, &caller);
}
return KSuccess;
}
auto* tracer = peer_process.tracer();
if (!tracer)
return EPERM;
if (tracer->tracer_pid() != caller.pid())
return EBUSY;
if (peer->state() == Thread::State::Running)
return EBUSY;
scheduler_lock.unlock();
switch (params.request) {
case PT_CONTINUE:
peer->send_signal(SIGCONT, &caller);
break;
case PT_DETACH:
peer_process.stop_tracing();
peer->send_signal(SIGCONT, &caller);
break;
case PT_SYSCALL:
tracer->set_trace_syscalls(true);
peer->send_signal(SIGCONT, &caller);
break;
case PT_GETREGS: {
if (!tracer->has_regs())
return EINVAL;
auto* regs = reinterpret_cast<PtraceRegisters*>(params.addr);
if (!copy_to_user(regs, &tracer->regs()))
return EFAULT;
break;
}
case PT_SETREGS: {
if (!tracer->has_regs())
return EINVAL;
PtraceRegisters regs {};
if (!copy_from_user(&regs, (const PtraceRegisters*)params.addr))
return EFAULT;
auto& peer_saved_registers = peer->get_register_dump_from_stack();
// Verify that the saved registers are in usermode context
if ((peer_saved_registers.cs & 0x03) != 3)
return EFAULT;
tracer->set_regs(regs);
copy_ptrace_registers_into_kernel_registers(peer_saved_registers, regs);
break;
}
case PT_PEEK: {
Kernel::Syscall::SC_ptrace_peek_params peek_params {};
if (!copy_from_user(&peek_params, reinterpret_cast<Kernel::Syscall::SC_ptrace_peek_params*>(params.addr)))
return EFAULT;
if (!is_user_address(VirtualAddress { peek_params.address }))
return EFAULT;
auto result = peer->process().peek_user_data(Userspace<const u32*> { (FlatPtr)peek_params.address });
if (result.is_error())
return result.error();
if (!copy_to_user(peek_params.out_data, &result.value()))
return EFAULT;
break;
}
case PT_POKE:
if (!is_user_address(VirtualAddress { params.addr }))
return EFAULT;
return peer->process().poke_user_data(Userspace<u32*> { (FlatPtr)params.addr }, params.data);
default:
return EINVAL;
}
return KSuccess;
}
int Process::sys$ptrace(Userspace<const Syscall::SC_ptrace_params*> user_params)
{
REQUIRE_PROMISE(ptrace);
Syscall::SC_ptrace_params params;
Syscall::SC_ptrace_params params {};
if (!copy_from_user(&params, user_params))
return -EFAULT;
auto result = Ptrace::handle_syscall(params, *this);
auto result = handle_ptrace(params, *this);
return result.is_error() ? result.error().error() : result.value();
}

5
Kernel/ThreadTracer.cpp
View file

@ -27,7 +27,6 @@
#include <AK/Memory.h>
#include <AK/kmalloc.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/Ptrace.h>
#include <Kernel/ThreadTracer.h>
namespace Kernel {
@ -39,8 +38,8 @@ ThreadTracer::ThreadTracer(ProcessID tracer_pid)
void ThreadTracer::set_regs(const RegisterState& regs)
{
PtraceRegisters r;
Ptrace::copy_kernel_registers_into_ptrace_registers(r, regs);
PtraceRegisters r {};
copy_kernel_registers_into_ptrace_registers(r, regs);
m_regs = r;
}