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user backtrace fix #291

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user backtrace fix #291

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ca3108f
checkAddressValid no longer panics. fix possible pf in user backtrace
Mar 24, 2023
022332f
add stack alignement check to user backtrace
Mar 24, 2023
1596de3
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Mar 24, 2023
e36c5e0
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Mar 24, 2023
fa7f0e4
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Mar 24, 2023
a56fd3e
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Mar 24, 2023
12ad6c4
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Mar 24, 2023
634d84a
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73677a9
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Mar 24, 2023
d256cb7
this time it's correct
Mar 24, 2023
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6 changes: 6 additions & 0 deletions arch/x86/64/source/ArchMemory.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -160,6 +160,12 @@ ArchMemory::~ArchMemory()

pointer ArchMemory::checkAddressValid(uint64 vaddress_to_check)
{
if (vaddress_to_check >= USER_BREAK && vaddress_to_check < KERNEL_START)
{
debug(A_MEMORY, "checkAddressValid %zx non-canonical -> false\n", vaddress_to_check);
return 0;
}

ArchMemoryMapping m = resolveMapping(page_map_level_4_, vaddress_to_check / PAGE_SIZE);
if (m.page != 0)
{
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26 changes: 23 additions & 3 deletions arch/x86/64/source/arch_backtrace.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,10 @@ int backtrace_user(pointer *call_stack, int size, Thread *thread, bool /*use_sto
if (!call_stack || !size || !thread->user_registers_)
return 0;

if (thread->user_registers_->rbp % sizeof(pointer))
{
debug(BACKTRACE, "stack not aligned. this could cause serious problems\n");
}
void *rbp = (void*)thread->user_registers_->rbp;
StackFrame *CurrentFrame = (StackFrame*)rbp;
StackFrame *CurrentFrameI = (StackFrame*)thread->loader_->arch_memory_.checkAddressValid((pointer)rbp);
Expand All @@ -82,13 +86,29 @@ int backtrace_user(pointer *call_stack, int size, Thread *thread, bool /*use_sto

while (i < size &&
ADDRESS_BETWEEN(CurrentFrame, StackEnd, StackStart) &&
ADDRESS_BETWEEN(&CurrentFrame->return_address, StackEnd, StackStart) &&
ADDRESS_BETWEEN(StackEnd, StartAddress, EndAddress) &&
ADDRESS_BETWEEN(StackStart, StartAddress, EndAddress) &&
CurrentFrameI &&
ADDRESS_BETWEEN(CurrentFrameI->return_address, StartAddress, EndAddress))
CurrentFrameI)
{
call_stack[i++] = (pointer)CurrentFrameI->return_address;
pointer return_address;
if ((((pointer)CurrentFrameI)-sizeof(pointer))%PAGE_SIZE == 0)
{
auto return_ptr = (pointer *)thread->loader_->arch_memory_.checkAddressValid((pointer)&CurrentFrameI->return_address);
return_address = return_ptr ? *return_ptr : 0;
}
else
{
return_address = (pointer)CurrentFrameI->return_address;
}

if (!ADDRESS_BETWEEN(CurrentFrameI->return_address, StartAddress, EndAddress))
break;

call_stack[i++] = return_address;

CurrentFrame = CurrentFrameI->previous_frame;

CurrentFrameI = (StackFrame*)thread->loader_->arch_memory_.checkAddressValid((pointer)CurrentFrameI->previous_frame);
}

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