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Kernel: Use copy_from_user() when appropriate during thread backtracing

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This commit is contained in:
Andreas Kling 2020-01-19 10:10:46 +01:00
parent 38fc31ff11
commit 87583aea9c
Notes: sideshowbarker 2024-07-19 09:57:49 +09:00
1 changed files with 47 additions and 30 deletions
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77
Kernel/Thread.cpp
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@ -722,57 +722,74 @@ String Thread::backtrace(ProcessInspectionHandle&) const
return backtrace_impl();
}
struct RecognizedSymbol {
u32 address;
const KSym* ksym;
};
static bool symbolicate(const RecognizedSymbol& symbol, const Process& process, StringBuilder& builder)
{
if (!symbol.address)
return false;
bool mask_kernel_addresses = !process.is_superuser();
if (!symbol.ksym) {
if (!is_user_address(VirtualAddress(symbol.address))) {
builder.append("0xdeadc0de\n");
} else {
if (!Scheduler::is_active() && process.elf_loader() && process.elf_loader()->has_symbols())
builder.appendf("%p %s\n", symbol.address, process.elf_loader()->symbolicate(symbol.address).characters());
else
builder.appendf("%p\n", symbol.address);
}
return true;
}
unsigned offset = symbol.address - symbol.ksym->address;
if (symbol.ksym->address == ksym_highest_address && offset > 4096) {
builder.appendf("%p\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address);
} else {
builder.appendf("%p %s +%u\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address, demangle(symbol.ksym->name).characters(), offset);
}
return true;
}
String Thread::backtrace_impl() const
{
Vector<RecognizedSymbol, 128> recognized_symbols;
u32 start_frame;
if (current == this) {
asm volatile("movl %%ebp, %%eax"
: "=a"(start_frame));
} else {
start_frame = frame_ptr();
recognized_symbols.append({ tss().eip, ksymbolicate(tss().eip) });
}
auto& process = const_cast<Process&>(this->process());
ProcessPagingScope paging_scope(process);
struct RecognizedSymbol {
u32 address;
const KSym* ksym;
};
StringBuilder builder;
Vector<RecognizedSymbol, 128> recognized_symbols;
if (current != this)
recognized_symbols.append({ tss().eip, ksymbolicate(tss().eip) });
u32 stack_ptr = start_frame;
for (;;) {
if (!process.validate_read_from_kernel(VirtualAddress((u32)stack_ptr), sizeof(void*) * 2))
break;
u32 retaddr;
copy_from_user(&retaddr, &((u32*)stack_ptr)[1]);
recognized_symbols.append({ retaddr, ksymbolicate(retaddr) });
copy_from_user(&stack_ptr, (u32*)stack_ptr);
if (is_user_range(VirtualAddress(stack_ptr), sizeof(void*) * 2)) {
copy_from_user(&retaddr, &((u32*)stack_ptr)[1]);
recognized_symbols.append({ retaddr, ksymbolicate(retaddr) });
copy_from_user(&stack_ptr, (u32*)stack_ptr);
} else {
memcpy(&retaddr, &((u32*)stack_ptr)[1], sizeof(void*));
recognized_symbols.append({ retaddr, ksymbolicate(retaddr) });
memcpy(&stack_ptr, (u32*)stack_ptr, sizeof(void*));
}
}
bool mask_kernel_addresses = !current->process().is_superuser();
StringBuilder builder;
for (auto& symbol : recognized_symbols) {
if (!symbol.address)
if (!symbolicate(symbol, process, builder))
break;
if (!symbol.ksym) {
if (!is_user_address(VirtualAddress(symbol.address))) {
builder.append("0xdeadc0de\n");
} else {
if (!Scheduler::is_active() && process.elf_loader() && process.elf_loader()->has_symbols())
builder.appendf("%p %s\n", symbol.address, process.elf_loader()->symbolicate(symbol.address).characters());
else
builder.appendf("%p\n", symbol.address);
}
continue;
}
unsigned offset = symbol.address - symbol.ksym->address;
if (symbol.ksym->address == ksym_highest_address && offset > 4096) {
builder.appendf("%p\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address);
} else {
builder.appendf("%p %s +%u\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address, demangle(symbol.ksym->name).characters(), offset);
}
}
return builder.to_string();
}