Author: Daniil Kovalev Date: 2024-04-16T09:53:33+03:00 New Revision: 7e49b0d5a67f212e84f8ec0ec2e39a6a8673bfaf
URL: https://github.com/llvm/llvm-project/commit/7e49b0d5a67f212e84f8ec0ec2e39a6a8673bfaf DIFF: https://github.com/llvm/llvm-project/commit/7e49b0d5a67f212e84f8ec0ec2e39a6a8673bfaf.diff LOG: [lldb] Fix nullptr dereference on running x86 binary with x86-disabled llvm (#82603) If `LLVM_TARGETS_TO_BUILD` does not contain `X86` and we try to run an x86 binary in lldb, we get a `nullptr` dereference in `LLVMDisasmInstruction(...)`. We try to call `getDisAsm()` method on a `LLVMDisasmContext *DC` which is null. The pointer is passed from `x86AssemblyInspectionEngine::instruction_length(...)` and is originally `m_disasm_context` member of `x86AssemblyInspectionEngine`. This should be filled by `LLVMCreateDisasm(...)` in the class constructor, but not having X86 target enabled in llvm makes `TargetRegistry::lookupTarget(...)` call return `nullptr`, which results in `m_disasm_context` initialized with `nullptr` as well. This patch adds if statements against `m_disasm_context` in `x86AssemblyInspectionEngine::GetNonCallSiteUnwindPlanFromAssembly(...)` and `x86AssemblyInspectionEngine::FindFirstNonPrologueInstruction(...)` so subsequent calls to `x86AssemblyInspectionEngine::instruction_length(...)` do not cause a null pointer dereference. Added: lldb/unittests/UnwindAssembly/x86-but-no-x86-target/CMakeLists.txt lldb/unittests/UnwindAssembly/x86-but-no-x86-target/Testx86AssemblyInspectionEngine.cpp Modified: lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp lldb/unittests/UnwindAssembly/CMakeLists.txt Removed: ################################################################################ diff --git a/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp b/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp index 2032c5a68d054c..6bfaa54135a959 100644 --- a/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp +++ b/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp @@ -909,6 +909,9 @@ bool x86AssemblyInspectionEngine::GetNonCallSiteUnwindPlanFromAssembly( if (!m_register_map_initialized) return false; + if (m_disasm_context == nullptr) + return false; + addr_t current_func_text_offset = 0; int current_sp_bytes_offset_from_fa = 0; bool is_aligned = false; @@ -1570,6 +1573,9 @@ bool x86AssemblyInspectionEngine::FindFirstNonPrologueInstruction( if (!m_register_map_initialized) return false; + if (m_disasm_context == nullptr) + return false; + while (offset < size) { int regno; int insn_len; diff --git a/lldb/unittests/UnwindAssembly/CMakeLists.txt b/lldb/unittests/UnwindAssembly/CMakeLists.txt index 136fcd9ae97981..d6e4471af4ecb3 100644 --- a/lldb/unittests/UnwindAssembly/CMakeLists.txt +++ b/lldb/unittests/UnwindAssembly/CMakeLists.txt @@ -9,3 +9,7 @@ endif() if ("X86" IN_LIST LLVM_TARGETS_TO_BUILD) add_subdirectory(x86) endif() + +if (NOT "X86" IN_LIST LLVM_TARGETS_TO_BUILD) + add_subdirectory(x86-but-no-x86-target) +endif() diff --git a/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/CMakeLists.txt b/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/CMakeLists.txt new file mode 100644 index 00000000000000..d28e9629a64cfc --- /dev/null +++ b/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/CMakeLists.txt @@ -0,0 +1,10 @@ +add_lldb_unittest(UnwindAssemblyX86ButNoX86TargetTests + Testx86AssemblyInspectionEngine.cpp + LINK_LIBS + lldbCore + lldbSymbol + lldbPluginUnwindAssemblyX86 + LINK_COMPONENTS + Support + ${LLVM_TARGETS_TO_BUILD} + ) diff --git a/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/Testx86AssemblyInspectionEngine.cpp b/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/Testx86AssemblyInspectionEngine.cpp new file mode 100644 index 00000000000000..ed093d146440e3 --- /dev/null +++ b/lldb/unittests/UnwindAssembly/x86-but-no-x86-target/Testx86AssemblyInspectionEngine.cpp @@ -0,0 +1,103 @@ +//===-- Testx86AssemblyInspectionEngine.cpp -------------------------------===// + +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "gtest/gtest.h" + +#include "Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.h" +#include "lldb/Core/AddressRange.h" +#include "lldb/Symbol/UnwindPlan.h" +#include "lldb/Utility/ArchSpec.h" + +#include "llvm/Support/TargetSelect.h" + +#include <memory> +#include <vector> + +using namespace lldb; +using namespace lldb_private; + +class Testx86AssemblyInspectionEngine : public testing::Test { +public: + static void SetUpTestCase(); +}; + +void Testx86AssemblyInspectionEngine::SetUpTestCase() { + llvm::InitializeAllTargets(); + llvm::InitializeAllAsmPrinters(); + llvm::InitializeAllTargetMCs(); + llvm::InitializeAllDisassemblers(); +} + +// only defining the register names / numbers that the unwinder is actually +// using today + +// names should match the constants below. These will be the eRegisterKindLLDB +// register numbers. + +const char *x86_64_reg_names[] = {"rax", "rbx", "rcx", "rdx", "rsp", "rbp", + "rsi", "rdi", "r8", "r9", "r10", "r11", + "r12", "r13", "r14", "r15", "rip"}; + +enum x86_64_regs { + k_rax = 0, + k_rbx = 1, + k_rcx = 2, + k_rdx = 3, + k_rsp = 4, + k_rbp = 5, + k_rsi = 6, + k_rdi = 7, + k_r8 = 8, + k_r9 = 9, + k_r10 = 10, + k_r11 = 11, + k_r12 = 12, + k_r13 = 13, + k_r14 = 14, + k_r15 = 15, + k_rip = 16 +}; + +std::unique_ptr<x86AssemblyInspectionEngine> Getx86_64Inspector() { + + ArchSpec arch("x86_64-apple-macosx"); + std::unique_ptr<x86AssemblyInspectionEngine> engine( + new x86AssemblyInspectionEngine(arch)); + + std::vector<x86AssemblyInspectionEngine::lldb_reg_info> lldb_regnums; + int i = 0; + for (const auto &name : x86_64_reg_names) { + x86AssemblyInspectionEngine::lldb_reg_info ri; + ri.name = name; + ri.lldb_regnum = i++; + lldb_regnums.push_back(ri); + } + + engine->Initialize(lldb_regnums); + return engine; +} + +TEST_F(Testx86AssemblyInspectionEngine, TestSimple64bitFrameFunction) { + std::unique_ptr<x86AssemblyInspectionEngine> engine = Getx86_64Inspector(); + + // 'int main() { }' compiled for x86_64-apple-macosx with clang + uint8_t data[] = { + 0x55, // offset 0 -- pushq %rbp + 0x48, 0x89, 0xe5, // offset 1 -- movq %rsp, %rbp + 0x31, 0xc0, // offset 4 -- xorl %eax, %eax + 0x5d, // offset 6 -- popq %rbp + 0xc3 // offset 7 -- retq + }; + + AddressRange sample_range(0x1000, sizeof(data)); + + UnwindPlan unwind_plan(eRegisterKindLLDB); + EXPECT_FALSE(engine->GetNonCallSiteUnwindPlanFromAssembly( + data, sizeof(data), sample_range, unwind_plan)); +} _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
