Skip to content

fix(relinker): reject LOCK-prefixed MOVNTSS and MOVNTSD #10713

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
oneandonlydean merged 1 commit into from
Oct 25, 2026
Merged

fix(relinker): reject LOCK-prefixed MOVNTSS and MOVNTSD #10713

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions core/relinker/codegen/src/x86/Amd64OnlyInstructionMatcher.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -201,6 +201,8 @@ class Amd64OnlyInstructionMatcher : public IAmd64OnlyInstructionMatcher {
Amd64OnlyMatch Amd64OnlyInstructionMatcher::_matchMovnts(const DecodedInstruction& instr, const Entry& entry) const {
using namespace X64OpcodeConstants;
const auto opcodeOffset = instr.OpcodeOffset();
if (std::find(instr.Data, instr.Data + opcodeOffset, PrefixLock) != instr.Data + opcodeOffset)
throw CodegenException("MOVNTSS/MOVNTSD with a LOCK prefix");
if (opcodeOffset + 2 >= instr.Length)
throw CodegenException("MOVNTSS/MOVNTSD truncated before its ModRM byte");
const auto modrm = instr.Data[opcodeOffset + 2];
Expand Down
9 changes: 9 additions & 0 deletions core/relinker/codegen/tests/Amd64OnlyConverterTests.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -322,6 +322,8 @@ void matcherSubstitutions() {
const auto movntsd = match({0xF2, 0x44, 0x0F, 0x2B, 0x4C, 0x24, 0x10});
require(movntsd && movntsd->Lowering == Codegen::Amd64OnlyLowering::InPlace && movntsd->ReplacementBytes == Bytes{0xF2, 0x44, 0x0F, 0x11, 0x4C, 0x24, 0x10} && movntsd->InstructionName == "MOVNTSD", "MOVNTSD was not rewritten to MOVSD");
requireFailure([&] { (void)match({0xF3, 0x0F, 0x2B, 0xC1}); }, "MOVNTSS with a register operand was accepted");
const auto movntssDisplacement = match({0xF3, 0x0F, 0x2B, 0x47, 0xF0});
require(movntssDisplacement && movntssDisplacement->ReplacementBytes == Bytes{0xF3, 0x0F, 0x11, 0x47, 0xF0}, "MOVNTSS displacement byte was treated as a LOCK prefix");
const auto monitorx = match({0x0F, 0x01, 0xFA});
require(monitorx && monitorx->Lowering == Codegen::Amd64OnlyLowering::InPlace && monitorx->ReplacementBytes == Bytes{0x0F, 0x1F, 0x00} && monitorx->InstructionName == "MONITORX", "MONITORX was not replaced by a NOP");
const auto mwaitx = match({0x0F, 0x01, 0xFB});
Expand Down Expand Up @@ -506,6 +508,13 @@ void converterSegment() {
lockedRdpru[0x211] = 0x01;
lockedRdpru[0x212] = 0xFD;
requireFailure([&] { (void)converter->Convert(lockedRdpru, {segmentHeader(20)}); }, "LOCK RDPRU was accepted");
for (const Bytes& instruction : {Bytes{0xF0, 0xF3, 0x0F, 0x2B, 0x07}, Bytes{0xF3, 0xF0, 0x0F, 0x2B, 0x07},
Bytes{0xF0, 0xF2, 0x0F, 0x2B, 0x07}, Bytes{0xF2, 0xF0, 0x0F, 0x2B, 0x07}}) {
auto lockedMovnts = file;
std::copy(instruction.begin(), instruction.end(), lockedMovnts.begin() + 0x20F);
lockedMovnts[0x214] = 0xC3;
require(failureOffset([&] { (void)converter->Convert(lockedMovnts, {segmentHeader(21)}); }, "LOCK MOVNTSS/MOVNTSD was accepted") == 0x20F, "LOCK MOVNTSS/MOVNTSD failure does not carry the file offset");
}
auto registerForm = file;
const Bytes extrqRegister = {0x66, 0x0F, 0x79, 0xCA};
std::copy(extrqRegister.begin(), extrqRegister.end(), registerForm.begin() + 0x20F);
Expand Down
Loading