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Fix - emit_sanitized_alu() with 64 bit immediate values #497

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Aug 7, 2023
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Fix - emit_sanitized_alu() with 64 bit immediate values #497

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16752c1
Fix emit_sanitized_alu() so that it supports 64 bit immediate values …
Lichtso Aug 3, 2023
b9503b6
Optimize emit_sanitized_load_immediate().
Lichtso Aug 4, 2023
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45 changes: 27 additions & 18 deletions src/jit.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -770,29 +770,35 @@ impl<'a, V: Verifier, C: ContextObject> JitCompiler<'a, V, C> {
fn emit_sanitized_load_immediate(&mut self, size: OperandSize, destination: u8, value: i64) {
match size {
OperandSize::S32 => {
let key: i32 = self.diversification_rng.gen();
self.emit_ins(X86Instruction::load_immediate(size, destination, (value as i32).wrapping_sub(key) as i64));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, key as i64, None));
},
OperandSize::S64 if destination == R11 => {
let key: i64 = self.diversification_rng.gen();
let lower_key = key as i32 as i64;
let upper_key = (key >> 32) as i32 as i64;
self.emit_ins(X86Instruction::load_immediate(size, destination, value.wrapping_sub(lower_key).rotate_right(32).wrapping_sub(upper_key)));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, upper_key, None)); // wrapping_add(upper_key)
self.emit_ins(X86Instruction::alu(size, 0xc1, 1, destination, 32, None)); // rotate_right(32)
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, lower_key, None)); // wrapping_add(lower_key)
let key = self.diversification_rng.gen::<i32>() as i64;
self.emit_ins(X86Instruction::load_immediate(size, destination, (value as i32).wrapping_sub(key as i32) as i64));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, key, None));
},
OperandSize::S64 if value >= i32::MIN as i64 && value <= i32::MAX as i64 => {
let key = self.diversification_rng.gen::<i32>() as i64;
self.emit_ins(X86Instruction::load_immediate(size, destination, value.wrapping_sub(key)));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, key, None));
},
OperandSize::S64 if value as u64 & u32::MAX as u64 == 0 => {
let key = self.diversification_rng.gen::<i32>() as i64;
self.emit_ins(X86Instruction::load_immediate(size, destination, value.rotate_right(32).wrapping_sub(key)));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, key, None)); // wrapping_add(key)
self.emit_ins(X86Instruction::alu(size, 0xc1, 4, destination, 32, None)); // shift_left(32)
},
OperandSize::S64 => {
let key: i64 = self.diversification_rng.gen();
self.emit_ins(X86Instruction::load_immediate(size, destination, value.wrapping_sub(key)));
self.emit_ins(X86Instruction::load_immediate(size, R11, key));
self.emit_ins(X86Instruction::alu(size, 0x01, R11, destination, 0, None));
let key = self.diversification_rng.gen::<i64>();
if destination != R11 {
self.emit_ins(X86Instruction::load_immediate(size, destination, value.wrapping_sub(key)));
self.emit_ins(X86Instruction::load_immediate(size, R11, key));
self.emit_ins(X86Instruction::alu(size, 0x01, R11, destination, 0, None));
} else {
let lower_key = key as i32 as i64;
let upper_key = (key >> 32) as i32 as i64;
self.emit_ins(X86Instruction::load_immediate(size, destination, value.wrapping_sub(lower_key).rotate_right(32).wrapping_sub(upper_key)));
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, upper_key, None)); // wrapping_add(upper_key)
self.emit_ins(X86Instruction::alu(size, 0xc1, 1, destination, 32, None)); // rotate_right(32)
self.emit_ins(X86Instruction::alu(size, 0x81, 0, destination, lower_key, None)); // wrapping_add(lower_key)
}
},
_ => {
#[cfg(debug_assertions)]
Expand All @@ -805,9 +811,12 @@ impl<'a, V: Verifier, C: ContextObject> JitCompiler<'a, V, C> {
fn emit_sanitized_alu(&mut self, size: OperandSize, opcode: u8, opcode_extension: u8, destination: u8, immediate: i64) {
if self.should_sanitize_constant(immediate) {
self.emit_sanitized_load_immediate(size, R11, immediate);
self.emit_ins(X86Instruction::alu(size, opcode, R11, destination, immediate, None));
} else {
self.emit_ins(X86Instruction::alu(size, opcode, R11, destination, 0, None));
} else if immediate >= i32::MIN as i64 && immediate <= i32::MAX as i64 {
self.emit_ins(X86Instruction::alu(size, 0x81, opcode_extension, destination, immediate, None));
} else {
self.emit_ins(X86Instruction::load_immediate(size, R11, immediate));
self.emit_ins(X86Instruction::alu(size, opcode, R11, destination, 0, None));
}
}

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