Unsoundness in opt-in ARMv8 assembly backend for keccak
Summary
The asm! block enabled by the off-by-default asm feature, when enabled on ARMv8 targets, misspecified the operand
type for all of its operands, using in for pointers and values which were subsequently mutated by operations performed
within the assembly block.
Impact
It's unclear what practical impact, if any, this actually had. Incorrect operand types are technically undefined
behavior, however changing them had no actual impact on the generated assembly for these targets. The possibility still
exists that it may lead to potential memory safety or other issues on hypothetical future versions of rustc.
Mitigation
The operand types were changed from in to inout, and the impacted versions of the keccak crate were yanked.
See advisory page for additional details.
keccak0.1.5Summary
The
asm!block enabled by the off-by-defaultasmfeature, when enabled on ARMv8 targets, misspecified the operandtype for all of its operands, using
infor pointers and values which were subsequently mutated by operations performedwithin the assembly block.
Impact
It's unclear what practical impact, if any, this actually had. Incorrect operand types are technically undefined
behavior, however changing them had no actual impact on the generated assembly for these targets. The possibility still
exists that it may lead to potential memory safety or other issues on hypothetical future versions of rustc.
Mitigation
The operand types were changed from
intoinout, and the impacted versions of thekeccakcrate were yanked.See advisory page for additional details.