Era Compiler Solidity

zksolc is a Solidity compiler for ZKsync. All LLVM versions since 2015 fold `(xor (shl 1, x), -1)` to `(rotl ~1, x)` if run with optimizations enabled. Here `~1` is generated as an unsigned 64 bits number (`2^64-1`). This number is zero-extended to 256 bits on EraVM target while it should have been sign-extended. Thus instead of producing `roti 2^256 - 1, x` the compiler produces `rotl 2^64 - 1, x`. Analysis has shown that no contracts were affected by the date of publishing this advisory. This issue has been addressed in version 1.5.3. Users are advised to upgrade and redeploy all contracts. There are no known workarounds for this vulnerability.

Published: 2024-08-29T16:55:53.281Z
Updated: 2024-08-29T17:16:47.076Z

ZKsync Era is a layer 2 rollup that uses zero-knowledge proofs to scale Ethereum. Prior to version 1.3.10, there is a very specific pattern `f(a(),b()); check_if_a_executed_last()` in Yul that exposes a bug in evaluation order of Yul function arguments. This vulnerability has been fixed in version 1.3.10. As a workaround, update and redeploy affected contracts.

Published: 2024-05-27T16:20:27.432Z
Updated: 2024-09-03T16:03:02.966Z

era-compiler-solidity is the ZKsync compiler for Solidity. The problem occurred during instruction selection in the `DAGCombine` phase while visiting the XOR operation. The issue arises when attempting to fold the expression `!(x cc y)` into `(x !cc y)`. To perform this transformation, the second operand of XOR should be a constant representing the true value. However, it was incorrectly assumed that -1 represents the true value, when in fact, 1 is the correct representation, so this transformation for this case should be skipped. This vulnerability is fixed in 1.4.1.

Published: 2024-05-13T19:13:27.510Z
Updated: 2024-08-02T02:59:21.780Z