Clang fsanitize=safe-stack RFC6979 miscompile issue #445

issue laanwj opened this issue on March 3, 2017

laanwj commented at 1:17 PM on March 3, 2017: member

There is a miscompile issue with LLVM 4.0 safe-stack and the secp256k1_rfc6979_hmac_sha256_generate function. This results in invalid deterministic signatures, (luckily) causing both the secp256k1 and bitcoin tests to fail.

I'm fairly sure that this is a clang bug, although it's curious that it only seems to affect that function (and not any other tested use of SHA256, for example). In any case FYI this is being investigated here: https://github.com/NuxiNL/cloudabi-ports/issues/30
laanwj commented at 4:58 PM on March 5, 2017: member

Update: this problem is confirmed to exist on LLVM 4.0-rc3, and also on the SVN trunk. A bug has been filed: https://bugs.llvm.org//show_bug.cgi?id=32143

Until fixed I'd strongly suggest not to use stafestack sanitize with secp256k1.
jonasschnelli commented at 2:28 PM on March 20, 2017: contributor

This bug is now active in LLVM 4.0 (release) and will very likely be fixed in 4.0.1
laanwj commented at 8:50 PM on March 1, 2018: member

This is fixed upstream, closing.
laanwj closed this on Mar 1, 2018

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