CVSROOT: /cvs Module name: src Changes by: t...@cvs.openbsd.org 2023/06/02 11:15:30
Modified files: lib/libcrypto/bn: bn_gcd.c Log message: Fix variable reuse in BN_mod_inverse() The somewhat strange calculation m = a^{-1} (mod m) can return 0. This breaks because of BN_nnmod() having delicate semantics of which variable can be reused. BN_nnmod(a, a, m, ctx) works and the library relies on that. Here, the code ends up doing BN_nnmod(m, a, m, ctx) and this doesn't work. If the result of the initial BN_mod() is negative, then BN_nnmod() will return 0. Problem reported by Guido Vranken in https://github.com/openssl/openssl/issues/21110 This code is well covered by regress, but it does not currently have explicit test coverage. Such will be added soon. ok beck jsing