From 68b3b1ea8661b98c7afc3243e84c998601b70f18 Mon Sep 17 00:00:00 2001 From: Paul Kehrer Date: Tue, 19 May 2015 13:05:21 -0700 Subject: convert to cffi 1.0 precompile system --- src/_cffi_src/hazmat_src/constant_time.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 src/_cffi_src/hazmat_src/constant_time.c (limited to 'src/_cffi_src/hazmat_src/constant_time.c') diff --git a/src/_cffi_src/hazmat_src/constant_time.c b/src/_cffi_src/hazmat_src/constant_time.c new file mode 100644 index 00000000..0a48fe83 --- /dev/null +++ b/src/_cffi_src/hazmat_src/constant_time.c @@ -0,0 +1,22 @@ +// This file is dual licensed under the terms of the Apache License, Version +// 2.0, and the BSD License. See the LICENSE file in the root of this +// repository for complete details. + +uint8_t Cryptography_constant_time_bytes_eq(uint8_t *a, size_t len_a, + uint8_t *b, size_t len_b) { + size_t i = 0; + uint8_t mismatch = 0; + if (len_a != len_b) { + return 0; + } + for (i = 0; i < len_a; i++) { + mismatch |= a[i] ^ b[i]; + } + + /* Make sure any bits set are copied to the lowest bit */ + mismatch |= mismatch >> 4; + mismatch |= mismatch >> 2; + mismatch |= mismatch >> 1; + /* Now check the low bit to see if it's set */ + return (mismatch & 1) == 0; +} -- cgit v1.2.3