| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/sunhe/incubator-teaclave/third_party/rust-sgx-sdk/sgx_types/src/memeq.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>memeq.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../sgx_types/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../sgx_types/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="comment">// Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License.. |
| |
| </span><span class="doccomment">//! Comparing buffer contents in constant time. |
| //! |
| //! This crate provides constant time memory comparison functions. These functions |
| //! are useful in cyptographic functions, defending against timing based side |
| //! channel attacks |
| |
| </span><span class="kw">use </span><span class="kw">crate</span>::marker::BytewiseEquality; |
| <span class="kw">use </span><span class="kw">crate</span>::types::{ |
| AlignEc256PrivateKey, AlignEc256SharedKey, AlignKey128bit, AlignKey256bit, AlignMac128bit, |
| AlignMac256bit, |
| }; |
| <span class="kw">use </span>core::mem; |
| <span class="kw">use </span>core::slice; |
| |
| <span class="kw">pub trait </span>ConstTimeEq<T: BytewiseEquality + <span class="question-mark">?</span>Sized = <span class="self">Self</span>> { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>T) -> bool; |
| <span class="kw">fn </span>ct_ne(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>T) -> bool { |
| !<span class="self">self</span>.ct_eq(other) |
| } |
| } |
| |
| <span class="kw">impl</span><T> ConstTimeEq<[T]> <span class="kw">for </span>[T] |
| <span class="kw">where |
| </span>T: Eq + BytewiseEquality, |
| { |
| default <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>[T]) -> bool { |
| <span class="kw">if </span><span class="self">self</span>.len() != other.len() { |
| <span class="kw">return </span><span class="bool-val">false</span>; |
| } |
| <span class="kw">if </span><span class="self">self</span>.as_ptr() == other.as_ptr() { |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| <span class="kw">let </span>size = mem::size_of_val(<span class="self">self</span>); |
| <span class="kw">unsafe </span>{ |
| consttime_memequal( |
| <span class="self">self</span>.as_ptr() <span class="kw">as </span><span class="kw-2">*const </span>u8, |
| other.as_ptr() <span class="kw">as </span><span class="kw-2">*const </span>u8, |
| size, |
| ) != <span class="number">0 |
| </span>} |
| } |
| } |
| |
| <span class="kw">impl</span><T> ConstTimeEq<T> <span class="kw">for </span>T |
| <span class="kw">where |
| </span>T: Eq + BytewiseEquality, |
| { |
| default <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>T) -> bool { |
| <span class="kw">let </span>size = mem::size_of_val(<span class="self">self</span>); |
| <span class="kw">if </span>size == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| <span class="kw">unsafe </span>{ |
| consttime_memequal( |
| <span class="self">self </span><span class="kw">as </span><span class="kw-2">*const </span>T <span class="kw">as </span><span class="kw-2">*const </span>u8, |
| other <span class="kw">as </span><span class="kw-2">*const </span>T <span class="kw">as </span><span class="kw-2">*const </span>u8, |
| size, |
| ) != <span class="number">0 |
| </span>} |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignKey128bit> <span class="kw">for </span>AlignKey128bit { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignKey128bit) -> bool { |
| <span class="self">self</span>.key.ct_eq(<span class="kw-2">&</span>other.key) |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignKey256bit> <span class="kw">for </span>AlignKey256bit { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignKey256bit) -> bool { |
| <span class="self">self</span>.key.ct_eq(<span class="kw-2">&</span>other.key) |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignMac128bit> <span class="kw">for </span>AlignMac128bit { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignMac128bit) -> bool { |
| <span class="self">self</span>.mac.ct_eq(<span class="kw-2">&</span>other.mac) |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignMac256bit> <span class="kw">for </span>AlignMac256bit { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignMac256bit) -> bool { |
| <span class="self">self</span>.mac.ct_eq(<span class="kw-2">&</span>other.mac) |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignEc256SharedKey> <span class="kw">for </span>AlignEc256SharedKey { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignEc256SharedKey) -> bool { |
| <span class="self">self</span>.key.ct_eq(<span class="kw-2">&</span>other.key) |
| } |
| } |
| |
| <span class="kw">impl </span>ConstTimeEq<AlignEc256PrivateKey> <span class="kw">for </span>AlignEc256PrivateKey { |
| <span class="kw">fn </span>ct_eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>AlignEc256PrivateKey) -> bool { |
| <span class="self">self</span>.key.ct_eq(<span class="kw-2">&</span>other.key) |
| } |
| } |
| |
| <span class="kw">unsafe fn </span>consttime_memequal(b1: <span class="kw-2">*const </span>u8, b2: <span class="kw-2">*const </span>u8, l: usize) -> i32 { |
| <span class="kw">let </span><span class="kw-2">mut </span>res = <span class="number">0_i32</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>len = l; |
| <span class="kw">let </span>p1 = slice::from_raw_parts(b1, l); |
| <span class="kw">let </span>p2 = slice::from_raw_parts(b2, l); |
| |
| <span class="kw">while </span>len > <span class="number">0 </span>{ |
| len -= <span class="number">1</span>; |
| res |= (p1[len] ^ p2[len]) <span class="kw">as </span>i32; |
| } |
| <span class="comment">/* |
| * Map 0 to 1 and [1, 256) to 0 using only constant-time |
| * arithmetic. |
| * |
| * This is not simply `!res' because although many CPUs support |
| * branchless conditional moves and many compilers will take |
| * advantage of them, certain compilers generate branches on |
| * certain CPUs for `!res'. |
| */ |
| </span><span class="number">1 </span>& ((res - <span class="number">1</span>) >> <span class="number">8</span>) |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="sgx_types" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |