| commit | 054e151b16be6ada891ee8fd71915088dda30886 | [log] [tgz] |
|---|---|---|
| author | David Benjamin <davidben@google.com> | Tue Mar 01 17:35:47 2016 -0500 |
| committer | David Benjamin <davidben@google.com> | Sat Mar 26 04:54:44 2016 +0000 |
| tree | aac89f08e31fb55354b8c31aabc5051a96db65f9 | |
| parent | dc6c1b83819cb3788c60dd669241adc6752a4604 [diff] |
Rewrite ARM feature detection. This removes the thread-unsafe SIGILL-based detection and the multi-consumer-hostile CRYPTO_set_NEON_capable API. (Changing OPENSSL_armcap_P after initialization is likely to cause problems.) The right way to detect ARM features on Linux is getauxval. On aarch64, we should be able to rely on this, so use it straight. Split this out into its own file. The #ifdefs in the old cpu-arm.c meant it shared all but no code with its arm counterpart anyway. Unfortunately, various versions of Android have different missing APIs, so, on arm, we need a series of workarounds. Previously, we used a SIGILL fallback based on OpenSSL's logic, but this is inherently not thread-safe. (SIGILL also does not tell us if the OS knows how to save and restore NEON state.) Instead, base the behavior on Android NDK's cpu-features library, what Chromium currently uses with CRYPTO_set_NEON_capable: - Android before API level 20 does not provide getauxval. Where missing, we can read from /proc/self/auxv. - On some versions of Android, /proc/self/auxv is also not readable, so use /proc/cpuinfo's Features line. - Linux only advertises optional features in /proc/cpuinfo. ARMv8 makes NEON mandatory, so /proc/cpuinfo can't be used without additional effort. Finally, we must blacklist a particular chip because the NEON unit is broken (https://crbug.com/341598). Unfortunately, this means CRYPTO_library_init now depends on /proc being available, which will require some care with Chromium's sandbox. The simplest solution is to just call CRYPTO_library_init before entering the sandbox. It's worth noting that Chromium's current EnsureOpenSSLInit function already depends on /proc/cpuinfo to detect the broken CPU, by way of base::CPU. android_getCpuFeatures also interally depends on it. We were already relying on both of those being stateful and primed prior to entering the sandbox. BUG=chromium:589200 Change-Id: Ic5d1c341aab5a614eb129d8aa5ada2809edd6af8 Reviewed-on: https://boringssl-review.googlesource.com/7506 Reviewed-by: David Benjamin <davidben@google.com>
BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.
Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.
Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.
BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.
Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.
There are other files in this directory which might be helpful: