boringssl/crypto/crypto.c
David Benjamin def85b403d Revise OPENSSL_ia32cap_P strategy to avoid TEXTRELs.
OPENSSL_ia32cap_addr avoids any relocations within the module, at the
cost of a runtime TEXTREL, which causes problems in some cases.
(Notably, if someone links us into a binary which uses the GCC "ifunc"
attribute, the loader crashes.)

We add a OPENSSL_ia32cap_addr_delta symbol (which is reachable
relocation-free from the module) stores the difference between
OPENSSL_ia32cap_P and its own address.  Next, reference
OPENSSL_ia32cap_P in code as usual, but always doing LEAQ (or the
equivalent GOTPCREL MOVQ) into a register first. This pattern we can
then transform into a LEAQ and ADDQ on OPENSSL_ia32cap_addr_delta.

ADDQ modifies the FLAGS register, so this is only a safe transformation
if we safe and restore flags first. That, in turn, is only a safe
transformation if code always uses %rsp as a stack pointer (specifically
everything below the stack must be fair game for scribbling over). Linux
delivers signals on %rsp, so this should already be an ABI requirement.
Further, we must clear the red zone (using LEAQ to avoid touching FLAGS)
which signal handlers may not scribble over.

This also fixes the GOTTPOFF logic to clear the red zone.

Change-Id: I4ca6133ab936d5a13d5c8ef265a12ab6bd0073c9
Reviewed-on: https://boringssl-review.googlesource.com/15545
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-04-27 21:07:33 +00:00

174 lines
5.0 KiB
C

/* Copyright (c) 2014, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/crypto.h>
#include <openssl/cpu.h>
#include "internal.h"
#if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_STATIC_ARMCAP) && \
(defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || \
defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64) || \
defined(OPENSSL_PPC64LE))
/* x86, x86_64, the ARMs and ppc64le need to record the result of a
* cpuid/getauxval call for the asm to work correctly, unless compiled without
* asm code. */
#define NEED_CPUID
#else
/* Otherwise, don't emit a static initialiser. */
#if !defined(BORINGSSL_NO_STATIC_INITIALIZER)
#define BORINGSSL_NO_STATIC_INITIALIZER
#endif
#endif /* !OPENSSL_NO_ASM && (OPENSSL_X86 || OPENSSL_X86_64 ||
OPENSSL_ARM || OPENSSL_AARCH64) */
/* The capability variables are defined in this file in order to work around a
* linker bug. When linking with a .a, if no symbols in a .o are referenced
* then the .o is discarded, even if it has constructor functions.
*
* This still means that any binaries that don't include some functionality
* that tests the capability values will still skip the constructor but, so
* far, the init constructor function only sets the capability variables. */
#if defined(OPENSSL_X86) || defined(OPENSSL_X86_64)
/* This value must be explicitly initialised to zero in order to work around a
* bug in libtool or the linker on OS X.
*
* If not initialised then it becomes a "common symbol". When put into an
* archive, linking on OS X will fail to resolve common symbols. By
* initialising it to zero, it becomes a "data symbol", which isn't so
* affected. */
uint32_t OPENSSL_ia32cap_P[4] = {0};
#elif defined(OPENSSL_PPC64LE)
unsigned long OPENSSL_ppc64le_hwcap2 = 0;
#elif defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)
#include <openssl/arm_arch.h>
#if defined(OPENSSL_STATIC_ARMCAP)
uint32_t OPENSSL_armcap_P =
#if defined(OPENSSL_STATIC_ARMCAP_NEON) || defined(__ARM_NEON__)
ARMV7_NEON |
#endif
#if defined(OPENSSL_STATIC_ARMCAP_AES)
ARMV8_AES |
#endif
#if defined(OPENSSL_STATIC_ARMCAP_SHA1)
ARMV8_SHA1 |
#endif
#if defined(OPENSSL_STATIC_ARMCAP_SHA256)
ARMV8_SHA256 |
#endif
#if defined(OPENSSL_STATIC_ARMCAP_PMULL)
ARMV8_PMULL |
#endif
0;
#else
uint32_t OPENSSL_armcap_P = 0;
#endif
#endif
#if defined(BORINGSSL_FIPS)
/* In FIPS mode, the power-on self-test function calls |CRYPTO_library_init|
* because we have to ensure that CPUID detection occurs first. */
#define BORINGSSL_NO_STATIC_INITIALIZER
#endif
#if defined(OPENSSL_WINDOWS) && !defined(BORINGSSL_NO_STATIC_INITIALIZER)
#define OPENSSL_CDECL __cdecl
#else
#define OPENSSL_CDECL
#endif
#if defined(BORINGSSL_NO_STATIC_INITIALIZER)
static CRYPTO_once_t once = CRYPTO_ONCE_INIT;
#elif defined(OPENSSL_WINDOWS)
#pragma section(".CRT$XCU", read)
static void __cdecl do_library_init(void);
__declspec(allocate(".CRT$XCU")) void(*library_init_constructor)(void) =
do_library_init;
#else
static void do_library_init(void) __attribute__ ((constructor));
#endif
/* do_library_init is the actual initialization function. If
* BORINGSSL_NO_STATIC_INITIALIZER isn't defined, this is set as a static
* initializer. Otherwise, it is called by CRYPTO_library_init. */
static void OPENSSL_CDECL do_library_init(void) {
/* WARNING: this function may only configure the capability variables. See the
* note above about the linker bug. */
#if defined(NEED_CPUID)
OPENSSL_cpuid_setup();
#endif
}
void CRYPTO_library_init(void) {
/* TODO(davidben): It would be tidier if this build knob could be replaced
* with an internal lazy-init mechanism that would handle things correctly
* in-library. https://crbug.com/542879 */
#if defined(BORINGSSL_NO_STATIC_INITIALIZER)
CRYPTO_once(&once, do_library_init);
#endif
}
int CRYPTO_is_confidential_build(void) {
#if defined(BORINGSSL_CONFIDENTIAL)
return 1;
#else
return 0;
#endif
}
int CRYPTO_has_asm(void) {
#if defined(OPENSSL_NO_ASM)
return 0;
#else
return 1;
#endif
}
const char *SSLeay_version(int unused) {
return "BoringSSL";
}
unsigned long SSLeay(void) {
return OPENSSL_VERSION_NUMBER;
}
int CRYPTO_malloc_init(void) {
return 1;
}
void ENGINE_load_builtin_engines(void) {}
int ENGINE_register_all_complete(void) {
return 1;
}
void OPENSSL_load_builtin_modules(void) {}