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am df7f24f3: am 7b68e3f7: Merge "Per-thread -fstack-protector guards for x86."

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* commit 'df7f24f310ee3ceb1dc9413d59d5a8816eb584ef':
  Per-thread -fstack-protector guards for x86.
This commit is contained in:
Elliott Hughes
2012-10-25 12:23:56 -07:00
committed by Android Git Automerger
parent 4cdc426207 df7f24f310
commit 0f96dd8dcb
10 changed files with 301 additions and 117 deletions
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2
libc/Android.mk
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@@ -740,7 +740,7 @@ WITH_MALLOC_CHECK_LIBC_A := $(strip $(WITH_MALLOC_CHECK_LIBC_A))
include $(CLEAR_VARS)
LOCAL_SRC_FILES := bionic/ssp.c
LOCAL_SRC_FILES := bionic/ssp.cpp
LOCAL_CFLAGS := $(libc_common_cflags) -fno-stack-protector
LOCAL_C_INCLUDES := $(libc_common_c_includes)
LOCAL_MODULE := libbionic_ssp

7
libc/bionic/pthread.c
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@@ -48,6 +48,7 @@
#include "bionic_atomic_inline.h"
#include "bionic_futex.h"
#include "bionic_pthread.h"
#include "bionic_ssp.h"
#include "bionic_tls.h"
#include "pthread_internal.h"
#include "thread_private.h"
@@ -171,12 +172,14 @@ void __init_tls(void** tls, void* thread) {
tls[i] = NULL;
}
// Slot 0 must point to the tls area, this is required by the implementation
// of the x86 Linux kernel thread-local-storage.
// Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
tls[TLS_SLOT_SELF] = (void*) tls;
tls[TLS_SLOT_THREAD_ID] = thread;
// Stack guard generation may make system calls, and those system calls may fail.
// If they do, they'll try to set errno, so we can only do this after calling __set_tls.
__set_tls((void*) tls);
tls[TLS_SLOT_STACK_GUARD] = __generate_stack_chk_guard();
}

100
libc/bionic/ssp.c
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@@ -1,100 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include "logd.h"
void *__stack_chk_guard = 0;
/* Initialize the canary with a random value from /dev/urandom.
* If that fails, use the "terminator canary". */
static void __attribute__ ((constructor))
__guard_setup(void)
{
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd != -1) {
ssize_t len = read(fd, &__stack_chk_guard,
sizeof(__stack_chk_guard));
close(fd);
if (len == sizeof(__stack_chk_guard))
return;
}
/* If that failed, switch to 'terminator canary' */
((unsigned char *)&__stack_chk_guard)[0] = 0;
((unsigned char *)&__stack_chk_guard)[1] = 0;
((unsigned char *)&__stack_chk_guard)[2] = '\n';
((unsigned char *)&__stack_chk_guard)[3] = 255;
}
/* This is the crash handler.
* Does a best effort at logging and calls _exit to terminate
* the process immediately (without atexit handlers, etc.) */
void __stack_chk_fail(void)
{
struct sigaction sa;
sigset_t sigmask;
static const char message[] = "stack corruption detected: aborted";
char path[PATH_MAX];
int count;
/* Immediately block all (but SIGABRT) signal handlers from running code */
sigfillset(&sigmask);
sigdelset(&sigmask, SIGABRT);
sigprocmask(SIG_BLOCK, &sigmask, NULL);
/* Use /proc/self/exe link to obtain the program name for logging
* purposes. If it's not available, we set it to "<unknown>" */
if ((count = readlink("/proc/self/exe", path, sizeof(path) - 1)) == -1) {
strlcpy(path, "<unknown>", sizeof(path));
} else {
path[count] = '\0';
}
/* Do a best effort at logging. This ends up calling writev(2) */
__libc_android_log_print(ANDROID_LOG_FATAL, path, message);
/* Make sure there is no default action for SIGABRT */
bzero(&sa, sizeof(struct sigaction));
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = SIG_DFL;
sigaction(SIGABRT, &sa, NULL);
/* Terminate the process and exit immediately */
kill(getpid(), SIGABRT);
_exit(127);
}

81
libc/bionic/ssp.cpp Normal file
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@@ -0,0 +1,81 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <ctype.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "bionic_ssp.h"
#include "logd.h"
void* __stack_chk_guard = NULL;
static void __attribute__((constructor)) __init_stack_check_guard() {
__stack_chk_guard = __generate_stack_chk_guard();
}
// This is the crash handler.
// Does a best effort at logging and calls _exit to terminate
// the process immediately (without atexit handlers, etc.).
void __stack_chk_fail() {
// Immediately block all (but SIGABRT) signal handlers from running code.
sigset_t sigmask;
sigfillset(&sigmask);
sigdelset(&sigmask, SIGABRT);
sigprocmask(SIG_BLOCK, &sigmask, NULL);
// Use /proc/self/exe link to obtain the program name for logging
// purposes. If it's not available, we set it to "<unknown>".
char path[PATH_MAX];
int count;
if ((count = readlink("/proc/self/exe", path, sizeof(path) - 1)) == -1) {
strlcpy(path, "<unknown>", sizeof(path));
} else {
path[count] = '\0';
}
// Do a best effort at logging. This ends up calling writev(2).
__libc_android_log_print(ANDROID_LOG_FATAL, path, "stack corruption detected: aborted");
// Make sure there is no default action for SIGABRT.
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = SIG_DFL;
sigaction(SIGABRT, &sa, NULL);
// Terminate the process and exit immediately.
kill(getpid(), SIGABRT);
_exit(127);
}

76
libc/private/bionic_ssp.h Normal file
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@@ -0,0 +1,76 @@
/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _PRIVATE_SSP_H
#define _PRIVATE_SSP_H
#include <errno.h>
#include <sys/cdefs.h>
__BEGIN_DECLS
/** WARNING WARNING WARNING
**
** This header file is *NOT* part of the public Bionic ABI/API
** and should not be used/included by user-serviceable parts of
** the system (e.g. applications).
**/
/* GCC uses this on ARM and MIPS. */
extern void* __stack_chk_guard;
/* GCC calls this if a stack guard check fails. */
extern void __stack_chk_fail();
__inline__ static void* __attribute__((always_inline)) __generate_stack_chk_guard(void) {
union {
uintptr_t value;
char bytes[sizeof(uintptr_t)];
} u;
/* Try pulling random bytes from /dev/urandom. */
int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY));
if (fd != -1) {
ssize_t byte_count = TEMP_FAILURE_RETRY(read(fd, &u.bytes, sizeof(u)));
close(fd);
if (byte_count == sizeof(u)) {
return (void*) u.value;
}
}
/* If that failed, switch to 'terminator canary'. */
u.bytes[0] = 0;
u.bytes[1] = 0;
u.bytes[2] = '\n';
u.bytes[3] = 255;
return (void*) u.value;
}
__END_DECLS
#endif

15
libc/private/bionic_tls.h
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@@ -43,24 +43,19 @@ __BEGIN_DECLS
** pre-allocated slot directly for performance reason).
**/
/* maximum number of elements in the TLS array */
/* Maximum number of elements in the TLS array. */
#define BIONIC_TLS_SLOTS 64
/* note that slot 0, called TLS_SLOT_SELF must point to itself.
* this is required to implement thread-local storage with the x86
* Linux kernel, that reads the TLS from fs:[0], where 'fs' is a
* thread-specific segment descriptor...
*/
/* Well-known TLS slots. */
#define TLS_SLOT_SELF 0
/* Well-known TLS slots. What data goes in which slot is arbitrary unless otherwise noted. */
#define TLS_SLOT_SELF 0 /* The kernel requires this specific slot for x86. */
#define TLS_SLOT_THREAD_ID 1
#define TLS_SLOT_ERRNO 2
#define TLS_SLOT_OPENGL_API 3
#define TLS_SLOT_OPENGL 4
#define TLS_SLOT_DLERROR 5
#define TLS_SLOT_STACK_GUARD 5 /* GCC requires this specific slot for x86. */
#define TLS_SLOT_DLERROR 6
#define TLS_SLOT_MAX_WELL_KNOWN TLS_SLOT_DLERROR