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Share the zygote's fopen overrides with nacl_helper.

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This will allow ChromeOS's version of NSS to initialize inside of nacl_helper
without killing the process, which in turn allows validation caching to be
enabled on ChromeOS.

BUG= https://code.google.com/p/chromium/issues/detail?id=134538
TEST= none


Review URL: https://chromiumcodereview.appspot.com/10736017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146498 0039d316-1c4b-4281-b951-d872f2087c98
This commit is contained in:
ncbray@chromium.org
2012-07-13 01:28:07 +00:00
parent ae100e6994
commit 59d816b014
9 changed files with 208 additions and 141 deletions

7
chrome/browser/nacl_host/nacl_browser.cc

@@ -22,14 +22,7 @@ const char kValidationCacheSequenceName[] = "NaClValidationCache";
const FilePath::CharType kValidationCacheFileName[] =
FILE_PATH_LITERAL("nacl_validation_cache.bin");
#if defined(OS_CHROMEOS)
// TODO(ncbray) enable on ChromeOS.
// http://code.google.com/p/chromium/issues/detail?id=131218
const bool kValidationCacheEnabledByDefault = false;
#else
const bool kValidationCacheEnabledByDefault = true;
#endif
enum ValidationCacheStatus {
CACHE_MISS = 0,

1
chrome/nacl.gypi

@@ -141,6 +141,7 @@
],
'dependencies': [
'../crypto/crypto.gyp:crypto',
'../sandbox/sandbox.gyp:libc_urandom_override',
'nacl',
],
'sources': [

1
chrome/nacl/DEPS

@@ -1,6 +1,7 @@
include_rules = [
"+chrome/app/breakpad_win.h",
"+content/public/app/startup_helper_win.h",
"+sandbox/linux/services",
"+sandbox/src",
"+seccompsandbox",
"+native_client/src",

5
chrome/nacl/nacl_helper_linux.cc

@@ -29,6 +29,7 @@
#include "crypto/nss_util.h"
#include "ipc/ipc_descriptors.h"
#include "ipc/ipc_switches.h"
#include "sandbox/linux/services/libc_urandom_override.h"
namespace {
@@ -201,6 +202,10 @@ int main(int argc, char *argv[]) {
CommandLine::Init(argc, argv);
base::AtExitManager exit_manager;
base::RandUint64(); // acquire /dev/urandom fd before sandbox is raised
#if !defined(CHROMIUM_SELINUX)
// Allows NSS to fopen() /dev/urandom.
sandbox::InitLibcUrandomOverrides();
#endif
#if defined(USE_NSS)
// Configure NSS for use inside the NaCl process.
// The fork check has not caused problems for NaCl, but this appears to be

1
content/content_browser.gypi

@@ -852,6 +852,7 @@
['OS=="linux"', {
'dependencies': [
'../build/linux/system.gyp:udev',
'../sandbox/sandbox.gyp:libc_urandom_override',
],
# Set LINUX_SANDBOX_PATH for Linux, including Chrome OS
'conditions': [

136
content/zygote/zygote_main_linux.cc

@@ -36,6 +36,7 @@
#include "content/public/common/sandbox_linux.h"
#include "content/public/common/zygote_fork_delegate_linux.h"
#include "content/zygote/zygote_linux.h"
#include "sandbox/linux/services/libc_urandom_override.h"
#include "skia/ext/SkFontHost_fontconfig_control.h"
#include "unicode/timezone.h"
@@ -51,8 +52,6 @@ namespace content {
// See http://code.google.com/p/chromium/wiki/LinuxZygote
static const char kUrandomDevPath[] = "/dev/urandom";
// The SUID sandbox sets this environment variable to a file descriptor
// over which we can signal that we have completed our startup and can be
// chrooted.
@@ -141,10 +140,6 @@ static bool g_am_zygote_or_renderer = false;
typedef struct tm* (*LocaltimeFunction)(const time_t* timep);
typedef struct tm* (*LocaltimeRFunction)(const time_t* timep,
struct tm* result);
typedef FILE* (*FopenFunction)(const char* path, const char* mode);
typedef int (*XstatFunction)(int version, const char *path, struct stat *buf);
typedef int (*Xstat64Function)(int version, const char *path,
struct stat64 *buf);
static pthread_once_t g_libc_localtime_funcs_guard = PTHREAD_ONCE_INIT;
static LocaltimeFunction g_libc_localtime;
@@ -152,15 +147,6 @@ static LocaltimeFunction g_libc_localtime64;
static LocaltimeRFunction g_libc_localtime_r;
static LocaltimeRFunction g_libc_localtime64_r;
// http://crbug.com/123263, see below.
#if !defined(ADDRESS_SANITIZER)
static pthread_once_t g_libc_file_io_funcs_guard = PTHREAD_ONCE_INIT;
static FopenFunction g_libc_fopen;
static FopenFunction g_libc_fopen64;
static XstatFunction g_libc_xstat;
static Xstat64Function g_libc_xstat64;
#endif
static void InitLibcLocaltimeFunctions() {
g_libc_localtime = reinterpret_cast<LocaltimeFunction>(
dlsym(RTLD_NEXT, "localtime"));
@@ -266,125 +252,6 @@ struct tm* localtime64_r_override(const time_t* timep, struct tm* result) {
}
}
// TODO(sergeyu): Currently this code doesn't work properly under ASAN
// - it crashes content_unittests. Make sure it works properly and
// enable it here. http://crbug.com/123263
#if !defined(ADDRESS_SANITIZER)
static void InitLibcFileIOFunctions() {
g_libc_fopen = reinterpret_cast<FopenFunction>(
dlsym(RTLD_NEXT, "fopen"));
g_libc_fopen64 = reinterpret_cast<FopenFunction>(
dlsym(RTLD_NEXT, "fopen64"));
if (!g_libc_fopen) {
LOG(FATAL) << "Failed to get fopen() from libc.";
} else if (!g_libc_fopen64) {
#if !defined(OS_OPENBSD) && !defined(OS_FREEBSD)
LOG(WARNING) << "Failed to get fopen64() from libc. Using fopen() instead.";
#endif // !defined(OS_OPENBSD) && !defined(OS_FREEBSD)
g_libc_fopen64 = g_libc_fopen;
}
// TODO(sergeyu): This works only on systems with glibc. Fix it to
// work properly on other systems if necessary.
g_libc_xstat = reinterpret_cast<XstatFunction>(
dlsym(RTLD_NEXT, "__xstat"));
g_libc_xstat64 = reinterpret_cast<Xstat64Function>(
dlsym(RTLD_NEXT, "__xstat64"));
if (!g_libc_xstat) {
LOG(FATAL) << "Failed to get __xstat() from libc.";
}
if (!g_libc_xstat64) {
LOG(WARNING) << "Failed to get __xstat64() from libc.";
}
}
// fopen() and fopen64() are intercepted here so that NSS can open
// /dev/urandom to seed its random number generator. NSS is used by
// remoting in the sendbox.
// fopen() call may be redirected to fopen64() in stdio.h using
// __REDIRECT(), which sets asm name for fopen() to "fopen64". This
// means that we cannot override fopen() directly here. Instead the
// the code below defines fopen_override() function with asm name
// "fopen", so that all references to fopen() will resolve to this
// function.
__attribute__ ((__visibility__("default")))
FILE* fopen_override(const char* path, const char* mode) __asm__ ("fopen");
__attribute__ ((__visibility__("default")))
FILE* fopen_override(const char* path, const char* mode) {
if (g_am_zygote_or_renderer && strcmp(path, kUrandomDevPath) == 0) {
int fd = HANDLE_EINTR(dup(base::GetUrandomFD()));
if (fd < 0) {
PLOG(ERROR) << "dup() failed.";
return NULL;
}
return fdopen(fd, mode);
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_fopen(path, mode);
}
}
__attribute__ ((__visibility__("default")))
FILE* fopen64(const char* path, const char* mode) {
if (g_am_zygote_or_renderer && strcmp(path, kUrandomDevPath) == 0) {
int fd = HANDLE_EINTR(dup(base::GetUrandomFD()));
if (fd < 0) {
PLOG(ERROR) << "dup() failed.";
return NULL;
}
return fdopen(fd, mode);
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_fopen64(path, mode);
}
}
// stat() is subject to the same problem as fopen(), so we have to use
// the same trick to override it.
__attribute__ ((__visibility__("default")))
int xstat_override(int version,
const char *path,
struct stat *buf) __asm__ ("__xstat");
__attribute__ ((__visibility__("default")))
int xstat_override(int version, const char *path, struct stat *buf) {
if (g_am_zygote_or_renderer && strcmp(path, kUrandomDevPath) == 0) {
int result = __fxstat(version, base::GetUrandomFD(), buf);
return result;
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_xstat(version, path, buf);
}
}
__attribute__ ((__visibility__("default")))
int xstat64_override(int version,
const char *path,
struct stat64 *buf) __asm__ ("__xstat64");
__attribute__ ((__visibility__("default")))
int xstat64_override(int version, const char *path, struct stat64 *buf) {
if (g_am_zygote_or_renderer && strcmp(path, kUrandomDevPath) == 0) {
int result = __fxstat64(version, base::GetUrandomFD(), buf);
return result;
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
CHECK(g_libc_xstat64);
return g_libc_xstat64(version, path, buf);
}
}
#endif // !ADDRESS_SANITIZER
#endif // !CHROMIUM_SELINUX
// This function triggers the static and lazy construction of objects that need
@@ -622,6 +489,7 @@ bool ZygoteMain(const MainFunctionParams& params,
ZygoteForkDelegate* forkdelegate) {
#if !defined(CHROMIUM_SELINUX)
g_am_zygote_or_renderer = true;
sandbox::InitLibcUrandomOverrides();
#endif
int proc_fd_for_seccomp = -1;

166
sandbox/linux/services/libc_urandom_override.cc Normal file

@@ -0,0 +1,166 @@
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "sandbox/linux/services/libc_urandom_override.h"
#include <dlfcn.h>
#include <pthread.h>
#include <stdio.h>
#include <sys/stat.h>
#include "base/eintr_wrapper.h"
#include "base/logging.h"
#include "base/rand_util.h"
// Note: this file is used by the zygote and nacl_helper.
namespace sandbox {
// With SELinux we can carve out a precise sandbox, so we don't have to play
// with intercepting libc calls.
#if !defined(CHROMIUM_SELINUX)
static bool g_override_urandom = false;
void InitLibcUrandomOverrides() {
// Make sure /dev/urandom is open.
base::GetUrandomFD();
g_override_urandom = true;
}
// TODO(sergeyu): Currently this code doesn't work properly under ASAN
// - it crashes content_unittests. Make sure it works properly and
// enable it here. http://crbug.com/123263
#if !defined(ADDRESS_SANITIZER)
static const char kUrandomDevPath[] = "/dev/urandom";
typedef FILE* (*FopenFunction)(const char* path, const char* mode);
typedef int (*XstatFunction)(int version, const char *path, struct stat *buf);
typedef int (*Xstat64Function)(int version, const char *path,
struct stat64 *buf);
static pthread_once_t g_libc_file_io_funcs_guard = PTHREAD_ONCE_INIT;
static FopenFunction g_libc_fopen;
static FopenFunction g_libc_fopen64;
static XstatFunction g_libc_xstat;
static Xstat64Function g_libc_xstat64;
static void InitLibcFileIOFunctions() {
g_libc_fopen = reinterpret_cast<FopenFunction>(
dlsym(RTLD_NEXT, "fopen"));
g_libc_fopen64 = reinterpret_cast<FopenFunction>(
dlsym(RTLD_NEXT, "fopen64"));
if (!g_libc_fopen) {
LOG(FATAL) << "Failed to get fopen() from libc.";
} else if (!g_libc_fopen64) {
#if !defined(OS_OPENBSD) && !defined(OS_FREEBSD)
LOG(WARNING) << "Failed to get fopen64() from libc. Using fopen() instead.";
#endif // !defined(OS_OPENBSD) && !defined(OS_FREEBSD)
g_libc_fopen64 = g_libc_fopen;
}
// TODO(sergeyu): This works only on systems with glibc. Fix it to
// work properly on other systems if necessary.
g_libc_xstat = reinterpret_cast<XstatFunction>(
dlsym(RTLD_NEXT, "__xstat"));
g_libc_xstat64 = reinterpret_cast<Xstat64Function>(
dlsym(RTLD_NEXT, "__xstat64"));
if (!g_libc_xstat) {
LOG(FATAL) << "Failed to get __xstat() from libc.";
}
if (!g_libc_xstat64) {
LOG(WARNING) << "Failed to get __xstat64() from libc.";
}
}
// fopen() and fopen64() are intercepted here so that NSS can open
// /dev/urandom to seed its random number generator. NSS is used by
// remoting in the sendbox.
// fopen() call may be redirected to fopen64() in stdio.h using
// __REDIRECT(), which sets asm name for fopen() to "fopen64". This
// means that we cannot override fopen() directly here. Instead the
// the code below defines fopen_override() function with asm name
// "fopen", so that all references to fopen() will resolve to this
// function.
__attribute__ ((__visibility__("default")))
FILE* fopen_override(const char* path, const char* mode) __asm__ ("fopen");
__attribute__ ((__visibility__("default")))
FILE* fopen_override(const char* path, const char* mode) {
if (g_override_urandom && strcmp(path, kUrandomDevPath) == 0) {
int fd = HANDLE_EINTR(dup(base::GetUrandomFD()));
if (fd < 0) {
PLOG(ERROR) << "dup() failed.";
return NULL;
}
return fdopen(fd, mode);
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_fopen(path, mode);
}
}
__attribute__ ((__visibility__("default")))
FILE* fopen64(const char* path, const char* mode) {
if (g_override_urandom && strcmp(path, kUrandomDevPath) == 0) {
int fd = HANDLE_EINTR(dup(base::GetUrandomFD()));
if (fd < 0) {
PLOG(ERROR) << "dup() failed.";
return NULL;
}
return fdopen(fd, mode);
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_fopen64(path, mode);
}
}
// stat() is subject to the same problem as fopen(), so we have to use
// the same trick to override it.
__attribute__ ((__visibility__("default")))
int xstat_override(int version,
const char *path,
struct stat *buf) __asm__ ("__xstat");
__attribute__ ((__visibility__("default")))
int xstat_override(int version, const char *path, struct stat *buf) {
if (g_override_urandom && strcmp(path, kUrandomDevPath) == 0) {
int result = __fxstat(version, base::GetUrandomFD(), buf);
return result;
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
return g_libc_xstat(version, path, buf);
}
}
__attribute__ ((__visibility__("default")))
int xstat64_override(int version,
const char *path,
struct stat64 *buf) __asm__ ("__xstat64");
__attribute__ ((__visibility__("default")))
int xstat64_override(int version, const char *path, struct stat64 *buf) {
if (g_override_urandom && strcmp(path, kUrandomDevPath) == 0) {
int result = __fxstat64(version, base::GetUrandomFD(), buf);
return result;
} else {
CHECK_EQ(0, pthread_once(&g_libc_file_io_funcs_guard,
InitLibcFileIOFunctions));
CHECK(g_libc_xstat64);
return g_libc_xstat64(version, path, buf);
}
}
#endif // !ADDRESS_SANITIZER
#endif // !CHROMIUM_SELINUX
} // namespace content

18
sandbox/linux/services/libc_urandom_override.h Normal file

@@ -0,0 +1,18 @@
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_
#define SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_
namespace sandbox {
#if !defined(CHROMIUM_SELINUX)
void InitLibcUrandomOverrides();
#endif // !CHROMIUM_SELINUX
} // namespace sandbox
#endif // SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_

14
sandbox/sandbox_linux.gypi

@@ -86,5 +86,19 @@
'..',
],
},
{
'target_name': 'libc_urandom_override',
'type': 'static_library',
'sources': [
'linux/services/libc_urandom_override.cc',
'linux/services/libc_urandom_override.h',
],
'dependencies': [
'../base/base.gyp:base',
],
'include_dirs': [
'..',
],
},
],
}