зеркало из https://github.com/mozilla/gecko-dev.git
Backed out 2 changesets (bug 1440203) for causing bug 1670277. CLOSED TREE
Backed out changeset 0b10bf76fe35 (bug 1440203) Backed out changeset 468878422866 (bug 1440203)
This commit is contained in:
Razvan Maries
Родитель
efdb198637
Коммит
5fa72e54df
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@ -809,14 +809,6 @@ add_task(async function() {
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continue;
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}
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// "Files" from memfd_create() are similar to tmpfs but never
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// exist in the filesystem; however, they have names which are
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// exposed in procfs, and the I/O interposer observes when
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// they're close()d.
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if (LINUX && filename.startsWith("/memfd:")) {
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continue;
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}
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// Shared memory uses temporary files on MacOS <= 10.11 to avoid
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// a kernel security bug that will never be patched (see
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// https://crbug.com/project-zero/1671 for details). This can
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@ -65,14 +65,6 @@ check_headers(
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'byteswap.h',
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)
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# memfd_create(2) -- Note that older versions of the Linux man-pages
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# project incorrectly cite <sys/memfd.h>, which doesn't exist; this
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# was fixed in the man-pages-5.00 release.
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set_define('HAVE_MEMFD_CREATE',
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try_compile(includes=['sys/mman.h'],
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body='memfd_create("", 0);',
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check_msg='for memfd_create in sys/mman.h'))
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# TODO: Move these checks to file specific to --enable-project=js.
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have_perf_event_h = check_header('linux/perf_event.h',
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when=building_linux)
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@ -1349,10 +1349,5 @@ if CONFIG['OS_TARGET'] == 'Linux' and CONFIG['CPU_ARCH'].startswith('mips'):
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'sys/cachectl.h',
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]
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if CONFIG['OS_TARGET'] == 'FreeBSD':
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system_headers += [
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'sys/capsicum.h',
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]
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if CONFIG['MOZ_APP_SYSTEM_HEADERS']:
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include("../" + CONFIG['MOZ_BUILD_APP'] + "/app-system-headers.mozbuild")
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@ -1,69 +0,0 @@
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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#ifndef BASE_LINUX_MEMFD_DEFS_H
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#define BASE_LINUX_MEMFD_DEFS_H
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#include <sys/syscall.h>
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// glibc before 2.27 didn't have a memfd_create wrapper, and if the
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// build system is old enough then it won't have the syscall number
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// and various related constants either.
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#if defined(__x86_64__)
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# define MEMFD_CREATE_NR 319
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#elif defined(__i386__)
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# define MEMFD_CREATE_NR 356
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#elif defined(__aarch64__)
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# define MEMFD_CREATE_NR 279
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#elif defined(__arm__)
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# define MEMFD_CREATE_NR 385
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#elif defined(__powerpc__)
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# define MEMFD_CREATE_NR 360
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#elif defined(__s390__)
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# define MEMFD_CREATE_NR 350
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#elif defined(__mips__)
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# include <sgidefs.h>
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# if _MIPS_SIM == _MIPS_SIM_ABI32
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# define MEMFD_CREATE_NR 4354
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# elif _MIPS_SIM == _MIPS_SIM_ABI64
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# define MEMFD_CREATE_NR 5314
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# elif _MIPS_SIM == _MIPS_SIM_NABI32
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# define MEMFD_CREATE_NR 6318
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# endif // mips subarch
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#endif // arch
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#ifdef MEMFD_CREATE_NR
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# ifdef SYS_memfd_create
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static_assert(MEMFD_CREATE_NR == SYS_memfd_create,
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"MEMFD_CREATE_NR should match the actual SYS_memfd_create value");
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# else // defined here but not in system headers
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# define SYS_memfd_create MEMFD_CREATE_NR
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# endif
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#endif
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#ifndef MFD_CLOEXEC
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# define MFD_CLOEXEC 0x0001U
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# define MFD_ALLOW_SEALING 0x0002U
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#endif
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#ifndef F_ADD_SEALS
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# ifndef F_LINUX_SPECIFIC_BASE
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# define F_LINUX_SPECIFIC_BASE 1024
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# endif
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# define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
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# define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
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# define F_SEAL_SEAL 0x0001 /* prevent further seals from being set */
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# define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */
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# define F_SEAL_GROW 0x0004 /* prevent file from growing */
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# define F_SEAL_WRITE 0x0008 /* prevent writes */
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#endif
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#ifndef F_SEAL_FUTURE_WRITE
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# define F_SEAL_FUTURE_WRITE 0x0010
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#endif
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#endif // BASE_LINUX_MEMFD_DEFS_H
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@ -218,7 +218,6 @@ class SharedMemory {
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bool external_section_ = false;
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#elif defined(OS_POSIX)
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mozilla::UniqueFileHandle frozen_file_;
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bool is_memfd_ = false;
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#endif
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bool read_only_ = false;
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bool freezeable_ = false;
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@ -16,18 +16,6 @@
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# include "mozilla/Ashmem.h"
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#endif
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#ifdef OS_LINUX
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# include "linux_memfd_defs.h"
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#endif
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#ifdef __FreeBSD__
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# include <sys/capsicum.h>
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#endif
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#ifdef MOZ_VALGRIND
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# include <valgrind/valgrind.h>
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#endif
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#include "base/eintr_wrapper.h"
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#include "base/logging.h"
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#include "base/string_util.h"
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@ -63,7 +51,6 @@ bool SharedMemory::SetHandle(SharedMemoryHandle handle, bool read_only) {
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freezeable_ = false;
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mapped_file_.reset(handle.fd);
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read_only_ = read_only;
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// is_memfd_ only matters for freezing, which isn't possible
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return true;
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}
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@ -75,120 +62,11 @@ bool SharedMemory::IsHandleValid(const SharedMemoryHandle& handle) {
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// static
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SharedMemoryHandle SharedMemory::NULLHandle() { return SharedMemoryHandle(); }
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// memfd_create is a nonstandard interface for creating anonymous
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// shared memory accessible as a file descriptor but not tied to any
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// filesystem. It first appeared in Linux 3.17, and was adopted by
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// FreeBSD in version 13.
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#if !defined(HAVE_MEMFD_CREATE) && defined(OS_LINUX) && \
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defined(SYS_memfd_create)
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// Older libc versions (e.g., glibc before 2.27) don't have the
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// wrapper, but we can supply our own; see `linux_memfd_defs.h`.
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static int memfd_create(const char* name, unsigned int flags) {
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return syscall(SYS_memfd_create, name, flags);
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}
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# define HAVE_MEMFD_CREATE 1
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#endif
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// memfd supports having "seals" applied to the file, to prevent
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// various types of changes (which apply to all fds referencing the
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// file). Unfortunately, we can't rely on F_SEAL_WRITE to implement
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// Freeze(); see the comments in ReadOnlyCopy() below.
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//
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// Instead, to prevent a child process from regaining write access to
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// a read-only copy, the OS must also provide a way to remove write
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// permissions at the file descriptor level. This next section
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// attempts to accomplish that.
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#ifdef HAVE_MEMFD_CREATE
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# define USE_MEMFD_CREATE 1
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# ifdef OS_LINUX
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// To create a read-only duplicate of an fd, we can use procfs; the
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// same operation could restore write access, but sandboxing prevents
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// child processes from accessing /proc.
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static int DupReadOnly(int fd) {
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std::string path = StringPrintf("/proc/self/fd/%d", fd);
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// procfs opens probably won't EINTR, but checking for it can't hurt
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return HANDLE_EINTR(open(path.c_str(), O_RDONLY | O_CLOEXEC));
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}
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# elif defined(__FreeBSD__)
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// FreeBSD's Capsicum framework allows irrevocably restricting the
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// operations permitted on a file descriptor.
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static int DupReadOnly(int fd) {
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int rofd = dup(fd);
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if (rofd < 0) {
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return -1;
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}
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cap_rights_t rights;
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cap_rights_init(&rights, CAP_FSTAT, CAP_MMAP_R);
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if (cap_rights_limit(rofd, &rights) < 0) {
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int err = errno;
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close(rofd);
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errno = err;
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return -1;
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}
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return rofd;
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}
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# else // unhandled OS
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# warning "OS has memfd_create but no DupReadOnly implementation"
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# undef USE_MEMFD_CREATE
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# endif // OS selection
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#endif // HAVE_MEMFD_CREATE
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static bool HaveMemfd() {
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#ifdef USE_MEMFD_CREATE
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static const bool kHave = [] {
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# ifdef OS_LINUX
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// The Tor Browser project was, at one point, attempting to run
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// Firefox in an environment without /proc mounted, to reduce
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// possibilities for fingerprinting. If that's the case, we can't
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// use memfd, because ReadOnlyCopy requires access to procfs to
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// remove write permissions.
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//
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// Complicating this further, in a sandboxed child process, the
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// first call to this function may happen after sandboxing is
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// started; in that case, it's expected that procfs isn't
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// reachable, but it's also expected that ReadOnlyCopy may not be
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// possible.
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if (!PR_GetEnv("MOZ_SANDBOXED") &&
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access("/proc/self/fd", R_OK | X_OK) < 0) {
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CHROMIUM_LOG(WARNING) << "can't use memfd without procfs";
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return false;
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}
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# endif
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int fd = memfd_create("mozilla-ipc-test", MFD_CLOEXEC | MFD_ALLOW_SEALING);
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if (fd < 0) {
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DCHECK_EQ(errno, ENOSYS);
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return false;
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}
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close(fd);
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return true;
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}();
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return kHave;
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#else
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return false;
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#endif // USE_MEMFD_CREATE
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}
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// static
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bool SharedMemory::AppendPosixShmPrefix(std::string* str, pid_t pid) {
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#if defined(ANDROID)
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return false;
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#else
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if (HaveMemfd()) {
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return false;
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}
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*str += '/';
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# ifdef OS_LINUX
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// The Snap package environment doesn't provide a private /dev/shm
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@ -225,73 +103,47 @@ bool SharedMemory::CreateInternal(size_t size, bool freezeable) {
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mozilla::UniqueFileHandle fd;
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mozilla::UniqueFileHandle frozen_fd;
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bool needs_truncate = true;
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bool is_memfd = false;
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#ifdef USE_MEMFD_CREATE
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if (HaveMemfd()) {
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const unsigned flags = MFD_CLOEXEC | (freezeable ? MFD_ALLOW_SEALING : 0);
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fd.reset(memfd_create("mozilla-ipc", flags));
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if (!fd) {
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// In general it's too late to fall back here -- in a sandboxed
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// child process, shm_open is already blocked. And it shouldn't
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// be necessary.
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CHROMIUM_LOG(WARNING) << "failed to create memfd: " << strerror(errno);
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return false;
|
||||
}
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is_memfd = true;
|
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if (freezeable) {
|
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frozen_fd.reset(DupReadOnly(fd.get()));
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if (!frozen_fd) {
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CHROMIUM_LOG(WARNING)
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<< "failed to create read-only memfd: " << strerror(errno);
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return false;
|
||||
}
|
||||
}
|
||||
}
|
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#endif
|
||||
|
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if (!fd) {
|
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#ifdef ANDROID
|
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// Android has its own shared memory facility:
|
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fd.reset(mozilla::android::ashmem_create(nullptr, size));
|
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if (!fd) {
|
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CHROMIUM_LOG(WARNING) << "failed to open shm: " << strerror(errno);
|
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return false;
|
||||
}
|
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needs_truncate = false;
|
||||
// Android has its own shared memory facility:
|
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fd.reset(mozilla::android::ashmem_create(nullptr, size));
|
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if (!fd) {
|
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CHROMIUM_LOG(WARNING) << "failed to open shm: " << strerror(errno);
|
||||
return false;
|
||||
}
|
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needs_truncate = false;
|
||||
#else
|
||||
// Generic Unix: shm_open + shm_unlink
|
||||
do {
|
||||
// The names don't need to be unique, but it saves time if they
|
||||
// usually are.
|
||||
static mozilla::Atomic<size_t> sNameCounter;
|
||||
std::string name;
|
||||
CHECK(AppendPosixShmPrefix(&name, getpid()));
|
||||
StringAppendF(&name, "%zu", sNameCounter++);
|
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// O_EXCL means the names being predictable shouldn't be a problem.
|
||||
fd.reset(HANDLE_EINTR(
|
||||
shm_open(name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600)));
|
||||
if (fd) {
|
||||
if (freezeable) {
|
||||
frozen_fd.reset(HANDLE_EINTR(shm_open(name.c_str(), O_RDONLY, 0400)));
|
||||
if (!frozen_fd) {
|
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int open_err = errno;
|
||||
shm_unlink(name.c_str());
|
||||
DLOG(FATAL) << "failed to re-open freezeable shm: "
|
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<< strerror(open_err);
|
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return false;
|
||||
}
|
||||
}
|
||||
if (shm_unlink(name.c_str()) != 0) {
|
||||
// This shouldn't happen, but if it does: assume the file is
|
||||
// in fact leaked, and bail out now while it's still 0-length.
|
||||
DLOG(FATAL) << "failed to unlink shm: " << strerror(errno);
|
||||
// Generic Unix: shm_open + shm_unlink
|
||||
do {
|
||||
// The names don't need to be unique, but it saves time if they
|
||||
// usually are.
|
||||
static mozilla::Atomic<size_t> sNameCounter;
|
||||
std::string name;
|
||||
CHECK(AppendPosixShmPrefix(&name, getpid()));
|
||||
StringAppendF(&name, "%zu", sNameCounter++);
|
||||
// O_EXCL means the names being predictable shouldn't be a problem.
|
||||
fd.reset(
|
||||
HANDLE_EINTR(shm_open(name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600)));
|
||||
if (fd) {
|
||||
if (freezeable) {
|
||||
frozen_fd.reset(HANDLE_EINTR(shm_open(name.c_str(), O_RDONLY, 0400)));
|
||||
if (!frozen_fd) {
|
||||
int open_err = errno;
|
||||
shm_unlink(name.c_str());
|
||||
DLOG(FATAL) << "failed to re-open freezeable shm: "
|
||||
<< strerror(open_err);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
} while (!fd && errno == EEXIST);
|
||||
if (shm_unlink(name.c_str()) != 0) {
|
||||
// This shouldn't happen, but if it does: assume the file is
|
||||
// in fact leaked, and bail out now while it's still 0-length.
|
||||
DLOG(FATAL) << "failed to unlink shm: " << strerror(errno);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
} while (!fd && errno == EEXIST);
|
||||
#endif
|
||||
}
|
||||
|
||||
if (!fd) {
|
||||
CHROMIUM_LOG(WARNING) << "failed to open shm: " << strerror(errno);
|
||||
|
|
@ -348,7 +200,6 @@ bool SharedMemory::CreateInternal(size_t size, bool freezeable) {
|
|||
frozen_file_ = std::move(frozen_fd);
|
||||
max_size_ = size;
|
||||
freezeable_ = freezeable;
|
||||
is_memfd_ = is_memfd;
|
||||
return true;
|
||||
}
|
||||
|
||||
|
|
@ -362,80 +213,22 @@ bool SharedMemory::ReadOnlyCopy(SharedMemory* ro_out) {
|
|||
}
|
||||
|
||||
mozilla::UniqueFileHandle ro_file;
|
||||
bool is_ashmem = false;
|
||||
|
||||
#ifdef ANDROID
|
||||
if (!is_memfd_) {
|
||||
is_ashmem = true;
|
||||
DCHECK(!frozen_file_);
|
||||
ro_file = std::move(mapped_file_);
|
||||
if (mozilla::android::ashmem_setProt(ro_file.get(), PROT_READ) != 0) {
|
||||
CHROMIUM_LOG(WARNING)
|
||||
<< "failed to set ashmem read-only: " << strerror(errno);
|
||||
return false;
|
||||
}
|
||||
ro_file = std::move(mapped_file_);
|
||||
if (mozilla::android::ashmem_setProt(ro_file.get(), PROT_READ) != 0) {
|
||||
CHROMIUM_LOG(WARNING) << "failed to set ashmem read-only: "
|
||||
<< strerror(errno);
|
||||
return false;
|
||||
}
|
||||
#else
|
||||
DCHECK(frozen_file_);
|
||||
mapped_file_ = nullptr;
|
||||
ro_file = std::move(frozen_file_);
|
||||
#endif
|
||||
|
||||
#ifdef USE_MEMFD_CREATE
|
||||
# ifdef MOZ_VALGRIND
|
||||
// Valgrind allows memfd_create but doesn't understand F_ADD_SEALS.
|
||||
static const bool haveSeals = RUNNING_ON_VALGRIND == 0;
|
||||
# else
|
||||
static const bool haveSeals = true;
|
||||
# endif
|
||||
static const bool useSeals = !PR_GetEnv("MOZ_SHM_NO_SEALS");
|
||||
if (is_memfd_ && haveSeals && useSeals) {
|
||||
// Seals are added to the file as defense-in-depth. The primary
|
||||
// method of access control is creating a read-only fd (using
|
||||
// procfs in this case) and requiring that sandboxes processes not
|
||||
// have access to /proc/self/fd to regain write permission; this
|
||||
// is the same as with shm_open.
|
||||
//
|
||||
// Unfortunately, F_SEAL_WRITE is unreliable: if the process
|
||||
// forked while there was a writeable mapping, it will inherit a
|
||||
// copy of the mapping, which causes the seal to fail.
|
||||
//
|
||||
// (Also, in the future we may want to split this into separate
|
||||
// classes for mappings and shared memory handles, which would
|
||||
// complicate identifying the case where `F_SEAL_WRITE` would be
|
||||
// possible even in the absence of races with fork.)
|
||||
//
|
||||
// However, Linux 5.1 added F_SEAL_FUTURE_WRITE, which prevents
|
||||
// write operations afterwards, but existing writeable mappings
|
||||
// are unaffected (similar to ashmem protection semantics).
|
||||
|
||||
const int seals = F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL;
|
||||
int sealError = EINVAL;
|
||||
|
||||
# ifdef F_SEAL_FUTURE_WRITE
|
||||
sealError =
|
||||
fcntl(mapped_file_.get(), F_ADD_SEALS, seals | F_SEAL_FUTURE_WRITE) == 0
|
||||
? 0
|
||||
: errno;
|
||||
# endif // F_SEAL_FUTURE_WRITE
|
||||
if (sealError == EINVAL) {
|
||||
sealError =
|
||||
fcntl(mapped_file_.get(), F_ADD_SEALS, seals) == 0 ? 0 : errno;
|
||||
}
|
||||
if (sealError != 0) {
|
||||
CHROMIUM_LOG(WARNING) << "failed to seal memfd: " << strerror(errno);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
#else // !USE_MEMFD_CREATE
|
||||
DCHECK(!is_memfd_);
|
||||
#endif
|
||||
|
||||
if (!is_ashmem) {
|
||||
DCHECK(frozen_file_);
|
||||
DCHECK(mapped_file_);
|
||||
mapped_file_ = nullptr;
|
||||
ro_file = std::move(frozen_file_);
|
||||
}
|
||||
|
||||
DCHECK(ro_file);
|
||||
freezeable_ = false;
|
||||
|
||||
ro_out->Close();
|
||||
ro_out->mapped_file_ = std::move(ro_file);
|
||||
ro_out->max_size_ = max_size_;
|
||||
|
|
|
|||
|
|
@ -704,10 +704,6 @@ class SandboxPolicyCommon : public SandboxPolicyBase {
|
|||
case __NR_munmap:
|
||||
return Allow();
|
||||
|
||||
// Shared memory
|
||||
case __NR_memfd_create:
|
||||
return Allow();
|
||||
|
||||
// ipc::Shmem; also, glibc when creating threads:
|
||||
case __NR_mprotect:
|
||||
return Allow();
|
||||
|
|
@ -1399,6 +1395,11 @@ class ContentSandboxPolicy : public SandboxPolicyCommon {
|
|||
case __NR_eventfd2:
|
||||
return Allow();
|
||||
|
||||
# ifdef __NR_memfd_create
|
||||
case __NR_memfd_create:
|
||||
return Allow();
|
||||
# endif
|
||||
|
||||
# ifdef __NR_rt_tgsigqueueinfo
|
||||
// Only allow to send signals within the process.
|
||||
case __NR_rt_tgsigqueueinfo: {
|
||||
|
|
|
|||
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