services/service_manager/sandbox/mac/common.sb

; Copyright 2017 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.
(version 1)

; Helper function to check if a param is set to true.
(define (param-true? str) (string=? (param str) "TRUE"))

; Helper function to determine if a parameter is defined or not.
(define (param-defined? str) (string? (param str)))

; Define constants for all of the parameter strings passed in.
(define browser-pid "BROWSER_PID")
(define bundle-id "BUNDLE_ID")
(define bundle-path "BUNDLE_PATH")
(define component-path "COMPONENT_PATH")
(define current-pid "CURRENT_PID")
(define disable-sandbox-denial-logging "DISABLE_SANDBOX_DENIAL_LOGGING")
(define enable-logging "ENABLE_LOGGING")
(define executable-path "EXECUTABLE_PATH")
(define homedir-as-literal "USER_HOMEDIR_AS_LITERAL")
(define log-file-path "LOG_FILE_PATH")
(define os-version (string->number (param "OS_VERSION")))
(define darwin-user-cache-dir "DARWIN_USER_CACHE_DIR")
(define darwin-user-dir "DARWIN_USER_DIR")
(define darwin-user-temp-dir "DARWIN_USER_TEMP_DIR")
; There are two separate flags for syscall filtering to allow it
; to be rolled out to one process type at a time, while still allowing
; local development.
(define filter-syscalls "FILTER_SYSCALLS")
(define filter-syscalls-debug "FILTER_SYSCALLS_DEBUG")

; Backwards compatibility for 10.10.
(if (not (defined? 'path))
  (define path literal))
; Backwards compatibility for 10.11.
(if (not (defined? 'iokit-registry-entry-class))
  (define iokit-registry-entry-class iokit-user-client-class))

; --enable-sandbox-logging causes the sandbox to log failures to the syslog.
(if (param-true? disable-sandbox-denial-logging)
  (deny default (with no-log))
  (deny default))

(if (param-true? enable-logging) (debug deny))

; Allow sending signals to self - https://crbug.com/20370
(allow signal (target self))

; Consumes a subpath and appends it to the user's homedir path.
(define (user-homedir-path subpath)
  (string-append (param homedir-as-literal) subpath))

; A function that specific profiles (i.e. renderer) can call to allow
; font rendering.
(define (allow-font-access)
  (begin
    (allow file-read-data
      (subpath "/Library/Fonts")
      (subpath "/System/Library/Fonts")
      (subpath (user-homedir-path "/Library/Fonts"))
    )
    (allow mach-lookup
      ; https://crbug.com/756145, https://crbug.com/786615
      (global-name "com.apple.FontObjectsServer")
      (global-name "com.apple.fonts")
    )
    (if (< os-version 1012)
      (allow mach-lookup (global-name "com.apple.FontServer")))
    ; To allow accessing downloaded and other hidden fonts in
    ; /System/Library/Asssets/com_apple_MobileAsset_Font*.
    ; (https://crbug.com/662686)
    (allow file-read* (extension "com.apple.app-sandbox.read"))))

; Reads of signed Mach-O blobs created by the CVMS server.
; https://crbug.com/850021
(define (allow-cvms-blobs)
  (if (>= os-version 1014)
    (begin
      (allow file-read* file-write-unlink
        (prefix "/private/tmp/cvmsCodeSignObj"))
      (allow file-read*
        (extension "com.apple.cvms.kernel")
        (prefix "/private/var/db/CVMS/cvmsCodeSignObj"))
)))

; Allow logging for all processes.
(allow file-write*
  (require-all
    (path (param log-file-path))
    (vnode-type REGULAR-FILE)))

; Allow component builds to work.
(if (param-defined? component-path)
  (allow file-read* (subpath (param component-path))))

(allow process-exec (path (param executable-path)))
(allow file-read* (path (param executable-path)))

; The browser exposes Mach services at "bundle-id.service-name.browser-pid".
; This macro is a helper for doing the string concatenation.
(define (browser-service-name service-name)
  (global-name (string-append (param bundle-id)
                              "." service-name "."
                              (param browser-pid))))

(allow mach-lookup
  (browser-service-name "MachPortRendezvousServer")
)

; Allow realpath() to work.
(allow file-read-metadata (subpath "/"))

; All processes can read the bundle contents.
(allow file-read* (subpath (param bundle-path)))

; Allow reads of system libraries and frameworks.
(allow file-read*
  (subpath "/System/Library/CoreServices/CoreTypes.bundle")
  (subpath "/System/Library/CoreServices/SystemVersion.bundle")
  (subpath "/System/Library/Frameworks")
  (subpath "/System/Library/Preferences/Logging")
  (subpath "/System/Library/PrivateFrameworks")
  (subpath "/usr/lib")
)

; Reads from /etc.
; This is read by CFPrefs calling getpwuid in a loop. libinfo then fails to
; contact any of the opendirectoryd mach services, and falls back to
; the /etc/passwd file for the user info. The access is OK because
; no actual password hashes are in /etc/passwd anymore.
(allow file-read-data (path "/private/etc/passwd"))

; Access to /dev.
(allow file-ioctl file-read-data file-write-data
  (require-all
    (path "/dev/dtracehelper")
    (vnode-type CHARACTER-DEVICE)))

(allow file-read-data
  (path "/dev/null")
  (path "/dev/random")
  (path "/dev/urandom")
)

(if (>= os-version 1013)
  (begin (allow file-read* (subpath "/private/var/db/timezone"))
         (allow file-read-data (subpath "/usr/share/zoneinfo.default"))))

(if (< os-version 1013)
  (allow file-read-data (subpath "/usr/share/zoneinfo")))

; Reads from /Library.
(allow file-read-data
  (path "/Library/Preferences/.GlobalPreferences.plist")
)

; Reads from /System.
(allow file-read-data
  (path "/System/Library/CoreServices/SystemVersion.plist")
  (path "/System/Library/CoreServices/checkfixlist")
)

; Reads from /usr.
(allow file-read-data
  (subpath "/usr/share/icu")
)

; Access to the home directory.
(allow file-read-data
  (path (string-append (user-homedir-path "/Library/Preferences/") (param bundle-id) ".plist"))
  (path (user-homedir-path "/Library/Preferences/.GlobalPreferences.plist"))
  (regex (user-homedir-path #"/Library/Preferences/ByHost/.GlobalPreferences.*"))
  (path (user-homedir-path "/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist"))
)

; Mach IPC needed by all Chromium Helper instances.
(allow mach-lookup
  (global-name "com.apple.logd")  ; https://crbug.com/792229
  (global-name "com.apple.system.logger")
  (global-name "com.apple.system.opendirectoryd.libinfo")  ; https://crbug.com/792228
)

; sysctls permitted.
(allow sysctl-read
  (sysctl-name "hw.activecpu")
  (sysctl-name "hw.busfrequency_compat")
  (sysctl-name "hw.byteorder")
  (sysctl-name "hw.cachelinesize_compat")
  (sysctl-name "hw.cpufrequency_compat")
  (sysctl-name "hw.cputype")
  (sysctl-name "hw.logicalcpu_max")
  (sysctl-name "hw.machine")
  (sysctl-name "hw.ncpu")
  (sysctl-name "hw.pagesize_compat")
  (sysctl-name "hw.physicalcpu_max")
  (sysctl-name "hw.tbfrequency_compat")
  (sysctl-name "hw.vectorunit")
  (sysctl-name "kern.hostname")
  (sysctl-name "kern.maxfilesperproc")
  (sysctl-name "kern.osrelease")
  (sysctl-name "kern.ostype")
  (sysctl-name "kern.osvariant_status")
  (sysctl-name "kern.osversion")
  (sysctl-name "kern.usrstack64")
  (sysctl-name "kern.version")
  (sysctl-name "sysctl.proc_cputype")
  (sysctl-name (string-append "kern.proc.pid." (param current-pid)))
)

(allow network-outbound
  (literal "/private/var/run/asl_input")
  (literal "/private/var/run/syslog")
)

; This is available in 10.15+, and rolled out as a Finch experiment.
(if (param-true? filter-syscalls)
  (when (defined? 'syscall-unix)
    (allow syscall-unix
      (syscall-number SYS___disable_threadsignal)
      (syscall-number SYS___mac_syscall)
      (syscall-number SYS___pthread_kill)
      (syscall-number SYS___pthread_markcancel)
      (syscall-number SYS___pthread_sigmask)
      (syscall-number SYS___semwait_signal)
      (syscall-number SYS___semwait_signal_nocancel)
      (syscall-number SYS_access)
      (syscall-number SYS_bsdthread_create)
      (syscall-number SYS_bsdthread_ctl)
      (syscall-number SYS_bsdthread_register)
      (syscall-number SYS_bsdthread_terminate)
      (syscall-number SYS_close)
      (syscall-number SYS_close_nocancel)
      (syscall-number SYS_csops_audittoken)
      (syscall-number SYS_exit)
      (syscall-number SYS_fcntl)
      (syscall-number SYS_fileport_makefd)
      (syscall-number SYS_fileport_makeport)
      (syscall-number SYS_fstat64)
      (syscall-number SYS_fstatat64)
      (syscall-number SYS_fstatfs64)
      (syscall-number SYS_getattrlist)
      (syscall-number SYS_getattrlistbulk)
      (syscall-number SYS_getaudit_addr)
      (syscall-number SYS_getdirentries64)
      (syscall-number SYS_geteuid)
      (syscall-number SYS_getgid)
      (syscall-number SYS_gethostuuid)
      (syscall-number SYS_getpid)
      (syscall-number SYS_getppid)
      (syscall-number SYS_getrlimit)
      (syscall-number SYS_gettimeofday)
      (syscall-number SYS_getuid)
      (syscall-number SYS_ioctl)
      (syscall-number SYS_issetugid)
      (syscall-number SYS_kdebug_trace64)
      (syscall-number SYS_kevent64)
      (syscall-number SYS_kevent_id)
      (syscall-number SYS_kevent_qos)
      (syscall-number SYS_kqueue)
      (syscall-number SYS_lstat64)
      (syscall-number SYS_madvise)
      (syscall-number SYS_mmap)
      (syscall-number SYS_mprotect)
      (syscall-number SYS_munmap)
      (syscall-number SYS_open)
      (syscall-number SYS_open_dprotected_np)
      (syscall-number SYS_open_nocancel)
      (syscall-number SYS_pread)
      (syscall-number SYS_proc_info)
      (syscall-number SYS_psynch_mutexdrop)
      (syscall-number SYS_psynch_mutexwait)
      (syscall-number SYS_read)
      (syscall-number SYS_read_nocancel)
      (syscall-number SYS_readlink)
      (syscall-number SYS_shm_open)
      (syscall-number SYS_sigaction)
      (syscall-number SYS_sigprocmask)
      (syscall-number SYS_sigreturn)
      (syscall-number SYS_stat64)
      (syscall-number SYS_statfs64)
      (syscall-number SYS_sysctl)
      (syscall-number SYS_sysctlbyname)
      (syscall-number SYS_thread_selfid)
      (syscall-number SYS_ulock_wait)
      (syscall-number SYS_ulock_wake)
      (syscall-number SYS_workq_kernreturn)
      (syscall-number SYS_workq_open)
)))