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;;; emacs-tests.el --- unit tests for emacs.c -*- lexical-binding: t; -*-
;; Copyright (C) 2020-2021 Free Software Foundation, Inc.
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published
;; by the Free Software Foundation, either version 3 of the License,
;; or (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Unit tests for src/emacs.c.
;;; Code:
(require 'cl-lib)
(require 'ert)
(require 'rx)
(require 'subr-x)
(defconst emacs-tests--lib-src
(substitute-in-file-name "$EMACS_TEST_DIRECTORY/../lib-src/")
"Location of the lib-src directory.")
(ert-deftest emacs-tests/seccomp/absent-file ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(process-environment nil))
(skip-unless (file-executable-p emacs))
(should-not (file-exists-p "/does-not-exist.bpf"))
(should-not
(eql (call-process emacs nil nil nil
"--quick" "--batch"
"--seccomp=/does-not-exist.bpf")
0))))
(cl-defmacro emacs-tests--with-temp-file
(var (prefix &optional suffix text) &rest body)
"Evaluate BODY while a new temporary file exists.
Bind VAR to the name of the file. Pass PREFIX, SUFFIX, and TEXT
to `make-temp-file', which see."
(declare (indent 2) (debug (symbolp (form form form) body)))
(cl-check-type var symbol)
;; Use an uninterned symbol so that the code still works if BODY
;; changes VAR.
(let ((filename (make-symbol "filename")))
`(let ((,filename (make-temp-file ,prefix nil ,suffix ,text)))
(unwind-protect
(let ((,var ,filename))
,@body)
(delete-file ,filename)))))
(ert-deftest emacs-tests/seccomp/empty-file ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(process-environment nil))
(skip-unless (file-executable-p emacs))
(emacs-tests--with-temp-file filter ("seccomp-invalid-" ".bpf")
;; The --seccomp option is processed early, without filename
;; handlers. Therefore remote or quoted filenames wouldn't
;; work.
(should-not (file-remote-p filter))
(cl-callf file-name-unquote filter)
;; According to the Seccomp man page, a filter must have at
;; least one element, so Emacs should reject an empty file.
(should-not
(eql (call-process emacs nil nil nil
"--quick" "--batch"
(concat "--seccomp=" filter))
0)))))
(ert-deftest emacs-tests/seccomp/file-too-large ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(process-environment nil)
;; This value should be correct on all supported systems.
(ushort-max #xFFFF)
;; Either 8 or 16, but 16 should be large enough in all cases.
(filter-size 16))
(skip-unless (file-executable-p emacs))
(emacs-tests--with-temp-file
filter ("seccomp-too-large-" ".bpf"
(make-string (* (1+ ushort-max) filter-size) ?a))
;; The --seccomp option is processed early, without filename
;; handlers. Therefore remote or quoted filenames wouldn't
;; work.
(should-not (file-remote-p filter))
(cl-callf file-name-unquote filter)
;; The filter count must fit into an `unsigned short'. A bigger
;; file should be rejected.
(should-not
(eql (call-process emacs nil nil nil
"--quick" "--batch"
(concat "--seccomp=" filter))
0)))))
(ert-deftest emacs-tests/seccomp/invalid-file-size ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(process-environment nil))
(skip-unless (file-executable-p emacs))
(emacs-tests--with-temp-file filter ("seccomp-invalid-" ".bpf"
"123456")
;; The --seccomp option is processed early, without filename
;; handlers. Therefore remote or quoted filenames wouldn't
;; work.
(should-not (file-remote-p filter))
(cl-callf file-name-unquote filter)
;; The Seccomp filter file must have a file size that's a
;; multiple of the size of struct sock_filter, which is 8 or 16,
;; but never 6.
(should-not
(eql (call-process emacs nil nil nil
"--quick" "--batch"
(concat "--seccomp=" filter))
0)))))
(ert-deftest emacs-tests/seccomp/allows-stdout ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(filter (expand-file-name "seccomp-filter.bpf"
emacs-tests--lib-src))
(process-environment nil))
(skip-unless (file-executable-p emacs))
(skip-unless (file-readable-p filter))
;; The --seccomp option is processed early, without filename
;; handlers. Therefore remote or quoted filenames wouldn't work.
(should-not (file-remote-p filter))
(cl-callf file-name-unquote filter)
(with-temp-buffer
(let ((start-time (current-time))
(status (call-process
emacs nil t nil
"--quick" "--batch"
(concat "--seccomp=" filter)
(format "--eval=%S" '(message "Hi"))))
(end-time (current-time)))
(ert-info ((emacs-tests--seccomp-debug start-time end-time))
(should (eql status 0)))
(should (equal (string-trim (buffer-string)) "Hi"))))))
(ert-deftest emacs-tests/seccomp/forbids-subprocess ()
(skip-unless (string-match-p (rx bow "SECCOMP" eow)
system-configuration-features))
(let ((emacs
(expand-file-name invocation-name invocation-directory))
(filter (expand-file-name "seccomp-filter.bpf"
emacs-tests--lib-src))
(process-environment nil))
(skip-unless (file-executable-p emacs))
(skip-unless (file-readable-p filter))
;; The --seccomp option is processed early, without filename
;; handlers. Therefore remote or quoted filenames wouldn't work.
(should-not (file-remote-p filter))
(cl-callf file-name-unquote filter)
(with-temp-buffer
(let ((start-time (current-time))
(status
(call-process
emacs nil t nil
"--quick" "--batch"
(concat "--seccomp=" filter)
(format "--eval=%S" `(call-process ,emacs nil nil nil
"--version"))))
(end-time (current-time)))
(ert-info ((emacs-tests--seccomp-debug start-time end-time))
(should-not (eql status 0)))))))
(ert-deftest emacs-tests/bwrap/allows-stdout ()
(let ((bash (executable-find "bash"))
(bwrap (executable-find "bwrap"))
(emacs
(expand-file-name invocation-name invocation-directory))
(filter (expand-file-name "seccomp-filter-exec.bpf"
emacs-tests--lib-src))
(process-environment nil))
(skip-unless bash)
(skip-unless bwrap)
(skip-unless (file-executable-p emacs))
(skip-unless (file-readable-p filter))
(should-not (file-remote-p bwrap))
(should-not (file-remote-p emacs))
(should-not (file-remote-p filter))
(with-temp-buffer
(let* ((command
(concat
(mapconcat #'shell-quote-argument
`(,(file-name-unquote bwrap)
"--ro-bind" "/" "/"
"--seccomp" "20"
"--"
,(file-name-unquote emacs)
"--quick" "--batch"
,(format "--eval=%S" '(message "Hi")))
" ")
" 20< "
(shell-quote-argument (file-name-unquote filter))))
(start-time (current-time))
(status (call-process bash nil t nil "-c" command))
(end-time (current-time)))
(ert-info ((emacs-tests--seccomp-debug start-time end-time))
(should (eql status 0)))
(should (equal (string-trim (buffer-string)) "Hi"))))))
(defun emacs-tests--seccomp-debug (start-time end-time)
"Return potentially useful debugging information for Seccomp.
Assume that the current buffer contains subprocess output for the
failing process. START-TIME and END-TIME are time values between
which the process was running."
;; Add a bit of slack for the timestamps.
(cl-callf time-subtract start-time 5)
(cl-callf time-add end-time 5)
(with-output-to-string
(princ "Process output:")
(terpri)
(princ (buffer-substring-no-properties (point-min) (point-max)))
;; Search audit logs for Seccomp messages.
(when-let ((ausearch (executable-find "ausearch")))
(terpri)
(princ "Potentially relevant Seccomp audit events:")
(terpri)
(let ((process-environment '("LC_TIME=C")))
(call-process ausearch nil standard-output nil
"--message" "SECCOMP"
"--start"
(format-time-string "%D" start-time)
(format-time-string "%T" start-time)
"--end"
(format-time-string "%D" end-time)
(format-time-string "%T" end-time)
"--interpret")))
;; Print coredump information if available.
(when-let ((coredumpctl (executable-find "coredumpctl")))
(terpri)
(princ "Potentially useful coredump information:")
(terpri)
(call-process coredumpctl nil standard-output nil
"info"
"--since" (format-time-string "%F %T" start-time)
"--until" (format-time-string "%F %T" end-time)
"--no-pager"))))
;;; emacs-tests.el ends here
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