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Commit 4e7301e6 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

exec selftests: test ->recursion_depth 

Test that trivially recursing script onto itself doesn't work.

Note: this is different test from ELOOP tests in execveat.c Those test
that execveat(2) doesn't follow symlinks when told to do so.

Link: http://lkml.kernel.org/r/20190423192720.GA21433@avx2


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a6231d19

tools/testing/selftests/exec/.gitignore

+2 −1
Original line number Diff line number Diff line
@@ -6,4 +6,5 @@ execveat.moved 
execveat.path.ephemeral

execveat.ephemeral

execveat.denatured

/recursion-depth

xxxxxxxx*

tools/testing/selftests/exec/Makefile

+4 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

CFLAGS = -Wall

CFLAGS += -Wno-nonnull

CFLAGS += -D_GNU_SOURCE



TEST_GEN_PROGS := execveat

TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir

# Makefile is a run-time dependency, since it's accessed by the execveat test

TEST_FILES := Makefile



TEST_GEN_PROGS += recursion-depth



EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx*



include ../lib.mk

tools/testing/selftests/exec/recursion-depth.c

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

/* Test that pointing #! script interpreter to self doesn't recurse. */

#include <errno.h>

#include <sched.h>

#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <sys/mount.h>

#include <unistd.h>



int main(void)

{

	if (unshare(CLONE_NEWNS) == -1) {

		if (errno == ENOSYS || errno == EPERM) {

			fprintf(stderr, "error: unshare, errno %d\n", errno);

			return 4;

		}

		fprintf(stderr, "error: unshare, errno %d\n", errno);

		return 1;

	}

	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {

		fprintf(stderr, "error: mount '/', errno %d\n", errno);

		return 1;

	}

	/* Require "exec" filesystem. */

	if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1) {

		fprintf(stderr, "error: mount ramfs, errno %d\n", errno);

		return 1;

	}



#define FILENAME "/tmp/1"



	int fd = creat(FILENAME, 0700);

	if (fd == -1) {

		fprintf(stderr, "error: creat, errno %d\n", errno);

		return 1;

	}

#define S "#!" FILENAME "\n"

	if (write(fd, S, strlen(S)) != strlen(S)) {

		fprintf(stderr, "error: write, errno %d\n", errno);

		return 1;

	}

	close(fd);



	int rv = execve(FILENAME, NULL, NULL);

	if (rv == -1 && errno == ELOOP) {

		return 0;

	}

	fprintf(stderr, "error: execve, rv %d, errno %d\n", rv, errno);

	return 1;

}