Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933132AbaJVLvd (ORCPT ); Wed, 22 Oct 2014 07:51:33 -0400 Received: from mail-lb0-f202.google.com ([209.85.217.202]:62800 "EHLO mail-lb0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932845AbaJVLvc (ORCPT ); Wed, 22 Oct 2014 07:51:32 -0400 X-Greylist: delayed 412 seconds by postgrey-1.27 at vger.kernel.org; Wed, 22 Oct 2014 07:51:32 EDT From: David Drysdale To: "Eric W. Biederman" , Andy Lutomirski , Alexander Viro , Meredydd Luff , linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , Kees Cook , Arnd Bergmann , x86@kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, David Drysdale Subject: [PATCHv5 2/3] syscalls,x86: add selftest for execveat(2) Date: Wed, 22 Oct 2014 12:44:28 +0100 Message-Id: <1413978269-17274-3-git-send-email-drysdale@google.com> X-Mailer: git-send-email 2.1.0.rc2.206.gedb03e5 In-Reply-To: <1413978269-17274-1-git-send-email-drysdale@google.com> References: <1413978269-17274-1-git-send-email-drysdale@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: David Drysdale --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/exec/.gitignore | 6 + tools/testing/selftests/exec/Makefile | 22 +++ tools/testing/selftests/exec/execveat.c | 295 ++++++++++++++++++++++++++++++++ 4 files changed, 324 insertions(+) create mode 100644 tools/testing/selftests/exec/.gitignore create mode 100644 tools/testing/selftests/exec/Makefile create mode 100644 tools/testing/selftests/exec/execveat.c diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 36ff2e4c7b6f..210cf68b3511 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -14,6 +14,7 @@ TARGETS += powerpc TARGETS += user TARGETS += sysctl TARGETS += firmware +TARGETS += exec TARGETS_HOTPLUG = cpu-hotplug TARGETS_HOTPLUG += memory-hotplug diff --git a/tools/testing/selftests/exec/.gitignore b/tools/testing/selftests/exec/.gitignore new file mode 100644 index 000000000000..349a786899a7 --- /dev/null +++ b/tools/testing/selftests/exec/.gitignore @@ -0,0 +1,6 @@ +subdir* +script* +execveat +execveat.symlink +execveat.moved +execveat.ephemeral diff --git a/tools/testing/selftests/exec/Makefile b/tools/testing/selftests/exec/Makefile new file mode 100644 index 000000000000..428cb1d2a06a --- /dev/null +++ b/tools/testing/selftests/exec/Makefile @@ -0,0 +1,22 @@ +CC = $(CROSS_COMPILE)gcc +CFLAGS = -Wall +BINARIES = execveat +DEPS = execveat.symlink script subdir +all: $(BINARIES) $(DEPS) + +subdir: + mkdir -p $@ +script: + echo '#!/bin/sh' > $@ + echo 'exit $$*' >> $@ + chmod +x $@ +execveat.symlink: execveat + ln -s -f $< $@ +%: %.c + $(CC) $(CFLAGS) -o $@ $^ + +run_tests: all + ./execveat + +clean: + rm -rf $(BINARIES) $(DEPS) subdir.moved execveat.moved diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c new file mode 100644 index 000000000000..1f2722ed3847 --- /dev/null +++ b/tools/testing/selftests/exec/execveat.c @@ -0,0 +1,295 @@ +/* + * Copyright (c) 2014 Google, Inc. + * + * Licensed under the terms of the GNU GPL License version 2 + * + * Selftests for execveat(2). + */ + +#define _GNU_SOURCE /* to get O_PATH, AT_EMPTY_PATH */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static char *envp[] = { "IN_TEST=yes", NULL }; +static char *argv[] = { "execveat", "99", NULL }; + +static int execveat_(int fd, const char *path, char **argv, char **envp, + int flags) +{ +#ifdef __NR_execveat + return syscall(__NR_execveat, fd, path, argv, envp, flags); +#else + errno = -ENOSYS; + return -1; +#endif +} + +#define check_execveat_fail(fd, path, flags, errno) \ + _check_execveat_fail(fd, path, flags, errno, #errno) +static int _check_execveat_fail(int fd, const char *path, int flags, + int expected_errno, const char *errno_str) +{ + int rc; + + errno = 0; + printf("Check failure of execveat(%d, '%s', %d) with %s... ", + fd, path?:"(null)", flags, errno_str); + rc = execveat_(fd, path, argv, envp, flags); + + if (rc > 0) { + printf("[FAIL] (unexpected success from execveat(2))\n"); + return 1; + } + if (errno != expected_errno) { + printf("[FAIL] (expected errno %d (%s) not %d (%s)\n", + expected_errno, strerror(expected_errno), + errno, strerror(errno)); + return 1; + } + printf("[OK]\n"); + return 0; +} + +static int check_execveat_invoked_rc(int fd, const char *path, int flags, + int expected_rc) +{ + int status; + int rc; + pid_t child; + + printf("Check success of execveat(%d, '%s', %d)... ", + fd, path?:"(null)", flags); + child = fork(); + if (child < 0) { + printf("[FAIL] (fork() failed)\n"); + return 1; + } + if (child == 0) { + /* Child: do execveat(). */ + rc = execveat_(fd, path, argv, envp, flags); + printf("[FAIL]: execveat() failed, rc=%d errno=%d (%s)\n", + rc, errno, strerror(errno)); + exit(1); /* should not reach here */ + } + /* Parent: wait for & check child's exit status. */ + rc = waitpid(child, &status, 0); + if (rc != child) { + printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc); + return 1; + } + if (!WIFEXITED(status)) { + printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n", + child, status); + return 1; + } + if (WEXITSTATUS(status) != expected_rc) { + printf("[FAIL] (child %d exited with %d not %d)\n", + child, WEXITSTATUS(status), expected_rc); + return 1; + } + printf("[OK]\n"); + return 0; +} + +static int check_execveat(int fd, const char *path, int flags) +{ + return check_execveat_invoked_rc(fd, path, flags, 99); +} + +static char *concat(const char *left, const char *right) +{ + char *result = malloc(strlen(left) + strlen(right) + 1); + + strcpy(result, left); + strcat(result, right); + return result; +} + +static int open_or_die(const char *filename, int flags) +{ + int fd = open(filename, flags); + + if (fd < 0) { + printf("Failed to open '%s'; " + "check prerequisites are available\n", filename); + exit(1); + } + return fd; +} + +static int run_tests(void) +{ + int fail = 0; + char *fullname = realpath("execveat", NULL); + char *fullname_script = realpath("script", NULL); + char *fullname_symlink = concat(fullname, ".symlink"); + int subdir_dfd = open_or_die("subdir", O_DIRECTORY|O_RDONLY); + int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral", + O_DIRECTORY|O_RDONLY); + int dot_dfd = open_or_die(".", O_DIRECTORY|O_RDONLY); + int dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH); + int fd = open_or_die("execveat", O_RDONLY); + int fd_path = open_or_die("execveat", O_RDONLY|O_PATH); + int fd_symlink = open_or_die("execveat.symlink", O_RDONLY); + int fd_script = open_or_die("script", O_RDONLY); + int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY); + int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY); + + /* Normal executable file: */ + /* dfd + path */ + fail |= check_execveat(subdir_dfd, "../execveat", 0); + fail |= check_execveat(dot_dfd, "execveat", 0); + fail |= check_execveat(dot_dfd_path, "execveat", 0); + /* absolute path */ + fail |= check_execveat(AT_FDCWD, fullname, 0); + /* absolute path with nonsense dfd */ + fail |= check_execveat(99, fullname, 0); + /* fd + no path */ + fail |= check_execveat(fd, "", AT_EMPTY_PATH); + + /* Mess with executable file that's already open: */ + /* fd + no path to a file that's been renamed */ + rename("execveat.ephemeral", "execveat.moved"); + fail |= check_execveat(fd_ephemeral, "", AT_EMPTY_PATH); + /* fd + no path to a file that's been deleted */ + unlink("execveat.moved"); /* remove the file now fd open */ + fail |= check_execveat(fd_ephemeral, "", AT_EMPTY_PATH); + + /* Invalid argument failures */ + fail |= check_execveat_fail(fd, "", 0, ENOENT); + fail |= check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT); + + /* Symlink to executable file: */ + /* dfd + path */ + fail |= check_execveat(dot_dfd, "execveat.symlink", 0); + fail |= check_execveat(dot_dfd_path, "execveat.symlink", 0); + /* absolute path */ + fail |= check_execveat(AT_FDCWD, fullname_symlink, 0); + /* fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */ + fail |= check_execveat(fd_symlink, "", AT_EMPTY_PATH); + fail |= check_execveat(fd_symlink, "", + AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW); + + /* Symlink fails when AT_SYMLINK_NOFOLLOW set: */ + /* dfd + path */ + fail |= check_execveat_fail(dot_dfd, "execveat.symlink", + AT_SYMLINK_NOFOLLOW, ELOOP); + fail |= check_execveat_fail(dot_dfd_path, "execveat.symlink", + AT_SYMLINK_NOFOLLOW, ELOOP); + /* absolute path */ + fail |= check_execveat_fail(AT_FDCWD, fullname_symlink, + AT_SYMLINK_NOFOLLOW, ELOOP); + + /* Shell script wrapping executable file: */ + /* dfd + path */ + fail |= check_execveat(subdir_dfd, "../script", 0); + fail |= check_execveat(dot_dfd, "script", 0); + fail |= check_execveat(dot_dfd_path, "script", 0); + /* absolute path */ + fail |= check_execveat(AT_FDCWD, fullname_script, 0); + /* fd + no path */ + fail |= check_execveat(fd_script, "", AT_EMPTY_PATH); + fail |= check_execveat(fd_script, "", + AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW); + + /* Mess with script file that's already open: */ + /* fd + no path to a file that's been renamed */ + rename("script.ephemeral", "script.moved"); + fail |= check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH); + /* fd + no path to a file that's been deleted */ + unlink("script.moved"); /* remove the file while fd open */ + fail |= check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH); + + /* Rename a subdirectory in the path: */ + rename("subdir.ephemeral", "subdir.moved"); + fail |= check_execveat(subdir_dfd_ephemeral, "../script", 0); + fail |= check_execveat(subdir_dfd_ephemeral, "script", 0); + /* Remove the subdir and its contents */ + unlink("subdir.moved/script"); + unlink("subdir.moved"); + /* Shell loads via deleted subdir OK because name starts with .. */ + fail |= check_execveat(subdir_dfd_ephemeral, "../script", 0); + fail |= check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT); + + /* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */ + fail |= check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL); + /* Invalid path => ENOENT */ + fail |= check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT); + fail |= check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT); + fail |= check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT); + /* Attempt to execute directory => EACCES */ + fail |= check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES); + /* Attempt to execute non-executable => EACCES */ + fail |= check_execveat_fail(dot_dfd, "Makefile", 0, EACCES); + /* Attempt to execute file opened with O_PATH => EBADF */ + fail |= check_execveat_fail(dot_dfd_path, "", AT_EMPTY_PATH, EBADF); + fail |= check_execveat_fail(fd_path, "", AT_EMPTY_PATH, EBADF); + /* Attempt to execute nonsense FD => EBADF */ + fail |= check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF); + fail |= check_execveat_fail(99, "execveat", 0, EBADF); + /* Attempt to execute relative to non-directory => ENOTDIR */ + fail |= check_execveat_fail(fd, "execveat", 0, ENOTDIR); + + return fail ? -1 : 0; +} + +void exe_cp(const char *src, const char *dest) +{ + int in_fd = open_or_die(src, O_RDONLY); + int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755); + struct stat info; + + fstat(in_fd, &info); + sendfile(out_fd, in_fd, NULL, info.st_size); + close(in_fd); + close(out_fd); +} + +void prerequisites(void) +{ + int fd; + const char *script = "#!/bin/sh\nexit $*\n"; + + /* Create ephemeral copies of files */ + exe_cp("execveat", "execveat.ephemeral"); + exe_cp("script", "script.ephemeral"); + mkdir("subdir.ephemeral", 0755); + + fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755); + write(fd, script, strlen(script)); + close(fd); +} + +int main(int argc, char **argv) +{ + int rc; + + if (argc >= 2) { + /* If we are invoked with an argument, exit immediately. */ + /* Check expected environment transferred. */ + const char *in_test = getenv("IN_TEST"); + + if (!in_test || strcmp(in_test, "yes") != 0) { + printf("[FAIL] (no IN_TEST=yes in env)\n"); + return 1; + } + + /* Use the final argument as an exit code. */ + rc = atoi(argv[argc - 1]); + fflush(stdout); + } else { + prerequisites(); + rc = run_tests(); + } + return rc; +} -- 2.1.0.rc2.206.gedb03e5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/