diff options
Diffstat (limited to 'kernel/tools/testing/selftests/exec')
| -rw-r--r-- | kernel/tools/testing/selftests/exec/.gitignore | 9 | ||||
| -rw-r--r-- | kernel/tools/testing/selftests/exec/Makefile | 28 | ||||
| -rw-r--r-- | kernel/tools/testing/selftests/exec/execveat.c | 412 |
3 files changed, 449 insertions, 0 deletions
diff --git a/kernel/tools/testing/selftests/exec/.gitignore b/kernel/tools/testing/selftests/exec/.gitignore new file mode 100644 index 000000000..64073e050 --- /dev/null +++ b/kernel/tools/testing/selftests/exec/.gitignore @@ -0,0 +1,9 @@ +subdir* +script* +execveat +execveat.symlink +execveat.moved +execveat.path.ephemeral +execveat.ephemeral +execveat.denatured +xxxxxxxx*
\ No newline at end of file diff --git a/kernel/tools/testing/selftests/exec/Makefile b/kernel/tools/testing/selftests/exec/Makefile new file mode 100644 index 000000000..4edb7d0da --- /dev/null +++ b/kernel/tools/testing/selftests/exec/Makefile @@ -0,0 +1,28 @@ +CFLAGS = -Wall +BINARIES = execveat +DEPS = execveat.symlink execveat.denatured script subdir +all: $(BINARIES) $(DEPS) + +subdir: + mkdir -p $@ +script: + echo '#!/bin/sh' > $@ + echo 'exit $$*' >> $@ + chmod +x $@ +execveat.symlink: execveat + ln -s -f $< $@ +execveat.denatured: execveat + cp $< $@ + chmod -x $@ +%: %.c + $(CC) $(CFLAGS) -o $@ $^ + +TEST_PROGS := execveat +TEST_FILES := $(DEPS) + +include ../lib.mk + +override EMIT_TESTS := echo "mkdir -p subdir; (./execveat && echo \"selftests: execveat [PASS]\") || echo \"selftests: execveat [FAIL]\"" + +clean: + rm -rf $(BINARIES) $(DEPS) subdir.moved execveat.moved xxxxx* diff --git a/kernel/tools/testing/selftests/exec/execveat.c b/kernel/tools/testing/selftests/exec/execveat.c new file mode 100644 index 000000000..8d5d1d2ee --- /dev/null +++ b/kernel/tools/testing/selftests/exec/execveat.c @@ -0,0 +1,412 @@ +/* + * 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 <sys/sendfile.h> +#include <sys/stat.h> +#include <sys/syscall.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +static char longpath[2 * PATH_MAX] = ""; +static char *envp[] = { "IN_TEST=yes", NULL, 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 expected_rc2) +{ + int status; + int rc; + pid_t child; + int pathlen = path ? strlen(path) : 0; + + if (pathlen > 40) + printf("Check success of execveat(%d, '%.20s...%s', %d)... ", + fd, path, (path + pathlen - 20), flags); + else + 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) && + (WEXITSTATUS(status) != expected_rc2)) { + printf("[FAIL] (child %d exited with %d not %d nor %d)\n", + child, WEXITSTATUS(status), expected_rc, expected_rc2); + 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, 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 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); +} + +#define XX_DIR_LEN 200 +static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script) +{ + int fail = 0; + int ii, count, len; + char longname[XX_DIR_LEN + 1]; + int fd; + + if (*longpath == '\0') { + /* Create a filename close to PATH_MAX in length */ + memset(longname, 'x', XX_DIR_LEN - 1); + longname[XX_DIR_LEN - 1] = '/'; + longname[XX_DIR_LEN] = '\0'; + count = (PATH_MAX - 3) / XX_DIR_LEN; + for (ii = 0; ii < count; ii++) { + strcat(longpath, longname); + mkdir(longpath, 0755); + } + len = (PATH_MAX - 3) - (count * XX_DIR_LEN); + if (len <= 0) + len = 1; + memset(longname, 'y', len); + longname[len] = '\0'; + strcat(longpath, longname); + } + exe_cp(src, longpath); + + /* + * Execute as a pre-opened file descriptor, which works whether this is + * a script or not (because the interpreter sees a filename like + * "/dev/fd/20"). + */ + fd = open(longpath, O_RDONLY); + if (fd > 0) { + printf("Invoke copy of '%s' via filename of length %zu:\n", + src, strlen(longpath)); + fail += check_execveat(fd, "", AT_EMPTY_PATH); + } else { + printf("Failed to open length %zu filename, errno=%d (%s)\n", + strlen(longpath), errno, strerror(errno)); + fail++; + } + + /* + * Execute as a long pathname relative to ".". If this is a script, + * the interpreter will launch but fail to open the script because its + * name ("/dev/fd/5/xxx....") is bigger than PATH_MAX. + * + * The failure code is usually 127 (POSIX: "If a command is not found, + * the exit status shall be 127."), but some systems give 126 (POSIX: + * "If the command name is found, but it is not an executable utility, + * the exit status shall be 126."), so allow either. + */ + if (is_script) + fail += check_execveat_invoked_rc(dot_dfd, longpath, 0, + 127, 126); + else + fail += check_execveat(dot_dfd, longpath, 0); + + return fail; +} + +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 dot_dfd_cloexec = open_or_die(".", O_DIRECTORY|O_RDONLY|O_CLOEXEC); + 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_denatured = open_or_die("execveat.denatured", O_RDONLY); + int fd_denatured_path = open_or_die("execveat.denatured", + O_RDONLY|O_PATH); + int fd_script = open_or_die("script", O_RDONLY); + int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY); + int fd_ephemeral_path = open_or_die("execveat.path.ephemeral", + O_RDONLY|O_PATH); + int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY); + int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC); + int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC); + + /* Check if we have execveat at all, and bail early if not */ + errno = 0; + execveat_(-1, NULL, NULL, NULL, 0); + if (errno == ENOSYS) { + printf("[FAIL] ENOSYS calling execveat - no kernel support?\n"); + return 1; + } + + /* Change file position to confirm it doesn't affect anything */ + lseek(fd, 10, SEEK_SET); + + /* 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); + /* O_CLOEXEC fd + no path */ + fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH); + /* O_PATH fd */ + fail += check_execveat(fd_path, "", 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); + + /* Mess with executable file that's already open with O_PATH */ + /* fd + no path to a file that's been deleted */ + unlink("execveat.path.ephemeral"); + fail += check_execveat(fd_ephemeral_path, "", 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); + /* O_CLOEXEC fd fails for a script (as script file inaccessible) */ + fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH, + ENOENT); + fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT); + + /* 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); + fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES); + fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH, + EACCES); + /* 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); + + fail += check_execveat_pathmax(dot_dfd, "execveat", 0); + fail += check_execveat_pathmax(dot_dfd, "script", 1); + return fail; +} + +static void prerequisites(void) +{ + int fd; + const char *script = "#!/bin/sh\nexit $*\n"; + + /* Create ephemeral copies of files */ + exe_cp("execveat", "execveat.ephemeral"); + exe_cp("execveat", "execveat.path.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 ii; + int rc; + const char *verbose = getenv("VERBOSE"); + + if (argc >= 2) { + /* If we are invoked with an argument, don't run tests. */ + const char *in_test = getenv("IN_TEST"); + + if (verbose) { + printf(" invoked with:"); + for (ii = 0; ii < argc; ii++) + printf(" [%d]='%s'", ii, argv[ii]); + printf("\n"); + } + + /* Check expected environment transferred. */ + 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(); + if (verbose) + envp[1] = "VERBOSE=1"; + rc = run_tests(); + if (rc > 0) + printf("%d tests failed\n", rc); + } + return rc; +} |