Signed-off-by: David Drysdale <[email protected]>
---
 tools/testing/selftests/Makefile        |   1 +
 tools/testing/selftests/exec/.gitignore |   6 +
 tools/testing/selftests/exec/Makefile   |  32 ++++
 tools/testing/selftests/exec/execveat.c | 251 ++++++++++++++++++++++++++++++++
 4 files changed, 290 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 32487ed18354..26b7e6410fcd 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -10,6 +10,7 @@ TARGETS += timers
 TARGETS += vm
 TARGETS += powerpc
 TARGETS += user
+TARGETS += exec

 all:
        for TARGET in $(TARGETS); do \
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..55771ed05dda
--- /dev/null
+++ b/tools/testing/selftests/exec/Makefile
@@ -0,0 +1,32 @@
+CC = $(CROSS_COMPILE)gcc
+CFLAGS = -Wall
+BINARIES = execveat
+DEPS = execveat.symlink script execveat.ephemeral script.ephemeral subdir 
subdir.ephemeral subdir.ephemeral/script
+all: $(BINARIES) $(DEPS)
+
+subdir:
+       mkdir -p $@
+subdir.ephemeral:
+       mkdir -p $@
+subdir.ephemeral/script: | subdir.ephemeral
+       echo '#!/bin/sh' > $@
+       echo 'exit $$*' >> $@
+       chmod +x $@
+script:
+       echo '#!/bin/sh' > $@
+       echo 'exit $$*' >> $@
+       chmod +x $@
+script.ephemeral: script
+       cp $< $@
+execveat.symlink: execveat
+       ln -s -f $< $@
+execveat.ephemeral: execveat
+       cp $< $@
+%: %.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..f67862fa3f38
--- /dev/null
+++ b/tools/testing/selftests/exec/execveat.c
@@ -0,0 +1,251 @@
+/*
+ * 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 */
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+
+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)
+{
+       errno = 0;
+       printf("Check failure of execveat(%d, '%s', %d) with %s... ",
+               fd, path?:"(null)", flags, errno_str);
+       int 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, NULL, 0);
+
+       /* 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, NULL, 0);
+       /*   fd + no path to a file that's been deleted */
+       unlink("execveat.moved"); /* remove the file now fd open */
+       fail |= check_execveat(fd_ephemeral, NULL, 0);
+
+       /* 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, NULL, 0);
+       fail |= check_execveat(fd_symlink, NULL, 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, NULL, 0);
+       fail |= check_execveat(fd_script, NULL, 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, NULL, 0);
+       /*   fd + no path to a file that's been deleted */
+       unlink("script.moved"); /* remove the file while fd open */
+       /* Shell attempts to load the deleted file but fails => rc=127 */
+       fail |= check_execveat_invoked_rc(fd_script_ephemeral, NULL, 0, 127);
+
+       /* 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, NULL, 0, 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, NULL, 0, EBADF);
+       fail |= check_execveat_fail(fd_path, NULL, 0, EBADF);
+       /* Attempt to execute nonsense FD => EBADF */
+       fail |= check_execveat_fail(99, NULL, 0, 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;
+}
+
+int main(int argc, char **argv)
+{
+       if (argc >= 2) {
+               /* If we are invoked with an argument, exit immediately. */
+               /* Check expected environment transferred. */
+               if (strcmp(getenv("IN_TEST"), "yes") != 0) {
+                       printf("[FAIL] (no IN_TEST=yes in env)\n");
+                       return 1;
+               }
+
+               /* Use the argument as an exit code. */
+               int rc = atoi(argv[1]);
+               fflush(stdout);
+               return rc;
+       } else {
+               return run_tests();
+       }
+}
--
1.9.1.423.g4596e3a

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