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-rw-r--r--regress/check-perm.c205
1 files changed, 205 insertions, 0 deletions
diff --git a/regress/check-perm.c b/regress/check-perm.c
new file mode 100644
index 00000000..dac307d2
--- /dev/null
+++ b/regress/check-perm.c
@@ -0,0 +1,205 @@
+/*
+ * Placed in the public domain
+ */
+
+/* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <pwd.h>
+#ifdef HAVE_LIBGEN_H
+#include <libgen.h>
+#endif
+
+static void
+fatal(const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vfprintf(stderr, fmt, args);
+ fputc('\n', stderr);
+ va_end(args);
+ exit(1);
+}
+/* Based on session.c. NB. keep tests in sync */
+static void
+safely_chroot(const char *path, uid_t uid)
+{
+ const char *cp;
+ char component[PATH_MAX];
+ struct stat st;
+
+ if (*path != '/')
+ fatal("chroot path does not begin at root");
+ if (strlen(path) >= sizeof(component))
+ fatal("chroot path too long");
+
+ /*
+ * Descend the path, checking that each component is a
+ * root-owned directory with strict permissions.
+ */
+ for (cp = path; cp != NULL;) {
+ if ((cp = strchr(cp, '/')) == NULL)
+ strlcpy(component, path, sizeof(component));
+ else {
+ cp++;
+ memcpy(component, path, cp - path);
+ component[cp - path] = '\0';
+ }
+
+ /* debug3("%s: checking '%s'", __func__, component); */
+
+ if (stat(component, &st) != 0)
+ fatal("%s: stat(\"%s\"): %s", __func__,
+ component, strerror(errno));
+ if (st.st_uid != 0 || (st.st_mode & 022) != 0)
+ fatal("bad ownership or modes for chroot "
+ "directory %s\"%s\"",
+ cp == NULL ? "" : "component ", component);
+ if (!S_ISDIR(st.st_mode))
+ fatal("chroot path %s\"%s\" is not a directory",
+ cp == NULL ? "" : "component ", component);
+
+ }
+
+ if (chdir(path) == -1)
+ fatal("Unable to chdir to chroot path \"%s\": "
+ "%s", path, strerror(errno));
+}
+
+/* from platform.c */
+int
+platform_sys_dir_uid(uid_t uid)
+{
+ if (uid == 0)
+ return 1;
+#ifdef PLATFORM_SYS_DIR_UID
+ if (uid == PLATFORM_SYS_DIR_UID)
+ return 1;
+#endif
+ return 0;
+}
+
+/* from auth.c */
+int
+auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
+ uid_t uid, char *err, size_t errlen)
+{
+ char buf[PATH_MAX], homedir[PATH_MAX];
+ char *cp;
+ int comparehome = 0;
+ struct stat st;
+
+ if (realpath(name, buf) == NULL) {
+ snprintf(err, errlen, "realpath %s failed: %s", name,
+ strerror(errno));
+ return -1;
+ }
+ if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
+ comparehome = 1;
+
+ if (!S_ISREG(stp->st_mode)) {
+ snprintf(err, errlen, "%s is not a regular file", buf);
+ return -1;
+ }
+ if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
+ (stp->st_mode & 022) != 0) {
+ snprintf(err, errlen, "bad ownership or modes for file %s",
+ buf);
+ return -1;
+ }
+
+ /* for each component of the canonical path, walking upwards */
+ for (;;) {
+ if ((cp = dirname(buf)) == NULL) {
+ snprintf(err, errlen, "dirname() failed");
+ return -1;
+ }
+ strlcpy(buf, cp, sizeof(buf));
+
+ if (stat(buf, &st) < 0 ||
+ (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
+ (st.st_mode & 022) != 0) {
+ snprintf(err, errlen,
+ "bad ownership or modes for directory %s", buf);
+ return -1;
+ }
+
+ /* If are past the homedir then we can stop */
+ if (comparehome && strcmp(homedir, buf) == 0)
+ break;
+
+ /*
+ * dirname should always complete with a "/" path,
+ * but we can be paranoid and check for "." too
+ */
+ if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
+ break;
+ }
+ return 0;
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr, "check-perm -m [chroot | keys-command] [path]\n");
+ exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+ const char *path = ".";
+ char errmsg[256];
+ int ch, mode = -1;
+ extern char *optarg;
+ extern int optind;
+ struct stat st;
+
+ while ((ch = getopt(argc, argv, "hm:")) != -1) {
+ switch (ch) {
+ case 'm':
+ if (strcasecmp(optarg, "chroot") == 0)
+ mode = 1;
+ else if (strcasecmp(optarg, "keys-command") == 0)
+ mode = 2;
+ else {
+ fprintf(stderr, "Invalid -m option\n"),
+ usage();
+ }
+ break;
+ default:
+ usage();
+ }
+ }
+ argc -= optind;
+ argv += optind;
+
+ if (argc > 1)
+ usage();
+ else if (argc == 1)
+ path = argv[0];
+
+ if (mode == 1)
+ safely_chroot(path, getuid());
+ else if (mode == 2) {
+ if (stat(path, &st) < 0)
+ fatal("Could not stat %s: %s", path, strerror(errno));
+ if (auth_secure_path(path, &st, NULL, 0,
+ errmsg, sizeof(errmsg)) != 0)
+ fatal("Unsafe %s: %s", path, errmsg);
+ } else {
+ fprintf(stderr, "Invalid mode\n");
+ usage();
+ }
+ return 0;
+}