1 files changed, 387 insertions, 0 deletions

diff --git a/ssh-vulnkey.c b/ssh-vulnkey.c
new file mode 100644
index 000000000..f8125e0bb
--- /dev/null
+++ b/ssh-vulnkey.c
@@ -0,0 +1,387 @@
+/*
+ * Copyright (c) 2008 Canonical Ltd.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <openssl/evp.h>
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "log.h"
+#include "key.h"
+#include "authfile.h"
+#include "pathnames.h"
+#include "uidswap.h"
+#include "misc.h"
+
+extern char *__progname;
+
+/* Default files to check */
+static char *default_host_files[] = {
+        _PATH_HOST_RSA_KEY_FILE,
+        _PATH_HOST_DSA_KEY_FILE,
+        _PATH_HOST_KEY_FILE,
+        NULL
+};
+static char *default_files[] = {
+        _PATH_SSH_CLIENT_ID_RSA,
+        _PATH_SSH_CLIENT_ID_DSA,
+        _PATH_SSH_CLIENT_IDENTITY,
+        _PATH_SSH_USER_PERMITTED_KEYS,
+        _PATH_SSH_USER_PERMITTED_KEYS2,
+        NULL
+};
+
+static int verbosity = 0;
+
+static int some_keys = 0;
+static int some_unknown = 0;
+static int some_compromised = 0;
+
+static void
+usage(void)
+{
+        fprintf(stderr, "usage: %s [-aqv] [file ...]\n", __progname);
+        fprintf(stderr, "Options:\n");
+        fprintf(stderr, "  -a          Check keys of all users.\n");
+        fprintf(stderr, "  -q          Quiet mode.\n");
+        fprintf(stderr, "  -v          Verbose mode.\n");
+        exit(1);
+}
+
+static void
+describe_key(const char *filename, u_long linenum, const char *msg,
+    Key *key, const char *comment, int min_verbosity)
+{
+        char *fp;
+
+        fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
+        if (verbosity >= min_verbosity) {
+                if (strchr(filename, ':'))
+                        printf("\"%s\"", filename);
+                else
+                        printf("%s", filename);
+                printf(":%lu: %s: %s %u %s %s\n", linenum, msg,
+                    key_type(key), key_size(key), fp, comment);
+        }
+        xfree(fp);
+}
+
+static int
+do_key(const char *filename, u_long linenum,
+    Key *key, const char *comment)
+{
+        Key *public;
+        int blacklist_status;
+        int ret = 1;
+
+        some_keys = 1;
+
+        public = key_demote(key);
+        if (public->type == KEY_RSA1)
+                public->type = KEY_RSA;
+
+        blacklist_status = blacklisted_key(public, NULL);
+        if (blacklist_status == -1) {
+                describe_key(filename, linenum,
+                    "Unknown (blacklist file not installed)", key, comment, 0);
+                some_unknown = 1;
+        } else if (blacklist_status == 1) {
+                describe_key(filename, linenum,
+                    "COMPROMISED", key, comment, 0);
+                some_compromised = 1;
+                ret = 0;
+        } else
+                describe_key(filename, linenum,
+                    "Not blacklisted", key, comment, 1);
+
+        key_free(public);
+
+        return ret;
+}
+
+static int
+do_filename(const char *filename, int quiet_open)
+{
+        FILE *f;
+        char line[SSH_MAX_PUBKEY_BYTES];
+        char *cp;
+        u_long linenum = 0;
+        Key *key;
+        char *comment = NULL;
+        int found = 0, ret = 1;
+
+        /* Copy much of key_load_public's logic here so that we can read
+         * several keys from a single file (e.g. authorized_keys).
+         */
+
+        if (strcmp(filename, "-") != 0) {
+                int save_errno;
+                f = fopen(filename, "r");
+                save_errno = errno;
+                if (!f) {
+                        char pubfile[MAXPATHLEN];
+                        if (strlcpy(pubfile, filename, sizeof pubfile) <
+                            sizeof(pubfile) &&
+                            strlcat(pubfile, ".pub", sizeof pubfile) <
+                            sizeof(pubfile))
+                                f = fopen(pubfile, "r");
+                }
+                errno = save_errno; /* earlier errno is more useful */
+                if (!f) {
+                        if (!quiet_open)
+                                perror(filename);
+                        return -1;
+                }
+                if (verbosity > 0)
+                        printf("# %s\n", filename);
+        } else
+                f = stdin;
+        while (read_keyfile_line(f, filename, line, sizeof(line),
+                    &linenum) != -1) {
+                int i;
+                char *space;
+                int type;
+                char *end;
+
+                /* Chop trailing newline. */
+                i = strlen(line) - 1;
+                if (line[i] == '\n')
+                        line[i] = '\0';
+
+                /* Skip leading whitespace, empty and comment lines. */
+                for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
+                        ;
+                if (!*cp || *cp == '\n' || *cp == '#')
+                        continue;
+
+                /* Cope with ssh-keyscan output and options in
+                 * authorized_keys files.
+                 */
+                space = strchr(cp, ' ');
+                if (!space)
+                        continue;
+                *space = '\0';
+                type = key_type_from_name(cp);
+                *space = ' ';
+                /* Leading number (RSA1) or valid type (RSA/DSA) indicates
+                 * that we have no host name or options to skip.
+                 */
+                if ((strtol(cp, &end, 10) == 0 || *end != ' ') &&
+                    type == KEY_UNSPEC) {
+                        int quoted = 0;
+
+                        for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
+                                if (*cp == '\\' && cp[1] == '"')
+                                        cp++;   /* Skip both */
+                                else if (*cp == '"')
+                                        quoted = !quoted;
+                        }
+                        /* Skip remaining whitespace. */
+                        for (; *cp == ' ' || *cp == '\t'; cp++)
+                                ;
+                        if (!*cp)
+                                continue;
+                }
+
+                /* Read and process the key itself. */
+                key = key_new(KEY_RSA1);
+                if (key_read(key, &cp) == 1) {
+                        while (*cp == ' ' || *cp == '\t')
+                                cp++;
+                        if (!do_key(filename, linenum,
+                            key, *cp ? cp : filename))
+                                ret = 0;
+                        found = 1;
+                } else {
+                        key_free(key);
+                        key = key_new(KEY_UNSPEC);
+                        if (key_read(key, &cp) == 1) {
+                                while (*cp == ' ' || *cp == '\t')
+                                        cp++;
+                                if (!do_key(filename, linenum,
+                                    key, *cp ? cp : filename))
+                                        ret = 0;
+                                found = 1;
+                        }
+                }
+                key_free(key);
+        }
+        if (f != stdin)
+                fclose(f);
+
+        if (!found && filename) {
+                key = key_load_public(filename, &comment);
+                if (key) {
+                        if (!do_key(filename, 1, key, comment))
+                                ret = 0;
+                        found = 1;
+                }
+                if (comment)
+                        xfree(comment);
+        }
+
+        return ret;
+}
+
+static int
+do_host(int quiet_open)
+{
+        int i;
+        struct stat st;
+        int ret = 1;
+
+        for (i = 0; default_host_files[i]; i++) {
+                if (stat(default_host_files[i], &st) < 0 && errno == ENOENT)
+                        continue;
+                if (!do_filename(default_host_files[i], quiet_open))
+                        ret = 0;
+        }
+
+        return ret;
+}
+
+static int
+do_user(const char *dir)
+{
+        int i;
+        char *file;
+        struct stat st;
+        int ret = 1;
+
+        for (i = 0; default_files[i]; i++) {
+                xasprintf(&file, "%s/%s", dir, default_files[i]);
+                if (stat(file, &st) < 0 && errno == ENOENT) {
+                        xfree(file);
+                        continue;
+                }
+                if (!do_filename(file, 0))
+                        ret = 0;
+                xfree(file);
+        }
+
+        return ret;
+}
+
+int
+main(int argc, char **argv)
+{
+        int opt, all_users = 0;
+        int ret = 1;
+        extern int optind;
+
+        /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+        sanitise_stdfd();
+
+        __progname = ssh_get_progname(argv[0]);
+
+        SSLeay_add_all_algorithms();
+        log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
+
+        /* We don't need the RNG ourselves, but symbol references here allow
+         * ld to link us properly.
+         */
+        seed_rng();
+
+        while ((opt = getopt(argc, argv, "ahqv")) != -1) {
+                switch (opt) {
+                case 'a':
+                        all_users = 1;
+                        break;
+                case 'q':
+                        verbosity--;
+                        break;
+                case 'v':
+                        verbosity++;
+                        break;
+                case 'h':
+                default:
+                        usage();
+                }
+        }
+
+        if (all_users) {
+                struct passwd *pw;
+
+                if (!do_host(0))
+                        ret = 0;
+
+                while ((pw = getpwent()) != NULL) {
+                        if (pw->pw_dir) {
+                                temporarily_use_uid(pw);
+                                if (!do_user(pw->pw_dir))
+                                        ret = 0;
+                                restore_uid();
+                        }
+                }
+        } else if (optind == argc) {
+                struct passwd *pw;
+
+                if (!do_host(1))
+                        ret = 0;
+
+                if ((pw = getpwuid(geteuid())) == NULL)
+                        fprintf(stderr, "No user found with uid %u\n",
+                            (u_int)geteuid());
+                else {
+                        if (!do_user(pw->pw_dir))
+                                ret = 0;
+                }
+        } else {
+                while (optind < argc)
+                        if (!do_filename(argv[optind++], 0))
+                                ret = 0;
+        }
+
+        if (verbosity >= 0) {
+                if (some_unknown) {
+                        printf("#\n");
+                        printf("# The status of some keys on your system is unknown.\n");
+                        printf("# You may need to install additional blacklist files.\n");
+                }
+                if (some_compromised) {
+                        printf("#\n");
+                        printf("# Some keys on your system have been compromised!\n");
+                        printf("# You must replace them using ssh-keygen(1).\n");
+                }
+                if (some_unknown || some_compromised) {
+                        printf("#\n");
+                        printf("# See the ssh-vulnkey(1) manual page for further advice.\n");
+                } else if (some_keys && verbosity > 0) {
+                        printf("#\n");
+                        printf("# No blacklisted keys!\n");
+                }
+        }
+
+        return ret;
+}