upstream commit

Allow fingerprinting from standard input "ssh-keygen -lf
 -"

Support fingerprinting multiple plain keys in a file and authorized_keys
files too (bz#1319)

ok markus@

Upstream-ID: 903f8b4502929d6ccf53509e4e07eae084574b77

1 files changed, 127 insertions, 88 deletions

diff --git a/ssh-keygen.c b/ssh-keygen.c
index f58462044..5c02d7817 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.278 2015/11/13 04:34:15 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.279 2015/11/16 22:53:07 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -808,116 +808,155 @@ do_download(struct passwd *pw)
 #endif /* ENABLE_PKCS11 */
 }
 
+static struct sshkey *
+try_read_key(char **cpp)
+{
+        struct sshkey *ret;
+        int r;
+
+        if ((ret = sshkey_new(KEY_RSA1)) == NULL)
+                fatal("sshkey_new failed");
+        /* Try RSA1 */
+        if ((r = sshkey_read(ret, cpp)) == 0)
+                return ret;
+        /* Try modern */
+        sshkey_free(ret);
+        if ((ret = sshkey_new(KEY_UNSPEC)) == NULL)
+                fatal("sshkey_new failed");
+        if ((r = sshkey_read(ret, cpp)) == 0)
+                return ret;
+        /* Not a key */
+        sshkey_free(ret);
+        return NULL;
+}
+
 static void
-do_fingerprint(struct passwd *pw)
+fingerprint_one_key(const struct sshkey *public, const char *comment)
 {
-        FILE *f;
-        struct sshkey *public;
-        char *comment = NULL, *cp, *ep, line[16*1024], *fp, *ra;
-        int r, i, skip = 0, num = 0, invalid = 1;
+        char *fp = NULL, *ra = NULL;
         enum sshkey_fp_rep rep;
         int fptype;
-        struct stat st;
 
         fptype = print_bubblebabble ? SSH_DIGEST_SHA1 : fingerprint_hash;
         rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_DEFAULT;
+        fp = sshkey_fingerprint(public, fptype, rep);
+        ra = sshkey_fingerprint(public, fingerprint_hash, SSH_FP_RANDOMART);
+        if (fp == NULL || ra == NULL)
+                fatal("%s: sshkey_fingerprint failed", __func__);
+        printf("%u %s %s (%s)\n", sshkey_size(public), fp,
+            comment ? comment : "no comment", sshkey_type(public));
+        if (log_level >= SYSLOG_LEVEL_VERBOSE)
+                printf("%s\n", ra);
+        free(ra);
+        free(fp);
+}
+
+static void
+fingerprint_private(const char *path)
+{
+        struct stat st;
+        char *comment = NULL;
+        struct sshkey *public = NULL;
+        int r;
+
+        if (stat(identity_file, &st) < 0)
+                fatal("%s: %s", path, strerror(errno));
+        if ((r = sshkey_load_public(path, &public, &comment)) != 0)
+                fatal("Error loading public key \"%s\": %s", path, ssh_err(r));
+        fingerprint_one_key(public, comment);
+        sshkey_free(public);
+        free(comment);
+}
+
+static void
+do_fingerprint(struct passwd *pw)
+{
+        FILE *f;
+        struct sshkey *public = NULL;
+        char *comment = NULL, *cp, *ep, line[16*1024];
+        int i, invalid = 1;
+        const char *path;
+        long int lnum = 0;
+
         if (!have_identity)
                 ask_filename(pw, "Enter file in which the key is");
-        if (stat(identity_file, &st) < 0)
-                fatal("%s: %s", identity_file, strerror(errno));
-        if ((r = sshkey_load_public(identity_file, &public, &comment)) != 0)
-                debug2("Error loading public key \"%s\": %s",
-                    identity_file, ssh_err(r));
-        else {
-                fp = sshkey_fingerprint(public, fptype, rep);
-                ra = sshkey_fingerprint(public, fingerprint_hash,
-                    SSH_FP_RANDOMART);
-                if (fp == NULL || ra == NULL)
-                        fatal("%s: sshkey_fingerprint fail", __func__);
-                printf("%u %s %s (%s)\n", sshkey_size(public), fp, comment,
-                    sshkey_type(public));
-                if (log_level >= SYSLOG_LEVEL_VERBOSE)
-                        printf("%s\n", ra);
-                sshkey_free(public);
-                free(comment);
-                free(ra);
-                free(fp);
-                exit(0);
-        }
-        if (comment) {
-                free(comment);
-                comment = NULL;
-        }
+        path = identity_file;
 
-        if ((f = fopen(identity_file, "r")) == NULL)
-                fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
+        if (strcmp(identity_file, "-") == 0) {
+                f = stdin;
+                path = "(stdin)";
+        } else if ((f = fopen(path, "r")) == NULL)
+                fatal("%s: %s: %s", __progname, path, strerror(errno));
 
-        while (fgets(line, sizeof(line), f)) {
-                if ((cp = strchr(line, '\n')) == NULL) {
-                        error("line %d too long: %.40s...",
-                            num + 1, line);
-                        skip = 1;
+        while (read_keyfile_line(f, path, line, sizeof(line), &lnum) == 0) {
+                cp = line;
+                cp[strcspn(cp, "\n")] = '\0';
+                /* Trim leading space and comments */
+                cp = line + strspn(line, " \t");
+                if (*cp == '#' || *cp == '\0')
                         continue;
+
+                /*
+                 * Input may be plain keys, private keys, authorized_keys
+                 * or known_hosts.
+                 */
+
+                /*
+                 * Try private keys first. Assume a key is private if
+                 * "SSH PRIVATE KEY" appears on the first line and we're
+                 * not reading from stdin (XXX support private keys on stdin).
+                 */
+                if (lnum == 1 && strcmp(identity_file, "-") != 0 &&
+                    strstr(cp, "SSH PRIVATE KEY") != NULL) {
+                        fclose(f);
+                        fingerprint_private(path);
+                        exit(0);
+                }
+
+                /*
+                 * If it's not a private key, then this must be prepared to
+                 * accept a public key prefixed with a hostname or options.
+                 * Try a bare key first, otherwise skip the leading stuff.
+                 */
+                if ((public = try_read_key(&cp)) == NULL) {
+                        i = strtol(cp, &ep, 10);
+                        if (i == 0 || ep == NULL ||
+                            (*ep != ' ' && *ep != '\t')) {
+                                int quoted = 0;
+
+                                comment = cp;
+                                for (; *cp && (quoted || (*cp != ' ' &&
+                                    *cp != '\t')); cp++) {
+                                        if (*cp == '\\' && cp[1] == '"')
+                                                cp++;   /* Skip both */
+                                        else if (*cp == '"')
+                                                quoted = !quoted;
+                                }
+                                if (!*cp)
+                                        continue;
+                                *cp++ = '\0';
+                        }
                 }
-                num++;
-                if (skip) {
-                        skip = 0;
+                /* Retry after parsing leading hostname/key options */
+                if (public == NULL && (public = try_read_key(&cp)) == NULL) {
+                        debug("%s:%ld: not a public key", path, lnum);
                         continue;
                 }
-                *cp = '\0';
 
-                /* Skip leading whitespace, empty and comment lines. */
-                for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
+                /* Find trailing comment, if any */
+                for (; *cp == ' ' || *cp == '\t'; cp++)
                         ;
-                if (!*cp || *cp == '\n' || *cp == '#')
-                        continue;
-                i = strtol(cp, &ep, 10);
-                if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
-                        int quoted = 0;
+                if (*cp != '\0' && *cp != '#')
                         comment = cp;
-                        for (; *cp && (quoted || (*cp != ' ' &&
-                            *cp != '\t')); cp++) {
-                                if (*cp == '\\' && cp[1] == '"')
-                                        cp++;   /* Skip both */
-                                else if (*cp == '"')
-                                        quoted = !quoted;
-                        }
-                        if (!*cp)
-                                continue;
-                        *cp++ = '\0';
-                }
-                ep = cp;
-                if ((public = sshkey_new(KEY_RSA1)) == NULL)
-                        fatal("sshkey_new failed");
-                if ((r = sshkey_read(public, &cp)) != 0) {
-                        cp = ep;
-                        sshkey_free(public);
-                        if ((public = sshkey_new(KEY_UNSPEC)) == NULL)
-                                fatal("sshkey_new failed");
-                        if ((r = sshkey_read(public, &cp)) != 0) {
-                                sshkey_free(public);
-                                continue;
-                        }
-                }
-                comment = *cp ? cp : comment;
-                fp = sshkey_fingerprint(public, fptype, rep);
-                ra = sshkey_fingerprint(public, fingerprint_hash,
-                    SSH_FP_RANDOMART);
-                if (fp == NULL || ra == NULL)
-                        fatal("%s: sshkey_fingerprint fail", __func__);
-                printf("%u %s %s (%s)\n", sshkey_size(public), fp,
-                    comment ? comment : "no comment", sshkey_type(public));
-                if (log_level >= SYSLOG_LEVEL_VERBOSE)
-                        printf("%s\n", ra);
-                free(ra);
-                free(fp);
+
+                fingerprint_one_key(public, comment);
                 sshkey_free(public);
-                invalid = 0;
+                invalid = 0; /* One good key in the file is sufficient */
         }
         fclose(f);
 
         if (invalid)
-                fatal("%s is not a public key file.", identity_file);
+                fatal("%s is not a public key file.", path);
         exit(0);
 }