upstream: factor out parsing of allowed-signers lines

OpenBSD-Commit-ID: 85ee6aeff608371826019ea85e55bfa87f79d06e

1 files changed, 87 insertions, 27 deletions

diff --git a/sshsig.c b/sshsig.c
index abba3f67b..6d72f92f5 100644
--- a/sshsig.c
+++ b/sshsig.c
@@ -679,56 +679,116 @@ sshsigopt_free(struct sshsigopt *opts)
 }
 
 static int
-check_allowed_keys_line(const char *path, u_long linenum, char *line,
-    const struct sshkey *sign_key, const char *principal,
-    const char *sig_namespace)
+parse_principals_key_and_options(const char *path, u_long linenum, char *line,
+    const char *required_principal, char **principalsp, struct sshkey **keyp,
+    struct sshsigopt **sigoptsp)
 {
-        struct sshkey *found_key = NULL;
-        char *cp, *opts = NULL, *identities = NULL;
-        int r, found = 0;
+        char *opts = NULL, *tmp, *cp, *principals = NULL;
         const char *reason = NULL;
         struct sshsigopt *sigopts = NULL;
+        struct sshkey *key = NULL;
+        int r = SSH_ERR_INTERNAL_ERROR;
 
-        if ((found_key = sshkey_new(KEY_UNSPEC)) == NULL) {
-                error("%s: sshkey_new failed", __func__);
-                return SSH_ERR_ALLOC_FAIL;
-        }
+        if (principalsp != NULL)
+                *principalsp = NULL;
+        if (sigoptsp != NULL)
+                *sigoptsp = NULL;
+        if (keyp != NULL)
+                *keyp = NULL;
 
-        /* format: identity[,identity...] [option[,option...]] key */
         cp = line;
         cp = cp + strspn(cp, " \t"); /* skip leading whitespace */
         if (*cp == '#' || *cp == '\0')
-                goto done;
-        if ((identities = strdelimw(&cp)) == NULL) {
+                return SSH_ERR_KEY_NOT_FOUND; /* blank or all-comment line */
+
+        /* format: identity[,identity...] [option[,option...]] key */
+        if ((tmp = strdelimw(&cp)) == NULL) {
                 error("%s:%lu: invalid line", path, linenum);
-                goto done;
+                r = SSH_ERR_INVALID_FORMAT;
+                goto out;
         }
-        if (match_pattern_list(principal, identities, 0) != 1) {
-                /* principal didn't match */
-                goto done;
+        if ((principals = strdup(tmp)) == NULL) {
+                error("%s: strdup failed", __func__);
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        /*
+         * Bail out early if we're looking for a particular principal and this
+         * line does not list it.
+         */
+        if (required_principal != NULL) {
+                if (match_pattern_list(required_principal,
+                    principals, 0) != 1) {
+                        /* principal didn't match */
+                        r = SSH_ERR_KEY_NOT_FOUND;
+                        goto out;
+                }
+                debug("%s: %s:%lu: matched principal \"%s\"",
+                    __func__, path, linenum, required_principal);
         }
-        debug("%s: %s:%lu: matched principal \"%s\"",
-            __func__, path, linenum, principal);
 
-        if (sshkey_read(found_key, &cp) != 0) {
+        if ((key = sshkey_new(KEY_UNSPEC)) == NULL) {
+                error("%s: sshkey_new failed", __func__);
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if (sshkey_read(key, &cp) != 0) {
                 /* no key? Check for options */
                 opts = cp;
                 if (sshkey_advance_past_options(&cp) != 0) {
-                        error("%s:%lu: invalid options",
-                            path, linenum);
-                        goto done;
+                        error("%s:%lu: invalid options", path, linenum);
+                        r = SSH_ERR_INVALID_FORMAT;
+                        goto out;
                 }
                 *cp++ = '\0';
                 skip_space(&cp);
-                if (sshkey_read(found_key, &cp) != 0) {
-                        error("%s:%lu: invalid key", path,
-                            linenum);
-                        goto done;
+                if (sshkey_read(key, &cp) != 0) {
+                        error("%s:%lu: invalid key", path, linenum);
+                        r = SSH_ERR_INVALID_FORMAT;
+                        goto out;
                 }
         }
         debug3("%s:%lu: options %s", path, linenum, opts == NULL ? "" : opts);
         if ((sigopts = sshsigopt_parse(opts, path, linenum, &reason)) == NULL) {
                 error("%s:%lu: bad options: %s", path, linenum, reason);
+                r = SSH_ERR_INVALID_FORMAT;
+                goto out;
+        }
+        /* success */
+        if (principalsp != NULL) {
+                *principalsp = principals;
+                principals = NULL; /* transferred */
+        }
+        if (sigoptsp != NULL) {
+                *sigoptsp = sigopts;
+                sigopts = NULL; /* transferred */
+        }
+        if (keyp != NULL) {
+                *keyp = key;
+                key = NULL; /* transferred */
+        }
+        r = 0;
+ out:
+        free(principals);
+        sshsigopt_free(sigopts);
+        sshkey_free(key);
+        return r;
+}
+
+static int
+check_allowed_keys_line(const char *path, u_long linenum, char *line,
+    const struct sshkey *sign_key, const char *principal,
+    const char *sig_namespace)
+{
+        struct sshkey *found_key = NULL;
+        int r, found = 0;
+        const char *reason = NULL;
+        struct sshsigopt *sigopts = NULL;
+
+        /* Parse the line */
+        if ((r = parse_principals_key_and_options(path, linenum, line,
+            principal, NULL, &found_key, &sigopts)) != 0) {
+                /* error already logged */
                 goto done;
         }