factor SSH_AGENT_CONSTRAIN_EXTENSION parsing into its own function

and remove an unused variable; ok dtucker@

diff --git a/usr.bin/ssh/ssh-agent.c b/usr.bin/ssh/ssh-agent.c
index 8731075..f49306b 100644 (file)
--- a/usr.bin/ssh/ssh-agent.c
+++ b/usr.bin/ssh/ssh-agent.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-agent.c,v 1.276 2021/02/02 22:35:14 djm Exp $ */
+/* $OpenBSD: ssh-agent.c,v 1.277 2021/02/12 03:14:18 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -560,6 +560,44 @@ reaper(void)
                return (deadline - now);
 }
 
+static int
+parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp)
+{
+       char *ext_name = NULL;
+       int r;
+
+       if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) {
+               error_fr(r, "parse constraint extension");
+               goto out;
+       }
+       debug_f("constraint ext %s", ext_name);
+       if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
+               if (sk_providerp == NULL) {
+                       error_f("%s not valid here", ext_name);
+                       r = SSH_ERR_INVALID_FORMAT;
+                       goto out;
+               }
+               if (*sk_providerp != NULL) {
+                       error_f("%s already set", ext_name);
+                       r = SSH_ERR_INVALID_FORMAT;
+                       goto out;
+               }
+               if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) {
+                       error_fr(r, "parse %s", ext_name);
+                       goto out;
+               }
+       } else {
+               error_f("unsupported constraint \"%s\"", ext_name);
+               r = SSH_ERR_FEATURE_UNSUPPORTED;
+               goto out;
+       }
+       /* success */
+       r = 0;
+ out:
+       free(ext_name);
+       return r;
+}
+
 static int
 parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
     u_int *secondsp, int *confirmp, char **sk_providerp)
@@ -567,23 +605,22 @@ parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
        u_char ctype;
        int r;
        u_int seconds, maxsign = 0;
-       char *ext_name = NULL;
-       struct sshbuf *b = NULL;
 
        while (sshbuf_len(m)) {
                if ((r = sshbuf_get_u8(m, &ctype)) != 0) {
                        error_fr(r, "parse constraint type");
-                       goto err;
+                       goto out;
                }
                switch (ctype) {
                case SSH_AGENT_CONSTRAIN_LIFETIME:
                        if (*deathp != 0) {
                                error_f("lifetime already set");
-                               goto err;
+                               r = SSH_ERR_INVALID_FORMAT;
+                               goto out;
                        }
                        if ((r = sshbuf_get_u32(m, &seconds)) != 0) {
                                error_fr(r, "parse lifetime constraint");
-                               goto err;
+                               goto out;
                        }
                        *deathp = monotime() + seconds;
                        *secondsp = seconds;
@@ -591,65 +628,46 @@ parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
                case SSH_AGENT_CONSTRAIN_CONFIRM:
                        if (*confirmp != 0) {
                                error_f("confirm already set");
-                               goto err;
+                               r = SSH_ERR_INVALID_FORMAT;
+                               goto out;
                        }
                        *confirmp = 1;
                        break;
                case SSH_AGENT_CONSTRAIN_MAXSIGN:
                        if (k == NULL) {
                                error_f("maxsign not valid here");
-                               goto err;
+                               r = SSH_ERR_INVALID_FORMAT;
+                               goto out;
                        }
                        if (maxsign != 0) {
                                error_f("maxsign already set");
-                               goto err;
+                               r = SSH_ERR_INVALID_FORMAT;
+                               goto out;
                        }
                        if ((r = sshbuf_get_u32(m, &maxsign)) != 0) {
                                error_fr(r, "parse maxsign constraint");
-                               goto err;
+                               goto out;
                        }
                        if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
                                error_fr(r, "enable maxsign");
-                               goto err;
+                               goto out;
                        }
                        break;
                case SSH_AGENT_CONSTRAIN_EXTENSION:
-                       if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) {
-                               error_fr(r, "parse constraint extension");
-                               goto err;
-                       }
-                       debug_f("constraint ext %s", ext_name);
-                       if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
-                               if (sk_providerp == NULL) {
-                                       error_f("%s not valid here", ext_name);
-                                       goto err;
-                               }
-                               if (*sk_providerp != NULL) {
-                                       error_f("%s already set", ext_name);
-                                       goto err;
-                               }
-                               if ((r = sshbuf_get_cstring(m,
-                                   sk_providerp, NULL)) != 0) {
-                                       error_fr(r, "parse %s", ext_name);
-                                       goto err;
-                               }
-                       } else {
-                               error_f("unsupported constraint \"%s\"",
-                                   ext_name);
-                               goto err;
-                       }
-                       free(ext_name);
+                       if ((r = parse_key_constraint_extension(m,
+                           sk_providerp)) != 0)
+                               goto out; /* error already logged */
                        break;
                default:
                        error_f("Unknown constraint %d", ctype);
- err:
-                       free(ext_name);
-                       sshbuf_free(b);
-                       return -1;
+                       r = SSH_ERR_FEATURE_UNSUPPORTED;
+                       goto out;
                }
        }
        /* success */
-       return 0;
+       r = 0;
+ out:
+       return r;
 }
 
 static void