- djm@cvs.openbsd.org 2009/11/20 03:24:07

     [misc.c]
     correct off-by-one in percent_expand(): we would fatal() when trying
     to expand EXPAND_MAX_KEYS, allowing only EXPAND_MAX_KEYS-1 to actually
     work.  Note that nothing in OpenSSH actually uses close to this limit at
     present.  bz#1607 from Jan.Pechanec AT Sun.COM

2 files changed, 15 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index b677213f8..7a2a0e322 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -81,6 +81,12 @@
    - dtucker@cvs.openbsd.org 2009/11/20 00:59:36
      [sshconnect2.c]
      Use the HostKeyAlias when prompting for passwords.  bz#1039, ok djm@
+   - djm@cvs.openbsd.org 2009/11/20 03:24:07
+     [misc.c]
+     correct off-by-one in percent_expand(): we would fatal() when trying
+     to expand EXPAND_MAX_KEYS, allowing only EXPAND_MAX_KEYS-1 to actually
+     work.  Note that nothing in OpenSSH actually uses close to this limit at
+     present.  bz#1607 from Jan.Pechanec AT Sun.COM
 
 20091226
  - (tim) [contrib/cygwin/Makefile] Install ssh-copy-id and ssh-copy-id.1
diff --git a/misc.c b/misc.c
index f0f1fd841..21db00a13 100644
--- a/misc.c
+++ b/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.72 2009/10/28 16:38:18 reyk Exp $ */
+/* $OpenBSD: misc.c,v 1.73 2009/11/20 03:24:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -597,11 +597,11 @@ char *
 percent_expand(const char *string, ...)
 {
 #define EXPAND_MAX_KEYS 16
+        u_int num_keys, i, j;
         struct {
                 const char *key;
                 const char *repl;
         } keys[EXPAND_MAX_KEYS];
-        u_int num_keys, i, j;
         char buf[4096];
         va_list ap;
 
@@ -613,13 +613,12 @@ percent_expand(const char *string, ...)
                         break;
                 keys[num_keys].repl = va_arg(ap, char *);
                 if (keys[num_keys].repl == NULL)
-                        fatal("percent_expand: NULL replacement");
+                        fatal("%s: NULL replacement", __func__);
         }
+        if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
+                fatal("%s: too many keys", __func__);
         va_end(ap);
 
-        if (num_keys >= EXPAND_MAX_KEYS)
-                fatal("percent_expand: too many keys");
-
         /* Expand string */
         *buf = '\0';
         for (i = 0; *string != '\0'; string++) {
@@ -627,23 +626,24 @@ percent_expand(const char *string, ...)
  append:
                         buf[i++] = *string;
                         if (i >= sizeof(buf))
-                                fatal("percent_expand: string too long");
+                                fatal("%s: string too long", __func__);
                         buf[i] = '\0';
                         continue;
                 }
                 string++;
+                /* %% case */
                 if (*string == '%')
                         goto append;
                 for (j = 0; j < num_keys; j++) {
                         if (strchr(keys[j].key, *string) != NULL) {
                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
                                 if (i >= sizeof(buf))
-                                        fatal("percent_expand: string too long");
+                                        fatal("%s: string too long", __func__);
                                 break;
                         }
                 }
                 if (j >= num_keys)
-                        fatal("percent_expand: unknown key %%%c", *string);
+                        fatal("%s: unknown key %%%c", __func__, *string);
         }
         return (xstrdup(buf));
 #undef EXPAND_MAX_KEYS