upstream: switch percent_expand() to use sshbuf instead of a limited

fixed buffer; ok markus@

OpenBSD-Commit-ID: 3f9ef20bca5ef5058b48c1cac67c53b9a1d15711

1 files changed, 24 insertions, 15 deletions

diff --git a/misc.c b/misc.c
index b90aac5c0..c94d2c266 100644
--- a/misc.c
+++ b/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.139 2019/06/28 13:35:04 deraadt Exp $ */
+/* $OpenBSD: misc.c,v 1.140 2019/08/16 06:13:15 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -1049,13 +1049,18 @@ char *
 percent_expand(const char *string, ...)
 {
 #define EXPAND_MAX_KEYS 16
-        u_int num_keys, i, j;
+        u_int num_keys, i;
         struct {
                 const char *key;
                 const char *repl;
         } keys[EXPAND_MAX_KEYS];
-        char buf[4096];
+        struct sshbuf *buf;
         va_list ap;
+        int r;
+        char *ret;
+
+        if ((buf = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
 
         /* Gather keys */
         va_start(ap, string);
@@ -1072,14 +1077,13 @@ percent_expand(const char *string, ...)
         va_end(ap);
 
         /* Expand string */
-        *buf = '\0';
         for (i = 0; *string != '\0'; string++) {
                 if (*string != '%') {
  append:
-                        buf[i++] = *string;
-                        if (i >= sizeof(buf))
-                                fatal("%s: string too long", __func__);
-                        buf[i] = '\0';
+                        if ((r = sshbuf_put_u8(buf, *string)) != 0) {
+                                fatal("%s: sshbuf_put_u8: %s",
+                                    __func__, ssh_err(r));
+                        }
                         continue;
                 }
                 string++;
@@ -1088,18 +1092,23 @@ percent_expand(const char *string, ...)
                         goto append;
                 if (*string == '\0')
                         fatal("%s: invalid format", __func__);
-                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("%s: string too long", __func__);
+                for (i = 0; i < num_keys; i++) {
+                        if (strchr(keys[i].key, *string) != NULL) {
+                                if ((r = sshbuf_put(buf, keys[i].repl,
+                                    strlen(keys[i].repl))) != 0) {
+                                        fatal("%s: sshbuf_put: %s",
+                                            __func__, ssh_err(r));
+                                }
                                 break;
                         }
                 }
-                if (j >= num_keys)
+                if (i >= num_keys)
                         fatal("%s: unknown key %%%c", __func__, *string);
         }
-        return (xstrdup(buf));
+        if ((ret = sshbuf_dup_string(buf)) == NULL)
+                fatal("%s: sshbuf_dup_string failed", __func__);
+        sshbuf_free(buf);
+        return ret;
 #undef EXPAND_MAX_KEYS
 }