1 files changed, 26 insertions, 9 deletions

diff --git a/src/lib/libc/net/inet_ntop.c b/src/lib/libc/net/inet_ntop.c
index 212c0396b2..5293e80fc0 100644
--- a/src/lib/libc/net/inet_ntop.c
+++ b/src/lib/libc/net/inet_ntop.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: inet_ntop.c,v 1.3 2002/05/24 21:22:37 deraadt Exp $   */
+/*      $OpenBSD: inet_ntop.c,v 1.4 2002/08/19 03:01:54 itojun Exp $    */
 
 /* Copyright (c) 1996 by Internet Software Consortium.
  *
@@ -20,7 +20,7 @@
 #if 0
 static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.3 2002/05/24 21:22:37 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.4 2002/08/19 03:01:54 itojun Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -116,10 +116,12 @@ inet_ntop6(src, dst, size)
          * Keep this in mind if you think this function should have been coded
          * to use pointer overlays.  All the world's not a VAX.
          */
-        char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
+        char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
+        char *tp, *ep;
         struct { int base, len; } best, cur;
         u_int words[IN6ADDRSZ / INT16SZ];
         int i;
+        int advance;
 
         /*
          * Preprocess:
@@ -156,30 +158,45 @@ inet_ntop6(src, dst, size)
          * Format the result.
          */
         tp = tmp;
-        for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
+        ep = tmp + sizeof(tmp);
+        for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
                 /* Are we inside the best run of 0x00's? */
                 if (best.base != -1 && i >= best.base &&
                     i < (best.base + best.len)) {
-                        if (i == best.base)
+                        if (i == best.base) {
+                                if (tp + 1 >= ep)
+                                        return (NULL);
                                 *tp++ = ':';
+                        }
                         continue;
                 }
                 /* Are we following an initial run of 0x00s or any real hex? */
-                if (i != 0)
+                if (i != 0) {
+                        if (tp + 1 >= ep)
+                                return (NULL);
                         *tp++ = ':';
+                }
                 /* Is this address an encapsulated IPv4? */
                 if (i == 6 && best.base == 0 &&
                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
-                        if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
+                        if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
                                 return (NULL);
                         tp += strlen(tp);
                         break;
                 }
-                tp += sprintf(tp, "%x", words[i]);
+                advance = snprintf(tp, ep - tp, "%x", words[i]);
+                if (advance <= 0 || advance >= ep - tp)
+                        return (NULL);
+                tp += advance;
         }
         /* Was it a trailing run of 0x00's? */
-        if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
+        if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
+                if (tp + 1 >= ep)
+                        return (NULL);
                 *tp++ = ':';
+        }
+        if (tp + 1 >= ep)
+                return (NULL);
         *tp++ = '\0';
 
         /*