[src/trunk]: src/lib/libc/net be more picky about string buffer manipulation....

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8d850384ad38
branches:  trunk
changeset: 535351:8d850384ad38
user:      itojun <itojun%NetBSD.org@localhost>
date:      Fri Aug 16 07:39:44 2002 +0000

description:
be more picky about string buffer manipulation.  hints from freebsd

diffstat:

 lib/libc/net/inet_ntop.c |  48 ++++++++++++++++++++++++++++++------------------
 1 files changed, 30 insertions(+), 18 deletions(-)

diffs (125 lines):

diff -r e9c1a7985163 -r 8d850384ad38 lib/libc/net/inet_ntop.c
--- a/lib/libc/net/inet_ntop.c  Fri Aug 16 07:10:56 2002 +0000
+++ b/lib/libc/net/inet_ntop.c  Fri Aug 16 07:39:44 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: inet_ntop.c,v 1.10 2002/05/14 18:57:31 kleink Exp $    */
+/*     $NetBSD: inet_ntop.c,v 1.11 2002/08/16 07:39:44 itojun Exp $    */
 
 /* Copyright (c) 1996 by Internet Software Consortium.
  *
@@ -21,7 +21,7 @@
 #if 0
 static char rcsid[] = "Id: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp ";
 #else
-__RCSID("$NetBSD: inet_ntop.c,v 1.10 2002/05/14 18:57:31 kleink Exp $");
+__RCSID("$NetBSD: inet_ntop.c,v 1.11 2002/08/16 07:39:44 itojun Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -43,12 +43,6 @@
 __weak_alias(inet_ntop,_inet_ntop)
 #endif
 
-#ifdef SPRINTF_CHAR
-# define SPRINTF(x) strlen(sprintf/**/x)
-#else
-# define SPRINTF(x) ((size_t)sprintf x)
-#endif
-
 /*
  * WARNING: Don't even consider trying to compile this on a system where
  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
@@ -107,17 +101,19 @@
        char *dst;
        socklen_t size;
 {
-       static const char fmt[] = "%u.%u.%u.%u";
        char tmp[sizeof "255.255.255.255"];
+       int l;
 
        _DIAGASSERT(src != NULL);
        _DIAGASSERT(dst != NULL);
 
-       if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
+       l = snprintf(tmp, sizeof(tmp), "%u.%u.%u.%u",
+           src[0], src[1], src[2], src[3]);
+       if (l <= 0 || l > size) {
                errno = ENOSPC;
                return (NULL);
        }
-       strcpy(dst, tmp);
+       strlcpy(dst, tmp, size);
        return (dst);
 }
 
@@ -140,10 +136,12 @@
         * 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;
 
        _DIAGASSERT(src != NULL);
        _DIAGASSERT(dst != NULL);
@@ -183,7 +181,8 @@
         * 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)) {
@@ -192,21 +191,34 @@
                        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, (socklen_t)(ep - tp)))
                                return (NULL);
                        tp += strlen(tp);
                        break;
                }
-               tp += SPRINTF((tp, "%x", words[i]));
+               advance = snprintf(tp, (size_t)(ep - tp), "%x", words[i]);
+               if (advance <= 0)
+                       return (NULL);
+               tp += advance;
        }
+       if (tp >= ep)
+               return (NULL);
        /* 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';
 
        /*
@@ -216,6 +228,6 @@
                errno = ENOSPC;
                return (NULL);
        }
-       strcpy(dst, tmp);
+       strlcpy(dst, tmp, size);
        return (dst);
 }