[src/trunk]: src/lib/libc/net avoid sprintf. use snprintf with picky error t...

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

details:   https://anonhg.NetBSD.org/src/rev/d61e91ba3b4e
branches:  trunk
changeset: 535369:d61e91ba3b4e
user:      itojun <itojun%NetBSD.org@localhost>
date:      Fri Aug 16 12:18:06 2002 +0000

description:
avoid sprintf.  use snprintf with picky error traps.

diffstat:

 lib/libc/net/inet_net_ntop.c |  76 ++++++++++++++++++++++++++++---------------
 1 files changed, 49 insertions(+), 27 deletions(-)

diffs (174 lines):

diff -r 52a7803d4880 -r d61e91ba3b4e lib/libc/net/inet_net_ntop.c
--- a/lib/libc/net/inet_net_ntop.c      Fri Aug 16 12:10:37 2002 +0000
+++ b/lib/libc/net/inet_net_ntop.c      Fri Aug 16 12:18:06 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: inet_net_ntop.c,v 1.14 2001/12/09 01:17:36 lukem Exp $ */
+/*     $NetBSD: inet_net_ntop.c,v 1.15 2002/08/16 12:18:06 itojun Exp $        */
 
 /*
  * Copyright (c) 1996,1999 by Internet Software Consortium.
@@ -22,7 +22,7 @@
 #if 0
 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.8 2001/09/27 15:08:36 marka Exp ";
 #else
-__RCSID("$NetBSD: inet_net_ntop.c,v 1.14 2001/12/09 01:17:36 lukem Exp $");
+__RCSID("$NetBSD: inet_net_ntop.c,v 1.15 2002/08/16 12:18:06 itojun Exp $");
 #endif
 #endif
 
@@ -42,12 +42,6 @@
 __weak_alias(inet_net_ntop,_inet_net_ntop)
 #endif
 
-#ifdef SPRINTF_CHAR
-# define SPRINTF(x) strlen(sprintf/**/x)
-#else
-# define SPRINTF(x) ((size_t)sprintf x)
-#endif
-
 static char *  inet_net_ntop_ipv4(const u_char *, int, char *, size_t);
 static char *  inet_net_ntop_ipv6(const u_char *, int, char *, size_t);
 
@@ -96,55 +90,69 @@
 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
 {
        char *odst = dst;
-       char *t;
        u_int m;
        int b;
+       char *ep;
+       int advance;
 
        _DIAGASSERT(src != NULL);
        _DIAGASSERT(dst != NULL);
 
+       ep = dst + size;
+       if (ep < dst)
+               goto emsgsize;
+
        if (bits < 0 || bits > 32) {
                errno = EINVAL;
                return (NULL);
        }
        if (bits == 0) {
-               if (size < sizeof "0")
+               if (ep - dst < sizeof "0")
                        goto emsgsize;
                *dst++ = '0';
-               size--;
                *dst = '\0';
        }
 
        /* Format whole octets. */
        for (b = bits / 8; b > 0; b--) {
-               if (size <= sizeof "255.")
+               if (ep - dst <= sizeof "255.")
+                       goto emsgsize;
+               advance = snprintf(dst, ep - dst, "%u", *src++);
+               if (advance <= 0 || advance >= ep - dst)
                        goto emsgsize;
-               t = dst;
-               dst += SPRINTF((dst, "%u", *src++));
+               dst += advance;
                if (b > 1) {
+                       if (dst + 1 >= ep)
+                               goto emsgsize;
                        *dst++ = '.';
                        *dst = '\0';
                }
-               size -= (size_t)(dst - t);
        }
 
        /* Format partial octet. */
        b = bits % 8;
        if (b > 0) {
-               if (size <= sizeof ".255")
+               if (ep - dst <= sizeof ".255")
                        goto emsgsize;
-               t = dst;
-               if (dst != odst)
+               if (dst != odst) {
+                       if (dst + 1 >= ep)
+                               goto emsgsize;
                        *dst++ = '.';
+               }
                m = ((1 << b) - 1) << (8 - b);
-               dst += SPRINTF((dst, "%u", *src & m));
-               size -= (size_t)(dst - t);
+               advance = snprintf(dst, ep - dst, "%u", *src & m);
+               if (advance <= 0 || advance >= ep - dst)
+                       goto emsgsize;
+               dst += advance;
        }
 
        /* Format CIDR /width. */
-       if (size <= sizeof "/32")
+       if (ep - dst <= sizeof "/32")
                goto emsgsize;
-       dst += SPRINTF((dst, "/%u", bits));
+       advance = snprintf(dst, ep - dst, "/%u", bits);
+       if (advance <= 0 || advance >= ep - dst)
+               goto emsgsize;
+       dst += advance;
        return (odst);
 
  emsgsize:
@@ -184,6 +192,8 @@
        char    *cp;
        int     words;
        u_char  *s;
+       char    *ep;
+       int     advance;
 
        _DIAGASSERT(src != NULL);
        _DIAGASSERT(dst != NULL);
@@ -194,6 +204,7 @@
        }
 
        cp = outbuf;
+       ep = outbuf + sizeof(outbuf);
 
        if (bits == 0) {
                *cp++ = ':';
@@ -256,25 +267,36 @@
                                continue;
                        }
 
-                       if (is_ipv4 && p > 5 ) {
+                       if (is_ipv4 && p > 5) {
                                *cp++ = (p == 6) ? ':' : '.';
-                               cp += SPRINTF((cp, "%u", *s++));
+                               advance = snprintf(cp, ep - cp, "%u", *s++);
+                               if (advance <= 0 || advance >= ep - cp)
+                                       goto emsgsize;
+                               cp += advance;
                                /* we can potentially drop the last octet */
                                if (p != 7 || bits > 120) {
                                        *cp++ = '.';
-                                       cp += SPRINTF((cp, "%u", *s++));
+                                       advance = snprintf(cp, ep - cp, "%u",
+                                           *s++);
+                                       if (advance <= 0 || advance >= ep - cp)
+                                               goto emsgsize;
+                                       cp += advance;
                                }
                        } else {
                                if (cp != outbuf)
                                        *cp++ = ':';
-                               cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
+                               advance = snprintf(cp, ep - cp, "%x",
+                                   *s * 256 + s[1]);
+                               if (advance <= 0 || advance >= ep - cp)
+                                       goto emsgsize;
+                               cp += advance;
                                s += 2;
                        }
                }
        }
        /* Format CIDR /width. */
        /* LINTED */
-       SPRINTF((cp, "/%u", bits));
+       snprintf(cp, ep - cp, "/%u", bits);
        if (strlen(outbuf) + 1 > size)
                goto emsgsize;
        strcpy(dst, outbuf);