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Fix DNS getnetbyname(), which has been broken for at least 5.5 years

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(if not longer).
This commit is contained in:
lukem 2008-05-08 05:06:18 +00:00
parent 1da90a4ef8
commit 6e5e2748b3
1 changed files with 49 additions and 26 deletions
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75
lib/libc/net/getnetnamadr.c
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@ -1,4 +1,4 @@
/* $NetBSD: getnetnamadr.c,v 1.37 2007/01/27 22:27:35 christos Exp $ */
/* $NetBSD: getnetnamadr.c,v 1.38 2008/05/08 05:06:18 lukem Exp $ */
/* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
* Dep. Matematica Universidade de Coimbra, Portugal, Europe
@ -43,7 +43,7 @@ static char sccsid[] = "@(#)getnetbyaddr.c 8.1 (Berkeley) 6/4/93";
static char sccsid_[] = "from getnetnamadr.c 1.4 (Coimbra) 93/06/03";
static char rcsid[] = "Id: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp ";
#else
__RCSID("$NetBSD: getnetnamadr.c,v 1.37 2007/01/27 22:27:35 christos Exp $");
__RCSID("$NetBSD: getnetnamadr.c,v 1.38 2008/05/08 05:06:18 lukem Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@ -115,6 +115,48 @@ int _yp_getnetbyname(void *, void *, va_list);
struct netent *_ypnetent(char *);
#endif
/*
* parse_reversed_addr --
* parse str, which should be of the form 'd.c.b.a.IN-ADDR.ARPA'
* (a PTR as per RFC 1101) and convert into an in_addr_t of the
* address 'a.b.c.d'.
* returns 0 on success (storing in *result), or -1 on error.
*/
static int
parse_reversed_addr(const char *str, in_addr_t *result)
{
unsigned long octet[4];
const char *sp;
char *ep;
int octidx;
sp = str;
/* find the four octets 'd.b.c.a.' */
for (octidx = 0; octidx < 4; octidx++) {
/* ensure it's a number */
if (!isdigit((unsigned char)*sp))
return -1;
octet[octidx] = strtoul(sp, &ep, 10);
/* with a trailing '.' */
if (*ep != '.')
return -1;
/* and is 0 <= octet <= 255 */
if (octet[octidx] > 255)
return -1;
sp = ep + 1;
}
/* ensure trailer is correct */
if (strcasecmp(sp, "IN-ADDR.ARPA") != 0)
return -1;
*result = 0;
/* build result from octets in reverse */
for (octidx = 3; octidx >= 0; octidx--) {
*result <<= 8;
*result |= (octet[octidx] & 0xff);
}
return 0;
}
static struct netent *
getnetanswer(querybuf *answer, int anslen, int net_i)
{
@ -122,10 +164,9 @@ getnetanswer(querybuf *answer, int anslen, int net_i)
u_char *cp;
int n;
u_char *eom;
int type, class, ancount, qdcount, haveanswer, i, nchar;
char aux1[MAXDNAME], aux2[MAXDNAME], ans[MAXDNAME];
char *in, *st, *pauxt, *bp, **ap;
char *paux1 = &aux1[0], *paux2 = &aux2[0], *ep;
int type, class, ancount, qdcount, haveanswer;
char ans[MAXDNAME];
char *in, *bp, **ap, *ep;
static char netbuf[PACKETSZ];
_DIAGASSERT(answer != NULL);
@ -187,7 +228,7 @@ getnetanswer(querybuf *answer, int anslen, int net_i)
cp += n;
return NULL;
}
cp += n;
cp += n;
*ap++ = bp;
bp += strlen(bp) + 1;
net_entry.n_addrtype =
@ -211,26 +252,8 @@ getnetanswer(querybuf *answer, int anslen, int net_i)
return NULL;
}
net_entry.n_name = ans;
aux2[0] = '\0';
for (i = 0; i < 4; i++) {
for (st = in, nchar = 0;
isdigit((unsigned char)*st);
st++, nchar++)
;
if (*st != '.' || nchar == 0 || nchar > 3)
goto next_alias;
if (i != 0)
nchar++;
(void)strlcpy(paux1, in, (size_t)nchar);
paux1[nchar] = '\0';
pauxt = paux2;
paux2 = strcat(paux1, paux2);
paux1 = pauxt;
in = ++st;
}
if (strcasecmp(in, "IN-ADDR.ARPA") != 0)
if (parse_reversed_addr(in, &net_entry.n_net) == -1)
goto next_alias;
net_entry.n_net = inet_network(paux2);
break;
}
net_entry.n_aliases++;