-/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
+/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996.
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
-#include <sys/syslog.h>
#include "nsswitch.h"
+#include <arpa/nameser.h>
-/* Get implementation for some internal functions. */
+#include <resolv/resolv-internal.h>
+#include <resolv/resolv_context.h>
+
+/* Get implementations of some internal functions. */
#include <resolv/mapv4v6addr.h>
#include <resolv/mapv4v6hostent.h>
#endif
#define MAXHOSTNAMELEN 256
-static const char AskedForGot[] = "\
-gethostby*.getanswer: asked for \"%s\", got \"%s\"";
-
-
/* We need this time later. */
typedef union querybuf
{
u_char buf[MAXPACKET];
} querybuf;
-/* These functions are defined in res_comp.c. */
-#define NS_MAXCDNAME 255 /* maximum compressed domain name */
-extern int __ns_name_ntop (const u_char *, char *, size_t);
-extern int __ns_name_unpack (const u_char *, const u_char *,
- const u_char *, u_char *, size_t);
-
-
-static enum nss_status getanswer_r (const querybuf *answer, int anslen,
+static enum nss_status getanswer_r (struct resolv_context *ctx,
+ const querybuf *answer, int anslen,
const char *qname, int qtype,
struct hostent *result, char *buffer,
size_t buflen, int *errnop, int *h_errnop,
int *errnop, int *h_errnop,
int32_t *ttlp);
-extern enum nss_status _nss_dns_gethostbyname3_r (const char *name, int af,
- struct hostent *result,
- char *buffer, size_t buflen,
- int *errnop, int *h_errnop,
- int32_t *ttlp,
- char **canonp);
-hidden_proto (_nss_dns_gethostbyname3_r)
+static enum nss_status gethostbyname3_context (struct resolv_context *ctx,
+ const char *name, int af,
+ struct hostent *result,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop,
+ int32_t *ttlp,
+ char **canonp);
+
+/* Return the expected RDATA length for an address record type (A or
+ AAAA). */
+static int
+rrtype_to_rdata_length (int type)
+{
+ switch (type)
+ {
+ case T_A:
+ return INADDRSZ;
+ case T_AAAA:
+ return IN6ADDRSZ;
+ default:
+ return -1;
+ }
+}
+
enum nss_status
_nss_dns_gethostbyname3_r (const char *name, int af, struct hostent *result,
char *buffer, size_t buflen, int *errnop,
int *h_errnop, int32_t *ttlp, char **canonp)
+{
+ struct resolv_context *ctx = __resolv_context_get ();
+ if (ctx == NULL)
+ {
+ *errnop = errno;
+ *h_errnop = NETDB_INTERNAL;
+ return NSS_STATUS_UNAVAIL;
+ }
+ enum nss_status status = gethostbyname3_context
+ (ctx, name, af, result, buffer, buflen, errnop, h_errnop, ttlp, canonp);
+ __resolv_context_put (ctx);
+ return status;
+}
+
+static enum nss_status
+gethostbyname3_context (struct resolv_context *ctx,
+ const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *h_errnop, int32_t *ttlp, char **canonp)
{
union
{
int olderr = errno;
enum nss_status status;
- if (__res_maybe_init (&_res, 0) == -1)
- return NSS_STATUS_UNAVAIL;
-
switch (af) {
case AF_INET:
size = INADDRSZ;
* function that looks up host names.
*/
if (strchr (name, '.') == NULL
- && (cp = res_hostalias (&_res, name, tmp, sizeof (tmp))) != NULL)
+ && (cp = __res_context_hostalias (ctx, name, tmp, sizeof (tmp))) != NULL)
name = cp;
host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024);
- n = __libc_res_nsearch (&_res, name, C_IN, type, host_buffer.buf->buf,
- 1024, &host_buffer.ptr, NULL, NULL, NULL);
+ n = __res_context_search (ctx, name, C_IN, type, host_buffer.buf->buf,
+ 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL);
if (n < 0)
{
switch (errno)
/* If we are looking for an IPv6 address and mapping is enabled
by having the RES_USE_INET6 bit in _res.options set, we try
another lookup. */
- if (af == AF_INET6 && (_res.options & RES_USE_INET6))
- n = __libc_res_nsearch (&_res, name, C_IN, T_A, host_buffer.buf->buf,
- host_buffer.buf != orig_host_buffer
- ? MAXPACKET : 1024, &host_buffer.ptr,
- NULL, NULL, NULL);
+ if (af == AF_INET6 && res_use_inet6 ())
+ n = __res_context_search (ctx, name, C_IN, T_A, host_buffer.buf->buf,
+ host_buffer.buf != orig_host_buffer
+ ? MAXPACKET : 1024, &host_buffer.ptr,
+ NULL, NULL, NULL, NULL);
if (n < 0)
{
result->h_length = INADDRSZ;
}
- status = getanswer_r (host_buffer.buf, n, name, type, result, buffer, buflen,
- errnop, h_errnop, map, ttlp, canonp);
+ status = getanswer_r
+ (ctx, host_buffer.buf, n, name, type, result, buffer, buflen,
+ errnop, h_errnop, map, ttlp, canonp);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
return status;
}
-hidden_def (_nss_dns_gethostbyname3_r)
-
enum nss_status
_nss_dns_gethostbyname2_r (const char *name, int af, struct hostent *result,
char *buffer, size_t buflen, int *errnop,
int *h_errnop)
{
+ struct resolv_context *ctx = __resolv_context_get ();
+ if (ctx == NULL)
+ {
+ *errnop = errno;
+ *h_errnop = NETDB_INTERNAL;
+ return NSS_STATUS_UNAVAIL;
+ }
enum nss_status status = NSS_STATUS_NOTFOUND;
-
- if (_res.options & RES_USE_INET6)
- status = _nss_dns_gethostbyname3_r (name, AF_INET6, result, buffer,
- buflen, errnop, h_errnop, NULL, NULL);
+ if (res_use_inet6 ())
+ status = gethostbyname3_context (ctx, name, AF_INET6, result, buffer,
+ buflen, errnop, h_errnop, NULL, NULL);
if (status == NSS_STATUS_NOTFOUND)
- status = _nss_dns_gethostbyname3_r (name, AF_INET, result, buffer,
- buflen, errnop, h_errnop, NULL, NULL);
-
+ status = gethostbyname3_context (ctx, name, AF_INET, result, buffer,
+ buflen, errnop, h_errnop, NULL, NULL);
+ __resolv_context_put (ctx);
return status;
}
char *buffer, size_t buflen, int *errnop,
int *herrnop, int32_t *ttlp)
{
- if (__res_maybe_init (&_res, 0) == -1)
- return NSS_STATUS_UNAVAIL;
+ struct resolv_context *ctx = __resolv_context_get ();
+ if (ctx == NULL)
+ {
+ *errnop = errno;
+ *herrnop = NETDB_INTERNAL;
+ return NSS_STATUS_UNAVAIL;
+ }
/*
* if there aren't any dots, it could be a user-level alias.
if (strchr (name, '.') == NULL)
{
char *tmp = alloca (NS_MAXDNAME);
- const char *cp = res_hostalias (&_res, name, tmp, NS_MAXDNAME);
+ const char *cp = __res_context_hostalias (ctx, name, tmp, NS_MAXDNAME);
if (cp != NULL)
name = cp;
}
- int anslen = 2048;
union
{
querybuf *buf;
u_char *ptr;
} host_buffer;
querybuf *orig_host_buffer;
- host_buffer.buf = orig_host_buffer = (querybuf *) alloca (anslen);
+ host_buffer.buf = orig_host_buffer = (querybuf *) alloca (2048);
u_char *ans2p = NULL;
int nans2p = 0;
int resplen2 = 0;
+ int ans2p_malloced = 0;
int olderr = errno;
enum nss_status status;
- int n = __libc_res_nsearch (&_res, name, C_IN, T_UNSPEC,
- host_buffer.buf->buf, anslen, &host_buffer.ptr,
- &ans2p, &nans2p, &resplen2);
- if (n < 0)
+ int n = __res_context_search (ctx, name, C_IN, T_QUERY_A_AND_AAAA,
+ host_buffer.buf->buf, 2048, &host_buffer.ptr,
+ &ans2p, &nans2p, &resplen2, &ans2p_malloced);
+ if (n >= 0)
+ {
+ status = gaih_getanswer (host_buffer.buf, n, (const querybuf *) ans2p,
+ resplen2, name, pat, buffer, buflen,
+ errnop, herrnop, ttlp);
+ }
+ else
{
switch (errno)
{
*errnop = EAGAIN;
else
__set_errno (olderr);
-
- if (host_buffer.buf != orig_host_buffer)
- free (host_buffer.buf);
-
- return status;
}
- status = gaih_getanswer(host_buffer.buf, n, (const querybuf *) ans2p,
- resplen2, name, pat, buffer, buflen,
- errnop, herrnop, ttlp);
-
/* Check whether ans2p was separately allocated. */
- if (host_buffer.buf != orig_host_buffer)
- anslen = MAXPACKET;
- if (ans2p != NULL
- && (ans2p < host_buffer.ptr || ans2p >= host_buffer.ptr + anslen))
+ if (ans2p_malloced)
free (ans2p);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
+ __resolv_context_put (ctx);
return status;
}
host_data = (struct host_data *) buffer;
- if (__res_maybe_init (&_res, 0) == -1)
- return NSS_STATUS_UNAVAIL;
+ struct resolv_context *ctx = __resolv_context_get ();
+ if (ctx == NULL)
+ {
+ *errnop = errno;
+ *h_errnop = NETDB_INTERNAL;
+ return NSS_STATUS_UNAVAIL;
+ }
if (af == AF_INET6 && len == IN6ADDRSZ
&& (memcmp (uaddr, mapped, sizeof mapped) == 0
default:
*errnop = EAFNOSUPPORT;
*h_errnop = NETDB_INTERNAL;
+ __resolv_context_put (ctx);
return NSS_STATUS_UNAVAIL;
}
if (size > len)
{
*errnop = EAFNOSUPPORT;
*h_errnop = NETDB_INTERNAL;
+ __resolv_context_put (ctx);
return NSS_STATUS_UNAVAIL;
}
(uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff));
break;
case AF_INET6:
- /* Only lookup with the byte string format if the user wants it. */
- if (__glibc_unlikely (_res.options & RES_USEBSTRING))
- {
- qp = stpcpy (qbuf, "\\[x");
- for (n = 0; n < IN6ADDRSZ; ++n)
- qp += sprintf (qp, "%02hhx", uaddr[n]);
- strcpy (qp, "].ip6.arpa");
- n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR,
- host_buffer.buf->buf, 1024, &host_buffer.ptr,
- NULL, NULL, NULL);
- if (n >= 0)
- goto got_it_already;
- }
qp = qbuf;
for (n = IN6ADDRSZ - 1; n >= 0; n--)
{
break;
}
- n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
- 1024, &host_buffer.ptr, NULL, NULL, NULL);
- if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0)
- {
- strcpy (qp, "ip6.int");
- n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
- host_buffer.buf != orig_host_buffer
- ? MAXPACKET : 1024, &host_buffer.ptr,
- NULL, NULL, NULL);
- }
+ n = __res_context_query (ctx, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
+ 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL);
if (n < 0)
{
*h_errnop = h_errno;
__set_errno (olderr);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
+ __resolv_context_put (ctx);
return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
}
- got_it_already:
- status = getanswer_r (host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
- errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
+ status = getanswer_r
+ (ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
+ errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
if (status != NSS_STATUS_SUCCESS)
- return status;
-
-#ifdef SUNSECURITY
- This is not implemented because it is not possible to use the current
- source from bind in a multi-threaded program.
-#endif
+ {
+ __resolv_context_put (ctx);
+ return status;
+ }
result->h_addrtype = af;
result->h_length = len;
memcpy (host_data->host_addr, addr, len);
host_data->h_addr_ptrs[0] = (char *) host_data->host_addr;
host_data->h_addr_ptrs[1] = NULL;
-#if 0
- /* XXX I think this is wrong. Why should an IPv4 address be
- converted to IPv6 if the user explicitly asked for IPv4? */
- if (af == AF_INET && (_res.options & RES_USE_INET6))
- {
- map_v4v6_address ((char *) host_data->host_addr,
- (char *) host_data->host_addr);
- result->h_addrtype = AF_INET6;
- result->h_length = IN6ADDRSZ;
- }
-#endif
*h_errnop = NETDB_SUCCESS;
+ __resolv_context_put (ctx);
return NSS_STATUS_SUCCESS;
}
hidden_def (_nss_dns_gethostbyaddr2_r)
errnop, h_errnop, NULL);
}
-#ifdef RESOLVSORT
-static void addrsort (char **ap, int num);
-
static void
-addrsort (char **ap, int num)
+addrsort (struct resolv_context *ctx, char **ap, int num)
{
int i, j;
char **p;
short aval[MAX_NR_ADDRS];
int needsort = 0;
+ size_t nsort = __resolv_context_sort_count (ctx);
p = ap;
if (num > MAX_NR_ADDRS)
num = MAX_NR_ADDRS;
for (i = 0; i < num; i++, p++)
{
- for (j = 0 ; (unsigned)j < _res.nsort; j++)
- if (_res.sort_list[j].addr.s_addr ==
- (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
- break;
+ for (j = 0 ; (unsigned)j < nsort; j++)
+ {
+ struct resolv_sortlist_entry e
+ = __resolv_context_sort_entry (ctx, j);
+ if (e.addr.s_addr == (((struct in_addr *)(*p))->s_addr & e.mask))
+ break;
+ }
aval[i] = j;
if (needsort == 0 && i > 0 && j < aval[i-1])
needsort = i;
else
break;
}
-#endif
static enum nss_status
-getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
+getanswer_r (struct resolv_context *ctx,
+ const querybuf *answer, int anslen, const char *qname, int qtype,
struct hostent *result, char *buffer, size_t buflen,
int *errnop, int *h_errnop, int map, int32_t *ttlp, char **canonp)
{
int have_to_map = 0;
uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data);
buffer += pad;
- if (__glibc_unlikely (buflen < sizeof (struct host_data) + pad))
+ buflen = buflen > pad ? buflen - pad : 0;
+ if (__glibc_unlikely (buflen < sizeof (struct host_data)))
{
/* The buffer is too small. */
too_small:
ancount = ntohs (hp->ancount);
qdcount = ntohs (hp->qdcount);
cp = answer->buf + HFIXEDSZ;
- if (__builtin_expect (qdcount, 1) != 1)
+ if (__glibc_unlikely (qdcount != 1))
{
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
packtmp, sizeof packtmp);
if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
{
- if (__builtin_expect (errno, 0) == EMSGSIZE)
+ if (__glibc_unlikely (errno == EMSGSIZE))
goto too_small;
n = -1;
if (n > 0 && bp[0] == '.')
bp[0] = '\0';
- if (__builtin_expect (n < 0 || ((*name_ok) (bp) == 0 && (errno = EBADMSG)),
- 0))
+ if (__glibc_unlikely (n < 0))
{
*errnop = errno;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
+ if (__glibc_unlikely (name_ok (bp) == 0))
+ {
+ errno = EBADMSG;
+ *errnop = EBADMSG;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
cp += n + QFIXEDSZ;
if (qtype == T_A || qtype == T_AAAA)
packtmp, sizeof packtmp);
if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
{
- if (__builtin_expect (errno, 0) == EMSGSIZE)
+ if (__glibc_unlikely (errno == EMSGSIZE))
goto too_small;
n = -1;
cp += INT32SZ; /* TTL */
n = __ns_get16 (cp);
cp += INT16SZ; /* len */
+
+ if (end_of_message - cp < n)
+ {
+ /* RDATA extends beyond the end of the packet. */
+ ++had_error;
+ continue;
+ }
+
if (__glibc_unlikely (class != C_IN))
{
/* XXX - debug? syslog? */
/* Store alias. */
*ap++ = bp;
n = strlen (bp) + 1; /* For the \0. */
- if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
+ if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
{
++had_error;
continue;
n = strlen (tbuf) + 1; /* For the \0. */
if (__glibc_unlikely (n > linebuflen))
goto too_small;
- if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
+ if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
{
++had_error;
continue;
if (qtype == T_PTR && type == T_CNAME)
{
+ /* A CNAME could also have a TTL entry. */
+ if (ttlp != NULL && ttl < *ttlp)
+ *ttlp = ttl;
+
n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf);
if (__glibc_unlikely (n < 0 || res_dnok (tbuf) == 0))
{
n = strlen (tbuf) + 1; /* For the \0. */
if (__glibc_unlikely (n > linebuflen))
goto too_small;
- if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
+ if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
{
++had_error;
continue;
linebuflen -= n;
continue;
}
- if (__builtin_expect (type == T_SIG, 0)
- || __builtin_expect (type == T_KEY, 0)
- || __builtin_expect (type == T_NXT, 0))
- {
- /* We don't support DNSSEC yet. For now, ignore the record
- and send a low priority message to syslog. */
- syslog (LOG_DEBUG | LOG_AUTH,
- "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
- qname, p_class (C_IN), p_type(qtype), p_type (type));
- cp += n;
- continue;
- }
if (type == T_A && qtype == T_AAAA && map)
have_to_map = 1;
else if (__glibc_unlikely (type != qtype))
{
- syslog (LOG_NOTICE | LOG_AUTH,
- "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
- qname, p_class (C_IN), p_type (qtype), p_type (type));
cp += n;
continue; /* XXX - had_error++ ? */
}
case T_PTR:
if (__glibc_unlikely (strcasecmp (tname, bp) != 0))
{
- syslog (LOG_NOTICE | LOG_AUTH, AskedForGot, qname, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
packtmp, sizeof packtmp);
if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
{
- if (__builtin_expect (errno, 0) == EMSGSIZE)
+ if (__glibc_unlikely (errno == EMSGSIZE))
goto too_small;
n = -1;
++had_error;
break;
}
-#if MULTI_PTRS_ARE_ALIASES
- cp += n;
- if (haveanswer == 0)
- result->h_name = bp;
- else if (ap < &host_data->aliases[MAXALIASES-1])
- *ap++ = bp;
- else
- n = -1;
- if (n != -1)
- {
- n = strlen (bp) + 1; /* for the \0 */
- if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN)
- {
- ++had_error;
- break;
- }
- bp += n;
- linebuflen -= n;
- }
- break;
-#else
+ if (ttlp != NULL && ttl < *ttlp)
+ *ttlp = ttl;
+ /* bind would put multiple PTR records as aliases, but we don't do
+ that. */
result->h_name = bp;
- if (have_to_map)
- {
- n = strlen (bp) + 1; /* for the \0 */
- if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
- {
- ++had_error;
- break;
- }
- bp += n;
- linebuflen -= n;
- if (map_v4v6_hostent (result, &bp, &linebuflen))
- goto too_small;
- }
*h_errnop = NETDB_SUCCESS;
return NSS_STATUS_SUCCESS;
-#endif
case T_A:
case T_AAAA:
- if (__builtin_expect (strcasecmp (result->h_name, bp), 0) != 0)
+ if (__glibc_unlikely (strcasecmp (result->h_name, bp) != 0))
{
- syslog (LOG_NOTICE | LOG_AUTH, AskedForGot, result->h_name, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
+
+ /* Stop parsing at a record whose length is incorrect. */
+ if (n != rrtype_to_rdata_length (type))
+ {
+ ++had_error;
+ break;
+ }
+
+ /* Skip records of the wrong type. */
if (n != result->h_length)
{
cp += n;
{
*ap = NULL;
*hap = NULL;
-#if defined RESOLVSORT
/*
* Note: we sort even if host can take only one address
* in its return structures - should give it the "best"
* address in that case, not some random one
*/
- if (_res.nsort && haveanswer > 1 && qtype == T_A)
- addrsort (host_data->h_addr_ptrs, haveanswer);
-#endif /*RESOLVSORT*/
+ if (haveanswer > 1 && qtype == T_A
+ && __resolv_context_sort_count (ctx) > 0)
+ addrsort (ctx, host_data->h_addr_ptrs, haveanswer);
if (result->h_name == NULL)
{
it later. */
if (n != -1 && __ns_name_ntop (packtmp, buffer, buflen) == -1)
{
- if (__builtin_expect (errno, 0) == EMSGSIZE)
+ if (__glibc_unlikely (errno == EMSGSIZE))
{
too_small:
*errnop = ERANGE;
n = -1;
}
- if (__builtin_expect (n < 0 || (res_hnok (buffer) == 0
- && (errno = EBADMSG)), 0))
+ if (__glibc_unlikely (n < 0))
{
*errnop = errno;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
+ if (__glibc_unlikely (res_hnok (buffer) == 0))
+ {
+ errno = EBADMSG;
+ *errnop = EBADMSG;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
cp += n + QFIXEDSZ;
int haveanswer = 0;
int h_namelen = 0;
if (ancount == 0)
- return NSS_STATUS_NOTFOUND;
+ {
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
while (ancount-- > 0 && cp < end_of_message && had_error == 0)
{
if (n != -1 &&
(h_namelen = __ns_name_ntop (packtmp, buffer, buflen)) == -1)
{
- if (__builtin_expect (errno, 0) == EMSGSIZE)
+ if (__glibc_unlikely (errno == EMSGSIZE))
goto too_small;
n = -1;
n = __ns_get16 (cp);
cp += INT16SZ; /* len */
+ if (end_of_message - cp < n)
+ {
+ /* RDATA extends beyond the end of the packet. */
+ ++had_error;
+ continue;
+ }
+
if (class != C_IN)
{
cp += n;
}
continue;
}
-#if 1
- // We should not see any types other than those explicitly listed
- // below. Some types sent by server seem missing, though. Just
- // collect the data for now.
- if (__glibc_unlikely (type != T_A && type != T_AAAA))
-#else
- if (__builtin_expect (type == T_SIG, 0)
- || __builtin_expect (type == T_KEY, 0)
- || __builtin_expect (type == T_NXT, 0)
- || __builtin_expect (type == T_PTR, 0)
- || __builtin_expect (type == T_DNAME, 0))
-#endif
- {
- /* We don't support DNSSEC yet. For now, ignore the record
- and send a low priority message to syslog.
- We also don't expect T_PTR or T_DNAME messages. */
- syslog (LOG_DEBUG | LOG_AUTH,
- "getaddrinfo*.gaih_getanswer: got type \"%s\"",
- p_type (type));
+ /* Stop parsing if we encounter a record with incorrect RDATA
+ length. */
+ if (type == T_A || type == T_AAAA)
+ {
+ if (n != rrtype_to_rdata_length (type))
+ {
+ ++had_error;
+ continue;
+ }
+ }
+ else
+ {
+ /* Skip unknown records. */
cp += n;
continue;
}
- if (type != T_A && type != T_AAAA)
- abort ();
+ assert (type == T_A || type == T_AAAA);
if (*pat == NULL)
{
uintptr_t pad = (-(uintptr_t) buffer
buffer += pad;
buflen = buflen > pad ? buflen - pad : 0;
- if (__builtin_expect (buflen < sizeof (struct gaih_addrtuple),
- 0))
+ if (__glibc_unlikely (buflen < sizeof (struct gaih_addrtuple)))
goto too_small;
*pat = (struct gaih_addrtuple *) buffer;
}
(*pat)->family = type == T_A ? AF_INET : AF_INET6;
- if (__builtin_expect ((type == T_A && n != INADDRSZ)
- || (type == T_AAAA && n != IN6ADDRSZ), 0))
- {
- ++had_error;
- continue;
- }
memcpy ((*pat)->addr, cp, n);
cp += n;
(*pat)->scopeid = 0;
/* Special case here: if the resolver sent a result but it only
contains a CNAME while we are looking for a T_A or T_AAAA record,
we fail with NOTFOUND instead of TRYAGAIN. */
- return canon == NULL ? NSS_STATUS_TRYAGAIN : NSS_STATUS_NOTFOUND;
+ if (canon != NULL)
+ {
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ *h_errnop = NETDB_INTERNAL;
+ return NSS_STATUS_TRYAGAIN;
}
enum nss_status status = NSS_STATUS_NOTFOUND;
+ /* Combining the NSS status of two distinct queries requires some
+ compromise and attention to symmetry (A or AAAA queries can be
+ returned in any order). What follows is a breakdown of how this
+ code is expected to work and why. We discuss only SUCCESS,
+ TRYAGAIN, NOTFOUND and UNAVAIL, since they are the only returns
+ that apply (though RETURN and MERGE exist). We make a distinction
+ between TRYAGAIN (recoverable) and TRYAGAIN' (not-recoverable).
+ A recoverable TRYAGAIN is almost always due to buffer size issues
+ and returns ERANGE in errno and the caller is expected to retry
+ with a larger buffer.
+
+ Lastly, you may be tempted to make significant changes to the
+ conditions in this code to bring about symmetry between responses.
+ Please don't change anything without due consideration for
+ expected application behaviour. Some of the synthesized responses
+ aren't very well thought out and sometimes appear to imply that
+ IPv4 responses are always answer 1, and IPv6 responses are always
+ answer 2, but that's not true (see the implementation of send_dg
+ and send_vc to see response can arrive in any order, particularly
+ for UDP). However, we expect it holds roughly enough of the time
+ that this code works, but certainly needs to be fixed to make this
+ a more robust implementation.
+
+ ----------------------------------------------
+ | Answer 1 Status / | Synthesized | Reason |
+ | Answer 2 Status | Status | |
+ |--------------------------------------------|
+ | SUCCESS/SUCCESS | SUCCESS | [1] |
+ | SUCCESS/TRYAGAIN | TRYAGAIN | [5] |
+ | SUCCESS/TRYAGAIN' | SUCCESS | [1] |
+ | SUCCESS/NOTFOUND | SUCCESS | [1] |
+ | SUCCESS/UNAVAIL | SUCCESS | [1] |
+ | TRYAGAIN/SUCCESS | TRYAGAIN | [2] |
+ | TRYAGAIN/TRYAGAIN | TRYAGAIN | [2] |
+ | TRYAGAIN/TRYAGAIN' | TRYAGAIN | [2] |
+ | TRYAGAIN/NOTFOUND | TRYAGAIN | [2] |
+ | TRYAGAIN/UNAVAIL | TRYAGAIN | [2] |
+ | TRYAGAIN'/SUCCESS | SUCCESS | [3] |
+ | TRYAGAIN'/TRYAGAIN | TRYAGAIN | [3] |
+ | TRYAGAIN'/TRYAGAIN' | TRYAGAIN' | [3] |
+ | TRYAGAIN'/NOTFOUND | TRYAGAIN' | [3] |
+ | TRYAGAIN'/UNAVAIL | UNAVAIL | [3] |
+ | NOTFOUND/SUCCESS | SUCCESS | [3] |
+ | NOTFOUND/TRYAGAIN | TRYAGAIN | [3] |
+ | NOTFOUND/TRYAGAIN' | TRYAGAIN' | [3] |
+ | NOTFOUND/NOTFOUND | NOTFOUND | [3] |
+ | NOTFOUND/UNAVAIL | UNAVAIL | [3] |
+ | UNAVAIL/SUCCESS | UNAVAIL | [4] |
+ | UNAVAIL/TRYAGAIN | UNAVAIL | [4] |
+ | UNAVAIL/TRYAGAIN' | UNAVAIL | [4] |
+ | UNAVAIL/NOTFOUND | UNAVAIL | [4] |
+ | UNAVAIL/UNAVAIL | UNAVAIL | [4] |
+ ----------------------------------------------
+
+ [1] If the first response is a success we return success.
+ This ignores the state of the second answer and in fact
+ incorrectly sets errno and h_errno to that of the second
+ answer. However because the response is a success we ignore
+ *errnop and *h_errnop (though that means you touched errno on
+ success). We are being conservative here and returning the
+ likely IPv4 response in the first answer as a success.
+
+ [2] If the first response is a recoverable TRYAGAIN we return
+ that instead of looking at the second response. The
+ expectation here is that we have failed to get an IPv4 response
+ and should retry both queries.
+
+ [3] If the first response was not a SUCCESS and the second
+ response is not NOTFOUND (had a SUCCESS, need to TRYAGAIN,
+ or failed entirely e.g. TRYAGAIN' and UNAVAIL) then use the
+ result from the second response, otherwise the first responses
+ status is used. Again we have some odd side-effects when the
+ second response is NOTFOUND because we overwrite *errnop and
+ *h_errnop that means that a first answer of NOTFOUND might see
+ its *errnop and *h_errnop values altered. Whether it matters
+ in practice that a first response NOTFOUND has the wrong
+ *errnop and *h_errnop is undecided.
+
+ [4] If the first response is UNAVAIL we return that instead of
+ looking at the second response. The expectation here is that
+ it will have failed similarly e.g. configuration failure.
+
+ [5] Testing this code is complicated by the fact that truncated
+ second response buffers might be returned as SUCCESS if the
+ first answer is a SUCCESS. To fix this we add symmetry to
+ TRYAGAIN with the second response. If the second response
+ is a recoverable error we now return TRYAGIN even if the first
+ response was SUCCESS. */
+
if (anslen1 > 0)
status = gaih_getanswer_slice(answer1, anslen1, qname,
&pat, &buffer, &buflen,
errnop, h_errnop, ttlp,
&first);
+
if ((status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND
|| (status == NSS_STATUS_TRYAGAIN
/* We want to look at the second answer in case of an
&pat, &buffer, &buflen,
errnop, h_errnop, ttlp,
&first);
+ /* Use the second response status in some cases. */
if (status != NSS_STATUS_SUCCESS && status2 != NSS_STATUS_NOTFOUND)
status = status2;
+ /* Do not return a truncated second response (unless it was
+ unavoidable e.g. unrecoverable TRYAGAIN). */
+ if (status == NSS_STATUS_SUCCESS
+ && (status2 == NSS_STATUS_TRYAGAIN
+ && *errnop == ERANGE && *h_errnop != NO_RECOVERY))
+ status = NSS_STATUS_TRYAGAIN;
}
return status;
projects / thirdparty / glibc.git / blobdiff