CPPFLAGS-gencat = -DNOT_IN_libc
generated = de.msg test1.cat test1.h test2.cat test2.h sample.SJIS.cat \
- test-gencat.h
+ test-gencat.h tst-catgets.mtrace tst-catgets-mem.out
generated-dirs = de
-tst-catgets-ENV = NLSPATH="$(objpfx)%l/%N.cat" LANG=de
+tst-catgets-ENV = NLSPATH="$(objpfx)%l/%N.cat" LANG=de MALLOC_TRACE=$(objpfx)tst-catgets.mtrace
# eglibc: ifneq ($(cross-compiling),yes)
ifeq (y,$(OPTION_EGLIBC_CATGETS))
tests: $(objpfx)de/libc.cat $(objpfx)test1.cat $(objpfx)test2.cat \
- $(objpfx)test-gencat.out
+ $(objpfx)test-gencat.out $(objpfx)tst-catgets-mem.out
endif
# This test just checks whether the program produces any error or not.
# The result is not tested.
$(objpfx)sample.SJIS.cat: sample.SJIS $(objpfx)gencat
GCONV_PATH=$(common-objpfx)iconvdata LC_ALL=C \
$(built-program-cmd) -H $(objpfx)test-gencat.h < $(word 1,$^) > $@
+
+$(objpfx)tst-catgets-mem.out: $(objpfx)tst-catgets.out
+ $(common-objpfx)malloc/mtrace $(objpfx)tst-catgets.mtrace > $@; \
+ $(evaluate-test)
# eglibc: endif
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
-#include <alloca.h>
#include <errno.h>
#include <locale.h>
#include <nl_types.h>
__nl_catd result;
const char *env_var = NULL;
const char *nlspath = NULL;
+ char *tmp = NULL;
if (strchr (cat_name, '/') == NULL)
{
{
/* Append the system dependent directory. */
size_t len = strlen (nlspath) + 1 + sizeof NLSPATH;
- char *tmp = alloca (len);
+ tmp = malloc (len);
+
+ if (__builtin_expect (tmp == NULL, 0))
+ return (nl_catd) -1;
__stpcpy (__stpcpy (__stpcpy (tmp, nlspath), ":"), NLSPATH);
nlspath = tmp;
result = (__nl_catd) malloc (sizeof (*result));
if (result == NULL)
- /* We cannot get enough memory. */
- return (nl_catd) -1;
-
- if (__open_catalog (cat_name, nlspath, env_var, result) != 0)
+ {
+ /* We cannot get enough memory. */
+ result = (nl_catd) -1;
+ }
+ else if (__open_catalog (cat_name, nlspath, env_var, result) != 0)
{
/* Couldn't open the file. */
free ((void *) result);
- return (nl_catd) -1;
+ result = (nl_catd) -1;
}
+ free (tmp);
return (nl_catd) result;
}
size_t tab_size;
const char *lastp;
int result = -1;
+ char *buf = NULL;
if (strchr (cat_name, '/') != NULL || nlspath == NULL)
fd = open_not_cancel_2 (cat_name, O_RDONLY);
if (__builtin_expect (bufact + (n) >= bufmax, 0)) \
{ \
char *old_buf = buf; \
- bufmax += 256 + (n); \
- buf = (char *) alloca (bufmax); \
- memcpy (buf, old_buf, bufact); \
+ bufmax += (bufmax < 256 + (n)) ? 256 + (n) : bufmax; \
+ buf = realloc (buf, bufmax); \
+ if (__builtin_expect (buf == NULL, 0)) \
+ { \
+ free (old_buf); \
+ return -1; \
+ } \
}
/* The RUN_NLSPATH variable contains a colon separated list of
descriptions where we expect to find catalogs. We have to
recognize certain % substitutions and stop when we found the
first existing file. */
- char *buf;
size_t bufact;
- size_t bufmax;
+ size_t bufmax = 0;
size_t len;
- buf = NULL;
- bufmax = 0;
-
fd = -1;
while (*run_nlspath != '\0')
{
/* Avoid dealing with directories and block devices */
if (__builtin_expect (fd, 0) < 0)
- return -1;
+ {
+ free (buf);
+ return -1;
+ }
if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0)
goto close_unlock_return;
/* Release the lock again. */
close_unlock_return:
close_not_cancel_no_status (fd);
+ free (buf);
return result;
}
+#include <assert.h>
#include <mcheck.h>
#include <nl_types.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
+#include <sys/resource.h>
static const char *msgs[] =
};
#define nmsgs (sizeof (msgs) / sizeof (msgs[0]))
+
+/* Test for unbounded alloca. */
+static int
+do_bz17905 (void)
+{
+ char *buf;
+ struct rlimit rl;
+ nl_catd result;
+
+ const int sz = 1024 * 1024;
+
+ getrlimit (RLIMIT_STACK, &rl);
+ rl.rlim_cur = sz;
+ setrlimit (RLIMIT_STACK, &rl);
+
+ buf = malloc (sz + 1);
+ memset (buf, 'A', sz);
+ buf[sz] = '\0';
+ setenv ("NLSPATH", buf, 1);
+
+ result = catopen (buf, NL_CAT_LOCALE);
+ assert (result == (nl_catd) -1);
+
+ free (buf);
+ return 0;
+}
+
#define ROUNDS 5
int
}
}
+ result += do_bz17905 ();
return result;
}
libc_hidden_proto (__res_state)
int __libc_res_nquery (res_state, const char *, int, int, u_char *, int,
- u_char **, u_char **, int *, int *);
+ u_char **, u_char **, int *, int *, int *);
int __libc_res_nsearch (res_state, const char *, int, int, u_char *, int,
- u_char **, u_char **, int *, int *);
+ u_char **, u_char **, int *, int *, int *);
int __libc_res_nsend (res_state, const u_char *, int, const u_char *, int,
- u_char *, int, u_char **, u_char **, int *, int *)
+ u_char *, int, u_char **, u_char **, int *, int *, int *)
attribute_hidden;
libresolv_hidden_proto (_sethtent)
buf.buf = origbuf = (querybuf *) alloca (1024);
if ((n = __libc_res_nsearch(&_res, name, C_IN, type, buf.buf->buf, 1024,
- &buf.ptr, NULL, NULL, NULL)) < 0) {
+ &buf.ptr, NULL, NULL, NULL, NULL)) < 0) {
if (buf.buf != origbuf)
free (buf.buf);
Dprintf("res_nsearch failed (%d)\n", n);
buf.buf = orig_buf = (querybuf *) alloca (1024);
n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf, 1024,
- &buf.ptr, NULL, NULL, NULL);
+ &buf.ptr, NULL, 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, buf.buf->buf,
buf.buf != orig_buf ? MAXPACKET : 1024,
- &buf.ptr, NULL, NULL, NULL);
+ &buf.ptr, NULL, NULL, NULL, NULL);
}
if (n < 0) {
if (buf.buf != orig_buf)
{
int r = __libc_res_nquery (&_res, name, ns_c_in, qtypes[i],
buf, sizeof (buf), &ansp.ptr, NULL, NULL,
- NULL);
+ NULL, NULL);
if (r > 0)
{
/* We need to decode the response. Just one question record.
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);
+ 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL);
if (n < 0)
{
switch (errno)
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);
+ NULL, NULL, NULL, NULL);
if (n < 0)
{
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, 2048, &host_buffer.ptr,
- &ans2p, &nans2p, &resplen2);
+ &ans2p, &nans2p, &resplen2, &ans2p_malloced);
if (n < 0)
{
if (errno == ESRCH)
resplen2, name, pat, buffer, buflen,
errnop, herrnop, ttlp);
+ /* Check whether ans2p was separately allocated. */
+ if (ans2p_malloced)
+ free (ans2p);
+
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
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);
+ NULL, NULL, NULL, NULL);
if (n >= 0)
goto got_it_already;
}
}
n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf,
- 1024, &host_buffer.ptr, NULL, NULL, NULL);
+ 1024, &host_buffer.ptr, NULL, 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);
+ NULL, NULL, NULL, NULL);
}
if (n < 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)
{
/* 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 implemetnation of send_dg
+ and send_vc to see response can arrive in any order, particlarly
+ 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
&& (errno != ERANGE || *h_errnop != NO_RECOVERY)))
&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;
net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
- 1024, &net_buffer.ptr, NULL, NULL, NULL);
+ 1024, &net_buffer.ptr, NULL, NULL, NULL, NULL);
if (anslen < 0)
{
/* Nothing found. */
net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
anslen = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
- 1024, &net_buffer.ptr, NULL, NULL, NULL);
+ 1024, &net_buffer.ptr, NULL, NULL, NULL, NULL);
if (anslen < 0)
{
/* Nothing found. */
__libc_res_nquerydomain(res_state statp, const char *name, const char *domain,
int class, int type, u_char *answer, int anslen,
u_char **answerp, u_char **answerp2, int *nanswerp2,
- int *resplen2);
+ int *resplen2, int *answerp2_malloced);
/*
* Formulate a normal query, send, and await answer.
u_char **answerp, /* if buffer needs to be enlarged */
u_char **answerp2,
int *nanswerp2,
- int *resplen2)
+ int *resplen2,
+ int *answerp2_malloced)
{
HEADER *hp = (HEADER *) answer;
int n, use_malloc = 0;
}
assert (answerp == NULL || (void *) *answerp == (void *) answer);
n = __libc_res_nsend(statp, query1, nquery1, query2, nquery2, answer,
- anslen, answerp, answerp2, nanswerp2, resplen2);
+ anslen, answerp, answerp2, nanswerp2, resplen2,
+ answerp2_malloced);
if (use_malloc)
free (buf);
if (n < 0) {
int anslen) /* size of answer buffer */
{
return __libc_res_nquery(statp, name, class, type, answer, anslen,
- NULL, NULL, NULL, NULL);
+ NULL, NULL, NULL, NULL, NULL);
}
libresolv_hidden_def (res_nquery)
u_char **answerp,
u_char **answerp2,
int *nanswerp2,
- int *resplen2)
+ int *resplen2,
+ int *answerp2_malloced)
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *) answer;
if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
return (__libc_res_nquery(statp, cp, class, type, answer,
anslen, answerp, answerp2,
- nanswerp2, resplen2));
+ nanswerp2, resplen2, answerp2_malloced));
#ifdef DEBUG
if (statp->options & RES_DEBUG)
if (dots >= statp->ndots || trailing_dot) {
ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
answer, anslen, answerp,
- answerp2, nanswerp2, resplen2);
- if (ret > 0 || trailing_dot)
+ answerp2, nanswerp2, resplen2,
+ answerp2_malloced);
+ if (ret > 0 || (ret == 0 && *resplen2 > 0) || trailing_dot)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
answer = *answerp;
anslen = MAXPACKET;
}
- if (answerp2
- && (*answerp2 < answer || *answerp2 >= answer + anslen))
+ if (answerp2 && *answerp2_malloced)
{
free (*answerp2);
*answerp2 = NULL;
+ *nanswerp2 = 0;
+ *answerp2_malloced = 0;
}
}
class, type,
answer, anslen, answerp,
answerp2, nanswerp2,
- resplen2);
- if (ret > 0)
+ resplen2, answerp2_malloced);
+ if ((ret > 0) || (ret == 0 && *resplen2 > 0))
return (ret);
if (answerp && *answerp != answer) {
answer = *answerp;
anslen = MAXPACKET;
}
- if (answerp2
- && (*answerp2 < answer
- || *answerp2 >= answer + anslen))
+ if (answerp2 && *answerp2_malloced)
{
free (*answerp2);
*answerp2 = NULL;
+ *nanswerp2 = 0;
+ *answerp2_malloced = 0;
}
/*
if (dots && !(tried_as_is || root_on_list)) {
ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
answer, anslen, answerp,
- answerp2, nanswerp2, resplen2);
- if (ret > 0)
+ answerp2, nanswerp2, resplen2,
+ answerp2_malloced);
+ if ((ret > 0) || (ret == 0 && *resplen2 > 0))
return (ret);
}
* else send back meaningless H_ERRNO, that being the one from
* the last DNSRCH we did.
*/
- if (answerp2 && (*answerp2 < answer || *answerp2 >= answer + anslen))
+ if (answerp2 && *answerp2_malloced)
{
free (*answerp2);
*answerp2 = NULL;
+ *nanswerp2 = 0;
+ *answerp2_malloced = 0;
}
if (saved_herrno != -1)
RES_SET_H_ERRNO(statp, saved_herrno);
int anslen) /* size of answer */
{
return __libc_res_nsearch(statp, name, class, type, answer,
- anslen, NULL, NULL, NULL, NULL);
+ anslen, NULL, NULL, NULL, NULL, NULL);
}
libresolv_hidden_def (res_nsearch)
u_char **answerp,
u_char **answerp2,
int *nanswerp2,
- int *resplen2)
+ int *resplen2,
+ int *answerp2_malloced)
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
}
return (__libc_res_nquery(statp, longname, class, type, answer,
anslen, answerp, answerp2, nanswerp2,
- resplen2));
+ resplen2, answerp2_malloced));
}
int
int anslen) /* size of answer */
{
return __libc_res_nquerydomain(statp, name, domain, class, type,
- answer, anslen, NULL, NULL, NULL, NULL);
+ answer, anslen, NULL, NULL, NULL, NULL,
+ NULL);
}
libresolv_hidden_def (res_nquerydomain)
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
/*
* Copyright (c) 1985, 1989, 1993
* The Regents of the University of California. All rights reserved.
static int send_vc(res_state, const u_char *, int,
const u_char *, int,
u_char **, int *, int *, int, u_char **,
- u_char **, int *, int *);
+ u_char **, int *, int *, int *);
static int send_dg(res_state, const u_char *, int,
const u_char *, int,
u_char **, int *, int *, int,
int *, int *, u_char **,
- u_char **, int *, int *);
+ u_char **, int *, int *, int *);
#ifdef DEBUG
static void Aerror(const res_state, FILE *, const char *, int,
const struct sockaddr *);
__libc_res_nsend(res_state statp, const u_char *buf, int buflen,
const u_char *buf2, int buflen2,
u_char *ans, int anssiz, u_char **ansp, u_char **ansp2,
- int *nansp2, int *resplen2)
+ int *nansp2, int *resplen2, int *ansp2_malloced)
{
int gotsomewhere, terrno, try, v_circuit, resplen, ns, n;
#ifdef USE_HOOKS
if (__builtin_expect (statp->qhook || statp->rhook, 0)) {
if (anssiz < MAXPACKET && ansp) {
+ /* Always allocate MAXPACKET, callers expect
+ this specific size. */
u_char *buf = malloc (MAXPACKET);
if (buf == NULL)
return (-1);
try = statp->retry;
n = send_vc(statp, buf, buflen, buf2, buflen2,
&ans, &anssiz, &terrno,
- ns, ansp, ansp2, nansp2, resplen2);
+ ns, ansp, ansp2, nansp2, resplen2,
+ ansp2_malloced);
if (n < 0)
return (-1);
if (n == 0)
n = send_dg(statp, buf, buflen, buf2, buflen2,
&ans, &anssiz, &terrno,
ns, &v_circuit, &gotsomewhere, ansp,
- ansp2, nansp2, resplen2);
+ ansp2, nansp2, resplen2, ansp2_malloced);
if (n < 0)
return (-1);
if (n == 0)
const u_char *buf, int buflen, u_char *ans, int anssiz)
{
return __libc_res_nsend(statp, buf, buflen, NULL, 0, ans, anssiz,
- NULL, NULL, NULL, NULL);
+ NULL, NULL, NULL, NULL, NULL);
}
libresolv_hidden_def (res_nsend)
/* Private */
+/* The send_vc function is responsible for sending a DNS query over TCP
+ to the nameserver numbered NS from the res_state STATP i.e.
+ EXT(statp).nssocks[ns]. The function supports sending both IPv4 and
+ IPv6 queries at the same serially on the same socket.
+
+ Please note that for TCP there is no way to disable sending both
+ queries, unlike UDP, which honours RES_SNGLKUP and RES_SNGLKUPREOP
+ and sends the queries serially and waits for the result after each
+ sent query. This implemetnation should be corrected to honour these
+ options.
+
+ Please also note that for TCP we send both queries over the same
+ socket one after another. This technically violates best practice
+ since the server is allowed to read the first query, respond, and
+ then close the socket (to service another client). If the server
+ does this, then the remaining second query in the socket data buffer
+ will cause the server to send the client an RST which will arrive
+ asynchronously and the client's OS will likely tear down the socket
+ receive buffer resulting in a potentially short read and lost
+ response data. This will force the client to retry the query again,
+ and this process may repeat until all servers and connection resets
+ are exhausted and then the query will fail. It's not known if this
+ happens with any frequency in real DNS server implementations. This
+ implementation should be corrected to use two sockets by default for
+ parallel queries.
+
+ The query stored in BUF of BUFLEN length is sent first followed by
+ the query stored in BUF2 of BUFLEN2 length. Queries are sent
+ serially on the same socket.
+
+ Answers to the query are stored firstly in *ANSP up to a max of
+ *ANSSIZP bytes. If more than *ANSSIZP bytes are needed and ANSCP
+ is non-NULL (to indicate that modifying the answer buffer is allowed)
+ then malloc is used to allocate a new response buffer and ANSCP and
+ ANSP will both point to the new buffer. If more than *ANSSIZP bytes
+ are needed but ANSCP is NULL, then as much of the response as
+ possible is read into the buffer, but the results will be truncated.
+ When truncation happens because of a small answer buffer the DNS
+ packets header feild TC will bet set to 1, indicating a truncated
+ message and the rest of the socket data will be read and discarded.
+
+ Answers to the query are stored secondly in *ANSP2 up to a max of
+ *ANSSIZP2 bytes, with the actual response length stored in
+ *RESPLEN2. If more than *ANSSIZP bytes are needed and ANSP2
+ is non-NULL (required for a second query) then malloc is used to
+ allocate a new response buffer, *ANSSIZP2 is set to the new buffer
+ size and *ANSP2_MALLOCED is set to 1.
+
+ The ANSP2_MALLOCED argument will eventually be removed as the
+ change in buffer pointer can be used to detect the buffer has
+ changed and that the caller should use free on the new buffer.
+
+ Note that the answers may arrive in any order from the server and
+ therefore the first and second answer buffers may not correspond to
+ the first and second queries.
+
+ It is not supported to call this function with a non-NULL ANSP2
+ but a NULL ANSCP. Put another way, you can call send_vc with a
+ single unmodifiable buffer or two modifiable buffers, but no other
+ combination is supported.
+
+ It is the caller's responsibility to free the malloc allocated
+ buffers by detecting that the pointers have changed from their
+ original values i.e. *ANSCP or *ANSP2 has changed.
+
+ If errors are encountered then *TERRNO is set to an appropriate
+ errno value and a zero result is returned for a recoverable error,
+ and a less-than zero result is returned for a non-recoverable error.
+
+ If no errors are encountered then *TERRNO is left unmodified and
+ a the length of the first response in bytes is returned. */
static int
send_vc(res_state statp,
const u_char *buf, int buflen, const u_char *buf2, int buflen2,
u_char **ansp, int *anssizp,
int *terrno, int ns, u_char **anscp, u_char **ansp2, int *anssizp2,
- int *resplen2)
+ int *resplen2, int *ansp2_malloced)
{
const HEADER *hp = (HEADER *) buf;
const HEADER *hp2 = (HEADER *) buf2;
- u_char *ans = *ansp;
- int orig_anssizp = *anssizp;
- // XXX REMOVE
- // int anssiz = *anssizp;
- HEADER *anhp = (HEADER *) ans;
+ HEADER *anhp = (HEADER *) *ansp;
struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
int truncating, connreset, resplen, n;
struct iovec iov[4];
* Receive length & response
*/
int recvresp1 = 0;
+ /* Skip the second response if there is no second query.
+ To do that we mark the second response as received. */
int recvresp2 = buf2 == NULL;
uint16_t rlen16;
read_len:
u_char **thisansp;
int *thisresplenp;
if ((recvresp1 | recvresp2) == 0 || buf2 == NULL) {
+ /* We have not received any responses
+ yet or we only have one response to
+ receive. */
thisanssizp = anssizp;
thisansp = anscp ?: ansp;
assert (anscp != NULL || ansp2 == NULL);
thisresplenp = &resplen;
} else {
- if (*anssizp != MAXPACKET) {
- /* No buffer allocated for the first
- reply. We can try to use the rest
- of the user-provided buffer. */
-#ifdef _STRING_ARCH_unaligned
- *anssizp2 = orig_anssizp - resplen;
- *ansp2 = *ansp + resplen;
-#else
- int aligned_resplen
- = ((resplen + __alignof__ (HEADER) - 1)
- & ~(__alignof__ (HEADER) - 1));
- *anssizp2 = orig_anssizp - aligned_resplen;
- *ansp2 = *ansp + aligned_resplen;
-#endif
- } else {
- /* The first reply did not fit into the
- user-provided buffer. Maybe the second
- answer will. */
- *anssizp2 = orig_anssizp;
- *ansp2 = *ansp;
- }
-
thisanssizp = anssizp2;
thisansp = ansp2;
thisresplenp = resplen2;
anhp = (HEADER *) *thisansp;
*thisresplenp = rlen;
- if (rlen > *thisanssizp) {
- /* Yes, we test ANSCP here. If we have two buffers
- both will be allocatable. */
- if (__builtin_expect (anscp != NULL, 1)) {
+ /* Is the answer buffer too small? */
+ if (*thisanssizp < rlen) {
+ /* If the current buffer is non-NULL and it's not
+ pointing at the static user-supplied buffer then
+ we can reallocate it. */
+ if (thisansp != NULL && thisansp != ansp) {
+ /* Always allocate MAXPACKET, callers expect
+ this specific size. */
u_char *newp = malloc (MAXPACKET);
if (newp == NULL) {
*terrno = ENOMEM;
}
*thisanssizp = MAXPACKET;
*thisansp = newp;
+ if (thisansp == ansp2)
+ *ansp2_malloced = 1;
anhp = (HEADER *) newp;
+ /* A uint16_t can't be larger than MAXPACKET
+ thus it's safe to allocate MAXPACKET but
+ read RLEN bytes instead. */
len = rlen;
} else {
Dprint(statp->options & RES_DEBUG,
return 1;
}
+/* The send_dg function is responsible for sending a DNS query over UDP
+ to the nameserver numbered NS from the res_state STATP i.e.
+ EXT(statp).nssocks[ns]. The function supports IPv4 and IPv6 queries
+ along with the ability to send the query in parallel for both stacks
+ (default) or serially (RES_SINGLKUP). It also supports serial lookup
+ with a close and reopen of the socket used to talk to the server
+ (RES_SNGLKUPREOP) to work around broken name servers.
+
+ The query stored in BUF of BUFLEN length is sent first followed by
+ the query stored in BUF2 of BUFLEN2 length. Queries are sent
+ in parallel (default) or serially (RES_SINGLKUP or RES_SNGLKUPREOP).
+
+ Answers to the query are stored firstly in *ANSP up to a max of
+ *ANSSIZP bytes. If more than *ANSSIZP bytes are needed and ANSCP
+ is non-NULL (to indicate that modifying the answer buffer is allowed)
+ then malloc is used to allocate a new response buffer and ANSCP and
+ ANSP will both point to the new buffer. If more than *ANSSIZP bytes
+ are needed but ANSCP is NULL, then as much of the response as
+ possible is read into the buffer, but the results will be truncated.
+ When truncation happens because of a small answer buffer the DNS
+ packets header feild TC will bet set to 1, indicating a truncated
+ message, while the rest of the UDP packet is discarded.
+
+ Answers to the query are stored secondly in *ANSP2 up to a max of
+ *ANSSIZP2 bytes, with the actual response length stored in
+ *RESPLEN2. If more than *ANSSIZP bytes are needed and ANSP2
+ is non-NULL (required for a second query) then malloc is used to
+ allocate a new response buffer, *ANSSIZP2 is set to the new buffer
+ size and *ANSP2_MALLOCED is set to 1.
+
+ The ANSP2_MALLOCED argument will eventually be removed as the
+ change in buffer pointer can be used to detect the buffer has
+ changed and that the caller should use free on the new buffer.
+
+ Note that the answers may arrive in any order from the server and
+ therefore the first and second answer buffers may not correspond to
+ the first and second queries.
+
+ It is not supported to call this function with a non-NULL ANSP2
+ but a NULL ANSCP. Put another way, you can call send_vc with a
+ single unmodifiable buffer or two modifiable buffers, but no other
+ combination is supported.
+
+ It is the caller's responsibility to free the malloc allocated
+ buffers by detecting that the pointers have changed from their
+ original values i.e. *ANSCP or *ANSP2 has changed.
+
+ If an answer is truncated because of UDP datagram DNS limits then
+ *V_CIRCUIT is set to 1 and the return value non-zero to indicate to
+ the caller to retry with TCP. The value *GOTSOMEWHERE is set to 1
+ if any progress was made reading a response from the nameserver and
+ is used by the caller to distinguish between ECONNREFUSED and
+ ETIMEDOUT (the latter if *GOTSOMEWHERE is 1).
+
+ If errors are encountered then *TERRNO is set to an appropriate
+ errno value and a zero result is returned for a recoverable error,
+ and a less-than zero result is returned for a non-recoverable error.
+
+ If no errors are encountered then *TERRNO is left unmodified and
+ a the length of the first response in bytes is returned. */
static int
send_dg(res_state statp,
const u_char *buf, int buflen, const u_char *buf2, int buflen2,
u_char **ansp, int *anssizp,
int *terrno, int ns, int *v_circuit, int *gotsomewhere, u_char **anscp,
- u_char **ansp2, int *anssizp2, int *resplen2)
+ u_char **ansp2, int *anssizp2, int *resplen2, int *ansp2_malloced)
{
const HEADER *hp = (HEADER *) buf;
const HEADER *hp2 = (HEADER *) buf2;
- u_char *ans = *ansp;
- int orig_anssizp = *anssizp;
struct timespec now, timeout, finish;
struct pollfd pfd[1];
int ptimeout;
int need_recompute = 0;
int nwritten = 0;
int recvresp1 = 0;
+ /* Skip the second response if there is no second query.
+ To do that we mark the second response as received. */
int recvresp2 = buf2 == NULL;
pfd[0].fd = EXT(statp).nssocks[ns];
pfd[0].events = POLLOUT;
int *thisresplenp;
if ((recvresp1 | recvresp2) == 0 || buf2 == NULL) {
+ /* We have not received any responses
+ yet or we only have one response to
+ receive. */
thisanssizp = anssizp;
thisansp = anscp ?: ansp;
assert (anscp != NULL || ansp2 == NULL);
thisresplenp = &resplen;
} else {
- if (*anssizp != MAXPACKET) {
- /* No buffer allocated for the first
- reply. We can try to use the rest
- of the user-provided buffer. */
-#ifdef _STRING_ARCH_unaligned
- *anssizp2 = orig_anssizp - resplen;
- *ansp2 = *ansp + resplen;
-#else
- int aligned_resplen
- = ((resplen + __alignof__ (HEADER) - 1)
- & ~(__alignof__ (HEADER) - 1));
- *anssizp2 = orig_anssizp - aligned_resplen;
- *ansp2 = *ansp + aligned_resplen;
-#endif
- } else {
- /* The first reply did not fit into the
- user-provided buffer. Maybe the second
- answer will. */
- *anssizp2 = orig_anssizp;
- *ansp2 = *ansp;
- }
-
thisanssizp = anssizp2;
thisansp = ansp2;
thisresplenp = resplen2;
}
if (*thisanssizp < MAXPACKET
- /* Yes, we test ANSCP here. If we have two buffers
- both will be allocatable. */
- && anscp
+ /* If the current buffer is non-NULL and it's not
+ pointing at the static user-supplied buffer then
+ we can reallocate it. */
+ && (thisansp != NULL && thisansp != ansp)
+ /* Is the size too small? */
&& (ioctl (pfd[0].fd, FIONREAD, thisresplenp) < 0
|| *thisanssizp < *thisresplenp)) {
+ /* Always allocate MAXPACKET, callers expect
+ this specific size. */
u_char *newp = malloc (MAXPACKET);
if (newp != NULL) {
- *anssizp = MAXPACKET;
- *thisansp = ans = newp;
+ *thisanssizp = MAXPACKET;
+ *thisansp = newp;
+ if (thisansp == ansp2)
+ *ansp2_malloced = 1;
}
}
+ /* We could end up with truncation if anscp was NULL
+ (not allowed to change caller's buffer) and the
+ response buffer size is too small. This isn't a
+ reliable way to detect truncation because the ioctl
+ may be an inaccurate report of the UDP message size.
+ Therefore we use this only to issue debug output.
+ To do truncation accurately with UDP we need
+ MSG_TRUNC which is only available on Linux. We
+ can abstract out the Linux-specific feature in the
+ future to detect truncation. */
+ if (__builtin_expect (*thisanssizp < *thisresplenp, 0)) {
+ Dprint(statp->options & RES_DEBUG,
+ (stdout, ";; response may be truncated (UDP)\n")
+ );
+ }
+
HEADER *anhp = (HEADER *) *thisansp;
socklen_t fromlen = sizeof(struct sockaddr_in6);
assert (sizeof(from) <= fromlen);
projects / external / eglibc.git / commitdiff