hesiod: Always use thread-local resolver state [BZ #19573]

The Hesiod implementation imported into glibc was enhanced
to support caller-supplied resolver states.  But its only
consumer is nss_hesiod, and it supplies the thread-local
resolver state.  Therefore, this commit changes the Hesiod
implementation to use the thread-local resolver state (_res)
directly.  This fixes bug 19573 because the Hesiod
implementation no longer has to initialize and free any
resolver state.

To avoid any risk of interposition of ABI-incompatible Hesiod
function implementations, this commit marks the Hesiod functions
as hidden.  (They were already hidden using a linker version
script.)
This commit is contained in:
Florian Weimer 2016-05-02 15:25:20 +02:00
parent 46cb402c6d
commit 5018f16c62
11 changed files with 89 additions and 156 deletions

View File

@ -1,3 +1,28 @@
2016-05-02 Florian Weimer <fweimer@redhat.com>
[BZ #19573]
* hesiod/Makefile (libnss_hesiod-routines): Remove hesiod-init.
* hesiod/nss_hesiod/hesiod-init.c: Remove file.
* hesiod/nss_hesiod/nss_hesiod.h: Likewise.
* hesiod/hesiod.h (__hesiod_res_get, __hesiod_res_set): Remove.
(hesiod_init, hesiod_end, hesiod_to_bind, hesiod_resolve)
(hesiod_free_list): Mark as hidden.
* hesiod/hesiod_p (struct hesiod_p): Remove res, free_res,
res_set, res_get.
* hesiod/hesiod.c: Remove unnecessary forward declarations.
(init, __hesiod_res_get, __hesiod_res_set): Remove.
(hesiod_init): Remove obsolete res_ninit call.
(hesiod_end): Do not free resolver state. Do not invoke callback.
(hesiod_bind): Do not call init.
(get_txt_records): Use res_mkquery, res_send instead of
res_nmkquery, res_nsend.
* hesiod/nss_hesiod/hesiod-grp.c (lookup): Call hesiod_init
instead of _nss_hesiod_init.
(_nss_hesiod_initgroups_dyn): Likewise.
* hesiod/nss_hesiod/hesiod-proto.c (lookup): Likewise.
* hesiod/nss_hesiod/hesiod-pwd.c (lookup): Likewise.
* hesiod/nss_hesiod/hesiod-service.c (lookup): Likewise.
2016-05-02 Florian Weimer <fweimer@redhat.com>
* hesiod/hesiod_p.h (DEF_RHS): Remove.

View File

@ -28,7 +28,7 @@ extra-libs-others = $(extra-libs)
subdir-dirs = nss_hesiod
vpath %.c nss_hesiod
libnss_hesiod-routines := hesiod hesiod-grp hesiod-init hesiod-proto \
libnss_hesiod-routines := hesiod hesiod-grp hesiod-proto \
hesiod-pwd hesiod-service
# Build only shared library
libnss_hesiod-inhibit-o = $(filter-out .os,$(object-suffixes))

View File

@ -1,3 +1,20 @@
/* Copyright (C) 1997-2016 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) 1996,1999 by Internet Software Consortium.
*
@ -47,18 +64,9 @@
/* Forward */
int hesiod_init(void **context);
void hesiod_end(void *context);
char * hesiod_to_bind(void *context, const char *name,
const char *type);
char ** hesiod_resolve(void *context, const char *name,
const char *type);
void hesiod_free_list(void *context, char **list);
static int parse_config_file(struct hesiod_p *ctx, const char *filename);
static char ** get_txt_records(struct hesiod_p *ctx, int class,
const char *name);
static int init(struct hesiod_p *ctx);
/* Public */
@ -77,7 +85,6 @@ hesiod_init(void **context) {
ctx->LHS = NULL;
ctx->RHS = NULL;
ctx->res = NULL;
/* Set default query classes. */
ctx->classes[0] = C_IN;
ctx->classes[1] = C_HS;
@ -114,11 +121,6 @@ hesiod_init(void **context) {
goto cleanup;
}
#if 0
if (res_ninit(ctx->res) < 0)
goto cleanup;
#endif
*context = ctx;
return (0);
@ -135,12 +137,8 @@ hesiod_end(void *context) {
struct hesiod_p *ctx = (struct hesiod_p *) context;
int save_errno = errno;
if (ctx->res)
res_nclose(ctx->res);
free(ctx->RHS);
free(ctx->LHS);
if (ctx->res && ctx->free_res)
(*ctx->free_res)(ctx->res);
free(ctx);
__set_errno(save_errno);
}
@ -215,10 +213,6 @@ hesiod_resolve(void *context, const char *name, const char *type) {
if (bindname == NULL)
return (NULL);
if (init(ctx) == -1) {
free(bindname);
return (NULL);
}
retvec = get_txt_records(ctx, ctx->classes[0], bindname);
@ -348,13 +342,13 @@ get_txt_records(struct hesiod_p *ctx, int class, const char *name) {
/*
* Construct the query and send it.
*/
n = res_nmkquery(ctx->res, QUERY, name, class, T_TXT, NULL, 0,
n = res_mkquery(QUERY, name, class, T_TXT, NULL, 0,
NULL, qbuf, MAX_HESRESP);
if (n < 0) {
__set_errno(EMSGSIZE);
return (NULL);
}
n = res_nsend(ctx->res, qbuf, n, abuf, MAX_HESRESP);
n = res_send(qbuf, n, abuf, MAX_HESRESP);
if (n < 0) {
__set_errno(ECONNREFUSED);
return (NULL);
@ -447,44 +441,3 @@ get_txt_records(struct hesiod_p *ctx, int class, const char *name) {
free(list);
return (NULL);
}
struct __res_state *
__hesiod_res_get(void *context) {
struct hesiod_p *ctx = context;
if (!ctx->res) {
struct __res_state *res;
res = (struct __res_state *)calloc(1, sizeof *res);
if (res == NULL)
return (NULL);
__hesiod_res_set(ctx, res, free);
}
return (ctx->res);
}
void
__hesiod_res_set(void *context, struct __res_state *res,
void (*free_res)(void *)) {
struct hesiod_p *ctx = context;
if (ctx->res && ctx->free_res) {
res_nclose(ctx->res);
(*ctx->free_res)(ctx->res);
}
ctx->res = res;
ctx->free_res = free_res;
}
static int
init(struct hesiod_p *ctx) {
if (!ctx->res && !__hesiod_res_get(ctx))
return (-1);
if (__res_maybe_init (ctx->res, 0) == -1)
return (-1);
return (0);
}

View File

@ -1,3 +1,20 @@
/* Copyright (C) 1997-2016 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) 1996,1999 by Internet Software Consortium.
*
@ -22,15 +39,12 @@
#ifndef _HESIOD_H_INCLUDED
#define _HESIOD_H_INCLUDED
int hesiod_init (void **context);
void hesiod_end (void *context);
int hesiod_init (void **context) attribute_hidden;
void hesiod_end (void *context) attribute_hidden;
char * hesiod_to_bind (void *context, const char *name,
const char *type);
const char *type) attribute_hidden;
char ** hesiod_resolve (void *context, const char *name,
const char *type);
void hesiod_free_list (void *context, char **list);
struct __res_state * __hesiod_res_get (void *context);
void __hesiod_res_set (void *context, struct __res_state *,
void (*)(void *));
const char *type) attribute_hidden;
void hesiod_free_list (void *context, char **list) attribute_hidden;
#endif /*_HESIOD_H_INCLUDED*/

View File

@ -1,3 +1,20 @@
/* Copyright (C) 1997-2016 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) 1996,1999 by Internet Software Consortium.
*
@ -31,11 +48,6 @@
struct hesiod_p {
char * LHS; /* normally ".ns" */
char * RHS; /* AKA the default hesiod domain */
struct __res_state * res; /* resolver context */
void (*free_res)(void *);
void (*res_set)(struct hesiod_p *, struct __res_state *,
void (*)(void *));
struct __res_state * (*res_get)(struct hesiod_p *);
int classes[2]; /* The class search order. */
};

View File

@ -26,8 +26,6 @@
#include <string.h>
#include <sys/param.h>
#include "nss_hesiod.h"
/* Get the declaration of the parser function. */
#define ENTNAME grent
#define STRUCTURE group
@ -58,8 +56,7 @@ lookup (const char *name, const char *type, struct group *grp,
size_t len;
int olderr = errno;
context = _nss_hesiod_init ();
if (context == NULL)
if (hesiod_init (&context) < 0)
return NSS_STATUS_UNAVAIL;
list = hesiod_resolve (context, name, type);
@ -179,8 +176,7 @@ _nss_hesiod_initgroups_dyn (const char *user, gid_t group, long int *start,
gid_t *groups = *groupsp;
int save_errno;
context = _nss_hesiod_init ();
if (context == NULL)
if (hesiod_init (&context) < 0)
return NSS_STATUS_UNAVAIL;
list = hesiod_resolve (context, user, "grplist");

View File

@ -1,38 +0,0 @@
/* Copyright (C) 2000-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 2000.
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/>. */
#include <sys/cdefs.h> /* Needs to come before <hesiod.h>. */
#include <hesiod.h>
#include <resolv.h>
#include <stddef.h>
#include "nss_hesiod.h"
void *
_nss_hesiod_init (void)
{
void *context;
if (hesiod_init (&context) == -1)
return NULL;
/* Use the default (per-thread) resolver state. */
__hesiod_res_set (context, &_res, NULL);
return context;
}

View File

@ -25,8 +25,6 @@
#include <stdlib.h>
#include <string.h>
#include "nss_hesiod.h"
/* Declare a parser for Hesiod protocol entries. Although the format
of the entries is identical to those in /etc/protocols, here is no
predefined parser for us to use. */
@ -68,8 +66,7 @@ lookup (const char *name, const char *type, struct protoent *proto,
int found;
int olderr = errno;
context = _nss_hesiod_init ();
if (context == NULL)
if (hesiod_init (&context) < 0)
return NSS_STATUS_UNAVAIL;
list = hesiod_resolve (context, name, type);

View File

@ -24,8 +24,6 @@
#include <stdlib.h>
#include <string.h>
#include "nss_hesiod.h"
/* Get the declaration of the parser function. */
#define ENTNAME pwent
#define STRUCTURE passwd
@ -56,8 +54,7 @@ lookup (const char *name, const char *type, struct passwd *pwd,
size_t len;
int olderr = errno;
context = _nss_hesiod_init ();
if (context == NULL)
if (hesiod_init (&context) < 0)
return NSS_STATUS_UNAVAIL;
list = hesiod_resolve (context, name, type);

View File

@ -25,8 +25,6 @@
#include <stdlib.h>
#include <string.h>
#include "nss_hesiod.h"
/* Hesiod uses a format for service entries that differs from the
traditional format. We therefore declare our own parser. */
@ -69,8 +67,7 @@ lookup (const char *name, const char *type, const char *protocol,
int found;
int olderr = errno;
context = _nss_hesiod_init ();
if (context == NULL)
if (hesiod_init (&context) < 0)
return NSS_STATUS_UNAVAIL;
list = hesiod_resolve (context, name, type);

View File

@ -1,20 +0,0 @@
/* Copyright (C) 2000-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 2000.
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/>. */
/* Initialize a Hesiod context. */
extern void *_nss_hesiod_init (void);