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authorJakub Jelinek <jakub@redhat.com>2007-01-31 09:14:21 +0000
committerJakub Jelinek <jakub@redhat.com>2007-01-31 09:14:21 +0000
commit1a77d37f9228d51d727f1caff2689137785232b9 (patch)
treed59b0c6fe37e90d5fa0cb1d2ce7e795521ac53cb /nscd/nscd_helper.c
parentee3142006a497a5216aef39ea8277a1c313b9747 (diff)
downloadglibc-1a77d37f9228d51d727f1caff2689137785232b9.tar.gz
* nscd/nscd-client.h (__nscd_cache_search): Remove const qualifier
from return value. * nscd/nscd_helper.c: Include string.h. (__nscd_cache_search): Remove const qualifier from return value. On strict alignment architectures check hash entry and data head alignment. * nscd/nscd_getpw_r.c (nscd_getpw_r): Don't crash or fail because mmapped data during GC cycle contains garbage. If __nscd_drop_map_ref fails, decrement mapped->counter when returning error or if retrying with NO_MAPPING, only __nscd_unmap if counter dropped to 0. * nscd/nscd_getgr_r.c (nscd_getgr_r): Likewise. * nscd/nscd_initgroups.c (__nscd_getgrouplist): Likewise. * nscd/nscd_gethst_r.c (nscd_gethst_r): Likewise. * nscd/nscd_getai.c (__nscd_getai): Likewise. * nscd/nscd_getserv_r.c (nscd_getserv_r): Likewise. 2007-01-31 Jakub Jelinek <jakub@redhat.com> * nscd/nscd-client.h (__nscd_cache_search): Remove const qualifier from return value. * nscd/nscd_helper.c: Include string.h. (__nscd_cache_search): Remove const qualifier from return value. On strict alignment architectures check hash entry and data head alignment. * nscd/nscd_getpw_r.c (nscd_getpw_r): Don't crash or fail because mmapped data during GC cycle contains garbage. If __nscd_drop_map_ref fails, decrement mapped->counter when returning error or if retrying with NO_MAPPING, only __nscd_unmap if counter dropped to 0. * nscd/nscd_getgr_r.c (nscd_getgr_r): Likewise. * nscd/nscd_initgroups.c (__nscd_getgrouplist): Likewise. * nscd/nscd_gethst_r.c (nscd_gethst_r): Likewise. * nscd/nscd_getai.c (__nscd_getai): Likewise. * nscd/nscd_getserv_r.c (nscd_getserv_r): Likewise.
Diffstat (limited to 'nscd/nscd_helper.c')
-rw-r--r--nscd/nscd_helper.c29
1 files changed, 25 insertions, 4 deletions
diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c
index 7c45981586..336adfee89 100644
--- a/nscd/nscd_helper.c
+++ b/nscd/nscd_helper.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1998-2002,2003,2004,2005,2006 Free Software Foundation, Inc.
+/* Copyright (C) 1998-2002,2003,2004,2005,2006,2007
+ Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
@@ -21,6 +22,7 @@
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
+#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/mman.h>
@@ -362,7 +364,10 @@ __nscd_get_map_ref (request_type type, const char *name,
}
-const struct datahead *
+/* Don't return const struct datahead *, as eventhough the record
+ is normally constant, it can change arbitrarily during nscd
+ garbage collection. */
+struct datahead *
__nscd_cache_search (request_type type, const char *key, size_t keylen,
const struct mapped_database *mapped)
{
@@ -374,16 +379,32 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
{
struct hashentry *here = (struct hashentry *) (mapped->data + work);
+#ifndef _STRING_ARCH_unaligned
+ /* Although during garbage collection when moving struct hashentry
+ records around we first copy from old to new location and then
+ adjust pointer from previous hashentry to it, there is no barrier
+ between those memory writes. It is very unlikely to hit it,
+ so check alignment only if a misaligned load can crash the
+ application. */
+ if ((uintptr_t) here & (__alignof__ (*here) - 1))
+ return NULL;
+#endif
+
if (type == here->type
&& keylen == here->len
- && here->key + here->len <= datasize
+ && here->key + keylen <= datasize
&& memcmp (key, mapped->data + here->key, keylen) == 0
&& here->packet + sizeof (struct datahead) <= datasize)
{
/* We found the entry. Increment the appropriate counter. */
- const struct datahead *dh
+ struct datahead *dh
= (struct datahead *) (mapped->data + here->packet);
+#ifndef _STRING_ARCH_unaligned
+ if ((uintptr_t) dh & (__alignof__ (*dh) - 1))
+ return NULL;
+#endif
+
/* See whether we must ignore the entry or whether something
is wrong because garbage collection is in progress. */
if (dh->usable && here->packet + dh->allocsize <= datasize)