nss_db: Fix initialization of iteration position [BZ #20237]

When get*ent is called without a preceding set*ent, we need
to set the initial iteration position in get*ent.

Reproducer: Add “services: db files” to /etc/nsswitch.conf, then run
“perl -e getservent”.  It will segfault before this change, and exit
silently after it.
This commit is contained in:
Florian Weimer 2016-06-11 12:12:56 +02:00
parent 073f82140c
commit 31d0a4fa64
2 changed files with 14 additions and 1 deletions

View File

@ -1,3 +1,10 @@
2016-06-11 Florian Weimer <fweimer@redhat.com>
[BZ #20237]
* nss/nss_db/db-XXX.c (set*ent): Reset entidx to NULL.
(get*ent): Set entidx to NULL during initialization. If entidx is
NULL, start iteration from the beginning.
2016-06-11 Florian Weimer <fweimer@redhat.com>
* malloc/malloc.c (musable): Return correct size for dumped fake

View File

@ -77,7 +77,7 @@ CONCAT(_nss_db_set,ENTNAME) (int stayopen)
keep_db |= stayopen;
/* Reset the sequential index. */
entidx = (const char *) state.header + state.header->valstroffset;
entidx = NULL;
}
__libc_lock_unlock (lock);
@ -253,8 +253,14 @@ CONCAT(_nss_db_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
H_ERRNO_SET (NETDB_INTERNAL);
goto out;
}
entidx = NULL;
}
/* Start from the beginning if freshly initialized or reset
requested by set*ent. */
if (entidx == NULL)
entidx = (const char *) state.header + state.header->valstroffset;
status = NSS_STATUS_UNAVAIL;
if (state.header != MAP_FAILED)
{