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[PATCH] nss_db: Fix initialization of iteration position [BZ #20237]
- From: fweimer at redhat dot com (Florian Weimer)
- To: libc-alpha at sourceware dot org
- Date: Fri, 10 Jun 2016 10:54:06 +0200
- Subject: [PATCH] nss_db: Fix initialization of iteration position [BZ #20237]
- Authentication-results: sourceware.org; auth=none
When get*ent is called without a preceding set*ent, we need
to set the initial iteration position in get*ent.
Reproducer: Add âservices: db filesâ to /etc/nsswitch.conf, then run
âperl -e getserventâ. It will segfault before this change, and exit
silently after it.
2016-06-10 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.
diff --git a/nss/nss_db/db-XXX.c b/nss/nss_db/db-XXX.c
index 125a5e9..2d13edd 100644
--- a/nss/nss_db/db-XXX.c
+++ b/nss/nss_db/db-XXX.c
@@ -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)
{