From 809cde4a640032f2f87319c9358be4fee8d6d7d5 Mon Sep 17 00:00:00 2001 From: Florian Weimer <fweimer@redhat.com> Date: Sat, 11 Jun 2016 12:12:56 +0200 Subject: [PATCH] nss_db: Fix initialization of iteration position [BZ #20237] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. (cherry picked from commit 31d0a4fa646db8b8c97ce24e0ec0a7b73de4fca1) --- ChangeLog | 7 +++++++ nss/nss_db/db-XXX.c | 8 +++++++- 2 files changed, 14 insertions(+), 1 deletion(-) #diff --git a/ChangeLog b/ChangeLog #index 3541385..bb8d618 100644 #--- a/ChangeLog #+++ b/ChangeLog #@@ -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. #+ # 2016-06-30 Andreas Schwab <schwab@suse.de> # # [BZ #20262] diff --git a/nss/nss_db/db-XXX.c b/nss/nss_db/db-XXX.c index 4a0766a..70b58be 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) { -- 2.10.2