nscd: Drop local address tuple variable [BZ #29607]

When a request needs to be resent (e.g. due to insufficient buffer
space), the references to subsequent tuples in the local variable are
stale and should not be used.  This used to work by accident before, but
since 1d495912a it no longer does.  Instead of trying to reset it, just
let gethostbyname4_r write into TUMPBUF6 for us, thus maintaining a
consistent state at all times.  This is now consistent with what is done
in gaih_inet for getaddrinfo.

Resolves: BZ #29607
Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

diff --git a/nscd/aicache.c b/nscd/aicache.c
index 51e793199fff83137548501949b553bc2cad2f37..e0baed170b36d6d1ca2ca6c3f758e50c131d5e97 100644 (file)
--- a/nscd/aicache.c
+++ b/nscd/aicache.c
@@ -110,11 +110,10 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
                                                          "gethostbyname4_r");
       if (fct4 != NULL)
        {
-         struct gaih_addrtuple atmem;
          struct gaih_addrtuple *at;
          while (1)
            {
-             at = &atmem;
+             at = NULL;
              rc6 = 0;
              herrno = 0;
              status[1] = DL_CALL_FCT (fct4, (key, &at,
@@ -137,7 +136,7 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
            goto next_nip;
 
          /* We found the data.  Count the addresses and the size.  */
-         for (const struct gaih_addrtuple *at2 = at = &atmem; at2 != NULL;
+         for (const struct gaih_addrtuple *at2 = at; at2 != NULL;
               at2 = at2->next)
            {
              ++naddrs;