From patchwork Wed Dec 10 15:13:34 2014
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Date: Wed, 10 Dec 2014 16:13:34 +0100
From: =?utf-8?B?T25kxZllaiBCw61sa2E=?= <neleai@seznam.cz>
To: Andreas Schwab <schwab@suse.de>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH][BZ #17657] Return allocated array instead array on
	stack.
Message-ID: <20141210151334.GA27824@domone>
References: <20141210132153.GA6395@domone> <mvmppbrtx3i.fsf@hawking.suse.de>
	<20141210143252.GA27265@domone> <mvmbnnbtv76.fsf@hawking.suse.de>
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User-Agent: Mutt/1.5.20 (2009-06-14)

On Wed, Dec 10, 2014 at 03:50:53PM +0100, Andreas Schwab wrote:
> Ondřej Bílka <neleai@seznam.cz> writes:
> 
> > On Wed, Dec 10, 2014 at 03:09:53PM +0100, Andreas Schwab wrote:
> >> Ondřej Bílka <neleai@seznam.cz> writes:
> >> 
> >> > here we return array on stack which is invalid. OK to fix it in obvious way?
> >> 
> >> The obvious way would be a static allocation.
> >> 
> > which breaks when user modifies array.
> 
> Which user?
> 
I meant caller, as I looked at code more caller cannot modify it so
static allocation is ok. Also found second occurence of same problem.

	[BZ #17657]
        * locale/programs/ld-ctype.c (find_translit2, read_widestring): Return
	static array.

diff --git a/locale/programs/ld-ctype.c b/locale/programs/ld-ctype.c
index 67846b3..eeaf645 100644
--- a/locale/programs/ld-ctype.c
+++ b/locale/programs/ld-ctype.c
@@ -114,6 +114,9 @@ struct translit_include_t
   struct translit_include_t *next;
 };
 
+/* Provide some dummy pointer for empty string.  */
+static uint32_t no_str[] = { 0 };
+
 
 /* Sparse table of uint32_t.  */
 #define TABLE idx_table
@@ -1777,7 +1780,7 @@ find_translit2 (struct locale_ctype_t *ctype, const struct charmap_t *charmap,
 
 	  for (wi = tirunp->from; wi <= wch; wi += tirunp->step)
 	    if (wi == wch)
-	      return (uint32_t []) { 0 };
+	      return no_str;
 	}
     }
 
@@ -1831,7 +1834,7 @@ read_widestring (struct linereader *ldfile, struct token *now,
 
   if (now->tok == tok_default_missing)
     /* The special name "" will denote this case.  */
-    wstr = ((uint32_t *) { 0 });
+    wstr = no_str;
   else if (now->tok == tok_bsymbol)
     {
       /* Get the value from the repertoire.  */
@@ -4090,9 +4093,6 @@ allocate_arrays (struct locale_ctype_t *ctype, const struct charmap_t *charmap,
     }
   else
     {
-      /* Provide some dummy pointers since we have nothing to write out.  */
-      static uint32_t no_str = { 0 };
-
       ctype->translit_from_idx = &no_str;
       ctype->translit_from_tbl = &no_str;
       ctype->translit_to_tbl = &no_str;