Bad alignment in locale-archive

Bad alignment in locale-archive

[Andreas Schwab]

This fixes invalid alignments in the locale-archive file.

Andreas.

2002-10-21  Andreas Schwab  <schwab@suse.de>

	* locale/programs/locarchive.c (create_archive): Properly align
	offsets.
	(enlarge_archive): Likewise.

--- locale/programs/locarchive.c.~1.16.~	2002-10-18 11:14:16.000000000 +0200
+++ locale/programs/locarchive.c	2002-10-21 13:28:27.000000000 +0200
@@ -72,6 +72,9 @@ static const char *locnames[] =
 #define INITIAL_NUM_SUMS	2000
 
 
+#define ALIGN(offset, alignment) \
+  (((offset) + (alignment) - 1) & -(alignment))
+
 static void
 create_archive (const char *archivefname, struct locarhandle *ah)
 {
@@ -90,7 +93,8 @@ create_archive (const char *archivefname
 
   /* Create the initial content of the archive.  */
   head.magic = AR_MAGIC;
-  head.namehash_offset = sizeof (struct locarhead);
+  head.namehash_offset = ALIGN (sizeof (struct locarhead),
+				__alignof__ (struct namehashent));
   head.namehash_used = 0;
   head.namehash_size = next_prime (INITIAL_NUM_NAMES);
 
@@ -99,12 +103,15 @@ create_archive (const char *archivefname
   head.string_used = 0;
   head.string_size = INITIAL_SIZE_STRINGS;
 
-  head.locrectab_offset = head.string_offset + head.string_size;
+  head.locrectab_offset = ALIGN (head.string_offset + head.string_size,
+				 __alignof__ (struct locrecent));
   head.locrectab_used = 0;
   head.locrectab_size = INITIAL_NUM_LOCREC;
 
-  head.sumhash_offset = (head.locrectab_offset
-			 + head.locrectab_size * sizeof (struct locrecent));
+  head.sumhash_offset = ALIGN (head.locrectab_offset
+			       + (head.locrectab_size
+				  * sizeof (struct locrecent)),
+			       __alignof__ (struct sumhashent));
   head.sumhash_used = 0;
   head.sumhash_size = next_prime (INITIAL_NUM_SUMS);
 
@@ -274,13 +281,16 @@ enlarge_archive (struct locarhandle *ah,
 			      * sizeof (struct namehashent)));
   newhead.string_size = MAX (2 * newhead.string_used, newhead.string_size);
 
-  newhead.locrectab_offset = newhead.string_offset + newhead.string_size;
+  newhead.locrectab_offset = ALIGN (newhead.string_offset
+				    + newhead.string_size,
+				    __alignof__ (struct locrecent));
   newhead.locrectab_size = MAX (2 * newhead.locrectab_used,
 				newhead.locrectab_size);
 
-  newhead.sumhash_offset = (newhead.locrectab_offset
-			    + (newhead.locrectab_size
-			       * sizeof (struct locrecent)));
+  newhead.sumhash_offset = ALIGN (newhead.locrectab_offset
+				  + (newhead.locrectab_size
+				     * sizeof (struct locrecent)),
+				  __alignof__ (struct sumhashent));
   newhead.sumhash_size = MAX (next_prime (2 * newhead.sumhash_used),
 			      newhead.sumhash_size);
 

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Bad alignment in locale-archive

[Jakub Jelinek]

On Mon, Oct 21, 2002 at 04:21:39PM +0200, Andreas Schwab wrote:
> This fixes invalid alignments in the locale-archive file.

I don't think we should use __alignof__, what if it is different among
arches with the same endianity. locale-archive format should be only
endianess dependent, not anything else.
Furthermore, all but one alignment is unnecessary, and in that one case
(enlarge_archive's
newhead.locrectab_offset = newhead.string_offset + newhead.string_size;
) it is IMHO better to make sure string_size is always multiple of 4, like:

2002-10-22  Jakub Jelinek  <jakub@redhat.com>

	* locale/programs/locarchive.c (enlarge_archive): Make sure
	string_size is always multiple of 4.
	Reported by Andreas Schwab <schwab@suse.de>.

--- libc/locale/programs/locarchive.c.jj	2002-10-22 15:34:37.000000000 +0200
+++ libc/locale/programs/locarchive.c	2002-10-22 16:32:38.000000000 +0200
@@ -272,7 +272,8 @@ enlarge_archive (struct locarhandle *ah,
   newhead.string_offset = (newhead.namehash_offset
 			   + (newhead.namehash_size
 			      * sizeof (struct namehashent)));
-  newhead.string_size = MAX (2 * newhead.string_used, newhead.string_size);
+  newhead.string_size = MAX ((2 * newhead.string_used + 3) & -4,
+			     newhead.string_size);
 
   newhead.locrectab_offset = newhead.string_offset + newhead.string_size;
   newhead.locrectab_size = MAX (2 * newhead.locrectab_used,

	Jakub

Re: Bad alignment in locale-archive

[Roland McGrath]

I put your version of the fix in, with a comment.  (Please add comments in
the code for changes such as this.  If it was nonobvious enough to have
missed when writing it the first time, it's nonbovious enough to warrant an
explanatory comment when reading the code.)

I agree that the alignment should always be 4.  No extant architecture that
I know of needs more for these types (all structs containing uint32_t
members).  OTOH, if __alignof__ ever reports more for some architecture and
we use 4, then we have a problem.  From what we know now the files should
be portable modulo byte order, but no current configuration/installation
plan actually assumes they are (except maybe between 32/64 modes of bi-arch
platforms).