[PATCH] Bug in NLS UTF-8 code

[PATCH] Bug in NLS UTF-8 code

[Liyang Hu]

Hi,

I've recently (actually, last month, but I had been a bit too busy
since then) come across a wee problem, in what I originally thought
was the VFAT code -- having `utf8' as one of the options, creating
UTF-8 file names on a VFAT partition mysteriously gains a couple of
(random) characters just after the UTF-8 escaped character: eg.
touch "fooCbar" where C is an UTF-8 escape sequence ends up creating
a file named "fooCRbar". (R being some random character.)

I eventually tracked it down to one line in fs/nls/nls_base.c -- the
UCS-2 (wchar_t) string pointer was being incremented too fast. After
consulting Ogawa Hirofumi-san on the subject, he mentioned that
include/linux/nls.h also needs to be changed for proper UTF-8
support in the NLS code.

Patch enclosed below.

/Liyang

----8<----snip----8<----

--- kernel-source-2.4.18/fs/nls/nls_base.c.orig	Mon Apr  1 00:26:37 2002
+++ kernel-source-2.4.18-nls/fs/nls/nls_base.c	Mon Apr  1 00:26:57 2002
@@ -1,5 +1,5 @@
 /*
- * linux/fs/nls.c
+ * linux/fs/nls_base.c
  *
  * Native language support--charsets and unicode translations.
  * By Gordon Chaffee 1996, 1997
@@ -93,7 +93,7 @@
 				ip++;
 				n--;
 			} else {
-				op += size;
+				op++;
 				ip += size;
 				n -= size;
 			}
--- kernel-source-2.4.18/include/linux/nls.h.orig	Fri Jul 20 20:53:03 2001
+++ kernel-source-2.4.18-nls/include/linux/nls.h	Mon Apr  1 00:28:16 2002
@@ -18,7 +18,7 @@
 };
 
 /* this value hold the maximum octet of charset */
-#define NLS_MAX_CHARSET_SIZE 3
+#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */
 
 /* nls.c */
 extern int register_nls(struct nls_table *);

----8<----snip----8<----

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