vfat: bug fix for vfat cannot handle filename with 255

This patch fix the problem that the buffer allocated for convert of unicode to
utf8 in fat/dir.c is too small.

And cannot handle filename with 255 asian characters when mounted with utf8
options.

Also it fix the filename length limitation checking in vfat/namei.c that the
filename length should be checked against the number of converted unicode
characters.

Not the length before NLS/UTF8 converted.

Signed-off-by: Keith Mok <ek9852@gmail.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 14 deletions

diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
index efc70576e4b4..ab4f3da770f0 100644
--- a/fs/vfat/namei.c
+++ b/fs/vfat/namei.c
@@ -176,15 +176,10 @@ static inline int vfat_is_used_badchars(const wchar_t *s, int len)
         for (i = 0; i < len; i++)
                 if (vfat_bad_char(s[i]))
                         return -EINVAL;
-        return 0;
-}
 
-static int vfat_valid_longname(const unsigned char *name, unsigned int len)
-{
-        if (name[len - 1] == ' ')
+        if (s[i - 1] == ' ') /* last character cannot be space */
                 return -EINVAL;
-        if (len >= 256)
-                return -ENAMETOOLONG;
+
         return 0;
 }
 
@@ -485,11 +480,14 @@ xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
                  */
                 *outlen -= (name_len - len);
 
+                if (*outlen > 255)
+                        return -ENAMETOOLONG;
+
                 op = &outname[*outlen * sizeof(wchar_t)];
         } else {
                 if (nls) {
                         for (i = 0, ip = name, op = outname, *outlen = 0;
-                             i < len && *outlen <= 260;
+                             i < len && *outlen <= 255;
                              *outlen += 1)
                         {
                                 if (escape && (*ip == ':')) {
@@ -525,18 +523,20 @@ xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
                                         op += 2;
                                 }
                         }
+                        if (i < len)
+                                return -ENAMETOOLONG;
                 } else {
                         for (i = 0, ip = name, op = outname, *outlen = 0;
-                             i < len && *outlen <= 260;
+                             i < len && *outlen <= 255;
                              i++, *outlen += 1)
                         {
                                 *op++ = *ip++;
                                 *op++ = 0;
                         }
+                        if (i < len)
+                                return -ENAMETOOLONG;
                 }
         }
-        if (*outlen > 260)
-                return -ENAMETOOLONG;
 
         *longlen = *outlen;
         if (*outlen % 13) {
@@ -574,9 +574,6 @@ static int vfat_build_slots(struct inode *dir, const unsigned char *name,
         loff_t offset;
 
         *nr_slots = 0;
-        err = vfat_valid_longname(name, len);
-        if (err)
-                return err;
 
         page = __get_free_page(GFP_KERNEL);
         if (!page)