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>

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 72cbcd6..7b62ffb 100644 (file)
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -124,8 +124,8 @@ static inline int fat_get_entry(struct inode *dir, loff_t *pos,
  * but ignore that right now.
  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
  */
-static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int uni_xlate,
-                      struct nls_table *nls)
+static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int len,
+                      int uni_xlate, struct nls_table *nls)
 {
        wchar_t *ip, ec;
        unsigned char *op, nc;
@@ -135,10 +135,11 @@ static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int uni_xlate,
        ip = uni;
        op = ascii;
 
-       while (*ip) {
+       while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
                ec = *ip++;
                if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
                        op += charlen;
+                       len -= charlen;
                } else {
                        if (uni_xlate == 1) {
                                *op = ':';
@@ -149,16 +150,19 @@ static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int uni_xlate,
                                        ec >>= 4;
                                }
                                op += 5;
+                               len -= 5;
                        } else {
                                *op++ = '?';
+                               len--;
                        }
                }
-               /* We have some slack there, so it's OK */
-               if (op>ascii+256) {
-                       op = ascii + 256;
-                       break;
-               }
        }
+
+       if (unlikely(*ip)) {
+               printk(KERN_WARNING "FAT: filename was truncated while "
+                      "converting.");
+       }
+
        *op = 0;
        return (op - ascii);
 }
@@ -311,9 +315,11 @@ int fat_search_long(struct inode *inode, const unsigned char *name,
        struct nls_table *nls_io = sbi->nls_io;
        struct nls_table *nls_disk = sbi->nls_disk;
        wchar_t bufuname[14];
-       unsigned char xlate_len, nr_slots;
+       unsigned char nr_slots;
+       int xlate_len;
        wchar_t *unicode = NULL;
-       unsigned char work[MSDOS_NAME], bufname[260];   /* 256 + 4 */
+       unsigned char work[MSDOS_NAME];
+       unsigned char *bufname = NULL;
        int uni_xlate = sbi->options.unicode_xlate;
        int utf8 = sbi->options.utf8;
        int anycase = (sbi->options.name_check != 's');
@@ -321,6 +327,10 @@ int fat_search_long(struct inode *inode, const unsigned char *name,
        loff_t cpos = 0;
        int chl, i, j, last_u, err;
 
+       bufname = (unsigned char*)__get_free_page(GFP_KERNEL);
+       if (!bufname)
+               return -ENOMEM;
+
        err = -ENOENT;
        while(1) {
                if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
@@ -386,8 +396,8 @@ parse_record:
 
                bufuname[last_u] = 0x0000;
                xlate_len = utf8
-                       ?utf8_wcstombs(bufname, bufuname, sizeof(bufname))
-                       :uni16_to_x8(bufname, bufuname, uni_xlate, nls_io);
+                       ?utf8_wcstombs(bufname, bufuname, PAGE_SIZE)
+                       :uni16_to_x8(bufname, bufuname, PAGE_SIZE, uni_xlate, nls_io);
                if (xlate_len == name_len)
                        if ((!anycase && !memcmp(name, bufname, xlate_len)) ||
                            (anycase && !nls_strnicmp(nls_io, name, bufname,
@@ -396,8 +406,8 @@ parse_record:
 
                if (nr_slots) {
                        xlate_len = utf8
-                               ?utf8_wcstombs(bufname, unicode, sizeof(bufname))
-                               :uni16_to_x8(bufname, unicode, uni_xlate, nls_io);
+                               ?utf8_wcstombs(bufname, unicode, PAGE_SIZE)
+                               :uni16_to_x8(bufname, unicode, PAGE_SIZE, uni_xlate, nls_io);
                        if (xlate_len != name_len)
                                continue;
                        if ((!anycase && !memcmp(name, bufname, xlate_len)) ||
@@ -416,6 +426,8 @@ Found:
        sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
        err = 0;
 EODir:
+       if (bufname)
+               free_page((unsigned long)bufname);
        if (unicode)
                free_page((unsigned long)unicode);
 
@@ -598,7 +610,7 @@ parse_record:
        if (isvfat) {
                bufuname[j] = 0x0000;
                i = utf8 ? utf8_wcstombs(bufname, bufuname, sizeof(bufname))
-                        : uni16_to_x8(bufname, bufuname, uni_xlate, nls_io);
+                        : uni16_to_x8(bufname, bufuname, sizeof(bufname), uni_xlate, nls_io);
        }
 
        fill_name = bufname;
@@ -610,7 +622,7 @@ parse_record:
                int buf_size = PAGE_SIZE - (261 * sizeof(unicode[0]));
                int long_len = utf8
                        ? utf8_wcstombs(longname, unicode, buf_size)
-                       : uni16_to_x8(longname, unicode, uni_xlate, nls_io);
+                       : uni16_to_x8(longname, unicode, buf_size, uni_xlate, nls_io);
 
                if (!both) {
                        fill_name = longname;

diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
index efc7057..ab4f3da 100644 (file)
--- 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)