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SubjectRe: [PATCH] vfat: bug fix for vfat cannot handle filename with 255 asian characters when mounted with utf8
Date
Keith Mok <ek9852@gmail.com> writes:

> Patch modified according to coding style in Linux.
> NLS and UTF8 filename length are checked and limited to 255 after convert to unicode in xlate_to_uni function.
>
>
> Signed-off-by: Keith Mok <ek9852@gmail.com>

Looks good to me. I'll submit after some test. (and maybe some cleanup
of this area).

Thanks.

> --- linux-source-2.6.22/fs/fat/dir.c.orig 2007-07-09 07:32:17.000000000 +0800
> +++ linux-source-2.6.22/fs/fat/dir.c 2008-02-15 17:24:18.000000000 +0800
> @@ -124,7 +124,7 @@ static inline int fat_get_entry(struct i
> * 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,
> +static int uni16_to_x8(unsigned char *ascii, wchar_t *uni, int len, int uni_xlate,
> struct nls_table *nls)
> {
> wchar_t *ip, ec;
> @@ -135,10 +135,11 @@ static int uni16_to_x8(unsigned char *as
> 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 = ':';
> @@ -149,15 +150,18 @@ static int uni16_to_x8(unsigned char *as
> 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: truncated while convert unicode characters in %s\n",
> + __FUNCTION__);
> }
> *op = 0;
> return (op - ascii);
> @@ -311,9 +315,11 @@ int fat_search_long(struct inode *inode,
> 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;
> + int xlate_len;
> + unsigned char nr_slots;
> wchar_t *unicode = NULL;
> - unsigned char work[8], bufname[260]; /* 256 + 4 */
> + unsigned char work[8];
> + 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,
> 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)
> @@ -383,8 +393,8 @@ 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,
> @@ -393,8 +403,8 @@ 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)) ||
> @@ -413,6 +423,8 @@ 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);
>
> @@ -593,7 +605,7 @@ 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;
> @@ -605,7 +617,7 @@ 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;
> --- linux-source-2.6.22/fs/vfat/namei.c.orig 2007-07-09 07:32:17.000000000 +0800
> +++ linux-source-2.6.22/fs/vfat/namei.c 2008-02-15 18:33:15.000000000 +0800
> @@ -176,15 +176,8 @@ static inline int vfat_is_used_badchars(
> 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] == 0x0020) /* last character cannot be space */
> return -EINVAL;
> - if (len >= 256)
> - return -ENAMETOOLONG;
> return 0;
> }
>
> @@ -485,11 +478,14 @@ xlate_to_uni(const unsigned char *name,
> */
> *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 +521,20 @@ xlate_to_uni(const unsigned char *name,
> 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 +572,6 @@ static int vfat_build_slots(struct inode
> loff_t offset;
>
> *nr_slots = 0;
> - err = vfat_valid_longname(name, len);
> - if (err)
> - return err;
>
> page = __get_free_page(GFP_KERNEL);
> if (!page)
>
>
>

--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>


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