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linux/fs/udf/unicode.c
Jan Kara 59285c28d1 udf: Fix oops when invalid character in filename occurs 
Functions udf_CS0toNLS() and udf_NLStoCS0() didn't count with the fact that
NLS can return negative length when invalid character is given to it for
conversion. Thus interesting things could happen (such as overwriting random
memory with the rest of filename). Add appropriate checks.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-04-02 12:29:53 +02:00

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/*
* unicode.c
*
* PURPOSE
* Routines for converting between UTF-8 and OSTA Compressed Unicode.
* Also handles filename mangling
*
* DESCRIPTION
* OSTA Compressed Unicode is explained in the OSTA UDF specification.
* http://www.osta.org/
* UTF-8 is explained in the IETF RFC XXXX.
* ftp://ftp.internic.net/rfc/rfcxxxx.txt
*
* COPYRIGHT
* This file is distributed under the terms of the GNU General Public
* License (GPL). Copies of the GPL can be obtained from:
* ftp://prep.ai.mit.edu/pub/gnu/GPL
* Each contributing author retains all rights to their own work.
*/
#include "udfdecl.h"
#include <linux/kernel.h>
#include <linux/string.h> /* for memset */
#include <linux/nls.h>
#include <linux/crc-itu-t.h>
#include "udf_sb.h"
static int udf_translate_to_linux(uint8_t *, uint8_t *, int, uint8_t *, int);
static int udf_char_to_ustr(struct ustr *dest, const uint8_t *src, int strlen)
{
if ((!dest) || (!src) || (!strlen) || (strlen > UDF_NAME_LEN - 2))
return 0;
memset(dest, 0, sizeof(struct ustr));
memcpy(dest->u_name, src, strlen);
dest->u_cmpID = 0x08;
dest->u_len = strlen;
return strlen;
}
/*
* udf_build_ustr
*/
int udf_build_ustr(struct ustr *dest, dstring *ptr, int size)
{
int usesize;
if (!dest || !ptr || !size)
return -1;
BUG_ON(size < 2);
usesize = min_t(size_t, ptr[size - 1], sizeof(dest->u_name));
usesize = min(usesize, size - 2);
dest->u_cmpID = ptr[0];
dest->u_len = usesize;
memcpy(dest->u_name, ptr + 1, usesize);
memset(dest->u_name + usesize, 0, sizeof(dest->u_name) - usesize);
return 0;
}
/*
* udf_build_ustr_exact
*/
static int udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
{
if ((!dest) || (!ptr) || (!exactsize))
return -1;
memset(dest, 0, sizeof(struct ustr));
dest->u_cmpID = ptr[0];
dest->u_len = exactsize - 1;
memcpy(dest->u_name, ptr + 1, exactsize - 1);
return 0;
}
/*
* udf_ocu_to_utf8
*
* PURPOSE
* Convert OSTA Compressed Unicode to the UTF-8 equivalent.
*
* PRE-CONDITIONS
* utf Pointer to UTF-8 output buffer.
* ocu Pointer to OSTA Compressed Unicode input buffer
* of size UDF_NAME_LEN bytes.
* both of type "struct ustr *"
*
* POST-CONDITIONS
* <return> Zero on success.
*
* HISTORY
* November 12, 1997 - Andrew E. Mileski
* Written, tested, and released.
*/
int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
{
const uint8_t *ocu;
uint8_t cmp_id, ocu_len;
int i;
ocu_len = ocu_i->u_len;
if (ocu_len == 0) {
memset(utf_o, 0, sizeof(struct ustr));
return 0;
}
cmp_id = ocu_i->u_cmpID;
if (cmp_id != 8 && cmp_id != 16) {
memset(utf_o, 0, sizeof(struct ustr));
printk(KERN_ERR "udf: unknown compression code (%d) stri=%s\n",
cmp_id, ocu_i->u_name);
return 0;
}
ocu = ocu_i->u_name;
utf_o->u_len = 0;
for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
/* Expand OSTA compressed Unicode to Unicode */
uint32_t c = ocu[i++];
if (cmp_id == 16)
c = (c << 8) | ocu[i++];
/* Compress Unicode to UTF-8 */
if (c < 0x80U)
utf_o->u_name[utf_o->u_len++] = (uint8_t)c;
else if (c < 0x800U) {
utf_o->u_name[utf_o->u_len++] =
(uint8_t)(0xc0 | (c >> 6));
utf_o->u_name[utf_o->u_len++] =
(uint8_t)(0x80 | (c & 0x3f));
} else {
utf_o->u_name[utf_o->u_len++] =
(uint8_t)(0xe0 | (c >> 12));
utf_o->u_name[utf_o->u_len++] =
(uint8_t)(0x80 |
((c >> 6) & 0x3f));
utf_o->u_name[utf_o->u_len++] =
(uint8_t)(0x80 | (c & 0x3f));
}
}
utf_o->u_cmpID = 8;
return utf_o->u_len;
}
/*
*
* udf_utf8_to_ocu
*
* PURPOSE
* Convert UTF-8 to the OSTA Compressed Unicode equivalent.
*
* DESCRIPTION
* This routine is only called by udf_lookup().
*
* PRE-CONDITIONS
* ocu Pointer to OSTA Compressed Unicode output
* buffer of size UDF_NAME_LEN bytes.
* utf Pointer to UTF-8 input buffer.
* utf_len Length of UTF-8 input buffer in bytes.
*
* POST-CONDITIONS
* <return> Zero on success.
*
* HISTORY
* November 12, 1997 - Andrew E. Mileski
* Written, tested, and released.
*/
static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length)
{
unsigned c, i, max_val, utf_char;
int utf_cnt, u_len;
memset(ocu, 0, sizeof(dstring) * length);
ocu[0] = 8;
max_val = 0xffU;
try_again:
u_len = 0U;
utf_char = 0U;
utf_cnt = 0U;
for (i = 0U; i < utf->u_len; i++) {
c = (uint8_t)utf->u_name[i];
/* Complete a multi-byte UTF-8 character */
if (utf_cnt) {
utf_char = (utf_char << 6) | (c & 0x3fU);
if (--utf_cnt)
continue;
} else {
/* Check for a multi-byte UTF-8 character */
if (c & 0x80U) {
/* Start a multi-byte UTF-8 character */
if ((c & 0xe0U) == 0xc0U) {
utf_char = c & 0x1fU;
utf_cnt = 1;
} else if ((c & 0xf0U) == 0xe0U) {
utf_char = c & 0x0fU;
utf_cnt = 2;
} else if ((c & 0xf8U) == 0xf0U) {
utf_char = c & 0x07U;
utf_cnt = 3;
} else if ((c & 0xfcU) == 0xf8U) {
utf_char = c & 0x03U;
utf_cnt = 4;
} else if ((c & 0xfeU) == 0xfcU) {
utf_char = c & 0x01U;
utf_cnt = 5;
} else {
goto error_out;
}
continue;
} else {
/* Single byte UTF-8 character (most common) */
utf_char = c;
}
}
/* Choose no compression if necessary */
if (utf_char > max_val) {
if (max_val == 0xffU) {
max_val = 0xffffU;
ocu[0] = (uint8_t)0x10U;
goto try_again;
}
goto error_out;
}
if (max_val == 0xffffU)
ocu[++u_len] = (uint8_t)(utf_char >> 8);
ocu[++u_len] = (uint8_t)(utf_char & 0xffU);
}
if (utf_cnt) {
error_out:
ocu[++u_len] = '?';
printk(KERN_DEBUG "udf: bad UTF-8 character\n");
}
ocu[length - 1] = (uint8_t)u_len + 1;
return u_len + 1;
}
static int udf_CS0toNLS(struct nls_table *nls, struct ustr *utf_o,
const struct ustr *ocu_i)
{
const uint8_t *ocu;
uint8_t cmp_id, ocu_len;
int i, len;
ocu_len = ocu_i->u_len;
if (ocu_len == 0) {
memset(utf_o, 0, sizeof(struct ustr));
return 0;
}
cmp_id = ocu_i->u_cmpID;
if (cmp_id != 8 && cmp_id != 16) {
memset(utf_o, 0, sizeof(struct ustr));
printk(KERN_ERR "udf: unknown compression code (%d) stri=%s\n",
cmp_id, ocu_i->u_name);
return 0;
}
ocu = ocu_i->u_name;
utf_o->u_len = 0;
for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
/* Expand OSTA compressed Unicode to Unicode */
uint32_t c = ocu[i++];
if (cmp_id == 16)
c = (c << 8) | ocu[i++];
len = nls->uni2char(c, &utf_o->u_name[utf_o->u_len],
UDF_NAME_LEN - utf_o->u_len);
/* Valid character? */
if (len >= 0)
utf_o->u_len += len;
else
utf_o->u_name[utf_o->u_len++] = '?';
}
utf_o->u_cmpID = 8;
return utf_o->u_len;
}
static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni,
int length)
{
int len;
unsigned i, max_val;
uint16_t uni_char;
int u_len;
memset(ocu, 0, sizeof(dstring) * length);
ocu[0] = 8;
max_val = 0xffU;
try_again:
u_len = 0U;
for (i = 0U; i < uni->u_len; i++) {
len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
if (!len)
continue;
/* Invalid character, deal with it */
if (len < 0) {
len = 1;
uni_char = '?';
}
if (uni_char > max_val) {
max_val = 0xffffU;
ocu[0] = (uint8_t)0x10U;
goto try_again;
}
if (max_val == 0xffffU)
ocu[++u_len] = (uint8_t)(uni_char >> 8);
ocu[++u_len] = (uint8_t)(uni_char & 0xffU);
i += len - 1;
}
ocu[length - 1] = (uint8_t)u_len + 1;
return u_len + 1;
}
int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname,
int flen)
{
struct ustr *filename, *unifilename;
int len = 0;
filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
if (!filename)
return 0;
unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
if (!unifilename)
goto out1;
if (udf_build_ustr_exact(unifilename, sname, flen))
goto out2;
if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
if (!udf_CS0toUTF8(filename, unifilename)) {
udf_debug("Failed in udf_get_filename: sname = %s\n",
sname);
goto out2;
}
} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
if (!udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
unifilename)) {
udf_debug("Failed in udf_get_filename: sname = %s\n",
sname);
goto out2;
}
} else
goto out2;
len = udf_translate_to_linux(dname, filename->u_name, filename->u_len,
unifilename->u_name, unifilename->u_len);
out2:
kfree(unifilename);
out1:
kfree(filename);
return len;
}
int udf_put_filename(struct super_block *sb, const uint8_t *sname,
uint8_t *dname, int flen)
{
struct ustr unifilename;
int namelen;
if (!udf_char_to_ustr(&unifilename, sname, flen))
return 0;
if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
namelen = udf_UTF8toCS0(dname, &unifilename, UDF_NAME_LEN);
if (!namelen)
return 0;
} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
namelen = udf_NLStoCS0(UDF_SB(sb)->s_nls_map, dname,
&unifilename, UDF_NAME_LEN);
if (!namelen)
return 0;
} else
return 0;
return namelen;
}
#define ILLEGAL_CHAR_MARK '_'
#define EXT_MARK '.'
#define CRC_MARK '#'
#define EXT_SIZE 5
static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName,
int udfLen, uint8_t *fidName,
int fidNameLen)
{
int index, newIndex = 0, needsCRC = 0;
int extIndex = 0, newExtIndex = 0, hasExt = 0;
unsigned short valueCRC;
uint8_t curr;
const uint8_t hexChar[] = "0123456789ABCDEF";
if (udfName[0] == '.' &&
(udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
needsCRC = 1;
newIndex = udfLen;
memcpy(newName, udfName, udfLen);
} else {
for (index = 0; index < udfLen; index++) {
curr = udfName[index];
if (curr == '/' || curr == 0) {
needsCRC = 1;
curr = ILLEGAL_CHAR_MARK;
while (index + 1 < udfLen &&
(udfName[index + 1] == '/' ||
udfName[index + 1] == 0))
index++;
}
if (curr == EXT_MARK &&
(udfLen - index - 1) <= EXT_SIZE) {
if (udfLen == index + 1)
hasExt = 0;
else {
hasExt = 1;
extIndex = index;
newExtIndex = newIndex;
}
}
if (newIndex < 256)
newName[newIndex++] = curr;
else
needsCRC = 1;
}
}
if (needsCRC) {
uint8_t ext[EXT_SIZE];
int localExtIndex = 0;
if (hasExt) {
int maxFilenameLen;
for (index = 0;
index < EXT_SIZE && extIndex + index + 1 < udfLen;
index++) {
curr = udfName[extIndex + index + 1];
if (curr == '/' || curr == 0) {
needsCRC = 1;
curr = ILLEGAL_CHAR_MARK;
while (extIndex + index + 2 < udfLen &&
(index + 1 < EXT_SIZE &&
(udfName[extIndex + index + 2] == '/' ||
udfName[extIndex + index + 2] == 0)))
index++;
}
ext[localExtIndex++] = curr;
}
maxFilenameLen = 250 - localExtIndex;
if (newIndex > maxFilenameLen)
newIndex = maxFilenameLen;
else
newIndex = newExtIndex;
} else if (newIndex > 250)
newIndex = 250;
newName[newIndex++] = CRC_MARK;
valueCRC = crc_itu_t(0, fidName, fidNameLen);
newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12];
newName[newIndex++] = hexChar[(valueCRC & 0x0f00) >> 8];
newName[newIndex++] = hexChar[(valueCRC & 0x00f0) >> 4];
newName[newIndex++] = hexChar[(valueCRC & 0x000f)];
if (hasExt) {
newName[newIndex++] = EXT_MARK;
for (index = 0; index < localExtIndex; index++)
newName[newIndex++] = ext[index];
}
}
return newIndex;
}
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