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linux/fs/udf/unicode.c
Andrew Gabbasov bb00c898ad udf: Check output buffer length when converting name to CS0 
If a name contains at least some characters with Unicode values
exceeding single byte, the CS0 output should have 2 bytes per character.
And if other input characters have single byte Unicode values, then
the single input byte is converted to 2 output bytes, and the length
of output becomes larger than the length of input. And if the input
name is long enough, the output length may exceed the allocated buffer
length.

All this means that conversion from UTF8 or NLS to CS0 requires
checking of output length in order to stop when it exceeds the given
output buffer size.

[JK: Make code return -ENAMETOOLONG instead of silently truncating the
name]

CC: stable@vger.kernel.org
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2016-01-04 15:57:49 +01:00

515 lines
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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 <linux/slab.h>
#include "udf_sb.h"
static int udf_translate_to_linux(uint8_t *, int, 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 void udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
{
memset(dest, 0, sizeof(struct ustr));
dest->u_cmpID = ptr[0];
dest->u_len = exactsize - 1;
memcpy(dest->u_name, ptr + 1, exactsize - 1);
}
/*
* udf_CS0toUTF8
*
* 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> >= 0 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));
pr_err("unknown compression code (%d) stri=%s\n",
cmp_id, ocu_i->u_name);
return -EINVAL;
}
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) {
if (utf_o->u_len > (UDF_NAME_LEN - 4))
break;
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 {
if (utf_o->u_len > (UDF_NAME_LEN - 5))
break;
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_UTF8toCS0
*
* 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, u_ch;
memset(ocu, 0, sizeof(dstring) * length);
ocu[0] = 8;
max_val = 0xffU;
u_ch = 1;
try_again:
u_len = 0U;
utf_char = 0U;
utf_cnt = 0U;
for (i = 0U; i < utf->u_len; i++) {
/* Name didn't fit? */
if (u_len + 1 + u_ch >= length)
return 0;
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;
u_ch = 2;
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 pr_fmt("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));
pr_err("unknown compression code (%d) stri=%s\n",
cmp_id, ocu_i->u_name);
return -EINVAL;
}
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 - 2 - 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, u_ch;
memset(ocu, 0, sizeof(dstring) * length);
ocu[0] = 8;
max_val = 0xffU;
u_ch = 1;
try_again:
u_len = 0U;
for (i = 0U; i < uni->u_len; i++) {
/* Name didn't fit? */
if (u_len + 1 + u_ch >= length)
return 0;
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;
u_ch = 2;
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, int slen,
uint8_t *dname, int dlen)
{
struct ustr *filename, *unifilename;
int ret;
if (!slen)
return -EIO;
filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
if (!filename)
return -ENOMEM;
unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
if (!unifilename) {
ret = -ENOMEM;
goto out1;
}
udf_build_ustr_exact(unifilename, sname, slen);
if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
ret = udf_CS0toUTF8(filename, unifilename);
if (ret < 0) {
udf_debug("Failed in udf_get_filename: sname = %s\n",
sname);
goto out2;
}
} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
ret = udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
unifilename);
if (ret < 0) {
udf_debug("Failed in udf_get_filename: sname = %s\n",
sname);
goto out2;
}
} else
BUG();
ret = udf_translate_to_linux(dname, dlen,
filename->u_name, filename->u_len,
unifilename->u_name, unifilename->u_len);
/* Zero length filename isn't valid... */
if (ret == 0)
ret = -EINVAL;
out2:
kfree(unifilename);
out1:
kfree(filename);
return ret;
}
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
/* Number of chars we need to store generated CRC to make filename unique */
#define CRC_LEN 5
static int udf_translate_to_linux(uint8_t *newName, int newLen,
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;
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 < newLen)
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 = newLen - CRC_LEN - localExtIndex;
if (newIndex > maxFilenameLen)
newIndex = maxFilenameLen;
else
newIndex = newExtIndex;
} else if (newIndex > newLen - CRC_LEN)
newIndex = newLen - CRC_LEN;
newName[newIndex++] = CRC_MARK;
valueCRC = crc_itu_t(0, fidName, fidNameLen);
newName[newIndex++] = hex_asc_upper_hi(valueCRC >> 8);
newName[newIndex++] = hex_asc_upper_lo(valueCRC >> 8);
newName[newIndex++] = hex_asc_upper_hi(valueCRC);
newName[newIndex++] = hex_asc_upper_lo(valueCRC);
if (hasExt) {
newName[newIndex++] = EXT_MARK;
for (index = 0; index < localExtIndex; index++)
newName[newIndex++] = ext[index];
}
}
return newIndex;
}
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