linux/fs/cifs/cifs_unicode.c
Steve French ce36d9ab3b [CIFS] fix mount failure with broken pathnames when smb3 mount with mapchars option
When we SMB3 mounted with mapchars (to allow reserved characters : \ / > < * ?
via the Unicode Windows to POSIX remap range) empty paths
(eg when we open "" to query the root of the SMB3 directory on mount) were not
null terminated so we sent garbarge as a path name on empty paths which caused
SMB2/SMB2.1/SMB3 mounts to fail when mapchars was specified.  mapchars is
particularly important since Unix Extensions for SMB3 are not supported (yet)

Signed-off-by: Steve French <smfrench@gmail.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: David Disseldorp <ddiss@suse.de>
2014-06-24 08:10:24 -05:00

417 lines
11 KiB
C

/*
* fs/cifs/cifs_unicode.c
*
* Copyright (c) International Business Machines Corp., 2000,2009
* Modified by Steve French (sfrench@us.ibm.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "cifs_unicode.h"
#include "cifs_uniupr.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"
/*
* cifs_utf16_bytes - how long will a string be after conversion?
* @utf16 - pointer to input string
* @maxbytes - don't go past this many bytes of input string
* @codepage - destination codepage
*
* Walk a utf16le string and return the number of bytes that the string will
* be after being converted to the given charset, not including any null
* termination required. Don't walk past maxbytes in the source buffer.
*/
int
cifs_utf16_bytes(const __le16 *from, int maxbytes,
const struct nls_table *codepage)
{
int i;
int charlen, outlen = 0;
int maxwords = maxbytes / 2;
char tmp[NLS_MAX_CHARSET_SIZE];
__u16 ftmp;
for (i = 0; i < maxwords; i++) {
ftmp = get_unaligned_le16(&from[i]);
if (ftmp == 0)
break;
charlen = codepage->uni2char(ftmp, tmp, NLS_MAX_CHARSET_SIZE);
if (charlen > 0)
outlen += charlen;
else
outlen++;
}
return outlen;
}
/*
* cifs_mapchar - convert a host-endian char to proper char in codepage
* @target - where converted character should be copied
* @src_char - 2 byte host-endian source character
* @cp - codepage to which character should be converted
* @mapchar - should character be mapped according to mapchars mount option?
*
* This function handles the conversion of a single character. It is the
* responsibility of the caller to ensure that the target buffer is large
* enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
*/
static int
cifs_mapchar(char *target, const __u16 src_char, const struct nls_table *cp,
bool mapchar)
{
int len = 1;
if (!mapchar)
goto cp_convert;
/*
* BB: Cannot handle remapping UNI_SLASH until all the calls to
* build_path_from_dentry are modified, as they use slash as
* separator.
*/
switch (src_char) {
case UNI_COLON:
*target = ':';
break;
case UNI_ASTERISK:
*target = '*';
break;
case UNI_QUESTION:
*target = '?';
break;
case UNI_PIPE:
*target = '|';
break;
case UNI_GRTRTHAN:
*target = '>';
break;
case UNI_LESSTHAN:
*target = '<';
break;
default:
goto cp_convert;
}
out:
return len;
cp_convert:
len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
if (len <= 0) {
*target = '?';
len = 1;
}
goto out;
}
/*
* cifs_from_utf16 - convert utf16le string to local charset
* @to - destination buffer
* @from - source buffer
* @tolen - destination buffer size (in bytes)
* @fromlen - source buffer size (in bytes)
* @codepage - codepage to which characters should be converted
* @mapchar - should characters be remapped according to the mapchars option?
*
* Convert a little-endian utf16le string (as sent by the server) to a string
* in the provided codepage. The tolen and fromlen parameters are to ensure
* that the code doesn't walk off of the end of the buffer (which is always
* a danger if the alignment of the source buffer is off). The destination
* string is always properly null terminated and fits in the destination
* buffer. Returns the length of the destination string in bytes (including
* null terminator).
*
* Note that some windows versions actually send multiword UTF-16 characters
* instead of straight UTF16-2. The linux nls routines however aren't able to
* deal with those characters properly. In the event that we get some of
* those characters, they won't be translated properly.
*/
int
cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
const struct nls_table *codepage, bool mapchar)
{
int i, charlen, safelen;
int outlen = 0;
int nullsize = nls_nullsize(codepage);
int fromwords = fromlen / 2;
char tmp[NLS_MAX_CHARSET_SIZE];
__u16 ftmp;
/*
* because the chars can be of varying widths, we need to take care
* not to overflow the destination buffer when we get close to the
* end of it. Until we get to this offset, we don't need to check
* for overflow however.
*/
safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
for (i = 0; i < fromwords; i++) {
ftmp = get_unaligned_le16(&from[i]);
if (ftmp == 0)
break;
/*
* check to see if converting this character might make the
* conversion bleed into the null terminator
*/
if (outlen >= safelen) {
charlen = cifs_mapchar(tmp, ftmp, codepage, mapchar);
if ((outlen + charlen) > (tolen - nullsize))
break;
}
/* put converted char into 'to' buffer */
charlen = cifs_mapchar(&to[outlen], ftmp, codepage, mapchar);
outlen += charlen;
}
/* properly null-terminate string */
for (i = 0; i < nullsize; i++)
to[outlen++] = 0;
return outlen;
}
/*
* NAME: cifs_strtoUTF16()
*
* FUNCTION: Convert character string to unicode string
*
*/
int
cifs_strtoUTF16(__le16 *to, const char *from, int len,
const struct nls_table *codepage)
{
int charlen;
int i;
wchar_t wchar_to; /* needed to quiet sparse */
/* special case for utf8 to handle no plane0 chars */
if (!strcmp(codepage->charset, "utf8")) {
/*
* convert utf8 -> utf16, we assume we have enough space
* as caller should have assumed conversion does not overflow
* in destination len is length in wchar_t units (16bits)
*/
i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
(wchar_t *) to, len);
/* if success terminate and exit */
if (i >= 0)
goto success;
/*
* if fails fall back to UCS encoding as this
* function should not return negative values
* currently can fail only if source contains
* invalid encoded characters
*/
}
for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
charlen = codepage->char2uni(from, len, &wchar_to);
if (charlen < 1) {
cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
*from, charlen);
/* A question mark */
wchar_to = 0x003f;
charlen = 1;
}
put_unaligned_le16(wchar_to, &to[i]);
}
success:
put_unaligned_le16(0, &to[i]);
return i;
}
/*
* cifs_strndup_from_utf16 - copy a string from wire format to the local
* codepage
* @src - source string
* @maxlen - don't walk past this many bytes in the source string
* @is_unicode - is this a unicode string?
* @codepage - destination codepage
*
* Take a string given by the server, convert it to the local codepage and
* put it in a new buffer. Returns a pointer to the new string or NULL on
* error.
*/
char *
cifs_strndup_from_utf16(const char *src, const int maxlen,
const bool is_unicode, const struct nls_table *codepage)
{
int len;
char *dst;
if (is_unicode) {
len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
len += nls_nullsize(codepage);
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return NULL;
cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
false);
} else {
len = strnlen(src, maxlen);
len++;
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return NULL;
strlcpy(dst, src, len);
}
return dst;
}
/*
* Convert 16 bit Unicode pathname to wire format from string in current code
* page. Conversion may involve remapping up the six characters that are
* only legal in POSIX-like OS (if they are present in the string). Path
* names are little endian 16 bit Unicode on the wire
*/
int
cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
const struct nls_table *cp, int mapChars)
{
int i, charlen;
int j = 0;
char src_char;
__le16 dst_char;
wchar_t tmp;
if (!mapChars)
return cifs_strtoUTF16(target, source, PATH_MAX, cp);
for (i = 0; i < srclen; j++) {
src_char = source[i];
charlen = 1;
switch (src_char) {
case 0:
goto ctoUTF16_out;
case ':':
dst_char = cpu_to_le16(UNI_COLON);
break;
case '*':
dst_char = cpu_to_le16(UNI_ASTERISK);
break;
case '?':
dst_char = cpu_to_le16(UNI_QUESTION);
break;
case '<':
dst_char = cpu_to_le16(UNI_LESSTHAN);
break;
case '>':
dst_char = cpu_to_le16(UNI_GRTRTHAN);
break;
case '|':
dst_char = cpu_to_le16(UNI_PIPE);
break;
/*
* FIXME: We can not handle remapping backslash (UNI_SLASH)
* until all the calls to build_path_from_dentry are modified,
* as they use backslash as separator.
*/
default:
charlen = cp->char2uni(source + i, srclen - i, &tmp);
dst_char = cpu_to_le16(tmp);
/*
* if no match, use question mark, which at least in
* some cases serves as wild card
*/
if (charlen < 1) {
dst_char = cpu_to_le16(0x003f);
charlen = 1;
}
}
/*
* character may take more than one byte in the source string,
* but will take exactly two bytes in the target string
*/
i += charlen;
put_unaligned(dst_char, &target[j]);
}
ctoUTF16_out:
put_unaligned(0, &target[j]); /* Null terminate target unicode string */
return j;
}
#ifdef CONFIG_CIFS_SMB2
/*
* cifs_local_to_utf16_bytes - how long will a string be after conversion?
* @from - pointer to input string
* @maxbytes - don't go past this many bytes of input string
* @codepage - source codepage
*
* Walk a string and return the number of bytes that the string will
* be after being converted to the given charset, not including any null
* termination required. Don't walk past maxbytes in the source buffer.
*/
static int
cifs_local_to_utf16_bytes(const char *from, int len,
const struct nls_table *codepage)
{
int charlen;
int i;
wchar_t wchar_to;
for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
charlen = codepage->char2uni(from, len, &wchar_to);
/* Failed conversion defaults to a question mark */
if (charlen < 1)
charlen = 1;
}
return 2 * i; /* UTF16 characters are two bytes */
}
/*
* cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
* @src - source string
* @maxlen - don't walk past this many bytes in the source string
* @utf16_len - the length of the allocated string in bytes (including null)
* @cp - source codepage
* @remap - map special chars
*
* Take a string convert it from the local codepage to UTF16 and
* put it in a new buffer. Returns a pointer to the new string or NULL on
* error.
*/
__le16 *
cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
const struct nls_table *cp, int remap)
{
int len;
__le16 *dst;
len = cifs_local_to_utf16_bytes(src, maxlen, cp);
len += 2; /* NULL */
dst = kmalloc(len, GFP_KERNEL);
if (!dst) {
*utf16_len = 0;
return NULL;
}
cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
*utf16_len = len;
return dst;
}
#endif /* CONFIG_CIFS_SMB2 */