[linux-cifs-client] [PATCH 1/3] cifs: Introduce helper to compute length of nls string in bytes

[Shirish Pargaonkar]

On Thu, Apr 23, 2009 at 12:56 AM, Jeff Layton <jlayton at redhat.com> wrote:
> On Thu, 23 Apr 2009 02:49:21 +0200
> Günter Kukkukk <linux at kukkukk.com> wrote:
>
>> just some further notes.
>> With "it's heavily used" i didn't mean the number of callers using this
>> function (only 1 in readdir.c) - i meant "the number of times" cifs_convertUCSpath()
>> is called in daily usage.... (readdir results)
>>
>> The current focus was mostly on cifs_strfromUCS_le() - but the _same_ applies
>> to cifs_convertUCSpath()!
>>
>> See the following code snippet:
>>
>> readdir.c --> static int cifs_get_name_from_search_buf()
>> ....
>>
>>       if (unicode) {
>>               /* BB fixme - test with long names */
>>               /* Note converted filename can be longer than in unicode */
>>               if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
>>                       pqst->len = cifs_convertUCSpath((char *)pqst->name,
>>                                       (__le16 *)filename, len/2, nlt);
>>               else
>>                       pqst->len = cifs_strfromUCS_le((char *)pqst->name,
>>                                       (__le16 *)filename, len/2, nlt);
>>
>> ....
>
> I see what you mean. Good catch. That function also has broken buffer
> length checking logic too.
>
> This patch is only compile-tested, but it should fix those problems. In
> the long run, we probably need to make all of these functions take an
> argument with the length of the destination buffer.
>
> Let's plan that overhaul after Suresh's latest set goes in though.
>
> --
> Jeff Layton <jlayton at redhat.com>
>
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>
>

A general question, the functions such as cifs_strtoUCS call uni2char
which assumes UTF-8 translation format.
If one of the characaters being encoded happens to be 6 bytes long,
will a SMB/CIFS server be able
to handle that i.e. if it is expecting a UCS-2LE encoding, thus a two
byte encoded value, (how) would it handle
6 byte encoded value!