[Kimchi-devel] [PATCH] bug fix: Avoid equals sign in VM console URL
Aline Manera
alinefm at linux.vnet.ibm.com
Mon Jul 28 15:06:18 UTC 2014
On 07/28/2014 11:15 AM, Sheldon wrote:
> On 07/28/2014 08:28 PM, Aline Manera wrote:
>>
>> On 07/28/2014 06:15 AM, Sheldon wrote:
>>> On 07/26/2014 05:01 AM, alinefm at linux.vnet.ibm.com wrote:
>>>> From: Aline Manera <alinefm at linux.vnet.ibm.com>
>>>>
>>>> >From python documentation, base64.urlsafe_b64encode(s) substitutes
>>>> - instead
>>>> of + and _ instead of / in the standard Base64 alphabet, BUT the
>>>> result can
>>>> still contain = which is not safe in a URL query component.
>>>> As token value is not decoded nowhere, replace = by A
>>>
>>> what about other character instead of A? such as "." or "~"
>>>
>>> This is the base64 alphabet:
>>> 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
>>>
>>> "A" is in the alphabet.
>>>
>>
>> Ok. I will use . to replace =
>>
>>>
>>> or do not pad the encode string.
>>> some base64 variant has no pad character.
>>> http://en.wikipedia.org/wiki/Base64#Implementations_and_history
>>>
>>
>> I think we can have problem in not using the pad if you have the same
>> code string to different sentence
>> Example:
>>
>> "abcd" = "YWJjZA="
>> "jdcf" = "YWJjZA"
>
> in python, I have try:
>
> In [51]: base64.urlsafe_b64encode("jdcf")
> Out[51]: 'amRjZg=='
>
> In [52]: base64.urlsafe_b64encode("abcd")
> Out[52]: 'YWJjZA=='
>
>
> and in UI I also try:
> atob("YWJjZA")
> "abcd"
> atob("YWJjZA=")
> [Exception... "String contains an invalid character" code: "5"
> nsresult: "0x80530005 (InvalidCharacterError)" location: "<unknown>"]
> atob("YWJjZA==")
> "abcd"
>
Ok. I will remove the padding encode
>
>>
>> If we ignore the = in the first string we will have 2 matches to the
>> different values.
>> Not sure it can happen in real world, but I think it is safe to use .
>> instead of =
>>
>>>
>>> Then in python, it can easy strip the "="
>>> In [21]: s1 = base64.urlsafe_b64encode("abcd")
>>> In [22]: s1.rstrip("=")
>>> Out[22]: 'YWJjZA'
>>>
>>> and In js add a funtion to
>>> $ git diff
>>> diff --git a/ui/js/src/kimchi.utils.js b/ui/js/src/kimchi.utils.js
>>> index 480b9b5..2d252a7 100644
>>> --- a/ui/js/src/kimchi.utils.js
>>> +++ b/ui/js/src/kimchi.utils.js
>>> @@ -191,3 +191,8 @@ kimchi.urlSafeB64Decode = function(str) {
>>> kimchi.urlSafeB64Encode = function(str) {
>>> return btoa(str).replace(/\+/g, '-').replace(/\//g, '_');
>>> }
>>> +
>>> +kimchi.padBase64 = function(str) {
>>> + padLen = str.length % 4;
>>> + return str + new Array(padLen? 4 - padLen + 1 : 0).join("=");
>>> +}
>>>
>>>
>>> Now test this method:
>>> in python:
>>> In [40]: base64.urlsafe_b64encode("abcd")
>>> Out[40]: 'YWJjZA=='
>>>
>>> In [41]: base64.urlsafe_b64encode("abcde")
>>> Out[41]: 'YWJjZGU='
>>>
>>> In UI:
>>> kimchi.padBase64("YWJjZA")
>>> "YWJjZA=="
>>>
>>> kimchi.padBase64("YWJjZGU")
>>> "YWJjZGU="
>>>
>>>
>>>>
>>>> The problem with equals sign was only identified on Spice connections.
>>>> noVNC can deal well with that.
>>>>
>>>> For reference: https://docs.python.org/2/library/base64.html
>>>>
>>>> Signed-off-by: Aline Manera <alinefm at linux.vnet.ibm.com>
>>>> ---
>>>> src/kimchi/vnc.py | 9 ++++++++-
>>>> ui/js/src/kimchi.api.js | 18 ++++++++++++++++--
>>>> 2 files changed, 24 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/src/kimchi/vnc.py b/src/kimchi/vnc.py
>>>> index 9380e21..4159049 100644
>>>> --- a/src/kimchi/vnc.py
>>>> +++ b/src/kimchi/vnc.py
>>>> @@ -54,7 +54,14 @@ def new_ws_proxy():
>>>>
>>>> def add_proxy_token(name, port):
>>>> with open(os.path.join(WS_TOKENS_DIR, name), 'w') as f:
>>>> - name = base64.urlsafe_b64encode(name)
>>>> + """
>>>> + From python documentation base64.urlsafe_b64encode(s)
>>>> + substitutes - instead of + and _ instead of / in the
>>>> + standard Base64 alphabet, BUT the result can still
>>>> + contain = which is not safe in a URL query component.
>>>> + As token value is not decoded nowhere, replace = by A
>>>> + """
>>>> + name = base64.urlsafe_b64encode(name).replace('=', 'A')
>>>> f.write('%s: localhost:%s' % (name.encode('utf-8'), port))
>>>>
>>>>
>>>> diff --git a/ui/js/src/kimchi.api.js b/ui/js/src/kimchi.api.js
>>>> index 8f5b68f..30360c5 100644
>>>> --- a/ui/js/src/kimchi.api.js
>>>> +++ b/ui/js/src/kimchi.api.js
>>>> @@ -352,7 +352,14 @@ var kimchi = {
>>>> }).done(function() {
>>>> url = 'https://' + location.hostname + ':' +
>>>> proxy_port;
>>>> url += "/console.html?url=vnc_auto.html&port=" +
>>>> proxy_port;
>>>> - url += "&path=?token=" + kimchi.urlSafeB64Encode(vm);
>>>> + /*
>>>> + * From python documentation
>>>> base64.urlsafe_b64encode(s)
>>>> + * substitutes - instead of + and _ instead of /
>>>> in the
>>>> + * standard Base64 alphabet, BUT the result can still
>>>> + * contain = which is not safe in a URL query
>>>> component.
>>>> + * As token value is not decoded nowhere, replace
>>>> = by A
>>>> + * */
>>>> + url += "&path=?token=" +
>>>> kimchi.urlSafeB64Encode(vm).replace(/=/g, 'A');
>>>> url += "&kimchi=" + location.port;
>>>> url += '&encrypt=1';
>>>> window.open(url);
>>>> @@ -377,7 +384,14 @@ var kimchi = {
>>>> url = 'https://' + location.hostname + ':' +
>>>> proxy_port;
>>>> url += "/console.html?url=spice.html&port=" +
>>>> proxy_port;
>>>> url += "&listen=" + location.hostname;
>>>> - url += "&token=" + kimchi.urlSafeB64Encode(vm);
>>>> + /*
>>>> + * From python documentation
>>>> base64.urlsafe_b64encode(s)
>>>> + * substitutes - instead of + and _ instead of /
>>>> in the
>>>> + * standard Base64 alphabet, BUT the result can still
>>>> + * contain = which is not safe in a URL query
>>>> component.
>>>> + * As token value is not decoded nowhere, replace
>>>> = by A
>>>> + * */
>>>> + url += "&token=" +
>>>> kimchi.urlSafeB64Encode(vm).replace(/=/g, 'A');
>>>> url += "&kimchi=" + location.port;
>>>> url += '&encrypt=1';
>>>> window.open(url);
>>>
>>>
>>
>>
>>
>
>
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