[xmlsec] Can't decrypt GCM based algorithms

[Aleksey Sanin]

FAQ section 3.2 if I recall (or somewhere close by).

Aleksey

On 3/29/22 5:34 PM, Timothy Legge wrote:
> Hi
> 
> It also seems to be an issue with a IdP SAMLResponse from okta:
> 
> I have attached the xml as test xml and the base64 version as well as
> the private key (that private key is from perl-Net-SAML2 and is
> already public so it is fine to post).  My perl XML::Enc module
> decrypts this file without any issues.
> 
> I am continuing to review.
> 
> Tim
> 
> xmlsec1 --decrypt --privkey-pem sign-private-rsa.pem test.xml
> func=xmlSecXPathDataExecute:file=xpath.c:line=246:obj=unknown:subj=xmlXPtrEval:error=5:libxml2
> library function
> failed:expr=xpointer(id('_040a0aae3380dc9275ae08c24a8ddd72')); xml
> error: 0: NULL
> func=xmlSecXPathDataListExecute:file=xpath.c:line=330:obj=unknown:subj=xmlSecXPathDataExecute:error=1:xmlsec
> library function failed:
> func=xmlSecTransformXPathExecute:file=xpath.c:line=430:obj=xpointer:subj=xmlSecXPathDataListExecute:error=1:xmlsec
> library function failed:
> func=xmlSecTransformDefaultPushXml:file=transforms.c:line=2108:obj=xpointer:subj=xmlSecTransformExecute:error=1:xmlsec
> library function failed:
> func=xmlSecTransformCtxXmlExecute:file=transforms.c:line=1044:obj=xpointer:subj=xmlSecTransformPushXml:error=1:xmlsec
> library function failed:
> func=xmlSecTransformCtxExecute:file=transforms.c:line=1092:obj=unknown:subj=xmlSecTransformCtxXmlExecute:error=1:xmlsec
> library function failed:
> func=xmlSecKeyDataRetrievalMethodXmlRead:file=keyinfo.c:line=1108:obj=retrieval-method:subj=xmlSecTransformCtxExecute:error=1:xmlsec
> library function failed:
> func=xmlSecKeyInfoNodeRead:file=keyinfo.c:line=121:obj=retrieval-method:subj=xmlSecKeyDataXmlRead:error=1:xmlsec
> library function failed:node=RetrievalMethod
> func=xmlSecKeysMngrGetKey:file=keys.c:line=1234:obj=unknown:subj=xmlSecKeyInfoNodeRead:error=1:xmlsec
> library function failed:node=KeyInfo
> func=xmlSecEncCtxEncDataNodeRead:file=xmlenc.c:line=779:obj=unknown:subj=unknown:error=45:key
> is not found:encMethod=aes256-gcm
> func=xmlSecEncCtxDecryptToBuffer:file=xmlenc.c:line=596:obj=unknown:subj=xmlSecEncCtxEncDataNodeRead:error=1:xmlsec
> library function failed:
> func=xmlSecEncCtxDecrypt:file=xmlenc.c:line=524:obj=unknown:subj=xmlSecEncCtxDecryptToBuffer:error=1:xmlsec
> library function failed:
> Error: failed to decrypt file
> Error: failed to decrypt file "test.xml"
> 
> Timothy Legge
> timlegge at gmail.com
> timlegge at cpan.org
> 
> On Tue, Mar 29, 2022 at 1:25 PM Timothy Legge <timlegge at gmail.com> wrote:
>>
>> perfect.  I do get errors but my laptop is home at the moment.  I will test again tonight and let you know.
>>
>> Tim
>>
>> On Tue., Mar. 29, 2022, 12:57 p.m. Aleksey Sanin, <aleksey at aleksey.com> wrote:
>>>
>>> Well, the gcm code for openssl is here:
>>>
>>> https://github.com/lsh123/xmlsec/blob/4b6ab2d86b71f8642f19ab3b7a0777984b6bce9a/src/openssl/ciphers.c#L80
>>>
>>> so adding printfs in these functions would help.
>>>
>>> Do you get any errors?
>>>
>>> Aleksey
>>>
>>> On 3/29/22 11:51 AM, Timothy Legge wrote:
>>>> Hi
>>>>
>>>> I am working on adding support for aes*-gcm to perl's XML::Enc.  I can:
>>>>
>>>> 1. Decrypt SAML responses encrypted with aes*-gcm using XML::Enc
>>>> 2. Decrypt xmlsec encrypted aes*-gcm XML using XML::Enc
>>>> 3. Encrypt XML using aes*-gcm with XML::Sec
>>>> 4. Decrypt XML that was encrypted with XML::Sec using ases*-gcm
>>>>
>>>> However, I cannot use xmlsec to decrypt XML::Sec encrypted XML that
>>>> uses aes*-gcm.
>>>>
>>>> I can't think of any issues that would allow me to encrypt and decrypt
>>>> XML successfully with XML::Enc but not allow xmlsec to decrypt those
>>>> files.
>>>>
>>>> I was wondering if there is a debug flag for XML sec that would allow
>>>> me to output the following:
>>>>
>>>> 1. base64 of the CipherValue it reads from the XML file
>>>> 2. base 64 of IV
>>>> 3 base64 of encrypted data
>>>> 4 base 64 of the tag
>>>> 5 base 64 of the key
>>>>
>>>> I don't mind adding some print debugging and recompiling if you can
>>>> point me to a starting place.  It has been a while since I wrote much
>>>> C but I have no issues.  Finding the correct spot though...
>>>>
>>>> Tim
>>>>
>>>> Timothy Legge
>>>> timlegge at gmail.com
>>>> timlegge at cpan.org
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