cognitoauth: Fix "Unexpected char 0x0a at 82 in header value" Error When Using Client Secret

[kyarosh]

This request fixes issue #315, which occurs whenever a client secret is used.

Pkce.encodeBase64() currently uses Base64.DEFAULT when creating the base64-encoded string to be used for the PKCE Authorization header. This breaks the ability to use a client secret, as Base64.DEFAULT adds a newline (0x0a) character at the end of the encoded string, which results in the call to httpsURLConnection.addRequestProperty() in AuthHttpClient.httpPost() to throw an exception with a stack trace similar to the following:

java.lang.IllegalArgumentException: Unexpected char 0x0a at 82 in header value: Basic M20zbG5majcxaDljYzZqamk5ajdmZDVndWM6NGxqaXZjdWYzMDlvNWM4NGhrNnYzc28zZDFnajdxNGZpN2lnM2R2aDdzdnY2MWp1Y3Iy
   at com.android.okhttp.Headers$Builder.checkNameAndValue(Headers.java:313)
   at com.android.okhttp.Headers$Builder.add(Headers.java:245)
   at com.android.okhttp.internal.huc.HttpURLConnectionImpl.addRequestProperty(HttpURLConnectionImpl.java:579)
   at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.addRequestProperty(DelegatingHttpsURLConnection.java:186)
   at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.addRequestProperty(HttpsURLConnectionImpl.java)
   at com.amazonaws.mobileconnectors.cognitoauth.util.AuthHttpClient.httpPost(AuthHttpClient.java:56)
   at com.amazonaws.mobileconnectors.cognitoauth.AuthClient$1.run(AuthClient.java:290)
   at java.lang.Thread.run(Thread.java:761)

[codecov-io]

Codecov Report

Merging #327 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master     #327   +/-   ##
=======================================
  Coverage    6.68%    6.68%           
=======================================
  Files        5114     5114           
  Lines      198418   198418           
  Branches    47401    47401           
=======================================
  Hits        13267    13267           
  Misses     184022   184022           
  Partials     1129     1129

Impacted Files	Coverage Δ
...zonaws/mobileconnectors/cognitoauth/util/Pkce.java	0% <0%> (ø)	⬆️

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[lexmakali]

Hi Kyarosh,

Thank you for using our SDK and submitting a pull request.

In 2.4.7 release we use Base64.NO_PADDING which omits the padding '=' characters. Does this fix your problem? Can you check with 2.4.7 version?

[kyarosh]

Hi @kvasukib,

The problem still persists in 2.4.7. Passing "Base64.NO_PADDING | Base64.NOWRAP" should incorporate both changes if needed, though I'm curious to know whether there are any details with regards to the 2.4.7 update and whether the padding characters really do need to be stripped.

[drxeno02]

Hello, I would like to push my commit that resolves issue #315 . The fix was that encodeBase64() required its flags to be updated to include Base64.NO_PADDING.

[mreddyg]

@drxeno02 Thank you. We will review the changes and merge them in a future release.

[lexmakali]

Hi, @kyarosh and @drxeno02, Sorry for the inconvenience caused. We will be doing the merge in the next few days. We will communicate here once we test and merge in the changes.

[lexmakali]

Hi @kyarosh and @drxeno02, We have fixed it and merged the PR #367 in the v2.6.13 release. Closing this PR.