Federation fails when using SP initiated SSO; the SP may see references such as "Invalid SAML signature" in their logs and will not be able to parse the signature or certificate blocks.
The Federation debug log will show the signature and certificate blocks with
at the end of lines, for example:
<ds:SignatureValue> 0n4tZCrMzco4uc91FvbWE+hSn6dJENYmxS8WJyEAlHjcBro3hOu07CK+rQqyTGU+OljbaUHF+zI/ Mgror3t3X+IeYcVg8PnRkmT1SXegl1wqmwZd/zg2WWXszC8W+XaQrlgIG+BNxg5j66HkDkTzegrE ... </ds:SignatureValue> <ds:KeyInfo> <ds:X509Data> <ds:X509Certificate> CwUAA4IBAQBIRSXFrUyt1JxaJUCKidkS5FHcsTI3u3k+MMYBkQhLZB8lAomTwkqRPRx+rOvqLEW/ EwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3d3cuZGlnaWNlcnQuY29tMR0w ... </ds:X509Certificate>
Upgraded to, or installed AM 6, 220.127.116.11, 18.104.22.168, 22.214.171.124 or 126.96.36.199.
The xmlsec library used in these versions is 2.1.1, which has a known issue that causes line breaks to be replaced with these characters when the ignorelinebreak property is enabled. This property is enabled using either of the following JVM options:
If the XML parser used by the SP to process the assertion is not permissive, these characters will cause federation to fail. However, if the XML parser is permissive (as used by AM), federation will succeed; this explains why this issue will not affect you if AM is also acting as the SP.
This issue can be resolved by upgrading to AM 188.8.131.52 or later; you can download this from BackStage.