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Diffstat (limited to 'libxmlsec/readme.txt')
-rw-r--r-- | libxmlsec/readme.txt | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/libxmlsec/readme.txt b/libxmlsec/readme.txt new file mode 100644 index 000000000000..55c6976f51f3 --- /dev/null +++ b/libxmlsec/readme.txt @@ -0,0 +1,32 @@ +The XML Security library has been modified, so that there is NO verification of +the certificate during sign or verification operation. On Windows this was done +in the function xmlSecMSCryptoX509StoreVerify (file src/mscrypto/x509vfy.c) and +on UNIX in xmlSecNssX509StoreVerify (file src/nss/x509vfy.c). + +The implementation creates certificates from all of the X509Data children, such +as X509IssuerSerial and X509Certificate and stores them in a certificate store +(see xmlsec/src/mscrypto/x509.c:xmlSecMSCryptoX509DataNodeRead). It must then +find the certificate containing the public key which is used for validation +within that store. This is done in xmlSecMSCryptoX509StoreVerify. This function +however only takes those certificates into account which can be validated. This +was changed by the patch xmlsec1-noverify.patch, which prevents this certificate +validation. + +xmlSecMSCryptoX509StoreVerify iterates over all certificates contained or +referenced in the X509Data elements and selects one which is no issuer of any of +the other certificates. This certificate is not necessarily the one which was +used for signing but it must contain the proper validation key, which is +sufficient to validate the signature. See +http://www.w3.org/TR/xmldsig-core/#sec-X509Data +for details. + +There is a flag XMLSEC_KEYINFO_FLAGS_X509DATA_DONT_VERIFY_CERTS that can be set +in a xmlSecKeyInfoCtx (see function xmlSecNssKeyDataX509XmlRead, in file +src/nss/x509.c), which indicates that one can turn off the validation. However, +setting it will cause that the validation key is not found. If the flag is set, +then the key is not extracted from the certificate store which contains all the +certificates of the X509Data elements. In other words, the certificates which +are delivered within the XML signature are not used when looking for suitable +validation key. + + |