Possible NULL Dereference When Processing CMS KeyTransportRecipientInfo

Issue summary: During processing of a crafted CMS EnvelopedData message

with KeyTransportRecipientInfo a NULL pointer dereference can happen.

Impact summary: Applications that process attacker-controlled CMS data may

crash before authentication or cryptographic operations occur resulting in

Denial of Service.

When a CMS EnvelopedData message that uses KeyTransportRecipientInfo with

RSA-OAEP encryption is processed, the optional parameters field of

RSA-OAEP SourceFunc algorithm identifier is examined without checking

for its presence. This results in a NULL pointer dereference if the field

is missing.

Applications and services that call CMS_decrypt() on untrusted input

(e.g., S/MIME processing or CMS-based protocols) are vulnerable.

The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this

issue, as the affected code is outside the OpenSSL FIPS module boundary.