Check for NULL cleanup function before using it in encoder_process
encoder_process assumes a cleanup function has been set in the currently
in-use encoder during processing, which can lead to segfaults if said
function hasn't been set
Add a NULL check for this condition, returning -1 if it is not set
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23069)
(cherry picked from commit
cf57c3ecfa416afbc47d36633981034809ee6792)