... if the fixed-size buffer is too small.

Fixes #9732
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NPatrick Steuer <patrick.steuer@de.ibm.com>
(Merged from https://github.com/openssl/openssl/pull/10276)

(cherry picked from commit 7c2d95d47ccb3797f0da6bd4446747c6eee07b87)