s_client's manpage states for -nextprotoneg:
"Empty list of protocols is treated specially and will cause the client
to advertise support for the TLS extension but disconnect just after
reciving ServerHello with a list of server supported protocols."
Consequently, the previous workaround of just quoting an empty variable
is insufficient and the "-nextprotoneg" parameter has to be removed
entirely from the command-line in case of an empty argument.
In other locations where "-nextprotoneg" is used
- its argument cannot be empty ($NPN_PROTOs is initialized to a non-
empty value and set read-only) or
- its argument is intended to be empty (line 3724) or
- the command will not be invoked at all (for-loop parameter, line 3725)
This fixes#467 - again.
Additionally this patch prefers usage of -alpn over -nextprotoneg if the
openssl binary used supports it.
The argument to -nextprotoneg is provided in sometimes empty an unquoted
variables. Because of the missing quotes, the next word on the line "-status"
gets parsed as "-nextprotoneg"'s argument instead of enabling the OCSP status
check.
This fixes#467.
Daniel Reichelt