OpenSSL DTLS problem in Debian buster

README.md

Stretch

docker build -t openssl_dtls:stretch -f Dockerfile.stretch .
docker run --rm openssl_dtls:stretch

Buster

docker build -t openssl_dtls:buster -f Dockerfile.buster .
docker run --rm openssl_dtls:buster

Dockerfile.buster

FROM debian:buster

RUN apt-get update && apt-get install -y openssl libssl-dev gcc

COPY example.c /example.c
RUN gcc -I/usr/include/openssl -lssl -lcrypto -o example example.c
CMD ["/example"]

Dockerfile.stretch

FROM debian:stretch

RUN apt-get update && apt-get install -y openssl libssl-dev gcc

COPY example.c /example.c
RUN gcc -I/usr/include/openssl -lssl -lcrypto -o example example.c
CMD ["/example"]

example.c

#include <stdio.h>
#include <openssl/ssl.h>

int main(int argc, char* argv) {
    SSL_CTX *context = SSL_CTX_new(DTLS_method());
    unsigned long error_code = ERR_peek_error();

    if (error_code) {
        char buf[512];
        ERR_error_string_n(error_code, &buf, 512);
        printf("Error create in SSL context: %s\n", buf);
        return 1;
    } else if (!context) {
        printf("No error but the context is empty\n");
        return 1;
    } else {
        printf("OK\n");
        return 0;
    }
}

Buster version returns error error:14187180:SSL routines:ssl_do_config:bad value while stretch works fine.

However if openssl package is removed from apt-get install command then buster also works fine.

We can be more specific in However if openssl package is removed from apt-get install command then buster also works fine.
since I have the error message error: 14187180: SSL routines: ssl_do_config: bad value in buster

Is there a workaround to this other than

sudo apt remove openssl

?

Because I'd like to be able to use WebRTC which uses DTLS on my Raspberry Pi Zero (Buster):

https://gitlab.freedesktop.org/gstreamer/gst-examples/-/issues/35#note_865398

I guess I could just recompile the WebRTC plugin and ignore the return code, if the context is still good? It sounds like it's just a false error code left in error_code.

Is it something to do with some global set min TLS version?

This indeed works and removes openssl system version without uninstalling node and lots of other packages:

sudo dpkg -r --force-depends "openssl"

And it indeed fixes the test above! Yay! Thanks!