dump the certificate and private in PEM format when used

nccsslkeyandcertlog.c

//
// based on https://git.lekensteyn.nl/peter/wireshark-notes/tree/src/
// Licensed under the terms of GPLv3 (or any later version) at your choice
//
// works for daemons which can be run in the foreground 
//
// gcc nccsslkeyandcertlog.c -shared -o nccsslkeyandcertlog.so -fPIC -ldl
//
//
 
#define _GNU_SOURCE
#include <dlfcn.h>
#include <openssl/ssl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
 
#ifndef OPENSSL_SONAME
#   define OPENSSL_SONAME   "libssl.so"
#endif
 
typedef int sslCB(char *buf, int size, int rwflag, void *password);
sslCB* funcsslCB = 0;
void* userData = 0;
 
static inline void *lookup_symbol(const char *sym)
{
    void *func = dlsym(RTLD_NEXT, sym);
    /* Symbol not found, OpenSSL is not loaded (linked) so try to load it
     * manually. This is error-prone as it depends on a fixed library name.
     * Perhaps it should be an env name? */
    if (!func) {
        void *handle = dlopen(OPENSSL_SONAME, RTLD_LAZY);
        if (!handle) {
            fprintf(stderr, "Lookup error for %s: %s", sym, dlerror());
            abort();
        }
        func = dlsym(handle, sym);
        if (!func) {
            fprintf(stderr, "Cannot lookup %s", sym);
            abort();
        }
        dlclose(handle);
    }
    return func;
}
 
 
SSL_CTX_use_certificate(SSL_CTX *ctx, X509 *x)
{
    fprintf(stderr,"%s called\n",__func__);

    static int (*func)();
    if (!func) {
        func = lookup_symbol(__func__);
    }


    char *subj = X509_NAME_oneline(X509_get_subject_name(x), NULL, 0);
    char *issuer = X509_NAME_oneline(X509_get_issuer_name(x), NULL, 0);
    fprintf(stderr,"cert subject %s\n",subj);
    fprintf(stderr,"cert issuer %s\n", issuer);

    char strFileName[256] = {0};

    sprintf(strFileName,"pubkey.pem");
    FILE* pFile = fopen(strFileName,"wt");
    if(PEM_write_X509(pFile,x)){
        fprintf(stderr,"wrote x509 %s\n",strFileName);
    }
    fclose(pFile);


    int ret = func(ctx,x);

    return ret;
}


int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey)
{
    fprintf(stderr,"%s called\n",__func__);

    static int (*func)();
    if (!func) {
        func = lookup_symbol(__func__);
    }

    fprintf(stderr,"address of private key %08x\n",(int)pkey);

    char strFileName[256] = {0};

    sprintf(strFileName,"privkey.pem");
    FILE* pFile = fopen(strFileName,"wt");
    if(PEM_write_PrivateKey(pFile,pkey,NULL,NULL,0,0,NULL)){
        fprintf(stderr,"wrote key %s\n",strFileName);
    }
    fclose(pFile);


    int ret = func(ctx,pkey);

    return ret;
}