Reason for the compilation error : In function sk_X509_num undefined reference to `OpenSSL_sk_num`

Question

I have a P12 file which I am trying to parse programmatically. I am successful in parsing it. When I use the code as standalone and use -ssl and -crypto on command line it works fine. But when I use the same code in my application I get Undefined reference error : In function sk_X509_num undefined reference to OpenSSL_sk_num and In function sk_X509_value undefined reference to OPENSSL_sk_value

Below is the code snippet I am using :

{
  Bio *b = Bio_new(BIO_s_mem());
 if(b != nullptr)
 {
   for(int i=0; i< sk_X509_num(ca);i++)
     {
      if(!PEM_write_bio_X509(b, sk_X509_value(ca,i)))
       {
         //some log message.....      
       }
      else
      {
        //some code here
      }
   }

I have included in makefile the following flags : LDFLAGS+= -lssl -lcrypto The OPENSSL Version is 1.1.1g

Answer 1

I could finally resolve my own question:

It seems the functions sk_num, sk_value have been replaced with OpenSSL_sk_num, OPENSSL_sk_value. There is an issue with linking, somehow there symbols have been missed in symbol file in the version 1.1.g.

I tried the following:

i) Using -lssl -lcrypto on command line. This worked but when you use in the application and use the makefile with the options -lssl -lcrypto it fails with error undefined reference.

ii) Downgraded the SSL to the version 1.0.2 where in function sk_num is not replaced with OPENSSL_sk_num but it didn't work with the same failure.

iii) Success: So you need to define the functions for sk_num, sk_value, sk_pop_free in the application where you are using these functions, which I took from the SSL version 1.1.n, which is the latest in 1.1 series. I hope it helps the people facing this issue. I tried upgrading SSL to version 1.1.n but it didn't work for me.