OpenSSL 3.0.0-alpha generated C code has different function name declaration than older OpenSSL versions

[alichry]

I was installing this, I've compiled OpenSSL and configured it with the advised arguments in the install instructions.

While trying to compile revsh, running make produced:

...
if [ ! -e keys/dh_params.c ]; then \
    ../openssl/apps/openssl dhparam -noout -C 2048 >keys/dh_params.c ; \
	echo "DH *(*get_dh)() = &get_dh2048;" >>keys/dh_params.c ; \
  fi
Generating DH parameters, 2048 bit long safe prime, generator 2
This is going to take a long time
.+........+......+..+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*
..+..+.+..+.........+..+...
...
keys/dh_params.c:75:20: error: 'get_dh2048' undeclared here (not in a function)
 DH *(*get_dh)() = &get_dh2048;

The generated C code in keys/dh_params.c is:

static DH *get_dh256(void)
{
    static unsigned char dhp_256[] = {
        0x96, 0x4E, 0x1B, 0xBE, 0x81, 0x01, 0x67, 0x67, 0x21, 0xFF,
        0x19, 0x63, 0x5C, 0x13, 0x02, 0x3E, 0xC0, 0xE7, 0xCA, 0x1A,
        0xB7, 0x59, 0x61, 0x08, 0x05, 0xE8, 0x0B, 0xF3, 0xB6, 0xD3,
        0x73, 0x3B, 0x26, 0x56, 0xF8, 0xB1, 0xDA, 0x42, 0xEB, 0x78,
        0xE9, 0xE5, 0x85, 0x70, 0x9E, 0x10, 0xA2, 0x80, 0x0D, 0x53,
        0xFF, 0x06, 0x61, 0xE1, 0x2F, 0xB7, 0x80, 0x42, 0x76, 0xE3,
        0x99, 0xAB, 0x32, 0x93, 0x65, 0xF0, 0xA2, 0xC6, 0x9E, 0x0F,
        0x52, 0xD1, 0x27, 0x6B, 0xDF, 0xCC, 0x99, 0x71, 0x65, 0x1E,
        0xBC, 0x89, 0xBC, 0x5D, 0xF4, 0x80, 0x9E, 0xC5, 0x19, 0xB5,
        0xE1, 0x0F, 0xE8, 0xAF, 0xE2, 0x75, 0x15, 0xED, 0xCE, 0x99,
        0xA6, 0xC5, 0xC5, 0xD1, 0xEA, 0xEE, 0x4E, 0xBB, 0x18, 0xAF,
        0xC5, 0x12, 0xE3, 0x93, 0x5D, 0xDC, 0xF7, 0xE2, 0xAB, 0x56,
        0x4A, 0x58, 0x60, 0x7D, 0x31, 0xA9, 0xCD, 0xA5, 0xF1, 0x40,
        0xD0, 0x93, 0xD4, 0x4A, 0x8B, 0x74, 0x43, 0xA3, 0x83, 0x3A,
        0xFA, 0xD7, 0xEE, 0x86, 0x59, 0xA3, 0x6F, 0xDA, 0x5E, 0x4C,
        0x39, 0xDB, 0x0E, 0x75, 0xCC, 0x40, 0xD5, 0xF5, 0x0B, 0x94,
        0xCC, 0xB2, 0xC7, 0x07, 0xEB, 0x1C, 0xEF, 0xFF, 0xD2, 0x9C,
        0x95, 0x5F, 0x48, 0x1D, 0x0B, 0x0E, 0xE5, 0xE1, 0x5F, 0x3E,
        0x01, 0xE8, 0xD6, 0xB6, 0x58, 0x86, 0x38, 0xBA, 0xC9, 0x50,
        0xB2, 0x5C, 0x83, 0xC1, 0xB2, 0x78, 0xAB, 0x07, 0xDD, 0x17,
        0xAC, 0x4D, 0xA6, 0x37, 0x0C, 0x3A, 0xCB, 0xE9, 0xE2, 0x0C,
        0x06, 0xB0, 0xE2, 0x6E, 0x19, 0x90, 0x00, 0xEA, 0xDA, 0x77,
        0xD2, 0xA4, 0xCE, 0x93, 0x7F, 0x13, 0x33, 0x7E, 0xF5, 0x3E,
        0x31, 0xF9, 0x77, 0xAA, 0x39, 0x71, 0xFF, 0xAD, 0x02, 0x41,
        0x62, 0x57, 0xF5, 0xC1, 0x26, 0xAE, 0xA2, 0xC0, 0x29, 0x48,
        0x28, 0xE2, 0x86, 0x4C, 0xB4, 0x0D
    };
    static unsigned char dhg_256[] = {
        0x0E, 0x5B, 0xAB, 0x57, 0x41, 0x6E, 0x82, 0x3C, 0x10, 0x92,
        0x8B, 0x18, 0x0D, 0xD5, 0x66, 0xF7, 0x33, 0x5E, 0x35, 0xAF,
        0xFF, 0x7A, 0x56, 0x87, 0x8A, 0xDA, 0x5D, 0xD4, 0xF4, 0x2E,
        0xB1, 0x77, 0x2F, 0x79, 0xB3, 0x77, 0x95, 0xC5, 0x8E, 0x9C,
        0xB0, 0x2A, 0xCE, 0x3A, 0x0F, 0xF5, 0x55, 0x0F, 0x06, 0x12,
        0x9B, 0xEC, 0x90, 0x42, 0x9B, 0x4B, 0xCA, 0xF5, 0x72, 0x70,
        0x8A, 0xE2, 0xEC, 0x5C, 0x13, 0x1D, 0xB3, 0x03, 0xC2, 0xCE,
        0xF4, 0x08, 0xF2, 0x63, 0x65, 0xF3, 0x53, 0xD6, 0x02, 0xA7,
        0x19, 0x11, 0x2D, 0x6C, 0x5A, 0x82, 0x06, 0xEF, 0xC7, 0x3E,
        0x92, 0x1E, 0xE1, 0x64, 0x71, 0xB4, 0x88, 0x91, 0x5E, 0xD3,
        0xCF, 0x16, 0xB3, 0x3E, 0xB2, 0x8D, 0xB0, 0x61, 0x7F, 0x23,
        0xA3, 0x39, 0x69, 0x3E, 0x9D, 0x44, 0x92, 0x57, 0xED, 0x90,
        0xF1, 0x0C, 0xB2, 0x28, 0xD0, 0x61, 0x4B, 0x2A, 0x70, 0xE7,
        0x82, 0xCC, 0x75, 0x92, 0x1E, 0x65, 0x3A, 0x56, 0x85, 0x0D,
        0x3F, 0x40, 0x59, 0x0A, 0x45, 0xEF, 0x99, 0x03, 0x88, 0x8C,
        0xD5, 0x82, 0xC3, 0xE2, 0x6F, 0x1F, 0x2B, 0xBD, 0x0F, 0x50,
        0xAD, 0xD6, 0x46, 0x26, 0xBD, 0x02, 0x58, 0x41, 0xA9, 0x00,
        0xE5, 0x23, 0x0E, 0x0A, 0xD6, 0x10, 0xEB, 0x9B, 0x81, 0x0B,
        0xB2, 0x53, 0x73, 0x35, 0xF9, 0xBE, 0x5C, 0x86, 0x33, 0xE4,
        0xAA, 0x10, 0x34, 0xA5, 0x0A, 0x63, 0x06, 0x0E, 0xF3, 0x4B,
        0x4C, 0xDB, 0xE4, 0x28, 0xED, 0x1B, 0x4D, 0x43, 0x62, 0x46,
        0xF5, 0xD3, 0x55, 0x67, 0x7D, 0xEC, 0x6A, 0x2F, 0x61, 0x5A,
        0x0F, 0x8C, 0xAA, 0xFA, 0x20, 0xE2, 0x40, 0xD2, 0x1D, 0x39,
        0xE9, 0x08, 0x99, 0xAF, 0x7E, 0x0A, 0x32, 0xBE, 0xA6, 0xC9,
        0xB0, 0x6E, 0x09, 0x94, 0xFB, 0xD7, 0xF8, 0xE4, 0xAC, 0xEB,
        0xFC, 0x1D, 0xD4, 0xB9, 0x0A, 0xF0
    };
    DH *dh = DH_new();
    BIGNUM *p, *g;

    if (dh == NULL)
        return NULL;
    p = BN_bin2bn(dhp_256, sizeof(dhp_256), NULL);
    g = BN_bin2bn(dhg_256, sizeof(dhg_256), NULL);
    if (p == NULL || g == NULL
            || !DH_set0_pqg(dh, p, NULL, g)) {
        DH_free(dh);
        BN_free(p);
        BN_free(g);
        return NULL;
    }
    return dh;
}
DH *(*get_dh)() = &get_dh2048;

If I generate the C code using the OpenSSL binary installed on my system and not the compiled one, the generated function declaration is

$ openssl dhparam -noout -C 2048
#ifndef HEADER_DH_H
#include <openssl/dh.h>
#endif
DH *get_dh2048()
        {
        static unsigned char dh2048_p[]={
                0x86,0xB5,0x48,0xF3,0x63,0xE2,0x92,0x97,0xC1,0x5B,0xEC,0x3A,
                0x40,0xFF,0x3E,0xA9,0x64,0xBC,0x24,0x11,0x3D,0xC0,0x9A,0x57,
                0xCF,0xF5,0x02,0xFA,0x08,0xF5,0x1A,0x50,0x08,0x77,0x2E,0xD9,
                0x20,0x5B,0xB0,0xA7,0xAA,0x32,0xC1,0x54,0xF1,0xF3,0x29,0xBE,
                0x34,0x54,0xD6,0xC1,0x57,0x2F,0x35,0xED,0x7F,0xE4,0xE0,0x46,
                0x82,0x28,0x0D,0xB2,0xB2,0x30,0x7E,0x43,0xCB,0x98,0xBA,0x09,
                0x75,0x72,0xED,0x71,0xD0,0x2D,0xE6,0xAD,0x45,0x2E,0xE8,0x37,
                0x48,0x81,0x1F,0x94,0x3C,0x1C,0x5B,0x22,0x67,0x6E,0xB2,0x96,
                0xBD,0x26,0x75,0x59,0x4E,0xCF,0x2F,0xA0,0x26,0x70,0x4A,0xF6,
                0x8C,0xAF,0x69,0x88,0x2B,0x05,0x59,0x5E,0x60,0xFD,0x4F,0xB7,
                0xBC,0x63,0x96,0x0F,0xC2,0xE1,0x9B,0xF9,0x71,0x1B,0x0F,0x05,
                0x74,0x5D,0xAB,0xF5,0x37,0x65,0x50,0xF0,0x9F,0xF4,0x3F,0xE6,
                0x21,0xB9,0x28,0xAA,0x68,0xC8,0x11,0xC2,0xB6,0x30,0xD3,0x8D,
                0xB8,0x3E,0x6E,0x9D,0x24,0xE0,0xE8,0xDF,0xEE,0x0E,0x4F,0xDD,
                0xC6,0x55,0x7F,0xC3,0x5D,0x48,0xC1,0x20,0x01,0x79,0xCE,0x12,
                0xEA,0x9C,0xAD,0x32,0xC5,0x62,0x01,0xA2,0x40,0x36,0xB9,0x8E,
                0x9B,0x72,0xF4,0xBB,0xA7,0x38,0xEF,0x44,0xC0,0x46,0xAC,0x91,
                0xE4,0xF2,0x5C,0x1A,0xC6,0xF4,0xE3,0x3C,0x36,0x17,0x6F,0x41,
                0x87,0xB7,0x2A,0xB8,0xF8,0xF9,0x5D,0x9C,0x6F,0x09,0x71,0x66,
                0xB1,0xD1,0xF5,0xA7,0x05,0x4F,0xB3,0x93,0x54,0x81,0x36,0x18,
                0x7D,0x93,0x50,0xFB,0x68,0x55,0xAB,0x48,0xE9,0x7B,0x4C,0xAF,
                0x74,0xB6,0xFA,0x03,
                };
        static unsigned char dh2048_g[]={
                0x02,
                };
        DH *dh;

        if ((dh=DH_new()) == NULL) return(NULL);
        dh->p=BN_bin2bn(dh2048_p,sizeof(dh2048_p),NULL);
        dh->g=BN_bin2bn(dh2048_g,sizeof(dh2048_g),NULL);
        if ((dh->p == NULL) || (dh->g == NULL))
                { DH_free(dh); return(NULL); }
        return(dh);
        }

Compiled OpenSSL version:

$ ../openssl/apps/openssl version  
OpenSSL 3.0.0-alpha5-dev  (Library: OpenSSL 3.0.0-alpha5-dev )

Installed OpenSSL version:

$ openssl version
OpenSSL 1.0.2k-fips  26 Jan 2017

Obviously cloning the latest branch commit of OpenSSL can raise compatibility issues with future releases of OpenSSL. I'll be happy to create a PR to modify the INSTALL instructions, or instead maybe we use can use sed to get the declared function name instead of hardcoding it.