harness2.c

#include <string.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>


//typedef for our exported target function.
typedef void (*CRASHME)(const uint8_t *Data, size_t Size);

//globals
CRASHME fpn_crashme = NULL;


int LLVMFuzzerTestOneInput(const unsigned char* data, size_t size){
    fpn_crashme(data, size);
    return 0;
}

int main(int argc, const char * argv[])
{

    for (int i = 1; i < argc; i++) {
        fprintf(stderr, "Running: %s\n", argv[i]);
        FILE *f = fopen(argv[i], "r");
        assert(f);
        fseek(f, 0, SEEK_END);
        size_t len = ftell(f);
        fseek(f, 0, SEEK_SET);
        unsigned char *buf = (unsigned char*)malloc(len);
        size_t n_read = fread(buf, 1, len, f);
        fclose(f);
        assert(n_read == len);
        LLVMFuzzerTestOneInput(buf, len);
        free(buf);
        fprintf(stderr, "Done:    %s: (%zd bytes)\n", argv[i], n_read);
    }

    return 0;
}

__attribute__((constructor()))
void constructor(void) {
    // handles to required libs
    void *dylib = NULL;

    dylib = dlopen("./libcrashme2.dylib", RTLD_NOW);
    if (dylib == NULL)
    {

        printf("[-] Failed to load lib\n");
        printf("[-] Dlerror: %s\n", dlerror());
        exit(1);

    }

    printf("[+] Resolve function\n");

    fpn_crashme = (CRASHME)dlsym(dylib, "crashme");
    if (!fpn_crashme)
    {

        printf("[-] Failed to find function\n");
        exit(1);

    }

    printf("[+] Found function.\n");
}