example of using dlopen and dlsym to dynamically resolve call to `puts`. String reference to `puts` is also obfuscated.

// how to compile: gcc dynamic_loading.c -o dynamic_loading -ldl #include <stdlib.h> #include <stdio.h> #include <dlfcn.h> #include <string.h>

int main(int argc, char **argv) { void *handle; void (*go)(char *);

// get a handle to the library that contains 'puts' function
handle = dlopen ("/lib/x86_64-linux-gnu/libc.so.6", RTLD_LAZY);

// each character in 'otsr' plus 1 in ascii is 'puts'
char *encoded = "otsr";
int encoded_length = strlen(encoded);
char *decoded = (char*)malloc((encoded_length+1) * sizeof(char));
for (int i = 0; i < encoded_length; i++){
    decoded[i] = encoded[i]+1;
}
*decoded += '\0';

// reference to the dynamically-resolved function 'puts'
go = dlsym(handle, decoded);

go("hi"); // == puts("hi");

// cleanup
free(decoded);
dlclose(handle);

}