c - HMAC_Init_ex Corrupting Stack Space -

i'm trying create sha256 hash key using openssl's hmac functions. stack keeps getting corrupted (every value set 0) after call hmac_init_ex. i'm using xcode , running os x 10.8.5. running "openssl version" in terminal outputs "openssl 0.9.8y 5 feb 2013".

here function , #includes:

#include <stdio.h> #include <openssl/hmac.h>  char* hash(char *str, char* key){     int inputlen = strlen(str);     int keylen = strlen(key);     hmac_ctx ctx;     hmac_ctx_init(&ctx);     hmac_init_ex(&ctx, key, keylen, evp_sha256(), null); // fine here.     hmac_update(&ctx, str, inputlen); // time line runs, str , key null, , inputlen , keylen 0.     char* ret = malloc(65*sizeof(char));     hmac_final(&ctx, ret, 65);     hmac_ctx_cleanup(&ctx);     ret[65] = '\0';     return ret; } 

this code should working. has libraries, don't know what. did wrong when importing libraries?

update: found example here uses encapsulated hmac function , says same doing before, , strangely, works. have circumvented problem, still answer in case helps else. except it's weird, specific issue libraries. working function:

char* hash(char *str, char* key){     int inputlen = strlen(str);     int keylen = strlen(key);     unsigned int retlen = 65;     char* ret = emalloc(retlen*sizeof(char));     ret = hmac(evp_sha256(), key, keylen, (unsigned char*)str, inputlen, null, null);     return ret; } 

you missed openssl/initialization.the engine or ssh config provides cipher methods, digest methods, etc.

#include <openssl/engine.h> #include <openssl/hmac.h>      hmac_ctx ctx;      result = (unsigned char*) malloc(sizeof(char) * result_len);      engine_load_builtin_engines();     engine_register_all_complete();      hmac_ctx_init(&ctx);     hmac_init_ex(&ctx, key, 16, evp_sha256(), null);     hmac_update(&ctx, data, 8);     hmac_final(&ctx, result, &result_len);     hmac_ctx_cleanup(&ctx);