test/drbgtest.c:554: error: NULL_DEREFERENCE
  pointer `ctx` last assigned on line 552 could be null and is dereferenced at line 554, column 25.
Showing all 13 steps of the trace


test/drbgtest.c:550:1: start of procedure unhook_drbg()
548.   
549.   /* Installs the hook for the get_entropy() callback of the given drbg */
550. > static void unhook_drbg(RAND_DRBG *drbg)
551.   {
552.       HOOK_CTX *ctx = get_hook_ctx(drbg);

test/drbgtest.c:552:5: 
550.   static void unhook_drbg(RAND_DRBG *drbg)
551.   {
552. >     HOOK_CTX *ctx = get_hook_ctx(drbg);
553.   
554.       drbg->get_entropy = ctx->get_entropy;

test/drbgtest.c:515:1: start of procedure get_hook_ctx()
  513.   static HOOK_CTX master_ctx, public_ctx, private_ctx;
  514.   
  515. > static HOOK_CTX *get_hook_ctx(RAND_DRBG *drbg)
  516.   {
  517.       return (HOOK_CTX *)RAND_DRBG_get_ex_data(drbg, app_data_index);

test/drbgtest.c:517:5: 
  515.   static HOOK_CTX *get_hook_ctx(RAND_DRBG *drbg)
  516.   {
  517. >     return (HOOK_CTX *)RAND_DRBG_get_ex_data(drbg, app_data_index);
  518.   }
  519.   

crypto/rand/drbg_lib.c:911:1: start of procedure RAND_DRBG_get_ex_data()
    909.   }
    910.   
    911. > void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
    912.   {
    913.       return CRYPTO_get_ex_data(&drbg->ex_data, idx);

crypto/rand/drbg_lib.c:913:5: 
    911.   void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
    912.   {
    913. >     return CRYPTO_get_ex_data(&drbg->ex_data, idx);
    914.   }
    915.   

crypto/ex_data.c:394:1: start of procedure CRYPTO_get_ex_data()
      392.    * particular index in the class used by this variable
      393.    */
      394. > void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
      395.   {
      396.       if (ad->sk == NULL || idx >= sk_void_num(ad->sk))

crypto/ex_data.c:396:9: Taking true branch
      394.   void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
      395.   {
      396.       if (ad->sk == NULL || idx >= sk_void_num(ad->sk))
                     ^
      397.           return NULL;
      398.       return sk_void_value(ad->sk, idx);

crypto/ex_data.c:397:9: 
      395.   {
      396.       if (ad->sk == NULL || idx >= sk_void_num(ad->sk))
      397. >         return NULL;
      398.       return sk_void_value(ad->sk, idx);
      399.   }

crypto/ex_data.c:399:1: return from a call to CRYPTO_get_ex_data
      397.           return NULL;
      398.       return sk_void_value(ad->sk, idx);
      399. > }

crypto/rand/drbg_lib.c:914:1: return from a call to RAND_DRBG_get_ex_data
    912.   {
    913.       return CRYPTO_get_ex_data(&drbg->ex_data, idx);
    914. > }
    915.   
    916.   

test/drbgtest.c:518:1: return from a call to get_hook_ctx
  516.   {
  517.       return (HOOK_CTX *)RAND_DRBG_get_ex_data(drbg, app_data_index);
  518. > }
  519.   
  520.   /* Intercepts and counts calls to the get_entropy() callback */

test/drbgtest.c:554:5: 
552.       HOOK_CTX *ctx = get_hook_ctx(drbg);
553.   
554. >     drbg->get_entropy = ctx->get_entropy;
555.       CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
556.   }
