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Ensure context is passed in to dummy_rand

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In fuzz_privkey, we switched over to using dummy_rand(), which uses
ctr_drbg internally, and thus requires an initialised ctr_drbg_context
to be passed in via p_rng when calling mbedtls_pk_parse_key().

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
This commit is contained in:
Paul Elliott 2022-02-11 19:10:14 +00:00
parent bebeae9428
commit 51a7679a8e
1 changed files with 18 additions and 3 deletions
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21
programs/fuzz/fuzz_privkey.c
View file

@ -2,26 +2,41 @@
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "mbedtls/pk.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "common.h"
//4 Kb should be enough for every bug ;-)
#define MAX_LEN 0x1000
#if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_CTR_DRBG_C)
const char *pers = "fuzz_privkey";
#endif // MBEDTLS_PK_PARSE_C && MBEDTLS_CTR_DRBG_C
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
#ifdef MBEDTLS_PK_PARSE_C
#if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_CTR_DRBG_C)
int ret;
mbedtls_pk_context pk;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_entropy_context entropy;
if (Size > MAX_LEN) {
//only work on small inputs
Size = MAX_LEN;
}
mbedtls_ctr_drbg_init( &ctr_drbg );
mbedtls_entropy_init( &entropy );
if( mbedtls_ctr_drbg_seed( &ctr_drbg, dummy_entropy, &entropy,
( const unsigned char * ) pers, strlen( pers ) ) != 0 )
return 1;
mbedtls_pk_init( &pk );
ret = mbedtls_pk_parse_key( &pk, Data, Size, NULL, 0,
dummy_random, NULL );
dummy_random, &ctr_drbg );
if (ret == 0) {
#if defined(MBEDTLS_RSA_C)
if( mbedtls_pk_get_type( &pk ) == MBEDTLS_PK_RSA )
@ -73,7 +88,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
#else
(void) Data;
(void) Size;
#endif //MBEDTLS_PK_PARSE_C
#endif // MBEDTLS_PK_PARSE_C && MBEDTLS_CTR_DRBG_C
return 0;
}