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#include "fuzz.h"
#include "session.h"
#include "fuzz-wrapfd.h"
#include "debug.h"
#include "dss.h"
static void setup_fuzzer(void) {
fuzz_common_setup();
}
static buffer *verifydata;
/* Tests reading a public key and verifying a signature */
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
static int once = 0;
if (!once) {
setup_fuzzer();
verifydata = buf_new(30);
buf_putstring(verifydata, "x", 1);
once = 1;
}
if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
return 0;
}
m_malloc_set_epoch(1);
if (setjmp(fuzz.jmp) == 0) {
sign_key *key = new_sign_key();
enum signkey_type keytype = DROPBEAR_SIGNKEY_ANY;
if (buf_get_pub_key(fuzz.input, key, &keytype) == DROPBEAR_SUCCESS) {
enum signature_type sigtype;
if (keytype == DROPBEAR_SIGNKEY_RSA) {
/* Flip a coin to decide rsa signature type */
int flag = buf_getbyte(fuzz.input);
if (flag & 0x01) {
sigtype = DROPBEAR_SIGNATURE_RSA_SHA256;
} else {
sigtype = DROPBEAR_SIGNATURE_RSA_SHA1;
}
} else {
sigtype = signature_type_from_signkey(keytype);
}
if (buf_verify(fuzz.input, key, sigtype, verifydata) == DROPBEAR_SUCCESS) {
/* The fuzzer is capable of generating keys with a signature to match.
We don't want false positives if the key is bogus, since a client/server
wouldn't be trusting a bogus key anyway */
int boguskey = 0;
if (keytype == DROPBEAR_SIGNKEY_DSS) {
/* So far have seen dss keys with bad p/q/g domain parameters */
int pprime, qprime, trials;
trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->p));
assert(mp_prime_is_prime(key->dsskey->p, trials, &pprime) == MP_OKAY);
trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->q));
assert(mp_prime_is_prime(key->dsskey->q, trials, &qprime) == MP_OKAY);
boguskey = !(pprime && qprime);
/* Could also check g**q mod p == 1 */
}
if (!boguskey) {
printf("Random key/signature managed to verify!\n");
abort();
}
}
}
sign_key_free(key);
m_malloc_free_epoch(1, 0);
} else {
m_malloc_free_epoch(1, 1);
TRACE(("dropbear_exit longjmped"))
/* dropbear_exit jumped here */
}
return 0;
}
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