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