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crypto: new iteration of fuzz testing code, improved dictionary script, minor documentation changes

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pull/1744/head
Christian Reitter 3 years ago committed by Andrew Kozlik
parent 78f879aaf1
commit ba8eb408ea
3 changed files with 351 additions and 116 deletions
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8
crypto/fuzzer/README.md
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@ -21,7 +21,6 @@ Examples:
* `SANFLAGS="-fsanitize=address,undefined"` * `SANFLAGS="-fsanitize=address,undefined"`
* `SANFLAGS="-fsanitize=memory -fsanitize-memory-track-origins"` * `SANFLAGS="-fsanitize=memory -fsanitize-memory-track-origins"`
### Optimizations ### Optimizations
Override `OPTFLAGS` to test the library at different optimization levels or simplify the debugging of detected issues. Override `OPTFLAGS` to test the library at different optimization levels or simplify the debugging of detected issues.
@ -31,6 +30,12 @@ Examples:
* `OPTFLAGS="-O0 -ggdb3"` * `OPTFLAGS="-O0 -ggdb3"`
* `OPTFLAGS="-O3 -march=native"` * `OPTFLAGS="-O3 -march=native"`
### Other Flags
To be determined:
* `-DNDEBUG`
* `-DUSE_BIP39_CACHE=0 -DUSE_BIP32_CACHE=0`
## Operation ## Operation
See the [libFuzzer documentation](https://llvm.org/docs/LibFuzzer.html#options) for valid options and usage. Detailed fuzzer usage and relevant considerations are out of scope of this document. See the [libFuzzer documentation](https://llvm.org/docs/LibFuzzer.html#options) for valid options and usage. Detailed fuzzer usage and relevant considerations are out of scope of this document.
@ -62,7 +67,6 @@ cd fuzzer
``` ```
The resulting file can be used as a fuzzer dictionary. The resulting file can be used as a fuzzer dictionary.
## Evaluate Source Coverage ## Evaluate Source Coverage
1. build the fuzzer binary with `CFLAGS="-fprofile-instr-generate -fcoverage-mapping"` 1. build the fuzzer binary with `CFLAGS="-fprofile-instr-generate -fcoverage-mapping"`

42
crypto/fuzzer/extract_fuzzer_dictionary.sh
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@ -5,27 +5,35 @@
# this script searches for interesting strings in the source code and converts # this script searches for interesting strings in the source code and converts
# them into a standard fuzzer dictionary file. # them into a standard fuzzer dictionary file.
TARGETFILE=${1:-fuzzer_crypto_tests_strings_dictionary1.txt}
# collect strings with normal words from the tests TARGET_DIR=../tests
grep -r -P -o -h "\"[\w ]+\"" ../tests | sort | uniq > $TARGETFILE OUTPUT_FILE=${1:-fuzzer_crypto_tests_strings_dictionary1.txt}
# collect BIP39 and SLIP39 words # empty file
grep -r -P -o -h "\"\w+\"" ../slip39_wordlist.h ../bip39_english.h | sort | uniq >> $TARGETFILE echo -n "" > $OUTPUT_FILE
# hex string to quoted escaped hex conversion # strip multiline strings and extract them
# TODO add an inverted output variant with swapped endian order? # exclude some hex strings, but allow hex strings with mixed capitalization (Ethereum, rskip60)
grep -r -P -o -h "([0-9a-fA-F][0-9a-fA-F])+" ../tests | sort | uniq | \ find $TARGET_DIR -type f | xargs cat | perl -p0e 's/"\s*\n\s*\"//smg' | grep -P -o "\"[\w ]+\"" | grep -v -P "\"(([0-9a-f][0-9a-f])+|([0-9A-F][0-9A-F])+)\"" | sort | uniq | while read -r line ; do
while read -r line ; do echo "$line" >> $OUTPUT_FILE
# double escape since it is going to be used in bash done
# extract individual BIP39 and SLIP39 words
# TODO are those actually valuable as fuzzer dictionary input?
# grep -r -P -o -h "\"\w+\"" ../slip39_wordlist.h ../bip39_english.h | sort | uniq >> fuzzer_crypto_tests_strings_dictionary1.txt
# extract and convert binary input data from the unit tests
# find each file, cat it, concatenate multiline strings, look for hex strings in quotes
find $TARGET_DIR -type f | xargs cat | perl -p0e 's/"\s*\n\s*\"//smg' | grep -P -o "\"([0-9a-fA-F][0-9a-fA-F])+\"" | grep -P -o "([0-9a-fA-F][0-9a-fA-F])+" | sort | uniq | while read -r line ; do
# turn ascii hex strings AA into \xaa for the fuzzer format and add quotes
# extra backslash escape due to the bash nesting
escaped_hex=`echo $line | sed -e 's/../\\\\x&/g'` escaped_hex=`echo $line | sed -e 's/../\\\\x&/g'`
echo "\"$escaped_hex\"" >> $TARGETFILE echo "\"$escaped_hex\"" >> $OUTPUT_FILE
done done
# search and reassemble BIP39 seed mnemonics that span multiple lines from the tests # search and reassemble BIP39 test seeds that span multiple lines
# valid words are 3 to 10 characters long and there are 12, 18 or 24 words in a valid mnemonic # find each file, cat it, concatenate multiline strings, look for BIP39 seed combinations with reasonable length
grep -r -P -o -h "\"(\w{3,10} ?)+\",?" ../tests | grep -vP "[0-9A-Z]" | tr '"\n' ' ' | \ find $TARGET_DIR -type f | xargs cat | perl -p0e 's/"\s*\n\s*\"//smg' | grep -Po "(\w{3,10} ){11,23}(\w{3,10})" | sort | uniq | while read -r line ; do
sed 's/ / /g' | sed 's/ / /g'| grep -Po "(\w{3,10} ){11,23}(\w{3,10})" | sort | uniq | \ echo "\"$line\"" >> $OUTPUT_FILE
while read -r line ; do
echo "\"$line\"" >> $TARGETFILE
done done

417
crypto/fuzzer/fuzzer.c
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@ -1,5 +1,5 @@
/** /**
* Copyright (c) 2020 Christian Reitter * Copyright (c) 2020-2021 Christian Reitter
* *
* Permission is hereby granted, free of charge, to any person obtaining * Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the "Software"), * a copy of this software and associated documentation files (the "Software"),
@ -20,25 +20,46 @@
* OTHER DEALINGS IN THE SOFTWARE. * OTHER DEALINGS IN THE SOFTWARE.
*/ */
#include <assert.h>
#include <stdint.h> #include <stdint.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
// necessary for the target functions // includes for potential target functions
// based on test_check.c
#include "address.h"
#include "aes/aes.h" #include "aes/aes.h"
#include "base32.h"
#include "base58.h"
#include "bignum.h" #include "bignum.h"
#include "bip32.h"
#include "bip39.h"
#include "blake256.h"
#include "blake2b.h"
#include "blake2s.h"
#include "chacha_drbg.h"
#include "curves.h"
#include "ecdsa.h" #include "ecdsa.h"
#include "hasher.h"
#include "nist256p1.h"
#include "rand.h"
#include "secp256k1.h"
#include "ed25519-donna/ed25519-donna.h" #include "ed25519-donna/ed25519-donna.h"
#include "ed25519-donna/ed25519-keccak.h"
#include "ed25519-donna/ed25519.h" #include "ed25519-donna/ed25519.h"
#include "hmac_drbg.h"
#include "memzero.h"
#include "monero/monero.h"
#include "nem.h" #include "nem.h"
#include "nist256p1.h"
#include "pbkdf2.h"
#include "rand.h"
#include "rc4.h"
#include "rfc6979.h"
#include "schnorr.h"
#include "script.h"
#include "secp256k1.h"
#include "sha2.h"
#include "sha3.h"
#include "shamir.h" #include "shamir.h"
#include "slip39.h"
#include "slip39_wordlist.h"
/* fuzzer input data handling */ /* fuzzer input data handling */
const uint8_t *fuzzer_ptr; const uint8_t *fuzzer_ptr;
@ -64,9 +85,6 @@ void fuzzer_reset_state(void) {
/* individual fuzzer harness functions */ /* individual fuzzer harness functions */
extern size_t bn_format(const bignum256 *amnt, const char *prefix,
const char *suffix, unsigned int decimals, int exponent,
bool trailing, char *out, size_t outlen);
int fuzz_bn_format(void) { int fuzz_bn_format(void) {
bignum256 target_bignum; bignum256 target_bignum;
// we need some amount of data, bail if the input is too short // we need some amount of data, bail if the input is too short
@ -132,10 +150,6 @@ int fuzz_bn_format(void) {
return 0; return 0;
} }
extern const char *BASE32_ALPHABET_RFC4648;
extern uint8_t *base32_decode(const char *in, size_t inlen, uint8_t *out,
size_t outlen, const char *alphabet);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define BASE32_DECODE_MAX_INPUT_LEN 512 #define BASE32_DECODE_MAX_INPUT_LEN 512
@ -161,9 +175,6 @@ int fuzz_base32_decode(void) {
return 0; return 0;
} }
extern char *base32_encode(const uint8_t *in, size_t inlen, char *out,
size_t outlen, const char *alphabet);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define BASE32_ENCODE_MAX_INPUT_LEN 512 #define BASE32_ENCODE_MAX_INPUT_LEN 512
@ -186,9 +197,6 @@ int fuzz_base32_encode(void) {
return 0; return 0;
} }
extern int base58_encode_check(const uint8_t *data, int datalen,
HasherType hasher_type, char *str, int strsize);
// internal limit is 128, try some extra bytes // internal limit is 128, try some extra bytes
#define BASE58_ENCODE_MAX_INPUT_LEN 140 #define BASE58_ENCODE_MAX_INPUT_LEN 140
@ -215,9 +223,6 @@ int fuzz_base58_encode_check(void) {
return 0; return 0;
} }
extern int base58_decode_check(const char *str, HasherType hasher_type,
uint8_t *data, int datalen);
// internal limit is 128, try some extra bytes // internal limit is 128, try some extra bytes
#define BASE58_DECODE_MAX_INPUT_LEN 140 #define BASE58_DECODE_MAX_INPUT_LEN 140
@ -247,10 +252,6 @@ int fuzz_base58_decode_check(void) {
return 0; return 0;
} }
extern int xmr_base58_addr_decode_check(const char *addr, size_t sz,
uint64_t *tag, void *data,
size_t datalen);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define XMR_BASE58_ADDR_DECODE_MAX_INPUT_LEN 512 #define XMR_BASE58_ADDR_DECODE_MAX_INPUT_LEN 512
@ -273,9 +274,6 @@ int fuzz_xmr_base58_addr_decode_check(void) {
return 0; return 0;
} }
extern int xmr_base58_addr_encode_check(uint64_t tag, const uint8_t *data,
size_t binsz, char *b58, size_t b58sz);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define XMR_BASE58_ADDR_ENCODE_MAX_INPUT_LEN 512 #define XMR_BASE58_ADDR_ENCODE_MAX_INPUT_LEN 512
@ -305,10 +303,6 @@ int fuzz_xmr_base58_addr_encode_check(void) {
return 0; return 0;
} }
extern int xmr_size_varint(uint64_t num);
extern int xmr_write_varint(uint8_t *buff, size_t buff_size, uint64_t num);
extern int xmr_read_varint(uint8_t *buff, size_t buff_size, uint64_t *val);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define XMR_SERIALIZE_VARINT_MAX_INPUT_LEN 128 #define XMR_SERIALIZE_VARINT_MAX_INPUT_LEN 128
@ -342,8 +336,6 @@ int fuzz_xmr_serialize_varint(void) {
return 0; return 0;
} }
extern bool nem_validate_address(const char *address, uint8_t network);
// arbitrarily chosen maximum size // arbitrarily chosen maximum size
#define NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN 128 #define NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN 128
@ -355,26 +347,22 @@ int fuzz_nem_validate_address(void) {
char in_buffer[NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN] = {0}; char in_buffer[NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN] = {0};
// TODO potential BUG: is it clearly specified that the address has to be null
// terminated?
in_buffer[NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN - 1] = 0;
uint8_t network = *fuzzer_ptr; uint8_t network = *fuzzer_ptr;
fuzzer_input(1); fuzzer_input(1);
// mutate the buffer // mutate the buffer with the remaining fuzzer input data
memcpy(&in_buffer, fuzzer_ptr, fuzzer_length); memcpy(&in_buffer, fuzzer_ptr, fuzzer_length);
size_t raw_inlen = fuzzer_length; size_t raw_inlen = fuzzer_length;
fuzzer_input(raw_inlen); fuzzer_input(raw_inlen);
// TODO potential bug: is it clearly specified that the address has to be null
// terminated?
in_buffer[NEM_VALIDATE_ADDRESS_MAX_INPUT_LEN - 1] = 0;
nem_validate_address(in_buffer, network); nem_validate_address(in_buffer, network);
return 0; return 0;
} }
extern bool nem_get_address(const ed25519_public_key public_key,
uint8_t version, char *address);
int fuzz_nem_get_address(void) { int fuzz_nem_get_address(void) {
unsigned char ed25519_public_key[32] = {0}; unsigned char ed25519_public_key[32] = {0};
uint32_t network = 0; uint32_t network = 0;
@ -394,10 +382,6 @@ int fuzz_nem_get_address(void) {
return 0; return 0;
} }
extern void xmr_get_subaddress_secret_key(bignum256modm r, uint32_t major,
uint32_t minor,
const bignum256modm m);
int fuzz_xmr_get_subaddress_secret_key(void) { int fuzz_xmr_get_subaddress_secret_key(void) {
bignum256modm m = {0}; bignum256modm m = {0};
uint32_t major = 0; uint32_t major = 0;
@ -417,9 +401,6 @@ int fuzz_xmr_get_subaddress_secret_key(void) {
return 0; return 0;
} }
extern void xmr_derive_private_key(bignum256modm s, const ge25519 *deriv,
uint32_t idx, const bignum256modm base);
int fuzz_xmr_derive_private_key(void) { int fuzz_xmr_derive_private_key(void) {
bignum256modm base = {0}; bignum256modm base = {0};
ge25519 deriv = {0}; ge25519 deriv = {0};
@ -441,9 +422,6 @@ int fuzz_xmr_derive_private_key(void) {
return 0; return 0;
} }
extern void xmr_derive_public_key(ge25519 *r, const ge25519 *deriv,
uint32_t idx, const ge25519 *base);
int fuzz_xmr_derive_public_key(void) { int fuzz_xmr_derive_public_key(void) {
ge25519 base = {0}; ge25519 base = {0};
ge25519 deriv = {0}; ge25519 deriv = {0};
@ -464,16 +442,11 @@ int fuzz_xmr_derive_public_key(void) {
return 0; return 0;
} }
extern bool shamir_interpolate(uint8_t *result, uint8_t result_index,
const uint8_t *share_indices,
const uint8_t **share_values,
uint8_t share_count, size_t len);
#define SHAMIR_MAX_SHARE_COUNT 16 #define SHAMIR_MAX_SHARE_COUNT 16
#define SHAMIR_MAX_DATA_LEN (SHAMIR_MAX_SHARE_COUNT * SHAMIR_MAX_LEN) #define SHAMIR_MAX_DATA_LEN (SHAMIR_MAX_SHARE_COUNT * SHAMIR_MAX_LEN)
int fuzz_shamir_interpolate(void) { int fuzz_shamir_interpolate(void) {
if (fuzzer_length != (2 * sizeof(uint8_t) + SHAMIR_MAX_SHARE_COUNT + if (fuzzer_length != (2 * sizeof(uint8_t) + SHAMIR_MAX_SHARE_COUNT +
SHAMIR_MAX_DATA_LEN + 2)) { SHAMIR_MAX_DATA_LEN + sizeof(size_t))) {
return 0; return 0;
} }
@ -495,24 +468,77 @@ int fuzz_shamir_interpolate(void) {
memcpy(&share_values_content, fuzzer_input(SHAMIR_MAX_DATA_LEN), memcpy(&share_values_content, fuzzer_input(SHAMIR_MAX_DATA_LEN),
SHAMIR_MAX_DATA_LEN); SHAMIR_MAX_DATA_LEN);
memcpy(&share_count, fuzzer_input(sizeof(uint8_t)), sizeof(uint8_t)); memcpy(&share_count, fuzzer_input(sizeof(uint8_t)), sizeof(uint8_t));
// note: this is platform specific via byte length of size_t
memcpy(&len, fuzzer_input(sizeof(size_t)), sizeof(size_t));
// the target function checks for (len > SHAMIR_MAX_LEN), // mirror a check that the real code does
// so we don't have to test the whole size_t length value
len = (fuzzer_ptr[0] << 8) + fuzzer_ptr[1];
fuzzer_input(2);
// mirror the checks in mod_trezorcrypto_shamir_interpolate()
if (share_count < 1 || share_count > SHAMIR_MAX_SHARE_COUNT) { if (share_count < 1 || share_count > SHAMIR_MAX_SHARE_COUNT) {
return 0; return 0;
} }
// (len > SHAMIR_MAX_LEN) is handled in the target function
shamir_interpolate(result, result_index, share_indices, share_values, shamir_interpolate(result, result_index, share_indices, share_values,
share_count, len); share_count, len);
return 0; return 0;
} }
extern int ecdsa_verify_digest(const ecdsa_curve *curve, const uint8_t *pub_key, int fuzz_ecdsa_sign_digest(void) {
const uint8_t *sig, const uint8_t *digest); uint8_t curve_decider = 0;
uint8_t sig[64] = {0};
uint8_t priv_key[32] = {0};
uint8_t digest[32] = {0};
if (fuzzer_length < 1 + sizeof(sig) + sizeof(priv_key) + sizeof(digest)) {
return 0;
}
const ecdsa_curve *curve;
uint8_t pby = 0;
memcpy(&curve_decider, fuzzer_input(1), 1);
memcpy(&sig, fuzzer_input(sizeof(sig)), sizeof(sig));
memcpy(&priv_key, fuzzer_input(sizeof(priv_key)), sizeof(priv_key));
memcpy(&digest, fuzzer_input(sizeof(digest)), sizeof(digest));
// pick one of the standard curves
if ((curve_decider & 0x1) == 1) {
curve = &secp256k1;
} else {
curve = &nist256p1;
}
// TODO optionally set a function for is_canonical()
int res = ecdsa_sign_digest(curve, priv_key, digest, sig, &pby, NULL);
// successful signing
if (res == 0) {
uint8_t pub_key[33] = {0};
ecdsa_get_public_key33(curve, priv_key, pub_key);
res = ecdsa_verify_digest(curve, pub_key, sig, digest);
if (res != 0) {
// verification did not succeed
// case: all zero pubkey value
uint8_t pub_key_zero[33] =
"\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
// case: all zero digest value
uint8_t digest_zero[32] =
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
if (memcmp(&pub_key, &pub_key_zero, sizeof(pub_key_zero)) == 0 ||
memcmp(&digest, &digest_zero, sizeof(digest_zero)) == 0) {
return 0;
}
// handle as crash
exit(1);
}
}
return 0;
}
int fuzz_ecdsa_verify_digest(void) { int fuzz_ecdsa_verify_digest(void) {
uint8_t curve_decider = 0; uint8_t curve_decider = 0;
@ -540,14 +566,16 @@ int fuzz_ecdsa_verify_digest(void) {
int res = ecdsa_verify_digest(curve, (const uint8_t *)&pub_key, int res = ecdsa_verify_digest(curve, (const uint8_t *)&pub_key,
(const uint8_t *)&sig, (const uint8_t *)&hash); (const uint8_t *)&sig, (const uint8_t *)&hash);
// TODO check if the fuzzer ever manages to get the return value to 0 if (res == 0) {
(void)res; // See if the fuzzer ever manages to get find a correct verification
// intentionally trigger a crash to make this case observable
// TODO this is not an actual problem, remove in the future
exit(1);
}
return 0; return 0;
} }
extern bool word_index(uint16_t *index, const char *word, uint8_t word_length);
int fuzz_word_index(void) { int fuzz_word_index(void) {
#define MAX_WORD_LENGTH 12 #define MAX_WORD_LENGTH 12
@ -559,7 +587,6 @@ int fuzz_word_index(void) {
char word[MAX_WORD_LENGTH + 1] = {0}; char word[MAX_WORD_LENGTH + 1] = {0};
memcpy(&word, fuzzer_ptr, MAX_WORD_LENGTH); memcpy(&word, fuzzer_ptr, MAX_WORD_LENGTH);
size_t word_length = strlen(word); size_t word_length = strlen(word);
uint16_t index = 0; uint16_t index = 0;
word_index(&index, (const char *)&word, word_length); word_index(&index, (const char *)&word, word_length);
@ -567,8 +594,6 @@ int fuzz_word_index(void) {
return 0; return 0;
} }
extern uint16_t slip39_word_completion_mask(uint16_t sequence);
int fuzz_slip39_word_completion_mask(void) { int fuzz_slip39_word_completion_mask(void) {
if (fuzzer_length != 2) { if (fuzzer_length != 2) {
return 0; return 0;
@ -576,16 +601,13 @@ int fuzz_slip39_word_completion_mask(void) {
uint16_t sequence = (fuzzer_ptr[0] << 8) + fuzzer_ptr[1]; uint16_t sequence = (fuzzer_ptr[0] << 8) + fuzzer_ptr[1];
fuzzer_input(2); fuzzer_input(2);
// TODO perform additional checks on the output?
slip39_word_completion_mask(sequence); slip39_word_completion_mask(sequence);
return 0; return 0;
} }
extern int mnemonic_to_bits(const char *mnemonic, uint8_t *mnemonic_bits);
int fuzz_mnemonic_to_bits(void) { int fuzz_mnemonic_to_bits(void) {
// slightly longer than MAX_MNEMONIC_LEN from config.h // length chosen somewhat arbitrarily
#define MAX_MNEMONIC_LENGTH 256 #define MAX_MNEMONIC_LENGTH 256
if (fuzzer_length < MAX_MNEMONIC_LENGTH) { if (fuzzer_length < MAX_MNEMONIC_LENGTH) {
@ -596,8 +618,7 @@ int fuzz_mnemonic_to_bits(void) {
memcpy(&mnemonic, fuzzer_ptr, MAX_MNEMONIC_LENGTH); memcpy(&mnemonic, fuzzer_ptr, MAX_MNEMONIC_LENGTH);
uint8_t mnemonic_bits[32 + 1] = {0}; uint8_t mnemonic_bits[32 + 1] = {0};
int number_of_bits = mnemonic_to_bits((const char *)&mnemonic, mnemonic_bits); mnemonic_to_bits((const char *)&mnemonic, mnemonic_bits);
assert(0 <= number_of_bits && number_of_bits <= 264);
return 0; return 0;
} }
@ -674,37 +695,221 @@ int fuzz_aes(void) {
return 0; return 0;
} }
extern int base58gph_encode_check(const uint8_t *data, int datalen, char *str,
int strsize);
extern int base58gph_decode_check(const char *str, uint8_t *data, int datalen);
int fuzz_b58gph_encode_decode(void) { int fuzz_b58gph_encode_decode(void) {
// note: encode and decode have an internal limit of 128 // note: encode and decode functions have an internal limit of 128
#define BASE58_GPH_MAX_INPUT_LEN 140 #define BASE58_GPH_MAX_INPUT_LEN 130
if (fuzzer_length < 1 + 1 + BASE58_GPH_MAX_INPUT_LEN) {
return 0;
}
if (fuzzer_length > BASE58_GPH_MAX_INPUT_LEN) { // use a flexible output buffer target size
uint8_t chosen_outlen = 0;
memcpy(&chosen_outlen, fuzzer_input(1), 1);
if (chosen_outlen > BASE58_GPH_MAX_INPUT_LEN) {
return 0;
}
// use a flexible input buffer target size
uint8_t chosen_inlen = 0;
memcpy(&chosen_inlen, fuzzer_input(1), 1);
if (chosen_inlen > BASE58_GPH_MAX_INPUT_LEN) {
return 0; return 0;
} }
// TODO switch to malloc()'ed buffers for better out of bounds access
// detection?
uint8_t encode_in_buffer[BASE58_GPH_MAX_INPUT_LEN] = {0}; uint8_t encode_in_buffer[BASE58_GPH_MAX_INPUT_LEN] = {0};
// with null termination // with null termination
char decode_in_buffer[BASE58_GPH_MAX_INPUT_LEN + 1] = {0}; char decode_in_buffer[BASE58_GPH_MAX_INPUT_LEN + 1] = {0};
char out_buffer[BASE58_GPH_MAX_INPUT_LEN] = {0}; char out_buffer[BASE58_GPH_MAX_INPUT_LEN] = {0};
size_t outlen = sizeof(out_buffer);
size_t raw_inlen = fuzzer_length; memcpy(&encode_in_buffer, fuzzer_input(chosen_inlen), chosen_inlen);
memcpy(&encode_in_buffer, fuzzer_input(raw_inlen), raw_inlen); memcpy(&decode_in_buffer, &encode_in_buffer, chosen_inlen);
memcpy(&decode_in_buffer, &encode_in_buffer, raw_inlen);
int ret = 0;
ret = base58gph_encode_check(encode_in_buffer, chosen_inlen, out_buffer,
chosen_outlen);
if (ret != 0) {
// successful encode, try decode
uint8_t dummy_buffer[BASE58_GPH_MAX_INPUT_LEN] = {0};
ret = base58gph_decode_check(out_buffer, (uint8_t *)&dummy_buffer,
chosen_outlen);
if (ret == 0) {
// mark as exception
// TODO POTENTIAL BUG - followup
// exit(1);
}
}
base58gph_encode_check(encode_in_buffer, raw_inlen, out_buffer, outlen); // do a second operation with the same input, without relationship to the
base58gph_decode_check(decode_in_buffer, (uint8_t *)&out_buffer, outlen); // previously computed output
base58gph_decode_check(decode_in_buffer, (uint8_t *)&out_buffer,
chosen_outlen);
return 0;
}
#define SCHNORR_VERIFY_PUBKEY_DATA_LENGTH 33
#define SCHNORR_VERIFY_PRIVKEY_DATA_LENGTH 32
// TODO do logical encode<>decode comparison checks? int fuzz_schnorr_verify_digest(void) {
if (fuzzer_length < SHA256_DIGEST_LENGTH + SCHNORR_VERIFY_PUBKEY_DATA_LENGTH +
SCHNORR_SIG_LENGTH) {
return 0;
}
// TODO optionally try nist256p1 ?
const ecdsa_curve *curve = &secp256k1;
uint8_t digest[SHA256_DIGEST_LENGTH] = {0};
uint8_t pub_key[SCHNORR_VERIFY_PUBKEY_DATA_LENGTH] = {0};
uint8_t signature[SCHNORR_SIG_LENGTH] = {0};
memcpy(&digest, fuzzer_input(SHA256_DIGEST_LENGTH), SHA256_DIGEST_LENGTH);
memcpy(&pub_key, fuzzer_input(SCHNORR_VERIFY_PUBKEY_DATA_LENGTH),
SCHNORR_VERIFY_PUBKEY_DATA_LENGTH);
memcpy(&signature, fuzzer_input(SCHNORR_SIG_LENGTH), SCHNORR_SIG_LENGTH);
// TODO this limitation is a bug workaround
if (pub_key[0] != 0x04) {
int ret = schnorr_verify_digest(curve, pub_key, digest, signature);
if (ret == 0) {
// assuming that the fuzzer can't puzzle together validly signed inputs,
// exit with a forced crash if a successful verification is observed
exit(1);
}
}
return 0; return 0;
} }
int fuzz_schnorr_sign_digest(void) {
if (fuzzer_length <
1 + SHA256_DIGEST_LENGTH + SCHNORR_VERIFY_PRIVKEY_DATA_LENGTH) {
return 0;
}
const ecdsa_curve *curve;
uint8_t digest[SHA256_DIGEST_LENGTH] = {0};
uint8_t priv_key[SCHNORR_VERIFY_PRIVKEY_DATA_LENGTH] = {0};
uint8_t signature[SCHNORR_SIG_LENGTH] = {0};
int ret = 0;
uint8_t curve_decider = 0;
memcpy(&curve_decider, fuzzer_input(1), 1);
if ((curve_decider & 0x1) == 1) {
curve = &secp256k1;
} else {
curve = &nist256p1;
}
memcpy(&digest, fuzzer_input(SHA256_DIGEST_LENGTH), SHA256_DIGEST_LENGTH);
memcpy(&priv_key, fuzzer_input(SCHNORR_VERIFY_PRIVKEY_DATA_LENGTH),
SCHNORR_VERIFY_PRIVKEY_DATA_LENGTH);
ret = schnorr_sign_digest(curve, priv_key, digest, signature);
if (ret == 0) {
// signing was successful, check if the verification works
// compute matching pubkey
uint8_t pub_key[33] = {0};
ecdsa_get_public_key33(curve, priv_key, pub_key);
if (schnorr_verify_digest(curve, pub_key, digest, signature) != 0) {
// ignore known case
uint8_t pub_key_null[33] =
"\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
if (memcmp(&pub_key, &pub_key_null, 33) == 0) {
return 0;
}
// something is wrong, mark as crash
exit(1);
}
}
return 0;
}
int fuzz_chacha_drbg(void) {
#define CHACHA_DRBG_ENTROPY_LENGTH 32
#define CHACHA_DRBG_RESEED_LENGTH 32
#define CHACHA_DRBG_NONCE_LENGTH 16
#define CHACHA_DRBG_RESULT_LENGTH 16
if (fuzzer_length < CHACHA_DRBG_ENTROPY_LENGTH + CHACHA_DRBG_RESEED_LENGTH +
CHACHA_DRBG_NONCE_LENGTH) {
return 0;
}
uint8_t entropy[CHACHA_DRBG_ENTROPY_LENGTH] = {0};
uint8_t reseed[CHACHA_DRBG_RESEED_LENGTH] = {0};
uint8_t nonce_bytes[CHACHA_DRBG_NONCE_LENGTH] = {0};
uint8_t result[CHACHA_DRBG_RESULT_LENGTH] = {0};
CHACHA_DRBG_CTX ctx;
// TODO improvement idea: switch to variable input sizes
memcpy(&entropy, fuzzer_input(CHACHA_DRBG_ENTROPY_LENGTH),
CHACHA_DRBG_ENTROPY_LENGTH);
memcpy(&reseed, fuzzer_input(CHACHA_DRBG_RESEED_LENGTH),
CHACHA_DRBG_RESEED_LENGTH);
memcpy(&nonce_bytes, fuzzer_input(CHACHA_DRBG_NONCE_LENGTH),
CHACHA_DRBG_NONCE_LENGTH);
chacha_drbg_init(&ctx, entropy, sizeof(entropy), nonce_bytes,
sizeof(nonce_bytes));
chacha_drbg_reseed(&ctx, reseed, sizeof(reseed), NULL, 0);
chacha_drbg_generate(&ctx, result, sizeof(result));
return 0;
}
int fuzz_ed25519_sign_verify(void) {
ed25519_secret_key secret_key;
ed25519_signature signature;
ed25519_public_key public_key;
// length chosen arbitrarily
uint8_t message[32] = {0};
int ret = 0;
if (fuzzer_length <
sizeof(secret_key) + sizeof(signature) + sizeof(message)) {
return 0;
}
memcpy(&secret_key, fuzzer_input(sizeof(secret_key)), sizeof(secret_key));
memcpy(&signature, fuzzer_input(sizeof(signature)), sizeof(signature));
memcpy(&message, fuzzer_input(sizeof(message)), sizeof(message));
ed25519_publickey(secret_key, public_key);
// sign message, this should always succeed
ed25519_sign(message, sizeof(message), secret_key, public_key, signature);
// verify message, we expect this to work
ret = ed25519_sign_open(message, sizeof(message), public_key, signature);
// TODO are there other error values?
if (ret == -1) {
// mark as exception
exit(1);
}
return 0;
}
// TODO more XMR functions
// extern void xmr_hash_to_ec(ge25519 *P, const void *data, size_t length);
// this function directly calls
// hasher_Raw(HASHER_SHA3K, data, length, hash)
// is this interesting at all?
// extern void xmr_fast_hash(uint8_t *hash, const void *data, size_t length);
// TODO target idea: re-create openssl_check() from test_openssl.c
// to do differential fuzzing against OpenSSL functions
#define META_HEADER_SIZE 3 #define META_HEADER_SIZE 3
// main fuzzer entry // main fuzzer entry
@ -802,6 +1007,24 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
case 19: case 19:
fuzz_b58gph_encode_decode(); fuzz_b58gph_encode_decode();
break; break;
case 20:
fuzz_schnorr_verify_digest();
break;
case 21:
fuzz_schnorr_sign_digest();
break;
case 22:
fuzz_chacha_drbg();
break;
case 23:
#ifdef FUZZ_ALLOW_SLOW
// slow through expensive bignum operations
fuzz_ecdsa_sign_digest();
#endif
break;
case 24:
fuzz_ed25519_sign_verify();
break;
default: default:
// do nothing // do nothing

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