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Update X509 fuzzer to verify a chain #20243

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Update X509 fuzzer to verify a chain #20243

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12 changes: 10 additions & 2 deletions fuzz/build.info
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@
-}

IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
PROGRAMS{noinst}=asn1 asn1parse bignum bndiv client conf crl server smime x509
PROGRAMS{noinst}=asn1 asn1parse bignum bndiv client conf crl server smime
PROGRAMS{noinst}=punycode pem decoder
PROGRAMS{noinst}=v3name

Expand All @@ -25,6 +25,10 @@ IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
PROGRAMS{noinst}=ct
ENDIF

IF[{- !$disabled{"ocsp"} -}]
PROGRAMS{noinst}=x509
ENDIF

SOURCE[asn1]=asn1.c driver.c fuzz_rand.c
INCLUDE[asn1]=../include {- $ex_inc -}
DEPEND[asn1]=../libcrypto ../libssl {- $ex_lib -}
Expand Down Expand Up @@ -95,7 +99,7 @@ IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
ENDIF

IF[{- !$disabled{tests} -}]
PROGRAMS{noinst}=asn1-test asn1parse-test bignum-test bndiv-test client-test conf-test crl-test server-test smime-test x509-test
PROGRAMS{noinst}=asn1-test asn1parse-test bignum-test bndiv-test client-test conf-test crl-test server-test smime-test
PROGRAMS{noinst}=punycode-test pem-test decoder-test
PROGRAMS{noinst}=v3name-test

Expand All @@ -111,6 +115,10 @@ IF[{- !$disabled{tests} -}]
PROGRAMS{noinst}=ct-test
ENDIF

IF[{- !$disabled{"ocsp"} -}]
PROGRAMS{noinst}=x509-test
ENDIF

SOURCE[asn1-test]=asn1.c test-corpus.c fuzz_rand.c
INCLUDE[asn1-test]=../include
DEPEND[asn1-test]=../libcrypto ../libssl
Expand Down
123 changes: 112 additions & 11 deletions fuzz/x509.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
*/

#include <openssl/x509.h>
#include <openssl/ocsp.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/rand.h>
Expand All @@ -17,31 +18,131 @@
int FuzzerInitialize(int *argc, char ***argv)
{
FuzzerSetRand();
OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS
| OPENSSL_INIT_ADD_ALL_CIPHERS | OPENSSL_INIT_ADD_ALL_DIGESTS, NULL);
ERR_clear_error();
CRYPTO_free_ex_index(0, -1);
return 1;
}

static int cb(int ok, X509_STORE_CTX *ctx)
{
return 1;
}

int FuzzerTestOneInput(const uint8_t *buf, size_t len)
{
const unsigned char *p = buf;
size_t orig_len = len;
unsigned char *der = NULL;
BIO *bio = NULL;
X509 *x509_1 = NULL, *x509_2 = NULL;
X509_STORE *store = NULL;
X509_VERIFY_PARAM *param = NULL;
X509_STORE_CTX *ctx = NULL;
X509_CRL *crl = NULL;
STACK_OF(X509_CRL) *crls = NULL;
STACK_OF(X509) *certs = NULL;
OCSP_RESPONSE *resp = NULL;
OCSP_BASICRESP *bs = NULL;
OCSP_CERTID *id = NULL;

x509_1 = d2i_X509(NULL, &p, len);
if (x509_1 == NULL)
goto err;

bio = BIO_new(BIO_s_null());
if (bio == NULL)
goto err;

/* This will load and print the public key as well as extensions */
X509_print(bio, x509_1);
BIO_free(bio);

X509_issuer_and_serial_hash(x509_1);

i2d_X509(x509_1, &der);
OPENSSL_free(der);

len = orig_len - (p - buf);
x509_2 = d2i_X509(NULL, &p, len);
if (x509_2 == NULL)
goto err;

len = orig_len - (p - buf);
crl = d2i_X509_CRL(NULL, &p, len);
if (crl == NULL)
goto err;

len = orig_len - (p - buf);
resp = d2i_OCSP_RESPONSE(NULL, &p, len);

store = X509_STORE_new();
X509_STORE_add_cert(store, x509_2);

X509 *x509 = d2i_X509(NULL, &p, len);
if (x509 != NULL) {
BIO *bio = BIO_new(BIO_s_null());
/* This will load and print the public key as well as extensions */
X509_print(bio, x509);
BIO_free(bio);
param = X509_VERIFY_PARAM_new();
X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_NO_CHECK_TIME);
X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_X509_STRICT);
X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_PARTIAL_CHAIN);
X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_CRL_CHECK);

X509_issuer_and_serial_hash(x509);
X509_STORE_set1_param(store, param);

i2d_X509(x509, &der);
OPENSSL_free(der);
X509_STORE_set_verify_cb(store, cb);

X509_free(x509);
ctx = X509_STORE_CTX_new();
if (ctx == NULL)
goto err;

X509_STORE_CTX_init(ctx, store, x509_1, NULL);

if (crl != NULL) {
crls = sk_X509_CRL_new_null();
if (crls == NULL)
goto err;

sk_X509_CRL_push(crls, crl);
X509_STORE_CTX_set0_crls(ctx, crls);
}

X509_verify_cert(ctx);

if (resp != NULL)
bs = OCSP_response_get1_basic(resp);

if (bs != NULL) {
int status, reason;
ASN1_GENERALIZEDTIME *revtime, *thisupd, *nextupd;

certs = sk_X509_new_null();
if (certs == NULL)
goto err;

sk_X509_push(certs, x509_1);
sk_X509_push(certs, x509_2);

OCSP_basic_verify(bs, certs, store, OCSP_PARTIAL_CHAIN);

id = OCSP_cert_to_id(NULL, x509_1, x509_2);
if (id == NULL)
goto err;
OCSP_resp_find_status(bs, id, &status, &reason, &revtime, &thisupd,
&nextupd);
}

err:
X509_STORE_CTX_free(ctx);
X509_VERIFY_PARAM_free(param);
X509_STORE_free(store);
X509_free(x509_1);
X509_free(x509_2);
X509_CRL_free(crl);
OCSP_CERTID_free(id);
OCSP_BASICRESP_free(bs);
OCSP_RESPONSE_free(resp);
sk_X509_CRL_free(crls);
sk_X509_free(certs);

ERR_clear_error();
return 0;
}
Expand Down
3 changes: 3 additions & 0 deletions test/recipes/99-test_fuzz_x509.t
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,9 @@ use OpenSSL::Test::Utils;
my $fuzzer = "x509";
setup("test_fuzz_${fuzzer}");

plan skip_all => "This test requires ocsp support"
if disabled("ocsp");
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is there no way how the test could be compiled with #ifndef OPENSSL_NO_OCSP?

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In theory, yes. Since it's the last part of the file, it will currently then ignore part of the file it reads, and just not cover as much. If at some later point, the test is extended to read more data, the files will not have proper coverage.


plan tests => 2; # one more due to below require_ok(...)

require_ok(srctop_file('test','recipes','fuzz.pl'));
Expand Down