Commit Graph

240 Commits

Author SHA1 Message Date
Darryl Green
0c6575a84d psa: Extend psa_generate_key to support persistent lifetimes 2018-11-20 15:40:32 +00:00
Darryl Green
d49a499d03 psa: Implement persistent keys
Allow use of persistent keys, including configuring them, importing and
exporting them, and destroying them.

When getting a slot using psa_get_key_slot, there are 3 scenarios that
can occur if the keys lifetime is persistent:

1. Key type is PSA_KEY_TYPE_NONE, no persistent storage entry:
   -  The key slot is treated as a standard empty key slot
2. Key type is PSA_KEY_TYPE_NONE, persistent storage entry exists:
   -  Attempt to load the key from persistent storage
3. Key type is not PSA_KEY_TYPE_NONE:
   -  As checking persistent storage on every use of the key could
      be expensive, the persistent key is assumed to be saved in
      persistent storage, the in-memory key is continued to be used.
2018-11-20 15:40:25 +00:00
Gilles Peskine
c7998b78b8 Factor common code into key_agreement_with_self 2018-11-14 21:17:16 +01:00
Gilles Peskine
3ec8ed8b51 Add multipart key agreement tests
Add test cases that do key agreement with raw selection in pieces, to
validate that selection works even when the application doesn't read
everything in one chunk.
2018-11-14 21:15:37 +01:00
Gilles Peskine
bf49197c9b key_agreement_capacity: test the actual capacity as well
After testing that the advertized capacity is what the test data says,
read that many bytes to test that this is also actual capacity.
2018-11-14 21:15:37 +01:00
Gilles Peskine
10df341436 Factor usage_to_exercise into its own function 2018-11-14 21:15:37 +01:00
Gilles Peskine
fc411f1ac1 Use ASSERT_ALLOC in key agreement tests 2018-11-14 21:15:37 +01:00
Gilles Peskine
1d7c082124 Fix a memory leak in a test 2018-11-14 21:15:37 +01:00
Gilles Peskine
5968559a9c Key agreement test functions 2018-11-14 21:15:37 +01:00
Gilles Peskine
01d718cee8 New API function: psa_key_agreement
Set up a generator from a key agreement.
2018-11-14 21:15:37 +01:00
Jaeden Amero
594a330eb7 psa: test: Fix truncation of message by snprintf
We had only allocated 40 bytes for printing into, but we wanted to print 46
bytes. Update the buffer to be 47 bytes, which is large enough to hold what
we want to print plus a terminating null byte.
2018-11-08 17:32:45 +00:00
Moran Peker
ce50007f90 Add tests of using cipher in bad state cases
- cipher setup after import key failure.
- cipher setup after set key policy but no key material
creation.
2018-11-07 16:20:07 +02:00
Moran Peker
3455009116 Add tests that check export failures after illegal behavior
- export a key after import key failure.
- export a key after the key was destroyed.
- export a key after set key policy but no key material
creation.
2018-11-07 16:19:34 +02:00
Moran Peker
28a38e6e38 Add tests that checks key management corner cases
- import a key into a non empty key slot.
- export a key from invalid slot number.
2018-11-07 16:18:24 +02:00
Jaeden Amero
fe9f771e88
Merge pull request #170 from ARMmbed/increase_psa_key_derivation_code_coverage
add tests that increase key derivation code coverage slightly
2018-11-06 09:17:19 +00:00
Jaeden Amero
40f1cb104f
Merge pull request #182 from ARMmbed/psa-asymmetric-format-raw_private_key
Asymmetric import/export format: raw private EC keys
2018-11-06 09:02:25 +00:00
itayzafrir
27e6945f43 Refactor and rename test hash_verify_bad_paths to hash_verify_bad_args
1. Updated test scenarios.
2. Renamed test and updated test description.
3. Some documentation updates.
4. Test dependency moved to .function file.
2018-11-05 18:36:05 +02:00
itayzafrir
b2dd5ed1e6 Rename test hash_finish_bad_paths to hash_finish_bad_args
Test dependency moved to .function file.
2018-11-05 18:36:05 +02:00
itayzafrir
f86548d674 Add test hash_bad_order
1. New test for testing bad order of hash function calls.
2. Removed test hash_update_bad_paths since it's test scenario
   was moved to the new test.
3. Moved some scenarios from test hash_verify_bad_paths to
   the new test.
2018-11-05 18:36:05 +02:00
itayzafrir
58028321b9 Split test hash_bad_paths into 3 different tests
1. Rename hash_bad_paths to hash_verify_bad_paths
2. Add test hash_update_bad_paths
3. Add test hash_finish_bad_paths

The different scenarios tested as part of hash_bad_paths are
moved to the relevant test.
2018-11-05 18:36:05 +02:00
itayzafrir
4271df932c Add scenario to test case hash_bad_paths
Tests where the verification hash digest is prefixed with
the expected digest but also has extra bytes appended at the end of it.
2018-11-05 18:36:05 +02:00
itayzafrir
69290f0e71 Update hash tests documentation 2018-11-05 18:36:05 +02:00
itayzafrir
02d6295e53 Move positive hash tests into a new test suite
Move hash_finish, hash_verify and hash_multi_part to a
new test suite test_suite_psa_crypto_hash.
2018-11-05 18:36:05 +02:00
itayzafrir
931fa6d663 Remove input parameter validations from hash test functions
Remove from hash_finish, hash_verify and hash_multi_part
2018-11-05 18:34:16 +02:00
itayzafrir
f5b3eb85b5 Add hash test for multipart operation
Test vectors migrated from mbedTLS
2018-11-05 18:34:16 +02:00
itayzafrir
ec93d30b45 Add hash bad paths test
Increase code coverage
2018-11-05 18:34:16 +02:00
Nir Sonnenschein
1caf6d24f2 Fix code style and clarify issue comment
* remove unneeded constants
* clarify comment reference to issue 183
* add additional reference comment
* fix brace spacing issues
2018-11-01 12:27:20 +02:00
Nir Sonnenschein
dd69d8b7ff Streamline test function API by removing parameter
streamline the API for the test test_derive_invalid_generator_state: by removing
the key_data parameter.
This parameter is not important for test flow and can be hard-coded.
2018-11-01 12:24:23 +02:00
Nir Sonnenschein
f8964b9580 updated test to work around https://github.com/ARMmbed/mbedtls-psa/issues/183
test should check the correct error values once this issue is fixed
2018-10-31 18:06:14 +02:00
Nir Sonnenschein
5078930459 fix whitespace issues 2018-10-31 12:16:38 +02:00
Nir Sonnenschein
4eda37bb9e streamline test function API by removing parameter
streamline the API for the test test_derive_invalid_generator_state by removing
the key type paramter (it is assumed to always be PSA_KEY_TYPE_DERIVE)
2018-10-31 12:15:58 +02:00
Gilles Peskine
5b802a366a Private EC key format: remove ASN.1-based sanity checks
In preparation for the import/export format change for private
elliptic curve keys from RFC 5915 to the raw secret value,
remove ASN.1-based sanity checks. For the raw secret value, most byte
strings of the correct length are valid (the details depend on the
curve), so as a sanity check, just check the length.
2018-10-29 19:21:41 +01:00
Gilles Peskine
d8b7d4f87e In export tests, also test PSA_KEY_EXPORT_MAX_SIZE
When testing psa_export_key or psa_export_public_key, test that the
expected result fits in the size given by PSA_KEY_EXPORT_MAX_SIZE.
2018-10-29 15:18:41 +01:00
Gilles Peskine
49c2591916 Improve export_public_key test function
In the test function for export_public_key, don't just check the
length of the result. Compare the actual result to the expected
result.

Take an extra argument that allows using an export buffer that's
larger or smaller than needed. Zero is the size given by
PSA_KEY_EXPORT_MAX_SIZE.

Don't check the output of psa_get_key_information. That's useful in
import_export because it tests both import and export, but not in
import_export_public_key whose goal is only to test public key export.

This commit adjusts the existing test data but does not add new test
cases.
2018-10-29 15:15:31 +01:00
Nir Sonnenschein
b46e7ca16b add additional generator tests and generalize key derivation test
Key derivation test now uses an indirect way to test generator validity
as the direct way previously used isn't compatible with the PSA IPC
implementation. Additional bad path test for the generator added
to check basic bad-path scenarios.
2018-10-25 14:46:09 +03:00
Nir Sonnenschein
e5204c94a1 add tests that increase key derivation code coverage slightly
added tests that increase code coverage for the key derivation functions slightly
by reaching error cases not covered before.
2018-10-22 17:24:55 +03:00
Gilles Peskine
e1f2d7d1ac Document and check the consistency of truncated MAC encodings
Add comments noting that the maximum length of a MAC must fit in
PSA_ALG_MAC_TRUNCATION_MASK. Add a unit test that verifies that the
maximum MAC size fits.
2018-10-17 13:54:47 +02:00
Gilles Peskine
7da96b0d91 Reorder parameters of AEAD unit tests to be more logical
Pass the nonce first, then the AD, then the input. This is the order
in which the data is processed and it's the order of the parameters to
the API functions.
2018-10-08 14:42:11 +02:00
Gilles Peskine
a7aa442c7c Add tests for mac_sign 2018-10-08 14:42:11 +02:00
Gilles Peskine
f7ab5ad13a Skip calling memset when the size is 0
memset(NULL, c, 0) has undefined behavior, so don't do it. clang-asan
complains.
2018-09-27 13:57:45 +02:00
Gilles Peskine
bd7dea9e64 Use ASSERT_COMPARE instead of memcmp in PSA tests
This commit fixes some missing size comparison. In
aead_encrypt_decrypt, aead_encrypt and aead_decrypt, the test code
would not have noticed if the library function had reported an output
length that was not the expected length.
2018-09-27 13:57:19 +02:00
Gilles Peskine
8cebbba7e6 Use ASSERT_ALLOC instead of mbedtls_calloc in PSA tests
This commit resolves a bug whereby some test cases failed on systems
where mbedtls_calloc returns NULL when the size of 0, because the test
case asserted `pointer != NULL` regardless of the size.
2018-09-27 13:54:18 +02:00
Gilles Peskine
acec7b6fa1 exercise_export_key: fix public key case
Public keys are always exportable, even if their usage doesn't include
the EXPORT flag.
2018-09-17 14:33:43 +02:00
itayzafrir
90d8c7a728 Ensure the module is initialized in key based functions 2018-09-16 12:15:47 +03:00
itayzafrir
0adf0fc31c Ensure the module is initialized in psa_generate_random 2018-09-16 12:15:46 +03:00
Jaeden Amero
c0454a7369 Merge pull request #135 from ARMmbed/export_sanity_tests
Document asymmetric key export formats
2018-09-14 10:02:30 +01:00
Gilles Peskine
dea46cf8f1 Clarify comment in test
In RSAPrivateKey, Version is an INTEGER. The version must be 0.
2018-09-14 10:02:29 +01:00
Gilles Peskine
c6290c043e Minor documentation improvements 2018-09-14 10:02:29 +01:00
Gilles Peskine
b67f308c4f Fix re-import size in import_export test with non-canonical input 2018-09-14 10:02:29 +01:00
Gilles Peskine
ae3d2a2c26 Avoid non-standard C constructs
Don't rely on static initialization of a flexible array member, that's
a GNU extension. The previous code also triggered a Clang warning
"suggest braces around initialization of subobject" (-Wmissing-braces)
for `struct {char a[]} = {"foo"}`.
2018-09-14 10:02:29 +01:00
Gilles Peskine
8f609239d5 Do export sanity checks in import_export as well
This is not useful to validate the implementation when importing
canonical input, which is the case for most import/export test cases,
but it helps validate the sanity checks themselves.
2018-09-14 10:02:29 +01:00
Gilles Peskine
dd2f95b855 Improve and augment export sanity checks
Implement sanity checks of exported public keys, using ASN.1 parsing.
Rewrite the sanity checks of key pairs using ASN.1 parsing, so as to
check more things with simpler code.
2018-09-14 10:02:29 +01:00
Jaeden Amero
df3b74f168 Merge pull request #125 from ARMmbed/key_slot_index-fix
Fix off-by-one errors in key slot index limits
2018-09-14 10:02:29 +01:00
Gilles Peskine
d14664a79b Move export key sanity check from generate to exercise
Move the code to perform sanity checks on the exported key from
generate_key to exercise_key. This way the sanity checks can be
performed after importing or deriving a key as well.

In addition to checking the exported key if its usage allows it, check
the exported public key if the key is asymmetric.
2018-09-14 10:02:29 +01:00
Gilles Peskine
9a05634558 psa_crypto_free: destroy the last slot
The last slot in the array was not freed due to an off-by-one error.

Amend the fill_slots test to serve as a non-regression test for this
issue: without this bug fix, it would cause a memory leak.
2018-09-14 10:02:29 +01:00
Gilles Peskine
996deb18cc Fix buffer overflow in the slot array
Slots are numbered from 1, but the slot array is a C array so it's
numbered from 0.

Add a non-regression test.
2018-09-14 10:02:29 +01:00
Gilles Peskine
c32f0304db Fix bad key type constant that worked by accident 2018-09-14 10:02:29 +01:00
Darryl Green
9c862253cc Add handling for zero-length buffers in tests
The buffer can be NULL if the length is zero, so we only check it's not NULL if the length is nonzero
2018-09-14 10:02:28 +01:00
Jaeden Amero
22e232ec04 Merge pull request #109 from ARMmbed/IAR-feature-psa
Ensure release testing job passes IAR tests
2018-09-12 16:50:07 +03:00
Gilles Peskine
9f900a8b25 Merge pull request #105 from ARMmbed/psa-derive_hkdf
PSA key derivation: simple-ish interface, HKDF
2018-09-12 16:50:07 +03:00
Gilles Peskine
d54931c7c4 HKDF: be more robust if we reach the maximum ouptut length
In psa_generator_hkdf_read, return BAD_STATE if we're trying to
construct more output than the algorithm allows. This can't happen
through the API due to the capacity limit, but it could potentially
happen in an internal call.

Also add a test case that verifies that we can set up HKDF with its
maximum capacity and read up to the maximum capacity.
2018-09-12 16:50:05 +03:00
Gilles Peskine
0386fbaa70 Key derivation: test deriving a key from the KDF output 2018-09-12 16:48:24 +03:00
Gilles Peskine
96ee5c70b9 HKDF: positive tests 2018-09-12 16:45:45 +03:00
Gilles Peskine
ea0fb4975c Add framework for simple key derivation
New key type PSA_KEY_TYPE_DERIVE. New usage flag PSA_KEY_USAGE_DERIVE.
New function psa_key_derivation.

No key derivation algorithm is implemented yet. The code may not
compile with -Wunused.

Write some unit test code for psa_key_derivation. Most of it cannot be
used yet due to the lack of a key derivation algorithm.
2018-09-12 16:44:04 +03:00
Moran Peker
cb088e7059 Replace ssize_t by ptrdiff_t
ssize_t is a POSIX thing, not standard C
2018-09-12 16:41:12 +03:00
Gilles Peskine
55c94dd500 Asymmetric encrypt/decrypt tests: check output length
In asymmetric_encrypt_decrypt, use the buffer size advertized by the
library for the ciphertext, and the length of the plaintext for the
re-decrypted output.

Test the output length if known. Require it to be 0 on error for
encrypt/decrypt functions. If the output length is unknown, test at
least that it's within the buffer limits.
2018-09-12 16:41:12 +03:00
Gilles Peskine
6842812188 Asymmetric encryption tests: allow label argument
Add a label argument to all asymmetric encryption test functions
(currently empty in all tests, but that will change soon).

In asymmetric_encrypt and asymmetric_decrypt, with an empty label,
test with both a null pointer and a non-null pointer.
2018-09-12 16:41:12 +03:00
Gilles Peskine
ef0cb40736 Fix bug in exercise_mac_key that almost always broke the SIGN case
That case isn't used in the test suite yet.
2018-09-12 16:41:12 +03:00
Gilles Peskine
f969b3ac74 Change a generate_key test to exercise with PSS
This required tweaking exercise_signature_key to use a payload size
for the signature based on the algorithm, since our implementation of
PSS requires that the input size matches the hash size. This would
also be the case for PKCS#1 v1.5 with a specified hash.
2018-09-12 16:41:11 +03:00
Gilles Peskine
66763a008a asymmetric_decrypt test: remove redundant argument
The expected output size is the size of the expected output, it
doesn't need to be passed separately.
2018-09-12 16:41:11 +03:00
Gilles Peskine
fe11951c16 Rename psa cipher functions to psa_cipher_xxx
Make function names for multipart operations more consistent (cipher
edition).

Rename symmetric cipher multipart operation functions so that they all
start with psa_cipher_:

* psa_encrypt_setup -> psa_cipher_encrypt_setup
* psa_decrypt_setup -> psa_cipher_decrypt_setup
* psa_encrypt_set_iv -> psa_cipher_set_iv
* psa_encrypt_generate_iv -> psa_cipher_generate_iv
2018-09-12 16:41:11 +03:00
Gilles Peskine
656896e4c3 Add positive asymmetric encryption tests
Revise the test function asymmetric_encrypt_fail into
asymmetric_encrypt and use it for positive tests as well. Get the
expected output length from PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE. Check
the actual output length against test data.

Add positive test cases for encryption: one with an RSA public
key (this is the only test for encryption with a public key rather
than a key pair) and one with a key pair.
2018-09-12 16:41:11 +03:00
Gilles Peskine
89167cb597 Split psa_mac_setup -> psa_mac_{sign,verify}_setup
Make function names for multipart operations more consistent (MAC
setup edition).

Split psa_mac_setup into two functions psa_mac_sign_setup and
psa_mac_verify_setup. These functions behave identically except that
they require different usage flags on the key. The goal of the split
is to enforce the key policy during setup rather than at the end of
the operation (which was a bit of a hack).

In psa_mac_sign_finish and psa_mac_verify_finish, if the operation is
of the wrong type, abort the operation before returning BAD_STATE.
2018-09-12 16:41:11 +03:00
Gilles Peskine
acd4be36fa Rename psa_mac_{finish,verify} -> psa_mac_{sign,verify}_finish
Make function names for multipart operations more consistent (MAC
finish edition).
2018-09-12 16:41:11 +03:00
Gilles Peskine
da8191d1cd Rename psa_hash_start -> psa_hash_setup
Make function names for multipart operations more consistent (hash
edition).
2018-09-12 16:41:11 +03:00
Gilles Peskine
2a91d612f5 Merge remote-tracking branch 'psa/pr/94' into feature-psa 2018-09-12 16:41:11 +03:00
Gilles Peskine
3ff2162d14 Remove salt from asymmetric_{sign,verify}
No common signature algorithm uses a salt (RSA-PKCS#1v1.5, RSA-PSS,
DSA, ECDSA, EdDSA). We don't even take an IV for MAC whereas MAC
algorithms with IV are uncommon but heard of. So remove the salt
parameter from psa_asymmetric_sign and psa_asymmetric_verify.
2018-09-12 16:41:11 +03:00
Gilles Peskine
9911b02f32 Add sign_verify test and use it to smoke-test PSS 2018-09-12 16:41:11 +03:00
Gilles Peskine
76f5c7b6a8 Tests: cover policy checks for all operations
Add tests of key policy checks for MAC, cipher, AEAD, asymmetric
encryption and asymmetric signature. For each category, test
with/without the requisite usage flag in each direction, and test
algorithm mismatch.
2018-09-12 16:41:11 +03:00
Janos Follath
25c4fa8fb0 Fix copy paste error PSA test suite
At this point it fixes memory leaks as well. These memory leaks are the
fault of the 'psa_cipher_finish()' function and the calls fixed in this
commit (among with many others in the test suite) will become obsolete
after fixing 'psa_cipher_finish()'.
2018-09-12 16:41:11 +03:00
mohammad1603
2701005b46 Modifications for psa-crypto in order to integrate with SPM
Add required includes in tests and psa_crypto.c file in order to be able to compilef for the SPM solution.
Some functions needed to be deprecated from psa_crypto.c since they already implemented in the SPM.
2018-09-12 16:41:11 +03:00
mohammad1603
3d91abefac Use PSA_BLOCK_CIPHER_BLOCK_SIZE() macro to get the cipher block size
Use PSA_BLOCK_CIPHER_BLOCK_SIZE() macro to get the cipher block size instead of accessing the operation struct
additionally, for SPM case, the 'block_size' member is not a member in the operation struct
2018-09-12 16:41:11 +03:00
Moran Peker
ed34695e08 Fix tests in test_suite_psa_crypto to set policy usage 2018-09-12 16:41:11 +03:00
Gilles Peskine
02b750781f Factor duplicated code into exercise_key
Also fail the test if the test code lacks a way to exercise the key.
2018-09-12 16:41:11 +03:00
Gilles Peskine
480416af9d Fix argument validation in asn1_write_10x
1 << bits doesn't work when bits is too large. Found by ASan.
2018-09-12 16:41:11 +03:00
Gilles Peskine
0b352bcf95 Test that creating RSA keys larger than the maximum fails
Test keypair import, public key import and key generation.
2018-09-12 16:41:11 +03:00
Gilles Peskine
69c1267fd2 Use PSA_xxx_MAX_SIZE for hash/MAC/signature size in tests
In tests that had a hard-coded buffer size, use PSA_MAC_MAX_SIZE or
PSA_ASYMMETRIC_SIGNATURE_MAX_SIZE as appropriate.

Test that PSA_xxx_MAX_SIZE is larger than the size used in tests that
expect a specific output.
2018-09-12 16:41:11 +03:00
Gilles Peskine
860ce9d9e5 Document what the signature tests are doing a bit better
Add a check that the purported output length is less than the buffer
size in sign_fail.
2018-09-12 16:41:11 +03:00
Gilles Peskine
d35a1cce7f Correct the documentation of mem_is_zero 2018-09-12 16:41:11 +03:00
Gilles Peskine
ca45c35e65 Fix exercise_signature_key for ECDSA
mbedtls_ecdsa_verify fails when the input is all-bits-zero (mbedtls
issue #1792). Use a different input.
2018-09-12 16:41:11 +03:00
Gilles Peskine
a680c7a9fc Add import-and-exercise tests for some signature algorithms 2018-09-12 16:41:10 +03:00
Mohammad AboMokh
65fa0b8433 fix if condition to validate encrypt key usage 2018-09-12 16:24:50 +03:00
Mohammad AboMokh
adb9b2372b fix PSA_BLOCK_CIPHER_BLOCK_SIZE() argument in test code 2018-09-12 16:24:50 +03:00
Jaeden Amero
2a671e9031 psa: export_public_key: Check for all zero on error 2018-09-12 16:24:50 +03:00
Jaeden Amero
f24c7f80a0 psa_export_key: Always set a valid data length
Make psa_export_key() always set a valid data_length when exporting,
even when there are errors. This makes the API easier to use for buggy
programs (like our test code).

Our test code previously used exported_length uninitialized when
checking to see that the buffer returned was all zero in import_export()
in the case where an error was returned from psa_export_key().
Initialize exported_length to an invalid length, and check that it gets
set properly by psa_export_key(), to avoid this using export_length
uninitialized. Note that the mem_is_zero() check is still valid when
psa_export_key() returns an error, e.g. where exported_length is 0, as
we want to check that nothing was written to the buffer on error.

Out test code also previous passed NULL for the data_length parameter of
psa_export_key() when it expected a failure (in key_policy_fail()).
However, data_length is not allowed to be NULL, especially now that we
write to data_length from psa_export_key() even when there are errors.
Update the test code to not pass in a NULL data_length.
2018-09-12 16:24:50 +03:00
Gilles Peskine
48c0ea14c6 Remove PSA_KEY_TYPE_IS_RAW_BYTES from crypto.h
It isn't used to define other macros and it doesn't seem that useful
for users. Remove it, we can reintroduce it if needed.

Define a similar function key_type_is_raw_bytes in the implementation
with a clear semantics: it's a key that's represented as a struct
raw_data.
2018-09-12 16:24:50 +03:00
Gilles Peskine
a50d7396f3 test of generate_random: focus on testing the output buffer size
In the test generate_random, focus on testing that psa_generate_random
is writing all the bytes of the output buffer and no more. Add a check
that it is writing to each byte of the output buffer. Do not try to
look for repeating output as the structure of a unit test isn't likely
to catch that sort of problem anyway.
2018-09-12 16:24:50 +03:00
Gilles Peskine
9ad29e2bee Add what little was missing to fully support DES
Also add what was missing in the test suite to support block ciphers
with a block size that isn't 16.

Fix some buggy test data that passed only due to problems with DES
support in the product.
2018-09-12 16:24:50 +03:00
Gilles Peskine
b866e2b4d2 Get rid of some casts in test_suite_psa_crypto
Use more auxiliary variables to unmarshall int values.
2018-09-12 16:24:49 +03:00
Gilles Peskine
3f669c374a Simplify mem_is_nonzero to mem_is_zero
This also fixes a bug that the value that mem_is_nonzero tried to
return could overflow int.
2018-09-12 16:23:54 +03:00