Commit graph

250 commits

Author SHA1 Message Date
Jaeden Amero 6f7703df3a rsa: Enable use of zero-length null output
Enable handling of zero-length null output in PKCS1 v1.5 decryption.
Prevent undefined behavior by avoiding a memcpy() to zero-length null
output buffers.
2019-02-11 03:39:51 -05:00
Gilles Peskine 004f87b98d RSA encryption: accept input=NULL if ilen=0
In mbedtls_rsa_rsaes_oaep_encrypt and
mbedtls_rsa_rsaes_pkcs1_v15_encrypt, if the input length is 0 (which
is unusual and mostly useless, but permitted) then it is fine for the
input pointer to be NULL. Don't return an error in this case.

When `input` is NULL, `memcpy( p, input, ilen )` has undefined behavior
even if `ilen` is zero. So skip the `memcpy` call in this case.
Likewise, in `mbedtls_rsa_rsaes_oaep_decrypt`, skip the `memcpy` call if
`*olen` is zero.
2019-02-11 03:39:21 -05:00
Jaeden Amero fb236739da Revert "Forbid passing NULL input buffers to RSA encryption routines"
Resolve incompatibilties in the RSA module where changes made for
parameter validation prevent Mbed Crypto from working. Mbed Crypto
depends on being able to pass zero-length buffers that are NULL to RSA
encryption functions.

This reverts commit 2f660d047d.
2019-02-08 08:43:31 -05:00
Andrzej Kurek c470b6b021 Merge development commit 8e76332 into development-psa
Additional changes to temporarily enable running tests:
ssl_srv.c and test_suite_ecdh use mbedtls_ecp_group_load instead of
mbedtls_ecdh_setup
test_suite_ctr_drbg uses mbedtls_ctr_drbg_update instead of 
mbedtls_ctr_drbg_update_ret
2019-01-31 08:20:20 -05:00
Simon Butcher cdd1a6c872 Merge remote-tracking branch 'restricted/pr/510' into development-restricted-proposed 2018-11-12 14:29:14 +00:00
Janos Follath b8fc1b02ee RSA: Use MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR 2018-10-09 16:33:27 +01:00
Jaeden Amero 3725bb2d6d rsa: pss: Enable use of big hashes with small keys
It should be valid to RSASSA-PSS sign a SHA-512 hash with a 1024-bit or
1032-bit RSA key, but with the salt size being always equal to the hash
size, this isn't possible: the key is too small.

To enable use of hashes that are relatively large compared to the key
size, allow reducing the salt size to no less than the hash size minus 2
bytes. We don't allow salt sizes smaller than the hash size minus 2
bytes because that too significantly changes the security guarantees the
library provides compared to the previous implementation which always
used a salt size equal to the hash size. The new calculated salt size
remains compliant with FIPS 186-4.

We also need to update the "hash too large" test, since we now reduce
the salt size when certain key sizes are used. We used to not support
1024-bit keys with SHA-512, but now we support this by reducing the salt
size to 62. Update the "hash too large" test to use a 1016-bit RSA key
with SHA-512, which still has too large of a hash because we will not
reduce the salt size further than 2 bytes shorter than the hash size.

The RSA private key used for the test was generated using "openssl
genrsa 1016" using OpenSSL 1.1.1-pre8.

    $ openssl genrsa 1016
    Generating RSA private key, 1016 bit long modulus (2 primes)
    ..............++++++
    ....++++++
    e is 65537 (0x010001)
    -----BEGIN RSA PRIVATE KEY-----
    MIICVwIBAAKBgACu54dKTbLxUQBEQF2ynxTfDze7z2H8vMmUo9McqvhYp0zI8qQK
    yanOeqmgaA9iz52NS4JxFFM/2/hvFvyd/ly/hX2GE1UZpGEf/FnLdHOGFhmnjj7D
    FHFegEz/gtbzLp9X3fOQVjYpiDvTT0Do20EyCbFRzul9gXpdZcfaVHNLAgMBAAEC
    gYAAiWht2ksmnP01B2nF8tGV1RQghhUL90Hd4D/AWFJdX1C4O1qc07jRBd1KLDH0
    fH19WocLCImeSZooGCZn+jveTuaEH14w6I0EfnpKDcpWVAoIP6I8eSdAttrnTyTn
    Y7VgPrcobyq4WkCVCD/jLUbn97CneF7EHNspXGMTvorMeQJADjy2hF5SginhnPsk
    YR5oWawc6n01mStuLnloI8Uq/6A0AOQoMPkGl/CESZw+NYfe/BnnSeckM917cMKL
    DIKAtwJADEj55Frjj9tKUUO+N9eaEM1PH5eC7yakhIpESccs/XEsaDUIGHNjhctK
    mrbbWu+OlsVRA5z8yJFYIa7gae1mDQJABjtQ8JOQreTDGkFbZR84MbgCWClCIq89
    5R3DFZUiAw4OdS1o4ja+Shc+8DFxkWDNm6+C63g/Amy5sVuWHX2p9QI/a69Cxmns
    TxHoXm1w9Azublk7N7DgB26yqxlTfWJo+ysOFmLEk47g0ekoCwLPxkwXlYIEoad2
    JqPh418DwYExAkACcqrd9+rfxtrbCbTXHEizW7aHR+fVOr9lpXXDEZTlDJ57sRkS
    SpjXbAmylqQuKLqH8h/72RbiP36kEm5ptmw2
    -----END RSA PRIVATE KEY-----
2018-09-27 18:23:08 +01:00
Jaeden Amero ff215726b4 rsa: pss: Use size_t when computing signatures
Functions like `mbedtls_md_get_size()` and `mgf_mask()` work with
`size_t`. Use local variables with `size_t` to match.
2018-09-11 14:36:03 +01:00
Jaeden Amero a331e0f0af Merge remote-tracking branch 'upstream-restricted/pr/421' into development-proposed 2018-05-04 14:39:24 +01:00
Andres Amaya Garcia 1f6301b3c8 Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
Andres Amaya Garcia e32df087fb Remove individual copies of mbedtls_zeroize()
This commit removes all the static occurrencies of the function
mbedtls_zeroize() in each of the individual .c modules. Instead the
function has been moved to utils.h that is included in each of the
modules.
2018-04-17 09:19:05 -05:00
Jethro Beekman c645bfe176 Generate RSA keys according to FIPS 186-4
The specification requires that P and Q are not too close. The specification
also requires that you generate a P and stick with it, generating new Qs until
you have found a pair that works. In practice, it turns out that sometimes a
particular P results in it being very unlikely a Q can be found matching all
the constraints. So we keep the original behavior where a new P and Q are
generated every round.
2018-04-11 08:38:37 -07:00
Jethro Beekman 97f95c9ef3 Avoid small private exponents during RSA key generation
Attacks against RSA exist for small D. [Wiener] established this for
D < N^0.25. [Boneh] suggests the bound should be N^0.5.

Multiple possible values of D might exist for the same set of E, P, Q. The
attack works when there exists any possible D that is small. To make sure that
the generated key is not susceptible to attack, we need to make sure we have
found the smallest possible D, and then check that D is big enough. The
Carmichael function λ of p*q is lcm(p-1, q-1), so we can apply Carmichael's
theorem to show that D = d mod λ(n) is the smallest.

[Wiener] Michael J. Wiener, "Cryptanalysis of Short RSA Secret Exponents"
[Boneh] Dan Boneh and Glenn Durfee, "Cryptanalysis of RSA with Private Key d Less than N^0.292"
2018-04-11 08:38:37 -07:00
Gilles Peskine 15ad579895 Merge tag 'mbedtls-2.8.0' into iotssl-1381-x509-verify-refactor-restricted
Conflict resolution:

* ChangeLog
* tests/data_files/Makefile: concurrent additions, order irrelevant
* tests/data_files/test-ca.opensslconf: concurrent additions, order irrelevant
* tests/scripts/all.sh: one comment change conflicted with a code
  addition. In addition some of the additions in the
  iotssl-1381-x509-verify-refactor-restricted branch need support for
  keep-going mode, this will be added in a subsequent commit.
2018-03-23 02:16:22 +01:00
Manuel Pégourié-Gonnard 1ba8a3fc55 Yet another dependency issue (PKCS1_V15)
Found by running:

CC=clang cmake -D CMAKE_BUILD_TYPE="Check"
tests/scripts/depend-pkalgs.pl

(Also tested with same command but CC=gcc)

Another PR will address improving all.sh and/or the depend-xxx.pl scripts
themselves to catch this kind of thing.
2018-03-13 13:42:38 +01:00
Hanno Becker a3389ebb09 Merge branch 'development-restricted' into iotssl-1306-rsa-is-vulnerable-to-bellcore-glitch-attack 2018-03-06 11:55:21 +00:00
Jaeden Amero 66954e1c1f Merge branch 'development' into development-restricted 2018-01-25 17:28:31 +00:00
Gilles Peskine 9e4f77c606 New MD API: rename functions from _ext to _ret
The _ext suffix suggests "new arguments", but the new functions have
the same arguments. Use _ret instead, to convey that the difference is
that the new functions return a value.
2018-01-22 11:54:42 +01:00
Gilles Peskine d91f2a26cb Merge branch 'development' into iotssl-1251-2.7
Conflict resolution:

* ChangeLog: put the new entries in their rightful place.
* library/x509write_crt.c: the change in development was whitespace
  only, so use the one from the iotssl-1251 feature branch.
2018-01-19 11:25:10 +01:00
Gilles Peskine d40c22ba20 Merge branch 'development' into development-restricted 2018-01-17 08:03:33 +01:00
Hanno Becker 87ae197f3e Add explicit uint truncation casts
This commit adds some explicit downcasts from `size_t` to `uint8_t` in
the RSASSA signature encoding function `rsa_rsassa_pkcs1_v15_encode`.
The truncation is safe as it has been checked beforehand that the
respective values are in the range of a `uint8_t`.
2018-01-15 15:27:56 +00:00
Hanno Becker 71b0060af7 Merge branch 'development' into iotssl-247 2018-01-15 11:31:34 +00:00
Jaeden Amero 31f3f0b87b Merge branch 'development' into development-restricted 2018-01-10 13:17:02 +00:00
Hanno Becker d4d60579e4 Address issues found by coverity
1) `mbedtls_rsa_import_raw` used an uninitialized return
   value when it was called without any input parameters.
   While not sensible, this is allowed and should be a
   succeeding no-op.

2) The MPI test for prime generation missed a return value
   check for a call to `mbedtls_mpi_shift_r`. This is neither
   critical nor new but should be fixed.

3) Both the RSA keygeneration example program and the
   RSA test suites contained code initializing an RSA context
   after a potentially failing call to CTR DRBG initialization,
   leaving the corresponding RSA context free call in the
   cleanup section of the respective function orphaned.
   While this defect existed before, Coverity picked up on
   it again because of newly introduced MPI's that were
   also wrongly initialized only after the call to CTR DRBG
   init. The commit fixes both the old and the new issue
   by moving the initializtion of both the RSA context and
   all MPI's prior to the first potentially failing call.
2018-01-10 07:30:47 +00:00
Jaeden Amero f342cb791b Merge branch 'development' into development-restricted 2018-01-09 13:16:37 +00:00
Hanno Becker 3a760a1857 Add size check for RSA modulus to mbedtls_rsa_complete
The function `mbedtls_rsa_complete` is supposed to guarantee that
RSA operations will complete without failure. In contrast, it does
not ensure consistency of parameters, which is the task of the
checking functions `rsa_check_pubkey` and `rsa_check_privkey`.

Previously, the maximum allowed size of the RSA modulus was checked
in `mbedtls_rsa_check_pubkey`. However, exceeding this size would lead
to failure of some RSA operations, hence this check belongs to
`mbedtls_rsa_complete` rather than `mbedtls_rsa_check_pubkey`.
This commit moves it accordingly.
2018-01-05 08:14:49 +00:00
Hanno Becker 63073aa3d3 Don't require P,Q in rsa_private in case of non-blinded non-CRT
For non-CRT, P and Q are only used for the purpose of blinding the exponent.
2017-11-27 15:33:18 +00:00
Gilles Peskine 91048a3aac RSA PSS: remove redundant check; changelog
Remove a check introduced in the previous buffer overflow fix with keys of
size 8N+1 which the subsequent fix for buffer start calculations made
redundant.

Added a changelog entry for the buffer start calculation fix.
2017-10-19 17:46:14 +02:00
Gilles Peskine b00b0da452 RSA PSS: fix first byte check for keys of size 8N+1
For a key of size 8N+1, check that the first byte after applying the
public key operation is 0 (it could have been 1 instead). The code was
incorrectly doing a no-op check instead, which led to invalid
signatures being accepted. Not a security flaw, since you would need the
private key to craft such an invalid signature, but a bug nonetheless.
2017-10-19 15:23:49 +02:00
Gilles Peskine 139108af94 RSA PSS: fix minimum length check for keys of size 8N+1
The check introduced by the previous security fix was off by one. It
fixed the buffer overflow but was not compliant with the definition of
PSS which technically led to accepting some invalid signatures (but
not signatures made without the private key).
2017-10-18 19:03:42 +02:00
Gilles Peskine 6a54b0240d RSA: Fix another buffer overflow in PSS signature verification
Fix buffer overflow in RSA-PSS signature verification when the masking
operation results in an all-zero buffer. This could happen at any key size.
2017-10-17 19:12:36 +02:00
Gilles Peskine 28a0c72795 RSA: Fix buffer overflow in PSS signature verification
Fix buffer overflow in RSA-PSS signature verification when the hash is
too large for the key size. Found by Seth Terashima, Qualcomm.

Added a non-regression test and a positive test with the smallest
permitted key size for a SHA-512 hash.
2017-10-17 19:01:38 +02:00
Hanno Becker f8c028a2fb Minor corrections 2017-10-17 09:20:57 +01:00
Hanno Becker c36aab69b5 Swap D,E parameters in mbedtls_rsa_deduce_primes 2017-10-17 09:15:06 +01:00
Hanno Becker ebd2c024dc Don't require P,Q in rsa_private if neither CRT nor blinding used 2017-10-12 10:57:39 +01:00
Hanno Becker b82a5b554c Fix typos and mixup related to RSA_NO_CRT 2017-10-11 19:12:00 +01:00
Hanno Becker a565f54c4c Introduce new files rsa_internal.[ch] for RSA helper functions
This commit splits off the RSA helper functions into separate headers and
compilation units to have a clearer separation of the public RSA interface,
intended to be used by end-users, and the helper functions which are publicly
provided only for the benefit of designers of alternative RSA implementations.
2017-10-11 11:00:19 +01:00
Hanno Becker 705fc68d72 Unify sanity checks for RSA private and public keys 2017-10-10 18:01:25 +01:00
Hanno Becker e867489ff6 Remove outdated comments from mbedtls_rsa_complete 2017-10-10 17:56:14 +01:00
Hanno Becker 7f25f850ac Adapt uses of mbedtls_rsa_complete to removed PRNG argument 2017-10-10 16:56:22 +01:00
Hanno Becker f9e184b9df Remove PRNG argument from mbedtls_rsa_complete 2017-10-10 16:55:41 +01:00
Hanno Becker 68b4d58bd8 Remove PRNG argument from mbedtls_rsa_deduce_moduli
It is not necessary to pass a CSPRNG to `mbedtls_rsa_deduce_moduli`, as there
exist well-working static strategies, and even if a PRNG is preferred, a
non-secure one would be sufficient.

Further, the implementation is changed to use a static strategy for the choice
of candidates which according to some benchmarks even performs better than the
previous one using random candidate choices.
2017-10-10 16:39:10 +01:00
Hanno Becker 0f65e0ca03 Rename rsa_deduce_moduli to rsa_deduce_primes 2017-10-03 14:40:44 +01:00
Hanno Becker 8ba6ce4f4f Rename rsa_deduce_private to rsa_deduce_private_exponent 2017-10-03 14:40:43 +01:00
Hanno Becker 45a0ef32d9 Correct memory leak in mbedtls_rsa_validate_crt 2017-10-03 14:32:56 +01:00
Hanno Becker e58d38c66f Minor improvements 2017-10-03 07:59:29 +01:00
Hanno Becker 2b2f898cbd Streamline code-path in rsa_rsassa_pkcs1_v15_encode 2017-10-03 07:59:29 +01:00
Hanno Becker 64a8c0acd6 Verify PKCS1 v1.5 signature without parsing
This commit modifies the PKCS1 v1.5 signature verification function `mbedtls_rsa_rsassa_pkcs1_v15_verify` to prepare the
expected PKCS1-v1.5-encoded hash using the function also used by the signing routine `mbedtls_rsa_rsassa_pkcs1_v15_sign`
and comparing it to the provided byte-string afterwards. This comes at the benefits of (1) avoiding any error-prone
parsing, (2) removing the dependency of the RSA module on the ASN.1 parsing module, and (3) reducing code size.
2017-10-03 07:58:00 +01:00
Hanno Becker fdf38030de Outsource code for generating PKCS1 v1.5 encoding
This commit moves the code preparing PKCS1 v1.5 encoded hashes from `mbedtls_rsa_rsassa_pkcs1_v15_sign` to a separate
non-public function `rsa_rsassa_pkcs1_v15_encode`. This code-path will then be re-used by the signature verification function
`mbetls_rsa_rsassa_pkcs1_v15_verify` in a later commit.
2017-10-03 07:58:00 +01:00
Hanno Becker 171a8f1c95 Move constant time memcmp for signature verification
This commit replaces the ad-hoc code for constant-time double-checking the PKCS1 v1.5 RSA signature by an invocation of
`mbedtls_safer_memcmp`.
2017-10-03 07:58:00 +01:00