- Sep 09, 2019
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Billy Brumley authored
Reviewed-by:
Matt Caswell <matt@openssl.org> Reviewed-by:
Nicola Tuveri <nic.tuv@gmail.com> (Merged from https://github.com/openssl/openssl/pull/9821) (cherry picked from commit 1d3cd983f56e0a580ee4216692ee3c9c7bf14de9)
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Bernd Edlinger authored
crypto/rand/rand_win.c(70) : error C2065: 'BCRYPT_USE_SYSTEM_PREFERRED_RNG' : undeclared identifier Reviewed-by:
Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/9827) (cherry picked from commit d3a1128bc25ec8bf835c81821e1be68fba39ab4b)
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Bernd Edlinger authored
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Paul Dale <paul.dale@oracle.com> (Merged from https://github.com/openssl/openssl/pull/9796) (cherry picked from commit fa01370f7dc8f0a379483bbe74de11225857e5fe)
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Bernd Edlinger authored
so results were undefined. Reviewed-by:
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Bernd Edlinger authored
For for G=2 and 5 DH_generate_parameters will continue to generate the order 2q subgroup for compatibility with previous versions. For G=3 DH_generate_parameters generates an order q subgroup, but it will not pass the check in DH_check with previous OpenSSL versions. Reviewed-by:
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Nicola Tuveri authored
(cherry picked from commit 65936a56461fe09e8c81bca45122af5adcfabb00) Reviewed-by:
Bernd Edlinger <bernd.edlinger@hotmail.de> (Merged from https://github.com/openssl/openssl/pull/9813)
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Nicola Tuveri authored
Description ----------- Upon `EC_GROUP_new_from_ecparameters()` check if the parameters match any of the built-in curves. If that is the case, return a new `EC_GROUP_new_by_curve_name()` object instead of the explicit parameters `EC_GROUP`. This affects all users of `EC_GROUP_new_from_ecparameters()`: - direct calls to `EC_GROUP_new_from_ecparameters()` - direct calls to `EC_GROUP_new_from_ecpkparameters()` with an explicit parameters argument - ASN.1 parsing of explicit parameters keys (as it eventually ends up calling `EC_GROUP_new_from_ecpkparameters()`) A parsed explicit parameter key will still be marked with the `OPENSSL_EC_EXPLICIT_CURVE` ASN.1 flag on load, so, unless programmatically forced otherwise, if the key is eventually serialized the output will still be encoded with explicit parameters, even if internally it is treated as a named curve `EC_GROUP`. Before this change, creating any `EC_GROUP` object using `EC_GROUP_new_from_ecparameters()`, yielded an object associated with the default generic `EC_METHOD`, but this was never guaranteed in the documentation. After this commit, users of the library that intentionally want to create an `EC_GROUP` object using a specific `EC_METHOD` can still explicitly call `EC_GROUP_new(foo_method)` and then manually set the curve parameters using `EC_GROUP_set_*()`. Motivation ---------- This has obvious performance benefits for the built-in curves with specialized `EC_METHOD`s and subtle but important security benefits: - the specialized methods have better security hardening than the generic implementations - optional fields in the parameter encoding, like the `cofactor`, cannot be leveraged by an attacker to force execution of the less secure code-paths for single point scalar multiplication - in general, this leads to reducing the attack surface Check the manuscript at https://arxiv.org/abs/1909.01785 for an in depth analysis of the issues related to this commit. It should be noted that `libssl` does not allow to negotiate explicit parameters (as per RFC 8422), so it is not directly affected by the consequences of using explicit parameters that this commit fixes. On the other hand, we detected external applications and users in the wild that use explicit parameters by default (and sometimes using 0 as the cofactor value, which is technically not a valid value per the specification, but is tolerated by parsers for wider compatibility given that the field is optional). These external users of `libcrypto` are exposed to these vulnerabilities and their security will benefit from this commit. Related commits --------------- While this commit is beneficial for users using built-in curves and explicit parameters encoding for serialized keys, commit b783beeadf6b80bc431e6f3230b5d5585c87ef87 (and its equivalents for the 1.0.2, 1.1.0 and 1.1.1 stable branches) fixes the consequences of the invalid cofactor values more in general also for other curves (CVE-2019-1547). The following list covers commits in `master` that are related to the vulnerabilities presented in the manuscript motivating this commit: - d2baf88c43 [crypto/rsa] Set the constant-time flag in multi-prime RSA too - 311e903d84 [crypto/asn1] Fix multiple SCA vulnerabilities during RSA key validation. - b783beeadf [crypto/ec] for ECC parameters with NULL or zero cofactor, compute it - 724339ff44 Fix SCA vulnerability when using PVK and MSBLOB key formats Note that the PRs that contributed the listed commits also include other commits providing related testing and documentation, in addition to links to PRs and commits backporting the fixes to the 1.0.2, 1.1.0 and 1.1.1 branches. This commit includes a partial backport of https://github.com/openssl/openssl/pull/8555 (commit 8402cd5f75f8c2f60d8bd39775b24b03dd8b3b38) for which the main author is Shane Lontis. Responsible Disclosure ---------------------- This and the other issues presented in https://arxiv.org/abs/1909.01785 were reported by Cesar Pereida García, Sohaib ul Hassan, Nicola Tuveri, Iaroslav Gridin, Alejandro Cabrera Aldaya and Billy Bob Brumley from the NISEC group at Tampere University, FINLAND. The OpenSSL Security Team evaluated the security risk for this vulnerability as low, and encouraged to propose fixes using public Pull Requests. _______________________________________________________________________________ Co-authored-by:
Shane Lontis <shane.lontis@oracle.com> (Backport from https://github.com/openssl/openssl/pull/9808 ) Reviewed-by:
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- Sep 08, 2019
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Dr. Matthias St. Pierre authored
While gcc ignores unknown options of the type '-Wno-xxx', clang by default issues a warning [-Wunknown-warning-option] (see [3]), which together with '-Werror' causes the build to fail. This turned out to be a problem on the 1.0.2 stable branch in the case of the '-Wextended-offsetof' option, which was removed in version 6.0.0, but needs to be kept here in order to support older clang versions, too (see #9446). Incidentally, master and 1.1.1 branch already contained the -Wno-unknown-warning-option option. Due to its special role and its importance, this commit adds an explaining commit message and moves the option to the front. [extended tests] Reviewed-by:
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- Sep 07, 2019
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Nicola Tuveri authored
This amends the entry added in a6186f39 with the relevant CVE. Reviewed-by:
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Bernd Edlinger authored
This leaves VPAES and AESNI support. The VPAES performance is comparable but BSAES is not completely constant time. There are table lookups using secret key data in AES_set_encrypt/decrypt_key and in ctr mode short data uses the non-constant time AES_encrypt function instead of bit-slicing. Furthermore the AES_ASM is by far outperformed by recent GCC versions. Since BSAES calls back to AES_ASM for short data blocks the performance on those is also worse than the pure software implementaion. Fixes: #9640 Reviewed-by:
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Billy Brumley authored
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Tomas Mraz <tmraz@fedoraproject.org> Reviewed-by:
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Billy Brumley authored
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Billy Brumley authored
The cofactor argument to EC_GROUP_set_generator is optional, and SCA mitigations for ECC currently use it. So the library currently falls back to very old SCA-vulnerable code if the cofactor is not present. This PR allows EC_GROUP_set_generator to compute the cofactor for all curves of cryptographic interest. Steering scalar multiplication to more SCA-robust code. This issue affects persisted private keys in explicit parameter form, where the (optional) cofactor field is zero or absent. It also affects curves not built-in to the library, but constructed programatically with explicit parameters, then calling EC_GROUP_set_generator with a nonsensical value (NULL, zero). The very old scalar multiplication code is known to be vulnerable to local uarch attacks, outside of the OpenSSL threat model. New results suggest the code path is also vulnerable to traditional wall clock timing attacks. CVE-2019-1547 Reviewed-by:
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- Sep 06, 2019
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Nicola Tuveri authored
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Nicola Tuveri authored
Replace flip_endian() by using the little endian specific BN_bn2lebinpad() and BN_lebin2bn(). Reviewed-by:
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Nicola Tuveri authored
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Nicola Tuveri authored
This issue was partially addressed by commit 972c87df , which hardened its callee BN_num_bits_word() to avoid leaking the most-significant word of its argument via branching and memory access pattern. The commit message also reported: > There are a few places where BN_num_bits is called on an input where > the bit length is also secret. This does *not* fully resolve those > cases as we still only look at the top word. BN_num_bits() is called directly or indirectly (e.g., through BN_num_bytes() or BN_bn2binpad() ) in various parts of the `crypto/ec` code, notably in all the currently supported implementations of scalar multiplication (in the generic path through ec_scalar_mul_ladder() as well as in dedicated methods like ecp_nistp{224,256,521}.c and ecp_nistz256.c). Under the right conditions, a motivated SCA attacker could retrieve the secret bitlength of a secret nonce through this vulnerability, potentially leading, ultimately, to recover a long-term secret key. With this commit, exclusively for BIGNUMs that are flagged with BN_FLG_CONSTTIME, instead of accessing only bn->top, all the limbs of the BIGNUM are accessed up to bn->dmax and bitwise masking is used to avoid branching. Memory access pattern still leaks bn->dmax, the size of the lazily allocated buffer for representing the BIGNUM, which is inevitable with the current BIGNUM architecture: reading past bn->dmax would be an out-of-bound read. As such, it's the caller responsibility to ensure that bn->dmax does not leak secret information, by explicitly expanding the internal BIGNUM buffer to a public value sufficient to avoid any lazy reallocation while manipulating it: this should be already done at the top level alongside setting the BN_FLG_CONSTTIME. Thanks to David Schrammel and Samuel Weiser for reporting this issue through responsible disclosure. Reviewed-by:
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Nicola Tuveri authored
BN_bn2bin() is not constant-time and leaks the number of bits in the processed BIGNUM. The specialized methods in ecp_nistp224.c, ecp_nistp256.c and ecp_nistp521.c internally used BN_bn2bin() to convert scalars into the internal fixed length representation. This can leak during ECDSA/ECDH key generation or handling the nonce while generating an ECDSA signature, when using these implementations. The amount and risk of leaked information useful for a SCA attack varies for each of the three curves, as it depends mainly on the ratio between the bitlength of the curve subgroup order (governing the size of the secret nonce/key) and the limb size for the internal BIGNUM representation (which depends on the compilation target architecture). To fix this, we replace BN_bn2bin() with BN_bn2binpad(), bounding the output length to the width of the internal representation buffer: this length is public. Internally the final implementation of both BN_bn2binpad() and BN_bn2bin() already has masking in place to avoid leaking bn->top through memory access patterns. Memory access pattern still leaks bn->dmax, the size of the lazily allocated buffer for representing the BIGNUM, which is inevitable with the current BIGNUM architecture: reading past bn->dmax would be an out-of-bound read. As such, it's the caller responsibility to ensure that bn->dmax does not leak secret information, by explicitly expanding the internal BIGNUM buffer to a public value sufficient to avoid any lazy reallocation while manipulating it: this is already done at the top level alongside setting the BN_FLG_CONSTTIME. Finally, the internal implementation of BN_bn2binpad() indirectly calls BN_num_bits() via BN_num_bytes(): the current implementation of BN_num_bits() can leak information to a SCA attacker, and is addressed in the next commit. Thanks to David Schrammel and Samuel Weiser for reporting this issue through responsible disclosure. Reviewed-by:
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Bernd Edlinger authored
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Cesar Pereida Garcia authored
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Cesar Pereida Garcia authored
This commit addresses multiple side-channel vulnerabilities present during RSA key validation. Private key parameters are re-computed using variable-time functions. This issue was discovered and reported by the NISEC group at TAU Finland. Reviewed-by:
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Matt Caswell authored
We also use this in test_tls13messages to check that the extensions we expect to see in a CertificateRequest are there. Reviewed-by:
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Matt Caswell authored
If a TLSv1.3 server configured to respond to the status_request extension also attempted to send a CertificateRequest then it was incorrectly inserting a non zero length status_request extension into that message. The TLSv1.3 RFC does allow that extension in that message but it must always be zero length. In fact we should not be sending the extension at all in that message because we don't support it. Fixes #9767 Reviewed-by:
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- Sep 05, 2019
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Bernd Edlinger authored
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Bernd Edlinger authored
Fixes #9757 Reviewed-by:
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Bernd Edlinger authored
This will never be the case for 1.1.1 so removed. Fixes: comment 1 of #9757 Reviewed-by:
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- Sep 04, 2019
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Billy Brawner authored
Fixes #9080 Signed-off-by:
Billy Brawner <billy@wbrawner.com> Reviewed-by:
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raja-ashok authored
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raja-ashok authored
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David Woodhouse authored
In commit 6aca8d1a ("Honour mandatory digest on private key in has_usable_cert()") I added two checks for the capabilities of the EVP_PKEY being used. One of them was wrong, as it should only be checking the signature of the X.509 cert (by its issuer) against the sigalgs given in a TLS v1.3 signature_algorithms_cert extension. Remove it. Reviewed-by:
Ben Kaduk <kaduk@mit.edu> Reviewed-by:
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- Aug 30, 2019
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Pauli authored
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- Aug 29, 2019
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Pauli authored
It lacks exposure of the `shm*` functions and should prefer the GETRANDOM source. Reviewed-by:
Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> Reviewed-by:
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Pauli authored
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- Aug 27, 2019
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Cesar Pereida Garcia authored
This commit addresses a side-channel vulnerability present when PVK and MSBLOB key formats are loaded into OpenSSL. The public key was not computed using a constant-time exponentiation function. This issue was discovered and reported by the NISEC group at TAU Finland. Reviewed-by:
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- Aug 24, 2019
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Pauli authored
There is a problem in the rand_unix.c code when the random seed fd is greater than or equal to FD_SETSIZE and the FDSET overruns its limit and walks the stack. Reviewed-by:
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- Aug 23, 2019
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Richard Levitte authored
Parsing functions are at liberty to return: 1: when parsing on processing of the parsed value succeeded 0: when the parsed keyword is unknown -1: when the parsed value processing failed Some parsing functions didn't do this quite right, they returned 0 when they should have returned -1, causing a message like this: Line 123: unknown keyword PeerKey When this message (which is displayed when the parsing function returns -1) would have been more appropriate: Line 123: error processing keyword PeerKey = ffdhe2048-2-pub Reviewed-by:
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- Aug 22, 2019
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Richard Levitte authored
The input reading loop in 'openssl dgst' and 'openssl enc' doesn't check for end of input, and because of the way BIO works, it thereby won't detect that the end is reached before the read is an error. With the FILE BIO, an error occurs when trying to read past EOF, which is fairly much ok, except when the command is used interactively, at least on Unix. The result in that case is that the user has to press Ctrl-D twice for the command to terminate. The issue is further complicated because both these commands use filter BIOs on top of the FILE BIO, so a naïve attempt to check BIO_eof() doesn't quite solve it, since that only checks the state of the source/sink BIO, and the filter BIO may have some buffered data that still needs to be read. Fortunately, there's BIO_pending() that checks exactly that, if any filter BIO has pending data that needs to be processed. We end up having to check both BIO_pending() and BIO_eof(). Thanks to Zsigmond Lőrinczy for the initial effort and inspiration. Fixes #9355 Reviewed-by:
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- Aug 20, 2019
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Johannes authored
CLA: trivial Reviewed-by:
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Pauli authored
Improve handling of low entropy at start up from /dev/urandom by waiting for a read(2) call on /dev/random to succeed. Once one such call has succeeded, a shared memory segment is created and persisted as an indicator to other processes that /dev/urandom is properly seeded. This does not fully prevent against attacks weakening the entropy source. An attacker who has control of the machine early in its boot sequence could create the shared memory segment preventing detection of low entropy conditions. However, this is no worse than the current situation. An attacker would also be capable of removing the shared memory segment and causing seeding to reoccur resulting in a denial of service attack. This is partially mitigated by keeping the shared memory alive for the duration of the process's existence. Thus, an attacker would not only need to have called call shmctl(2) with the IPC_RMID command but the system must subsequently enter a state where no instances of libcrypto exist in any process. Even one long running process will prevent this attack. The System V shared memory calls used here go back at least as far as Linux kernel 2.0. Linux kernels 4.8 and later, don't have a reliable way to detect that /dev/urandom has been properly seeded, so a failure is raised for this case (i.e. the getentropy(2) call has already failed). Reviewed-by:
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- Aug 19, 2019
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Bernd Edlinger authored
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