This issue was partially addressed by commit
972c87dfc7, 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: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/9511)
This function re-implements EVP_MD_meth_free(), but has a name that
isn't encumbered by legacy EVP_MD construction functionality.
We also refactor most of EVP_MD_meth_new() into an internal
evp_md_new() that's used when creating fetched methods.
EVP_MD_meth_new() and EVP_MD_meth_free() are rewritten in terms of
evp_md_new() and EVP_MD_free(). This means that at any time, we can
deprecate all the EVP_MD_meth_ functions with no harmful consequence.
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9758)
This should avoid half of the trial divisions in probable_prime_dh_safe
and avoid bn_probable_prime_dh generating primes with special properties.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9309)
The FIPS provider does not have a default OPENSSL_CTX so, where
necessary, we need to ensure we can always access an explicit
OPENSSL_CTX. We remove functions from the FIPS provider that use
the default OPENSSL_CTX, and fixup some places which were using
those removed functions.
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9310)
Happens when trying to generate 4 or 5 bit safe primes.
[extended tests]
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9311)
The BIGNUM rand functions were previously disabled for the FIPS module.
We can now re-enable them.
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/9193)
CLA: trivial
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/9288)
Tracing doesn't work in the FIPS module. Ensure we switch it off there.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9159)
Other commits will enable the RAND code in FIPS_MODE. Until those commits
are in place we temporarily disable making RAND calls while in FIPS_MODE.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9130)
Replace the low level SHA512_* function calls with EVP calls.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9130)
These variants of BN_CTX_new() and BN_CTX_secure_new() enable passing
an OPENSSL_CTX so that we can access this where needed throughout the
BIGNUM sub library.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9130)
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9123)
The callback should be called with 1 when a Miller-Rabin round marked
the candidate as probably prime.
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
GH: #8742
There are some compiling errors for mips32r6 and mips64r6:
crypto/bn/bn-mips.S:56: Error: opcode not supported on this processor: mips2 (mips2) `mulu $1,$12,$7'
crypto/mips_arch.h: Assembler messages:
crypto/mips_arch.h:15: Error: junk at end of line, first unrecognized character is `&'
Signed-off-by: Hua Zhang <hua.zhang1974@hotmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8464)
These are a couple of utility functions, to make import and export of
BIGNUMs to byte strings in platform native for (little-endian or
big-endian) easier.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8346)
Thanks to David Benjamin who reported this, performed the analysis and
suggested the patch. I have incorporated some of his analysis in the
comments below.
This issue can cause an out-of-bounds read. It is believed that this was
not reachable until the recent "fixed top" changes. Analysis has so far
only identified one code path that can encounter this - although it is
possible that others may be found. The one code path only impacts 1.0.2 in
certain builds. The fuzzer found a path in RSA where iqmp is too large. If
the input is all zeros, the RSA CRT logic will multiply a padded zero by
iqmp. Two mitigating factors:
- Private keys which trip this are invalid (iqmp is not reduced mod p).
Only systems which take untrusted private keys care.
- In OpenSSL 1.1.x, there is a check which rejects the oversize iqmp,
so the bug is only reproducible in 1.0.2 so far.
Fortunately, the bug appears to be relatively harmless. The consequences of
bn_cmp_word's misbehavior are:
- OpenSSL may crash if the buffers are page-aligned and the previous page is
non-existent.
- OpenSSL will incorrectly treat two BN_ULONG buffers as not equal when they
are equal.
- Side channel concerns.
The first is indeed a concern and is a DoS bug. The second is fine in this
context. bn_cmp_word and bn_cmp_part_words are used to compute abs(a0 - a1)
in Karatsuba. If a0 = a1, it does not matter whether we use a0 - a1 or
a1 - a0. The third would be worth thinking about, but it is overshadowed
by the entire Karatsuba implementation not being constant time.
Due to the difficulty of tripping this and the low impact no CVE is felt
necessary for this issue.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8326)
The add/double shortcut in ecp_nistz256-x86_64.pl left one instruction
point that did not unwind, and the "slow" path in AES_cbc_encrypt was
not annotated correctly. For the latter, add
.cfi_{remember,restore}_state support to perlasm.
Next, fill in a bunch of functions that are missing no-op .cfi_startproc
and .cfi_endproc blocks. libunwind cannot unwind those stack frames
otherwise.
Finally, work around a bug in libunwind by not encoding rflags. (rflags
isn't a callee-saved register, so there's not much need to annotate it
anyway.)
These were found as part of ABI testing work in BoringSSL.
Reviewed-by: Richard Levitte <levitte@openssl.org>
GH: #8109
"Windows friendliness" means a) unified PIC-ification, unified across
all platforms; b) unified commantary delimiter; c) explicit ldur/stur,
as Visual Studio assembler can't automatically encode ldr/str as
ldur/stur when needed.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8256)
"Windows friendliness" means a) flipping .thumb and .text directives,
b) always generate Thumb-2 code when asked(*); c) Windows-specific
references to external OPENSSL_armcap_P.
(*) so far *some* modules were compiled as .code 32 even if Thumb-2
was targeted. It works at hardware level because processor can alternate
between the modes with no overhead. But clang --target=arm-windows's
builtin assembler just refuses to compile .code 32...
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8252)
ARMv8.3 adds pointer authentication extension, which in this case allows
to ensure that, when offloaded to stack, return address is same at return
as at entry to the subroutine. The new instructions are nops on processors
that don't implement the extension, so that the vetification is backward
compatible.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8205)
Trim trailing whitespace. It doesn't match OpenSSL coding standards,
AFAICT, and it can cause problems with git tooling.
Trailing whitespace remains in test data and external source.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8092)
When the ret parameter is NULL the generated prime
is in rnd variable and not in ret.
CLA: trivial
Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8076)
Some Travis builds appear to fail because generated objects get
2019 copyrights now, and the diff complains.
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7986)
Make it just say "the License", which refers back to the standard
boilerplate.
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7764)
Previously, the API version limit was indicated with a numeric version
number. This was "natural" in the pre-3.0.0 because the version was
this simple number.
With 3.0.0, the version is divided into three separate numbers, and
it's only the major number that counts, but we still need to be able
to support pre-3.0.0 version limits.
Therefore, we allow OPENSSL_API_COMPAT to be defined with a pre-3.0.0
style numeric version number or with a simple major number, i.e. can
be defined like this for any application:
-D OPENSSL_API_COMPAT=0x10100000L
-D OPENSSL_API_COMPAT=3
Since the pre-3.0.0 numerical version numbers are high, it's easy to
distinguish between a simple major number and a pre-3.0.0 numerical
version number and to thereby support both forms at the same time.
Internally, we define the following macros depending on the value of
OPENSSL_API_COMPAT:
OPENSSL_API_0_9_8
OPENSSL_API_1_0_0
OPENSSL_API_1_1_0
OPENSSL_API_3
They indicate that functions marked for deprecation in the
corresponding major release shall not be built if defined.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7724)
Fixed-top interfaces tolerate zero-padded inputs and facilitate
constant-time-ness. bn_div_fixed_top tolerates zero-padded dividend,
but not divisor. It's argued that divisor's length is public even
when value is secret.
[extended tests]
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7589)
and add template for constant-time bn_div_3_words.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7589)
It's being replaced with constant-time alternative.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7589)
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/7599)
