The drbg's lock must be held across calls to RAND_DRBG_generate()
to prevent simultaneous modification of internal state.
This was observed in practice with simultaneous SSL_new() calls attempting
to seed the (separate) per-SSL RAND_DRBG instances from the global
rand_drbg instance; this eventually led to simultaneous calls to
ctr_BCC_update() attempting to increment drbg->bltmp_pos for their
respective partial final block, violating the invariant that bltmp_pos < 16.
The AES operations performed in ctr_BCC_blocks() makes the race window
quite easy to trigger. A value of bltmp_pos greater than 16 induces
catastrophic failure in ctr_BCC_final(), with subtraction overflowing
and leading to an attempt to memset() to zero a very large range,
which eventually reaches an unmapped page and segfaults.
Provide the needed locking in get_entropy_from_parent(), as well as
fixing a similar issue in RAND_priv_bytes(). There is also an
unlocked call to RAND_DRBG_generate() in ssl_randbytes(), but the
requisite serialization is already guaranteed by the requirements on
the application's usage of SSL objects, and no further locking is
needed for correct behavior. In that case, leave a comment noting
the apparent discrepancy and the reason for its safety (at present).
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4328)
The DRBG_RESEED state plays an analogue role to the |reseed_required_flag| in
Appendix B.3.4 of [NIST SP 800-90A Rev. 1]. The latter is a local variable,
the scope of which is limited to the RAND_DRBG_generate() function. Hence there
is no need for a DRBG_RESEED state outside of the generate function. This state
was removed and replaced by a local variable |reseed_required|.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4328)
Reseeding is handled very differently by the classic RAND_METHOD API
and the new RAND_DRBG api. These differences led to some problems when
the new RAND_DRBG was made the default OpenSSL RNG. In particular,
RAND_add() did not work as expected anymore. These issues are discussed
on the thread '[openssl-dev] Plea for a new public OpenSSL RNG API'
and in Pull Request #4328. This commit fixes the mentioned issues,
introducing the following changes:
- Replace the fixed size RAND_BYTES_BUFFER by a new RAND_POOL API which
facilitates collecting entropy by the get_entropy() callback.
- Don't use RAND_poll()/RAND_add() for collecting entropy from the
get_entropy() callback anymore. Instead, replace RAND_poll() by
RAND_POOL_acquire_entropy().
- Add a new function rand_drbg_restart() which tries to get the DRBG
in an instantiated state by all means, regardless of the current
state (uninstantiated, error, ...) the DRBG is in. If the caller
provides entropy or additional input, it will be used for reseeding.
- Restore the original documented behaviour of RAND_add() and RAND_poll()
(namely to reseed the DRBG immediately) by a new implementation based
on rand_drbg_restart().
- Add automatic error recovery from temporary failures of the entropy
source to RAND_DRBG_generate() using the rand_drbg_restart() function.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4328)
cryptilib.h is the second.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4188)
The one creating the DRBG should instantiate it, it's there that we
know which parameters we should use to instantiate it.
This splits the rand init in two parts to avoid a deadlock
because when the global drbg is created it wands to call
rand_add on the global rand method.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
GH: #4268
The DRBG callbacks 'get_entropy()' and 'cleanup_entropy()' are designed
in such a way that the randomness buffer does not have to be allocated
by the calling function. It receives the address of a dynamically
allocated buffer from get_entropy() and returns this address to
cleanup_entropy(), where it is freed. If these two calls are properly
paired, the address can be stored in a stack local variable of the
calling function, so there is no need for having a 'randomness' member
(and a 'filled' member) in 'RAND_DRBG'.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4266)
With the introduction of RAND_poll_ex(), the `RAND_add()` calls were
replaced by meaningless cb(...). This commit changes the 'cb(...)'
calls back to 'rand_add(...)' calls by changing the signature as follows:
-int RAND_poll_ex(RAND_poll_fn cb, void *arg);
+int RAND_poll_ex(RAND_poll_cb rand_add, void *arg);
Changed the function typedef name to 'RAND_poll_cb' to emphasize the fact
that the function type represents a callback function.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4266)
Unlike the NIST DRBG standard, entropy counts are in bits and
buffer lengths are in bytes. This has lead to some confusion and
errors in the past, see my comment on PR 3789.
To clarify the destinction between entropy counts and buffer lengths,
a 'len' suffix has been added to all member names of RAND_DRBG which
represent buffer lengths:
- {min,max}_{entropy,adin,nonce,pers}
+ {min,max}_{entropy,adin,nonce,pers}len
This change makes naming also more consistent, as can be seen in the
diffs, for example:
- else if (adinlen > drbg->max_adin) {
+ else if (adinlen > drbg->max_adinlen) {
Also replaced all 'ent's by 'entropy's, following a suggestion of Paul Dale.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4266)
Try to put DRBG and rand_bytes buffers in secure heap
Read the TSC fewer times (but it's still not enabled).
Short-circuit return in win RAND_poll_ex; other minor tweaks and
format-fixes.
Use the _bytes version of rdrand/rdseed
Fix ia32cap checks.
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/4100)
Use atfork to count child forks, and reseed DRBG when the counts don't
match.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4101)
Add a new global DRBG for private keys used by RAND_priv_bytes.
Add BN_priv_rand() and BN_priv_rand_range() which use RAND_priv_bytes().
Change callers to use the appropriate BN_priv... function.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4076)
Give each SSL object it's own DRBG, chained to the parent global
DRBG which is used only as a source of randomness into the per-SSL
DRBG. This is used for all session, ticket, and pre-master secret keys.
It is NOT used for ECDH key generation which use only the global
DRBG. (Doing that without changing the API is tricky, if not impossible.)
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4050)
If RAND_add wraps around, XOR with existing. Add test to drbgtest that
does the wrap-around.
Re-order seeding and stop after first success.
Add RAND_poll_ex()
Use the DF and therefore lower RANDOMNESS_NEEDED. Also, for child DRBG's,
mix in the address as the personalization bits.
Centralize the entropy callbacks, from drbg_lib to rand_lib.
(Conceptually, entropy is part of the enclosing application.)
Thanks to Dr. Matthias St Pierre for the suggestion.
Various code cleanups:
-Make state an enum; inline RANDerr calls.
-Add RAND_POLL_RETRIES (thanks Pauli for the idea)
-Remove most RAND_seed calls from rest of library
-Rename DRBG_CTX to RAND_DRBG, etc.
-Move some code from drbg_lib to drbg_rand; drbg_lib is now only the
implementation of NIST DRBG.
-Remove blocklength
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4019)
Instead of setting a "magic" global variable to force RAND to keep
consistent state and always generate the same bytestream, have
the fuzzing code install its own RAND_METHOD that does this. For
BN_RAND_DEBUG, we just don't do it; that debugging was about mucking
with BN's internal representation, not requiring predictable rand
bytes.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4025)
In 'crypto/rand/ossl_rand.c', a call to
'ASYNC_unblock_pause()' is missing in an error case.
CLA: trivial
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4020)
Add a new config param to specify how the CSPRNG should be seeded.
Illegal values or nonsensical combinations (e.g., anything other
than "os" on VMS or HP VOS etc) result in build failures.
Add RDSEED support.
Add RDTSC but leave it disabled for now pending more investigation.
Refactor and reorganization all seeding files (rand_unix/win/vms) so
that they are simpler.
Only require 128 bits of seeding material.
Many document improvements, including why to not use RAND_add() and the
limitations around using load_file/write_file.
Document RAND_poll().
Cleanup Windows RAND_poll and return correct status
More completely initialize the default DRBG.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3965)
Looking at
http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf
we see that in the CTR_DRBG_Update() algorithm (internal page number 51),
the provided input data is (after truncation to seedlen) xor-d with the
key and V vector (of length keylen and blocklen respectively). The comment
in ctr_XOR notes that xor-ing with 0 is the identity function, so we can
just ignore the case when the provided input is shorter than seedlen.
The code in ctr_XOR() then proceeds to xor the key with the input, up
to the amount of input present, and computes the remaining input that
could be used to xor with the V vector, before accessing a full 16-byte
stretch of the input vector and ignoring the calculated length. The correct
behavior is to respect the supplied input length and only xor the
indicated number of bytes.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3971)
Ported from the last FIPS release, with DUAL_EC and SHA1 and the
self-tests removed. Since only AES-CTR is supported, other code
simplifications were done. Removed the "entropy blocklen" concept.
Moved internal functions to new include/internal/rand.h.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3789)
Standardized the -rand flag and added a new one:
-rand file...
Always reads the specified files
-writerand file
Always writes to the file on exit
For apps that use a config file, the RANDFILE config parameter reads
the file at startup (to seed the RNG) and write to it on exit if
the -writerand flag isn't used.
Ensured that every app that took -rand also took -writerand, and
made sure all of that agreed with all the documentation.
Fix error reporting in write_file and -rand
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3862)
Remove unused rand_hw_xor, MD/EVP indirection
Make rand_pseudo same as rand.
Cleanup formatting and ifdef control
Rename some things:
- rand_meth to openssl_rand_meth; make it global
- source file
- lock/init functions, start per-thread state
- ossl_meth_init to ossl_rand_init
Put state into RAND_STATE structure
And put OSSL_RAND_STATE into ossl_typ.h
Use "randomness" instead of "entropy"
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/3758)
Use stdio and its buffering.
Limit to 255 bytes (could remove that if neceessary).
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3888)
Bounds checking strpy, strcat and sprintf.
These are the remaining easy ones to cover a recently removed commit.
Some are trivial, some have been modified and a couple left as they are because the reverted change didn't bounds check properly.
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3871)
Document an internal assumption that these are only for use with files,
and return an error if not. That made the code much simpler.
Leave it as writing 1024 bytes, even though we don't need more than 256
from a security perspective. But the amount isn't specified, now, so we
can change it later if we want.
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3864)
Original text:
Check if a random "file" is really a device file, and treat it
specially if it is.
Add a few OpenBSD-specific cases.
This is part of a large change submitted by Markus Friedl <markus@openbsd.or
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3700)
[extended tests]
Original text:
Use BUF_strlcpy() instead of strcpy().
Use BUF_strlcat() instead of strcat().
Use BIO_snprintf() instead of sprintf().
In some cases, keep better track of buffer lengths.
This is part of a large change submitted by Markus Friedl <markus@openbsd.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3701)
Run perltidy on util/mkerr
Change some mkerr flags, write some doc comments
Make generated tables "const" when genearting lib-internal ones.
Add "state" file for mkerr
Renerate error tables and headers
Rationalize declaration of ERR_load_XXX_strings
Fix out-of-tree build
Add -static; sort flags/vars for options.
Also tweak code output
Moved engines/afalg to engines (from master)
Use -static flag
Standard engine #include's of errors
Don't linewrap err string tables unless necessary
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3392)
When configured no-engine, we still refered to rand_engine_lock.
Rework the lock init code to avoid that.
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3145)
If no default method was yet given, RAND_get_rand_method() will set it
up. Doing so just to clean it away seems pretty silly, so instead,
use the default_RAND_meth variable directly.
This also clears a possible race condition where this will try to init
things, such as ERR or ENGINE when in the middle of a OPENSSL_cleanup.
Fixes#3128
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3136)
This removes the fips configure option. This option is broken as the
required FIPS code is not available.
FIPS_mode() and FIPS_mode_set() are retained for compatibility, but
FIPS_mode() always returns 0, and FIPS_mode_set() can only be used to
turn FIPS mode off.
Reviewed-by: Stephen Henson <steve@openssl.org>
According to the documentation, the return code should be -1 when
RAND_status does not return 1.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1886)
