When the new OpenSSL CSPRNG was introduced in version 1.1.1,
it was announced in the release notes that it would be fork-safe,
which the old CSPRNG hadn't been.
The fork-safety was implemented using a fork count, which was
incremented by a pthread_atfork handler. Initially, this handler
was enabled by default. Unfortunately, the default behaviour
had to be changed for other reasons in commit b5319bdbd0, so
the new OpenSSL CSPRNG failed to keep its promise.
This commit restores the fork-safety using a different approach.
It replaces the fork count by a fork id, which coincides with
the process id on UNIX-like operating systems and is zero on other
operating systems. It is used to detect when an automatic reseed
after a fork is necessary.
To prevent a future regression, it also adds a test to verify that
the child reseeds after fork.
CVE-2019-1549
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9832)
CRYPTO_atomic_read was added with intention to read statistics counters,
but readings are effectively indistinguishable from regular load (even
in non-lock-free case). This is because you can get out-dated value in
both cases. CRYPTO_atomic_write was added for symmetry and was never used.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/6883)
Updated indentations according project rules, renamed file-local define to the shorter version - USE_RWLOCK, fixed declaration after the if statement in CRYPTO_THREAD_lock_new().
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1981)
Fix compilation on platforms with missing pthread_rwlock_t implementation by replacing it with pthread_mutex_t. An example of such platform can be Android OS 2.0 - 2.1, API level 5 (Eclair), Android NDK platform - android-5 where pthread_rwlock_t is not implemented and is missing in pthread.h.
In case of missing pthread_rwlock_t implementation CRYPTO_RWLOCK will work as exclusive lock in write-only mode of pthread_rwlock_t lock.
The implementation based on pthread_mutex_t must be using PTHREAD_MUTEX_RECURSIVE mode to be compatible with recursive behavior of pthread_rwlock_rdlock.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1981)
For increments, the relaxed model is fine. For decrements, it's
recommended to use the acquire release model. We therefore go for the
latter.
Reviewed-by: Andy Polyakov <appro@openssl.org>
