to hold the malloc lock across mmap syscalls in all cases. dropping it
allows another thread to access the existing chunk cache if necessary.
could be improved to be a bit more aggressive, but i've been testing this
simple diff for some time now with good results.
circular lists. Amazingly, they managed to extend the requirements to no
longer match the behavior of the VAX instructions they were modeled after,
so the trivial VAX ASM versions have to go. Nice job breaking it, X/Open!
Based on a diff from enh (at) google.com
ok miod@
Move <sys/mman.h> and raise(SIGKILL) calls to OS-specific headers.
On OpenBSD, move thread_private.h as well to arc4random.h.
On Windows, use TerminateProcess on getentropy failure.
ok deraadt@
6.11.5 - Storage-class specifiers:
The placement of a storage-class specifier other than at the
beginning of the declaration specifiers in a declaration is
an obsolescent feature.
Diff from Jean-Philippe Ouellet (jean-philippe (at) ouellet.biz)
into one if a system has an awesome getentropy(). In that case it
is valid to totally throw away the rsx state in the child. If the
getentropy() is not very good and has a lazy reseed operation, this
combining is a bad idea, and the reseed should probably continue to
use the "something old, something new" mix. _rs_allocate() can
accomodate either method, but not on the fly.
ok matthew
now using this as upstream code. The particular problem is systems
that contain older arc4random derivations lacking arc4random_uniform().
ok tedu miod
improve the random stream itself (it doesn't), but to introduce
noise in the arc4random calling pattern. Thanks to matthew@ who
pointed out bias in a previous diff, ok deraadt@ matthew@
Modern compiler toolchains are capable of optimizing even across
translation unit boundaries, so simply moving the memory clearing into
a separate function is not guaranteed to clear memory.
To avoid this, we take advantage of ELF weak symbol semantics, and
insert a call to an empty, weakly named function. The semantics of
calling this function aren't determinable until load time, so the
compiler and linker need to keep the memset() call.
There are still ways a toolchain might defeat this trick (e.g.,
optimistically expecting the weak symbol to not be overloaded, and
only calling memset() if it is; promoting weak symbols to strong
symbols at link-time when emitting a static binary because they won't
be interposed; implementing load-time optimizations). But at least
for the foreseeable future, these seem unlikely.
ok deraadt
MAP_INHERIT_ZERO anymore. This restores arc4random's previous
behavior where fork children would mix in some randomness from the
parent process.
New behavior noticed by deraadt
ok deraadt, tedu
The extra argument doesn't hurt genuine atexit handlers and this fixes a
bug where we didn't provide the argument (effectively passing garbage) for
functions registered with __cxa_atexit in the main executable.
Pointed out by Dmitriy Ivanov <dimitry@google.com> and Elliott Hughes
<enh@google.com>.
ok matthew@
Now instead of calling getpid() each time a user invokes arc4random(),
we're able to rely on the kernel zero'ing out the RNG state if the
process forks.
ok deraadt, djm
tedu