These errors can occur if we are built on a system with support for
madvise(MADV_NOFORK) but then we are run on a system whose kernel
does not support that flag.
If the error is something that we don't tolerate at all, we now log
it before crashing.
Fixes bug 31696. I am calling this a bugfix on 0.4.1.1-alpha, where
we actually started using the map_anon code.
This is similar to, but not the same as, the fix for #31570.
These errors can occur if we are built on a system with support for
madvise(MADV_NOFORK) but then we are run on a system whose kernel
does not support that flag.
If the error is something that we don't tolerate at all, we now log
it before crashing.
Fixes bug 31570. I am calling this a bugfix on 0.4.1.1-alpha, where
we actually started using the map_anon code.
Fixes assertion failure in tests on NetBSD:
slow/prob_distr/stochastic_log_logistic: [forking] May 25 03:56:58.091 [err] tor_assertion_failed_(): Bug: src/lib/crypt_ops/crypto_rand_fast.c:184: crypto_fast_rng_new_from_seed: Assertion inherit != INHERIT_RES_KEEP failed; aborting. (on Tor 0.4.1.1-alpha-dev 29955f13e5)
May 25 03:56:58.091 [err] Bug: Assertion inherit != INHERIT_RES_KEEP failed in crypto_fast_rng_new_from_seed at src/lib/crypt_ops/crypto_rand_fast.c:184: . (Stack trace not available) (on Tor 0.4.1.1-alpha-dev 29955f13e5)
[Lost connection!]
This test was previously written to use the contents of the system
headers to decide whether INHERIT_NONE or INHERIT_ZERO was going to
work. But that won't work across different environments, such as
(for example) when the kernel doesn't match the headers. Instead,
we add a testing-only feature to the code to track which of these
options actually worked, and verify that it behaved as we expected.
Closes ticket 29541; bugfix not on any released version of Tor.
Using an anonymous mmap() is a good way to get pages that we can set
kernel-level flags on, like minherit() or madvise() or mlock().
We're going to use that so that we can make uninheritable locked
pages to store PRNG data.
Nick Mathewson
David Goulet
Taylor R Campbell