| History log of /src/tests/lib/libc/gen/t_arc4random.c |
| Revision | | Date | Author | Comments |
| 1.5 |
| 09-Mar-2025 |
riastradh | arc4random(3): Provide a fallback in case pthread_atfork fails.
This is considerably more work and burden on testing than simply
statically preallocating a bit of storage for pthread_atfork to
eliminate the failure mode altogether, but it is less work than
arguing further over the atfork interface:
https://mail-index.NetBSD.org/source-changes-d/2025/03/02/msg014387.html
PR lib/59117: arc4random has some failure modes it shouldn't
|
| 1.4 |
| 06-Mar-2025 |
riastradh | t_arc4random: Test arc4random_global.per_thread, not .initialized.
If arc4random_initialize has been called, and thr_keycreate failed,
then .initialized will be true but .per_thread will be false -- and
.thread_key will be garbage (some other thread key for another
purpose, most likely). This path was enabled by allowing
thr_keycreate to fail instead of aborting the process.
This hasn't caused trouble yet, mainly because we don't do anything
to inject faults into thr_keycreate in these tests. Tweak the
global_threadkeylimit test while here to provoke a crash with the
wrong conditional.
Fix a similar edge case in the little test program embedded in
arc4random.c (which should maybe just go away now that we have atf
tests).
PR lib/59117: arc4random has some failure modes it shouldn't
|
| 1.3 |
| 05-Mar-2025 |
riastradh | t_arc4random: Verify arc4random works without fds.
It must work in an empty chroot where /dev/urandom doesn't exist, and
it must work when the file descriptor resource limit is exceeded.
Prompted by discussion around:
PR lib/59117: arc4random has some failure modes it shouldn't
Fortunately these are not failure modes of the current arc4random
implementation! But it is important to test them nevertheless, to
forestall any temptation to invent new failure modes.
|
| 1.2 |
| 02-Mar-2025 |
riastradh | arc4random(3): Avoid failure due to thread key limits.
If thr_keycreate (a.k.a. pthread_key_create) fails, fall back to
using globally serialized state instead of per-thread state. This is
unlikely to happen but arc4random(3) should work even if it does.
New test case forces exercising this path (at least, simulating the
effect of key creation failure).
PR lib/59117: arc4random has some failure modes it shouldn't
|
| 1.1 |
| 27-Aug-2024 |
riastradh | branches: 1.1.2;
arc4random(3): Add automatic tests.
This verifies that:
- arc4random zeroes its state and reseeds itself on fork
- arc4random reseeds itself on entropy consolidation (e.g., VM clone)
- arc4random falls back to global state if it can't allocate local
state because address space limits cause mmap to fail
NOTE: This adds a new libc symbol __arc4random_global, but it's in
the reserved namespace and only used by t_arc4random, so no libc
minor bump.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
|
| 1.1.2.2 |
| 09-Oct-2024 |
martin | Pull up following revision(s) (requested by riastradh in ticket #939):
distrib/sets/lists/debug/module.md.amd64: revision 1.18
sys/modules/Makefile: revision 1.292
lib/libc/gen/arc4random.c: revision 1.34
lib/libc/gen/arc4random.c: revision 1.35
lib/libc/gen/arc4random.c: revision 1.36
lib/libc/gen/arc4random.c: revision 1.37
sys/kern/kern_entropy.c: revision 1.70
lib/libc/gen/arc4random.c: revision 1.38
sys/kern/kern_entropy.c: revision 1.71
lib/libc/gen/getentropy.3: revision 1.8
distrib/sets/lists/modules/md.amd64: revision 1.103
share/man/man4/rnd.4: revision 1.42
share/man/man4/rnd.4: revision 1.44
lib/libc/include/arc4random.h: revision 1.1
distrib/sets/lists/man/mi: revision 1.1786
sys/arch/i386/conf/GENERIC: revision 1.1258
sys/modules/acpivmgenid/acpivmgenid.ioconf: revision 1.1
sys/arch/amd64/conf/ALL: revision 1.190
distrib/sets/lists/debug/mi: revision 1.446
sys/arch/i386/conf/ALL: revision 1.521
lib/libc/gen/Makefile.inc: revision 1.219
distrib/sets/lists/debug/module.md.i386: revision 1.12
sys/dev/acpi/acpi_vmgenid.c: revision 1.1
sys/dev/acpi/acpi_vmgenid.c: revision 1.2
lib/libc/include/reentrant.h: revision 1.22
sys/arch/evbarm/conf/GENERIC64: revision 1.219
share/man/man4/Makefile: revision 1.735
distrib/sets/lists/modules/md.i386: revision 1.100
distrib/sets/lists/tests/mi: revision 1.1334
lib/libc/gen/arc4random.3: revision 1.22
sys/dev/acpi/files.acpi: revision 1.133
lib/libc/gen/arc4random.3: revision 1.23
tests/lib/libc/gen/t_arc4random.c: revision 1.1
sys/sys/entropy.h: revision 1.6
sys/arch/amd64/conf/GENERIC: revision 1.614
sys/modules/acpivmgenid/Makefile: revision 1.1
share/man/man4/acpivmgenid.4: revision 1.1
lib/libc/gen/Makefile.inc: revision 1.220
tests/lib/libc/gen/Makefile: revision 1.56
share/man/man4/acpivmgenid.4: revision 1.2
share/man/man4/acpivmgenid.4: revision 1.3
(all via patch)
Catch up with all the lint warnings since exit on warning was disabled.
Disable 'missing header declaration' and 'nested extern' warnings for now.
acpivmgenid(4): New driver for virtual machine generation ID.
Added to amd64/ALL and i386/ALL kernel configurations, and made
available as a loadable module acpivmgenid.kmod on x86, for now.
TBD: Add to all ACPI-supporting GENERIC kernels.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
entropy(9): Factor out subroutines to reset and gather entropy.
`Reset' means we keep the data in the pool, but assume it had zero
entropy. `Gather' means we request samples from all on-demand
sources and wait for the synchronous ones to complete.
No functional change intended, other than to expose new symbols --
just preparation to expose these to acpivmgenid(4), so it can use
these when the VM host notifies us that we, the guest, have been
cloned.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
acpivmgenid(4): Reset and gather entropy on VM clone notification.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
arc4random(3): Reseed if system entropy epoch changes.
This can happen, for example, if the system is a VM instance, and the
VM is cloned.
This incurs the cost of a system call on every arc4random call, which
is unfortunate, but
1. we don't currently have a (machine-independent) mechanism for
exposing a read-only page to userland shared by the kernel to
enable a cheaper access path to the entropy epoch; and
2. the algorithm here -- a simple application of ChaCha -- is likely
also a bottleneck and could be much cheaper by
(a) using sys/crypto/chacha for machine-dependent vectorized
ChaCha code, and
(b) filling a buffer (somewhere between a cipher block and a page)
in a batch at a time, instead of running ChaCha to generate
only 32 bytes at a time.
So although this might be a performance hit, the security benefit is
worthwhile and we have a clear path to do better than reversing the
performance hit later.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
acpivmgenid(4): Nix BUGS that have been squashed.
Reference kern.entropy.epoch for the remaining bug (which is a
performance issue, not a security issue).
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
entropy(9): Allow unprivileged reads of sysctl kern.entropy.epoch.
Applications need this in order to know when to reseed. (We should
also expose it through a page shared read-only with userland for
cheaper access, but until we do, let's let applications get at it
through sysctl.)
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
arc4random.c: Fix test program.
This isn't wired up anywhere, but let's reduce the bitrot. It was
helpful in reminding me that kern.entropy.epoch was, for reasons I
can't remember, restricted to privileged access.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
amd64, evbarm, i386: Add acpivmgenid(4) to GENERIC.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
rnd(4): Document kern.entropy.epoch is unprivileged and elaborate.
Cross-reference acpivmgenid(4).
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
arc4random(3): Note that arc4random respects kern.entropy.epoch.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
Add debug info for new acpivmgenid module
arc4random(3): Add automatic tests.
This verifies that:
- arc4random zeroes its state and reseeds itself on fork
- arc4random reseeds itself on entropy consolidation (e.g., VM clone)
- arc4random falls back to global state if it can't allocate local
state because address space limits cause mmap to fail
NOTE: This adds a new libc symbol __arc4random_global, but it's in
the reserved namespace and only used by t_arc4random, so no libc
minor bump.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
getentropy(3): Note intent to reseed on VM clone, and caveats.
Tidy markup and pacify some mandoc -Tlint complaints while here.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
Bump dates on man pages recently updated to mention VM clones.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
arc4random(3): Pacify some of lint's complaints.
PR kern/58632: getentropy(2) and arc4random(3) do not reseed on VM
fork
arc4random: suppress another lint warning
|
| 1.1.2.1 |
| 27-Aug-2024 |
martin | file t_arc4random.c was added on branch netbsd-10 on 2024-10-09 13:25:13 +0000
|
