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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
Pull up following revision(s) (requested by riastradh in ticket #938): lib/libc/gen/getentropy.3: revision 1.7 include/limits.h: revision 1.44 include/unistd.h: revision 1.167 getentropy(3): Make this visible to POSIX.1-2024 applications. Likewise GETENTROPY_MAX. It is now part of POSIX: https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/getentropy.html Cite standard in man page too. While here, use `.Nm' rather than `.Fn getentropy' for self-reference in the man page, for consistency with other usage. PR standards/58603: getentropy(3): update visibility and documentation for POSIX.1-2024
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
getentropy(3): Make this visible to POSIX.1-2024 applications. Likewise GETENTROPY_MAX. It is now part of POSIX: https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/getentropy.html Cite standard in man page too. While here, use `.Nm' rather than `.Fn getentropy' for self-reference in the man page, for consistency with other usage. PR standards/58603: getentropy(3): update visibility and documentation for POSIX.1-2024
Pull up following revision(s) (requested by riastradh in ticket #319): sys/dev/pci/ubsec.c: revision 1.64 sys/dev/pci/hifn7751.c: revision 1.82 lib/libc/gen/getentropy.3: revision 1.5 lib/libc/gen/getentropy.3: revision 1.6 share/man/man4/rnd.4: revision 1.41 lib/libc/sys/getrandom.2: revision 1.2 lib/libc/sys/getrandom.2: revision 1.3 share/man/man5/rc.conf.5: revision 1.193 share/man/man7/entropy.7: revision 1.5 share/man/man7/entropy.7: revision 1.6 share/man/man7/entropy.7: revision 1.7 share/man/man7/entropy.7: revision 1.8 etc/security: revision 1.130 share/man/man7/entropy.7: revision 1.9 etc/security: revision 1.131 sys/crypto/cprng_fast/cprng_fast.c: revision 1.19 sys/sys/rndio.h: revision 1.3 tests/lib/libc/sys/t_getrandom.c: revision 1.5 etc/defaults/rc.conf: revision 1.164 etc/defaults/rc.conf: revision 1.165 sys/sys/rndsource.h: revision 1.10 sys/kern/kern_entropy.c: revision 1.62 sys/kern/kern_entropy.c: revision 1.63 sys/kern/kern_entropy.c: revision 1.64 sys/kern/subr_cprng.c: revision 1.44 sys/kern/kern_entropy.c: revision 1.65 sys/kern/kern_clock.c: revision 1.149 sys/dev/pci/viornd.c: revision 1.22 share/man/man9/rnd.9: revision 1.32 sys/kern/subr_prf.c: revision 1.202 sys/sys/rndsource.h: revision 1.8 sys/sys/rndsource.h: revision 1.9 share/man/man7/entropy.7: revision 1.10 1. Reinstate netbsd<=9 entropy estimator to unblock /dev/random, in parallel with assessment of only confident entropy sources (seed, HWRNG) for security warnings like sshd keys in motd and daily insecurity report. 2. Make multiuser boot wait for first /dev/random output soon after loading a seed and configuring rndctl, so that getentropy(3) meets its contract starting early at boot without introducing blocking paths that could cause hangs in init(8) or single-user mode. Operators can choose to disable this wait in rc.conf. 3. Fix some bugs left over from reducing the global entropy lock from a spin lock at IPL_VM to an adaptive lock at IPL_SOFTSERIAL. 4. Update man pages.
getentropy(3): use .Sx to xref CAVEATS
getrandom(2), getentropy(3): Rework man pages. Make supportable promises. Omit needless verbiage. Give caveats with cross-references to entropy(7). Emphasize that security is necessarily relative to system configuration. XXX pullup-10
libc: Reintroduce getentropy.
This was introduced two years ago when the getrandom/getentropy API
question was still open, and removed because the discussion was
ongoing. Now getentropy is more widely adopted and soon to be in
POSIX. So reintroduce the symbol into libc since we'll be keeping it
anyway. Discussion of details of the semantics, as interpreted by
NetBSD, is ongoing, but the symbol needs to get in before the
netbsd-10 branch. The draft POSIX text is
(https://www.opengroup.org/austin/docs/austin_1110.pdf):
SYNOPSIS
#include <unistd.h>
int getentropy(void *buffer, size_t length);
DESCRIPTION
The getentropy() function shall write length bytes of data
starting at the location pointed to by buffer. The output
shall be unpredictable high quality random data, generated by
a cryptographically secure pseudo-random number
generator. The maximum permitted value for the length
argument is given by the {GETENTROPY_MAX} symbolic constant
defined in <limits.h>.
RETURN VALUES
Upon successful completion, getentropy() shall return 0;
otherwise, -1 shall be retunred and errno set to indicate the
error.
ERRORS
The getentropy() function shall fail if:
[EINVAL] The value of length is greater than
{GETENTROPY_MAX}.
The getentropy() function may fail if:
[ENOSYS] The system does not provide the necessary
source of entropy.
RATIONALE
The getentropy() function is not a cancellation point.
Minor changes from the previous introduction of getentropy into libc:
- Return EINVAL, not EIO, on buflen > 256.
- Define GETENTROPY_MAX in limits.h.
The declaration of getentropy in unistd.h and definition of
GETENTROPY_MAX in limits.h are currently conditional on
_NETBSD_SOURCE. When the next revision of POSIX is finalized, we can
expose them also under _POSIX_C_SOURCE > 20yymmL as usual -- and this
can be done as a pullup without breaking existing compiled programs.
remove getentropy bits
Fix macro usage. Fix typo. New sentence, new line.
Add getentropy() to libc - a simple wrapper to access the kernel CSPRNG.
Posted to tech-userlevel@ a week ago and reviewed by riastradh@.
GETENTROPY(3) Library Functions Manual GETENTROPY(3)
NAME
getentropy - fill a buffer with high quality random data
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
getentropy(void *buf, size_t buflen);
DESCRIPTION
The getentropy() function fills a buffer with high quality random data,
suitable for seeding cryptographically secure psuedorandom number
generators.
getentropy() is only intended for seeding random number generators and is
not intended for use by regular code which simply needs secure random
data. For this purpose, please use arc4random(3).
The maximum value for buflen is 256 bytes.
IMPLEMENTATION NOTES
getentropy() reads from the sysctl(7) variable kern.arandom.
RETURN VALUES
The getentropy() function returns 0 on success, and -1 if an error
occurred.
ERRORS
getentropy() will succeed unless:
[EFAULT] The buf argument points to an invalid memory address.
[EIO] Too many bytes were requested.
SEE ALSO
arc4random(3), rnd(4)
STANDARDS
The getentropy() function is non-standard.
HISTORY
The getentropy() function first appeared in OpenBSD 5.6, then in
FreeBSD 12.0, and NetBSD 10.