Pull more random number generator updates from Jason Donenfeld:
"This time with some large scale treewide cleanups.
The intent of this pull is to clean up the way callers fetch random
integers. The current rules for doing this right are:
- If you want a secure or an insecure random u64, use get_random_u64()
- If you want a secure or an insecure random u32, use get_random_u32()
The old function prandom_u32() has been deprecated for a while
now and is just a wrapper around get_random_u32(). Same for
get_random_int().
- If you want a secure or an insecure random u16, use get_random_u16()
- If you want a secure or an insecure random u8, use get_random_u8()
- If you want secure or insecure random bytes, use get_random_bytes().
The old function prandom_bytes() has been deprecated for a while
now and has long been a wrapper around get_random_bytes()
- If you want a non-uniform random u32, u16, or u8 bounded by a
certain open interval maximum, use prandom_u32_max()
I say "non-uniform", because it doesn't do any rejection sampling
or divisions. Hence, it stays within the prandom_*() namespace, not
the get_random_*() namespace.
I'm currently investigating a "uniform" function for 6.2. We'll see
what comes of that.
By applying these rules uniformly, we get several benefits:
- By using prandom_u32_max() with an upper-bound that the compiler
can prove at compile-time is ≤65536 or ≤256, internally
get_random_u16() or get_random_u8() is used, which wastes fewer
batched random bytes, and hence has higher throughput.
- By using prandom_u32_max() instead of %, when the upper-bound is
not a constant, division is still avoided, because
prandom_u32_max() uses a faster multiplication-based trick instead.
- By using get_random_u16() or get_random_u8() in cases where the
return value is intended to indeed be a u16 or a u8, we waste fewer
batched random bytes, and hence have higher throughput.
This series was originally done by hand while I was on an airplane
without Internet. Later, Kees and I worked on retroactively figuring
out what could be done with Coccinelle and what had to be done
manually, and then we split things up based on that.
So while this touches a lot of files, the actual amount of code that's
hand fiddled is comfortably small"
* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
prandom: remove unused functions
treewide: use get_random_bytes() when possible
treewide: use get_random_u32() when possible
treewide: use get_random_{u8,u16}() when possible, part 2
treewide: use get_random_{u8,u16}() when possible, part 1
treewide: use prandom_u32_max() when possible, part 2
treewide: use prandom_u32_max() when possible, part 1
Pull UML updates from Richard Weinberger:
- Move to strscpy()
- Improve panic notifiers
- Fix NR_CPUS usage
- Fixes for various comments
- Fixes for virtio driver
* tag 'for-linus-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
uml: Remove the initialization of statics to 0
um: Do not initialise statics to 0.
um: Fix comment typo
um: Improve panic notifiers consistency and ordering
um: remove unused reactivate_chan() declaration
um: mmaper: add __exit annotations to module exit funcs
um: virt-pci: add __init/__exit annotations to module init/exit funcs
hostfs: move from strlcpy with unused retval to strscpy
um: move from strlcpy with unused retval to strscpy
um: increase default virtual physical memory to 64 MiB
UM: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK
um: read multiple msg from virtio slave request fd
Pull non-MM updates from Andrew Morton:
- hfs and hfsplus kmap API modernization (Fabio Francesco)
- make crash-kexec work properly when invoked from an NMI-time panic
(Valentin Schneider)
- ntfs bugfixes (Hawkins Jiawei)
- improve IPC msg scalability by replacing atomic_t's with percpu
counters (Jiebin Sun)
- nilfs2 cleanups (Minghao Chi)
- lots of other single patches all over the tree!
* tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits)
include/linux/entry-common.h: remove has_signal comment of arch_do_signal_or_restart() prototype
proc: test how it holds up with mapping'less process
mailmap: update Frank Rowand email address
ia64: mca: use strscpy() is more robust and safer
init/Kconfig: fix unmet direct dependencies
ia64: update config files
nilfs2: replace WARN_ONs by nilfs_error for checkpoint acquisition failure
fork: remove duplicate included header files
init/main.c: remove unnecessary (void*) conversions
proc: mark more files as permanent
nilfs2: remove the unneeded result variable
nilfs2: delete unnecessary checks before brelse()
checkpatch: warn for non-standard fixes tag style
usr/gen_init_cpio.c: remove unnecessary -1 values from int file
ipc/msg: mitigate the lock contention with percpu counter
percpu: add percpu_counter_add_local and percpu_counter_sub_local
fs/ocfs2: fix repeated words in comments
relay: use kvcalloc to alloc page array in relay_alloc_page_array
proc: make config PROC_CHILDREN depend on PROC_FS
fs: uninline inode_maybe_inc_iversion()
...
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
Pull kernel hardening updates from Kees Cook:
"Most of the collected changes here are fixes across the tree for
various hardening features (details noted below).
The most notable new feature here is the addition of the memcpy()
overflow warning (under CONFIG_FORTIFY_SOURCE), which is the next step
on the path to killing the common class of "trivially detectable"
buffer overflow conditions (i.e. on arrays with sizes known at compile
time) that have resulted in many exploitable vulnerabilities over the
years (e.g. BleedingTooth).
This feature is expected to still have some undiscovered false
positives. It's been in -next for a full development cycle and all the
reported false positives have been fixed in their respective trees.
All the known-bad code patterns we could find with Coccinelle are also
either fixed in their respective trees or in flight.
The commit message in commit 54d9469bc5 ("fortify: Add run-time WARN
for cross-field memcpy()") for the feature has extensive details, but
I'll repeat here that this is a warning _only_, and is not intended to
actually block overflows (yet). The many patches fixing array sizes
and struct members have been landing for several years now, and we're
finally able to turn this on to find any remaining stragglers.
Summary:
Various fixes across several hardening areas:
- loadpin: Fix verity target enforcement (Matthias Kaehlcke).
- zero-call-used-regs: Add missing clobbers in paravirt (Bill
Wendling).
- CFI: clean up sparc function pointer type mismatches (Bart Van
Assche).
- Clang: Adjust compiler flag detection for various Clang changes
(Sami Tolvanen, Kees Cook).
- fortify: Fix warnings in arch-specific code in sh, ARM, and xen.
Improvements to existing features:
- testing: improve overflow KUnit test, introduce fortify KUnit test,
add more coverage to LKDTM tests (Bart Van Assche, Kees Cook).
- overflow: Relax overflow type checking for wider utility.
New features:
- string: Introduce strtomem() and strtomem_pad() to fill a gap in
strncpy() replacement needs.
- um: Enable FORTIFY_SOURCE support.
- fortify: Enable run-time struct member memcpy() overflow warning"
* tag 'hardening-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (27 commits)
Makefile.extrawarn: Move -Wcast-function-type-strict to W=1
hardening: Remove Clang's enable flag for -ftrivial-auto-var-init=zero
sparc: Unbreak the build
x86/paravirt: add extra clobbers with ZERO_CALL_USED_REGS enabled
x86/paravirt: clean up typos and grammaros
fortify: Convert to struct vs member helpers
fortify: Explicitly check bounds are compile-time constants
x86/entry: Work around Clang __bdos() bug
ARM: decompressor: Include .data.rel.ro.local
fortify: Adjust KUnit test for modular build
sh: machvec: Use char[] for section boundaries
kunit/memcpy: Avoid pathological compile-time string size
lib: Improve the is_signed_type() kunit test
LoadPin: Require file with verity root digests to have a header
dm: verity-loadpin: Only trust verity targets with enforcement
LoadPin: Fix Kconfig doc about format of file with verity digests
um: Enable FORTIFY_SOURCE
lkdtm: Update tests for memcpy() run-time warnings
fortify: Add run-time WARN for cross-field memcpy()
fortify: Use SIZE_MAX instead of (size_t)-1
...
Since binutils 2.39, ld will print a warning if any stack section is
executable, which is the default for stack sections on files without a
.note.GNU-stack section.
This was fixed for x86 in commit ffcf9c5700 ("x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments"),
but remained broken for UML, resulting in several warnings:
/usr/bin/ld: warning: arch/x86/um/vdso/vdso.o: missing .note.GNU-stack section implies executable stack
/usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
/usr/bin/ld: warning: .tmp_vmlinux.kallsyms1 has a LOAD segment with RWX permissions
/usr/bin/ld: warning: .tmp_vmlinux.kallsyms1.o: missing .note.GNU-stack section implies executable stack
/usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
/usr/bin/ld: warning: .tmp_vmlinux.kallsyms2 has a LOAD segment with RWX permissions
/usr/bin/ld: warning: .tmp_vmlinux.kallsyms2.o: missing .note.GNU-stack section implies executable stack
/usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
/usr/bin/ld: warning: vmlinux has a LOAD segment with RWX permissions
Link both the VDSO and vmlinux with -z noexecstack, fixing the warnings
about .note.GNU-stack sections. In addition, pass --no-warn-rwx-segments
to dodge the remaining warnings about LOAD segments with RWX permissions
in the kallsyms objects. (Note that this flag is apparently not
available on lld, so hide it behind a test for BFD, which is what the
x86 patch does.)
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ffcf9c5700e49c0aee42dcba9a12ba21338e8136
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Tested-by: Lukas Straub <lukasstraub2@web.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Richard Weinberger <richard@nod.at>
It is always unnecessary to initialise statics to 0.
Signed-off-by: Shaomin Deng <dengshaomin@cdjrlc.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The double `in' is duplicated in line 172, remove one.
Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Currently the panic notifiers from user mode linux don't follow
the convention for most of the other notifiers present in the
kernel (indentation, priority setting, numeric return).
More important, the priorities could be improved, since it's a
special case (userspace), hence we could run the notifiers earlier;
user mode linux shouldn't care much with other panic notifiers but
the ordering among the mconsole and arch notifier is important,
given that the arch one effectively triggers a core dump.
Fix that by running the mconsole notifier as the first panic
notifier, followed by the architecture one (that coredumps).
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
V3:
- No changes.
V2:
- Kept the notifier header to avoid implicit usage - thanks
Johannes for the suggestion!
Signed-off-by: Richard Weinberger <richard@nod.at>
Use READ_ONCE_NOCHECK() when reading the stack to prevent KASAN splats
when dump_stack() is used.
Fixes: 5b301409e8 ("UML: add support for KASAN under x86_64")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The current 32 MiB of RAM causes OOMs to appear shortly after
booting in a minimal OpenWrt 22.03 configuration with a
5.10.134 kernel.
Of course, passing a "mem=64M" (from the --help text) parameter
works too, but it produces the following (info) message:
| [ 0.000000] Unknown kernel command line parameters "mem=64M", will be passed to user space.
That's why, I think it would be nicer, if this is working out
of the box again :).
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
OpenWrt's UML with 5.15 was producing odd errors/warnings during preinit
part of the early userspace portion:
|[ 0.000000] Kernel command line: ubd0=root.img root=98:0 console=tty
|[...]
|[ 0.440000] random: jshn: uninitialized urandom read (4 bytes read)
|[ 0.460000] random: jshn: uninitialized urandom read (4 bytes read)
|/etc/preinit: line 47: can't create /dev/tty: No such device or address
|/etc/preinit: line 48: can't create /dev/tty: No such device or address
|/etc/preinit: line 58: can't open /dev/tty: No such device or address
|[...] repeated many times
That "/dev/tty" came from the command line (which is automatically
added if no console= parameter was specified for the uml binary).
The TLDP project tells the following about the /dev/tty:
<https://tldp.org/HOWTO/Text-Terminal-HOWTO-7.html#ss7.3>
| /dev/tty stands for the controlling terminal (if any) for the current
| process.[...]
| /dev/tty is something like a link to the actually terminal device[..]
The "(if any)" is important here, since it's possible for processes to
not have a controlling terminal.
I think this was a simple typo and the author wanted tty0 there.
CC: Thomas Meyer <thomas@m3y3r.de>
Fixes: d7ffac3363 ("um: stdio_console: Make preferred console")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
If VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS is activated, the user mode
linux virtio irq handler only read one msg from the corresponding socket.
This creates issues, when the device emulation creates multiple call
requests (e.g. for multiple virtqueues), as the socket buffer tend to fill
up and the call requests are delayed.
This creates a deadlock situation, when the device simulation blocks,
because of sending a msg and the kernel side blocks because of
synchronously waiting for an acknowledge of kick request.
Actually inband notifications are meant to be used in combination with the
time travel protocol, but it is not required, therefore this corner case
needs to be handled.
Anyways, in general it seems to be more natural to consume always all
messages from a socket, instead of only a single one.
Fixes: 2cd097ba8c ("um: virtio: Implement VHOST_USER_PROTOCOL_F_SLAVE_REQ")
Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Richard Weinberger <richard@nod.at>
Linus Torvalds
Jason A. Donenfeld
Matthew Wilcox (Oracle)
David Gow
Shaomin Deng
Xin Gao
Jason Wang
Guilherme G. Piccoli
Gaosheng Cui
Xiu Jianfeng
Vincent Whitchurch
Wolfram Sang
Christian Lamparter
Huacai Chen
Benjamin Beichler
Kefeng Wang
Arnd Bergmann
Kees Cook
Nick Desaulniers