Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull more random number generator updates from Jason Donenfeld:
"This time with some large scale tr

Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

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

show more ...

treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
t

treewide: use prandom_u32_max() when possible, part 1

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>

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Merge branch 'next' into for-linus

Prepare input updates for 5.20 (or 6.0) merge window.

Merge tag 'v5.18' into next

Sync up with mainline to get updates to OMAP4 keypad driver and other
upstream goodies.

Merge tag 'v5.18'

Linux 5.18

Merge tag 'asoc-fix-v5.18-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.18

A collection of fixes that came in since the merge window, plus

Merge tag 'asoc-fix-v5.18-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.18

A collection of fixes that came in since the merge window, plus one new
device ID for an x86 laptop. Nothing that really stands out with
particularly big impact outside of the affected device.

show more ...

Merge branch 'topic/cs35l41' into for-next

Pull CS35L41 codec updates

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Merge drm/drm-next into drm-intel-gt-next

Pull in TTM changes needed for DG2 CCS enabling from Ram.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge drm/drm-next into drm-intel-next

Sync up with v5.18-rc1, in particular to get 5e3094cfd9fb
("drm/i915/xehpsdv: Add has_flat_ccs to device info").

Signed-off-by: Jani Nikula <jani.nikula@intel

Merge drm/drm-next into drm-intel-next

Sync up with v5.18-rc1, in particular to get 5e3094cfd9fb
("drm/i915/xehpsdv: Add has_flat_ccs to device info").

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

show more ...

Merge drm/drm-fixes into drm-misc-fixes

Let's start the 5.18 fixes cycle.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Merge drm/drm-next into drm-misc-next

Let's start the 5.19 development cycle.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Merge remote-tracking branch 'torvalds/master' into perf/core

To pick up fixes that went thru perf/urgent and now are fixed by an
upcoming patch.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redha

Merge remote-tracking branch 'torvalds/master' into perf/core

To pick up fixes that went thru perf/urgent and now are fixed by an
upcoming patch.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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Merge tag 'for-5.18/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc architecture updates from Helge Deller:

- add vDSO support (allows us to use non-exec

Merge tag 'for-5.18/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc architecture updates from Helge Deller:

- add vDSO support (allows us to use non-executable stacks)

- many TLB and cache flush optimizations (by Dave Anglin)

- fix handling of probe non-access faults (by Dave Anglin)

- fix invalidate/flush vmap routines (by Dave Anglin)

- avoid using hardware single-step in kprobes

- enable ARCH_HAS_DEBUG_VM_PGTABLE

- many cleanups in unaligned handlers, e.g. rewrite of existing
assembly code

- always use the self-extracting kernel feature

- big refacturing and code reductions regarding space-register usage in
get_user() and put_user()

- add fillrect() support to stifb graphics driver

* tag 'for-5.18/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: (23 commits)
parisc: Fix invalidate/flush vmap routines
parisc: Avoid flushing cache on cache-less machines
parisc: Avoid using hardware single-step in kprobes
parisc: Improve CPU socket and core bootup info text
parisc: Enable ARCH_HAS_DEBUG_VM_PGTABLE
parisc: Avoid calling SMP cache flush functions on cache-less machines
parisc: Increase parisc_cache_flush_threshold setting
parisc/unaligned: Enhance user-space visible output
parisc/unaligned: Rewrite 32-bit inline assembly of emulate_sth()
parisc/unaligned: Rewrite 32-bit inline assembly of emulate_ldd()
parisc/unaligned: Rewrite inline assembly of emulate_ldw()
parisc/unaligned: Rewrite inline assembly of emulate_ldh()
parisc/unaligned: Use EFAULT fixup handler in unaligned handlers
parisc: Reduce code size by optimizing get_current() function calls
parisc: Use constants to encode the space registers like SR_KERNEL
parisc: Use SR_USER and SR_KERNEL in get_user() and put_user()
parisc: Add defines for various space register
parisc: Always use the self-extracting kernel feature
video/fbdev/stifb: Implement the stifb_fillrect() function
parisc: Add vDSO support
...

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parisc: Add vDSO support

Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.

The big benefit of this vDSO implement

parisc: Add vDSO support

Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.

The big benefit of this vDSO implementation is, that we now don't need
an executeable stack any longer. PA-RISC is one of the last
architectures where an executeable stack was needed in oder to implement
the signal trampolines by putting assembly instructions on the stack
which then gets executed. Instead the kernel will provide the relevant
code in the vDSO page and only put the pointers to the signal
information on the stack.

By dropping the need for executable stacks we avoid running into issues
with applications which want non executable stacks for security reasons.
Additionally, alternative stacks on memory areas without exec
permissions are supported too.

This code is based on an initial implementation by Randolph Chung from 2006:
https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/

I did the porting and lifted the code to current code base. Dave fixed
the unwind code so that gdb and glibc are able to backtrace through the
code. An additional patch to gdb will be pushed upstream by Dave.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: Randolph Chung <randolph@tausq.org>
Signed-off-by: Helge Deller <deller@gmx.de>

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