We use cpus_have_const_cap() to check for ARM64_HAS_EPAN but this is not
necessary and alternative_has_cap() or cpus_have_cap() would be
preferable.
For historical reasons, cpus_have_const_cap() is more complicated than
it needs to be. Before cpucaps are finalized, it will perform a bitmap
test of the system_cpucaps bitmap, and once cpucaps are finalized it
will use an alternative branch. This used to be necessary to handle some
race conditions in the window between cpucap detection and the
subsequent patching of alternatives and static branches, where different
branches could be out-of-sync with one another (or w.r.t. alternative
sequences). Now that we use alternative branches instead of static
branches, these are all patched atomically w.r.t. one another, and there
are only a handful of cases that need special care in the window between
cpucap detection and alternative patching.
Due to the above, it would be nice to remove cpus_have_const_cap(), and
migrate callers over to alternative_has_cap_*(), cpus_have_final_cap(),
or cpus_have_cap() depending on when their requirements. This will
remove redundant instructions and improve code generation, and will make
it easier to determine how each callsite will behave before, during, and
after alternative patching.
The ARM64_HAS_EPAN cpucap is used to affect two things:
1) The permision bits used for userspace executable mappings, which are
chosen by adjust_protection_map(), which is an arch_initcall. This is
called after the ARM64_HAS_EPAN cpucap has been detected and
alternatives have been patched, and before any userspace translation
tables exist.
2) The handling of faults taken from (user or kernel) accesses to
userspace executable mappings in do_page_fault(). Userspace
translation tables are created after adjust_protection_map() is
called, and hence after the ARM64_HAS_EPAN cpucap has been detected
and alternatives have been patched.
Neither of these run until after ARM64_HAS_EPAN cpucap has been detected
and alternatives have been patched, and hence there's no need to use
cpus_have_const_cap(). Since adjust_protection_map() is only executed
once at boot time it would be best for it to use cpus_have_cap(), and
since do_page_fault() is executed frequently it would be best for it to
use alternatives_have_cap_unlikely().
This patch replaces the uses of cpus_have_const_cap() with
cpus_have_cap() and alternative_has_cap_unlikely(), which will avoid
generating redundant code, and should be better for all subsequent calls
at runtime. The ARM64_HAS_EPAN cpucap is added to cpucap_is_possible()
so that code can be elided entirely when this is not possible.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 18107f8a2d ("arm64: Support execute-only permissions with
Enhanced PAN") re-introduced execute-only permissions when EPAN is
available. When EPAN is not available, arch_filter_pgprot() is supposed
to change a PAGE_EXECONLY permission into PAGE_READONLY_EXEC. However,
if BTI or MTE are present, such check does not detect the execute-only
pgprot in the presence of PTE_GP (BTI) or MT_NORMAL_TAGGED (MTE),
allowing the user to request PROT_EXEC with PROT_BTI or PROT_MTE.
Remove the arch_filter_pgprot() function, change the default VM_EXEC
permissions to PAGE_READONLY_EXEC and update the protection_map[] array
at core_initcall() if EPAN is detected.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 18107f8a2d ("arm64: Support execute-only permissions with Enhanced PAN")
Cc: <stable@vger.kernel.org> # 5.13.x
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Commit 507d664450 ("arm64: mm: Remove unused header file") removed
a bunch of apparently "unused" header inclusions from our mm/mmap.c
implementation, but in doing so introduced the following warning when
building with W=1:
>> arch/arm64/mm/mmap.c:17:5: warning: no previous prototype for 'valid_phys_addr_range' [-Wmissing-prototypes]
17 | int valid_phys_addr_range(phys_addr_t addr, size_t size)
| ^~~~~~~~~~~~~~~~~~~~~
>> arch/arm64/mm/mmap.c:36:5: warning: no previous prototype for 'valid_mmap_phys_addr_range' [-Wmissing-prototypes]
36 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
Add back the linux/io.h header inclusion to pull in the missing
prototypes.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/202101271438.V9TmBC31-lkp@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Patch series "exec: Pin stack limit during exec".
Attempts to solve problems with the stack limit changing during exec
continue to be frustrated[1][2]. In addition to the specific issues
around the Stack Clash family of flaws, Andy Lutomirski pointed out[3]
other places during exec where the stack limit is used and is assumed to
be unchanging. Given the many places it gets used and the fact that it
can be manipulated/raced via setrlimit() and prlimit(), I think the only
way to handle this is to move away from the "current" view of the stack
limit and instead attach it to the bprm, and plumb this down into the
functions that need to know the stack limits. This series implements
the approach.
[1] 04e35f4495 ("exec: avoid RLIMIT_STACK races with prlimit()")
[2] 779f4e1c6c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"")
[3] to security@kernel.org, "Subject: existing rlimit races?"
This patch (of 3):
Since it is possible that the stack rlimit can change externally during
exec (either via another thread calling setrlimit() or another process
calling prlimit()), provide a way to pass the rlimit down into the
per-architecture mm layout functions so that the rlimit can stay in the
bprm structure instead of sitting in the signal structure until exec is
finalized.
Link: http://lkml.kernel.org/r/1518638796-20819-2-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When running lscpu on an AArch64 system that has SMBIOS version 2.0
tables, it will segfault in the following way:
Unable to handle kernel paging request at virtual address ffff8000bfff0000
pgd = ffff8000f9615000
[ffff8000bfff0000] *pgd=0000000000000000
Internal error: Oops: 96000007 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 1284 Comm: lscpu Not tainted 4.11.0-rc3+ #103
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
task: ffff8000fa78e800 task.stack: ffff8000f9780000
PC is at __arch_copy_to_user+0x90/0x220
LR is at read_mem+0xcc/0x140
This is caused by the fact that lspci issues a read() on /dev/mem at the
offset where it expects to find the SMBIOS structure array. However, this
region is classified as EFI_RUNTIME_SERVICE_DATA (as per the UEFI spec),
and so it is omitted from the linear mapping.
So let's restrict /dev/mem read/write access to those areas that are
covered by the linear region.
Reported-by: Alexander Graf <agraf@suse.de>
Fixes: 4dffbfc48d ("arm64/efi: mark UEFI reserved regions as MEMBLOCK_NOMAP")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
We are going to split more MM APIs out of <linux/sched.h>, which
will have to be picked up from a couple of .c files.
The APIs that we are going to move are:
arch_pick_mmap_layout()
arch_get_unmapped_area()
arch_get_unmapped_area_topdown()
mm_update_next_owner()
Include the header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch_pick_mmap_layout is only called by fs/exec.c which is always built into
kernel, it looks the EXPORT_SYMBOL_GPL is pointless and no architectures export
it other than ARM64.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In preparation for splitting out ET_DYN ASLR, this refactors the use of
mmap_rnd() to be used similarly to arm and x86. This additionally
enables mmap ASLR on legacy mmap layouts, which appeared to be missing
on arm64, and was already supported on arm. Additionally removes a
copy/pasted declaration of an unused function.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 8a0a9bd4db ('random: make get_random_int() more
random'), get_random_int() returns a random value for each call,
so comment and hack introduced in mmap_rnd() as part of commit
1d18c47c73 ('arm64: MMU fault handling and page table management')
are incorrects.
Commit 1d18c47c73 seems to use the same hack introduced by
commit a5adc91a4b ('powerpc: Ensure random space between stack
and mmaps'), latter copied in commit 5a0efea09f ('sparc64: Sharpen
address space randomization calculations.').
But both architectures were cleaned up as part of commit
fa8cbaaf5a ('powerpc+sparc64/mm: Remove hack in mmap randomize
layout') as hack is no more needed since commit 8a0a9bd4db.
So the present patch removes the comment and the hack around
get_random_int() on AArch64's mmap_rnd().
Cc: David S. Miller <davem@davemloft.net>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Change the type of physical address from unsigned long to phys_addr_t,
make valid_phys_addr_range more readable.
Signed-off-by: Min-Hua Chen <orca.chen@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds support for the handling of the MMU faults (exception
entry code introduced by a previous patch) and page table management.
The user translation table is pointed to by TTBR0 and the kernel one
(swapper_pg_dir) by TTBR1. There is no translation information shared or
address space overlapping between user and kernel page tables.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
