kernel - Hosts the 0x221E linux distro kernel.

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Hosts the 0x221E linux distro kernel.

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't be too concerned about the overall performance since this should only occur when callers are doing something a bit dodgy in the first place. Particularly broken userspace might still be able to trick generic_perform_write() into an infinite loop by targeting write() at an mmap() of some read-only device register where the fault-in load succeeds but any store synchronously aborts such that copy_to_user() is genuinely unable to make progress, but, well, don't do that... CC: stable@vger.kernel.org Reported-by: Chen Huang <chenhuang5@huawei.com> Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/dc03d5c675731a1f24a62417dba5429ad744234e.1626098433.git.robin.murphy@arm.com Signed-off-by: Will Deacon <will@kernel.org> 2020-12-02arm64: uaccess cleanup macro namingMark Rutland Now the uaccess primitives use LDTR/STTR unconditionally, the uao_{ldp,stp,user_alternative} asm macros are misnamed, and have a redundant argument. Let's remove the redundant argument and rename these to user_{ldp,stp,ldst} respectively to clean this up. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Robin Murohy <robin.murphy@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201202131558.39270-9-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 2020-04-29arm64: Reorder the macro arguments in the copy routinesCatalin Marinas The current argument order is obviously buggy (memcpy.S): macro strb1 ptr, regB, val strb \ptr, [\regB], \val endm However, it cancels out as the calling sites in copy_template.S pass the address as the regB argument. Mechanically reorder the arguments to match the instruction mnemonics. There is no difference in objdump before and after this patch. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20200429183702.28445-1-catalin.marinas@arm.com Signed-off-by: Will Deacon <will@kernel.org> 2020-01-08arm64: lib: Use modern annotations for assembly functionsMark Brown In an effort to clarify and simplify the annotation of assembly functions in the kernel new macros have been introduced. These replace ENTRY and ENDPROC and also add a new annotation for static functions which previously had no ENTRY equivalent. Update the annotations in the library code to the new macros. Signed-off-by: Mark Brown <broonie@kernel.org> [will: Use SYM_FUNC_START_WEAK_PI] Signed-off-by: Will Deacon <will@kernel.org> 2019-11-20arm64: uaccess: Remove uaccess_*_not_uao asm macrosPavel Tatashin It is safer and simpler to drop the uaccess assembly macros in favour of inline C functions. Although this bloats the Image size slightly, it aligns our user copy routines with '{get,put}_user()' and generally makes the code a lot easier to reason about. Cc: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> [will: tweaked commit message and changed temporary variable names] Signed-off-by: Will Deacon <will@kernel.org> 2019-11-20arm64: uaccess: Ensure PAN is re-enabled after unhandled uaccess faultPavel Tatashin A number of our uaccess routines ('__arch_clear_user()' and '__arch_copy_{in,from,to}_user()') fail to re-enable PAN if they encounter an unhandled fault whilst accessing userspace. For CPUs implementing both hardware PAN and UAO, this bug has no effect when both extensions are in use by the kernel. For CPUs implementing hardware PAN but not UAO, this means that a kernel using hardware PAN may execute portions of code with PAN inadvertently disabled, opening us up to potential security vulnerabilities that rely on userspace access from within the kernel which would usually be prevented by this mechanism. In other words, parts of the kernel run the same way as they would on a CPU without PAN implemented/emulated at all. For CPUs not implementing hardware PAN and instead relying on software emulation via 'CONFIG_ARM64_SW_TTBR0_PAN=y', the impact is unfortunately much worse. Calling 'schedule()' with software PAN disabled means that the next task will execute in the kernel using the page-table and ASID of the previous process even after 'switch_mm()', since the actual hardware switch is deferred until return to userspace. At this point, or if there is a intermediate call to 'uaccess_enable()', the page-table and ASID of the new process are installed. Sadly, due to the changes introduced by KPTI, this is not an atomic operation and there is a very small window (two instructions) where the CPU is configured with the page-table of the old task and the ASID of the new task; a speculative access in this state is disastrous because it would corrupt the TLB entries for the new task with mappings from the previous address space. As Pavel explains: | I was able to reproduce memory corruption problem on Broadcom's SoC | ARMv8-A like this: | | Enable software perf-events with PERF_SAMPLE_CALLCHAIN so userland's | stack is accessed and copied. | | The test program performed the following on every CPU and forking | many processes: | | unsigned long *map = mmap(NULL, PAGE_SIZE, PROT_READ|PROT_WRITE, | MAP_SHARED | MAP_ANONYMOUS, -1, 0); | map[0] = getpid(); | sched_yield(); | if (map[0] != getpid()) { | fprintf(stderr, "Corruption detected!"); | } | munmap(map, PAGE_SIZE); | | From time to time I was getting map[0] to contain pid for a | different process. Ensure that PAN is re-enabled when returning after an unhandled user fault from our uaccess routines. Cc: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Cc: <stable@vger.kernel.org> Fixes: 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access Never") Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> [will: rewrote commit message] Signed-off-by: Will Deacon <will@kernel.org> 2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234Thomas Gleixner 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>


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