kernel/arch/arm/include/asm/assembler.h, branch linux-4.15.y

ARM: BUG if jumping to usermode address in kernel mode

2017-11-26T15:41:39Z

Detect if we are returning to usermode via the normal kernel exit paths but the saved PSR value indicates that we are in kernel mode. This could occur due to corrupted stack state, which has been observed with "ftracetest". This ensures that we catch the problem case before we get to user code. Signed-off-by: Russell King

ARM: Prepare for randomized task_struct

2017-06-30T19:00:50Z

With the new task struct randomization, we can run into a build failure for certain random seeds, which will place fields beyond the allow immediate size in the assembly: arch/arm/kernel/entry-armv.S: Assembler messages: arch/arm/kernel/entry-armv.S:803: Error: bad immediate value for offset (4096) Only two constants in asm-offset.h are affected, and I'm changing both of them here to work correctly in all configurations. One more macro has the problem, but is currently unused, so this removes it instead of adding complexity. Suggested-by: Ard Biesheuvel Signed-off-by: Arnd Bergmann [kees: Adjust commit log slightly] Signed-off-by: Kees Cook

ARM: 8605/1: V7M: fix notrace variant of save_and_disable_irqs

2016-09-06T14:51:07Z

Commit 8e43a905 "ARM: 7325/1: fix v7 boot with lockdep enabled" introduced notrace variant of save_and_disable_irqs to balance notrace variant of restore_irqs; however V7M case has been missed. It was not noticed because cache-v7.S the only place where notrace variant is used. So fix it, since we are going to extend V7 cache routines to handle V7M case too. Signed-off-by: Vladimir Murzin Tested-by: Andras Szemzo Tested-by: Joachim Eastwood Tested-by: Alexandre TORGUE Signed-off-by: Russell King

ARM: introduce svc_pt_regs structure

2016-06-22T18:54:52Z

Since the privileged mode pt_regs are an extended version of the saved userland pt_regs, introduce a new svc_pt_regs structure to describe this layout. Acked-by: Will Deacon Signed-off-by: Russell King

ARM: rename S_FRAME_SIZE to PT_REGS_SIZE

2016-06-22T18:54:28Z

S_FRAME_SIZE is no longer the size of the kernel stack frame, so this name is misleading. It is the size of the kernel pt_regs structure. Name it so. Acked-by: Will Deacon Signed-off-by: Russell King

Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

2015-09-14T19:24:10Z

Pull ARM fixes from Russell King: "A number of fixes for the merge window, fixing a number of cases missed when testing the uaccess code, particularly cases which only show up with certain compiler versions" * 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: ARM: 8431/1: fix alignement of __bug_table section entries arm/xen: Enable user access to the kernel before issuing a privcmd call ARM: domains: add memory dependencies to get_domain/set_domain ARM: domains: thread_info.h no longer needs asm/domains.h ARM: uaccess: fix undefined instruction on ARMv7M/noMMU ARM: uaccess: remove unneeded uaccess_save_and_disable macro ARM: swpan: fix nwfpe for uaccess changes ARM: 8429/1: disable GCC SRA optimization

ARM: uaccess: remove unneeded uaccess_save_and_disable macro

2015-09-09T22:26:40Z

This macro is never referenced, remove it. Signed-off-by: Russell King

Merge branches 'cleanup', 'fixes', 'misc', 'omap-barrier' and 'uaccess' into for-linus

2015-09-03T14:28:37Z

ARM: software-based priviledged-no-access support

2015-08-26T19:34:24Z

Provide a software-based implementation of the priviledged no access support found in ARMv8.1. Userspace pages are mapped using a different domain number from the kernel and IO mappings. If we switch the user domain to "no access" when we enter the kernel, we can prevent the kernel from touching userspace. However, the kernel needs to be able to access userspace via the various user accessor functions. With the wrapping in the previous patch, we can temporarily enable access when the kernel needs user access, and re-disable it afterwards. This allows us to trap non-intended accesses to userspace, eg, caused by an inadvertent dereference of the LIST_POISON* values, which, with appropriate user mappings setup, can be made to succeed. This in turn can allow use-after-free bugs to be further exploited than would otherwise be possible. Signed-off-by: Russell King

ARM: entry: provide uaccess assembly macro hooks

2015-08-26T19:27:02Z

Provide hooks into the kernel entry and exit paths to permit control of userspace visibility to the kernel. The intended use is: - on entry to kernel from user, uaccess_disable will be called to disable userspace visibility - on exit from kernel to user, uaccess_enable will be called to enable userspace visibility - on entry from a kernel exception, uaccess_save_and_disable will be called to save the current userspace visibility setting, and disable access - on exit from a kernel exception, uaccess_restore will be called to restore the userspace visibility as it was before the exception occurred. These hooks allows us to keep userspace visibility disabled for the vast majority of the kernel, except for localised regions where we want to explicitly access userspace. Signed-off-by: Russell King