commit dbd4d7ca563fd0a8949718d35ce197e5642d5d9d upstream.

We validate pstate using PSR_MODE32_BIT, which is part of the
user-provided pstate (and cannot be trusted). Also, we conflate
validation of AArch32 and AArch64 pstate values, making the code
difficult to reason about.

Instead, validate the pstate value based on the associated task. The
task may or may not be current (e.g. when using ptrace), so this must be
passed explicitly by callers. To avoid circular header dependencies via
sched.h, is_compat_task is pulled out of asm/ptrace.h.

To make the code possible to reason about, the AArch64 and AArch32
validation is split into separate functions. Software must respect the
RES0 policy for SPSR bits, and thus the kernel mirrors the hardware
policy (RAZ/WI) for bits as-yet unallocated. When these acquire an
architected meaning writes may be permitted (potentially with additional
validation).

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ rebased for v4.1+
  This avoids a user-triggerable Oops() if a task is switched to a mode
  not supported by the kernel (e.g. switching a 64-bit task to AArch32).
]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com> [backport]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 5db4fd8c52810bd9740c1240ebf89223b171aa70 upstream.

Make sure to clear out any ptrace singlestep state when a ptrace(2)
PTRACE_DETACH call is made on arm64 systems.

Otherwise, the previously ptraced task will die off with a SIGTRAP
signal if the debugger just previously singlestepped the ptraced task.

Signed-off-by: John Blackwood <john.blackwood@ccur.com>
[will: added comment to justify why this is in the arch code]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The compat ptrace interface allows access to the TLS register, hardware
breakpoints and watchpoints, syscall number. However, a native task
using the native ptrace interface to debug compat tasks (e.g. multi-arch
gdb) only has access to the general and VFP register sets. The compat
ptrace interface cannot be accessed from a native task.

This patch adds a new user_aarch32_ptrace_view which contains the TLS,
hardware breakpoint/watchpoint and syscall number regsets in addition to
the existing GPR and VFP regsets. This view is backwards compatible with
the previous kernels. Core dumping of 32-bit tasks and compat ptrace are
not affected since the original user_aarch32_view is preserved.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Yao Qi <yao.qi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

secure_computing() is called first in syscall_trace_enter() so that
a system call will be aborted quickly without doing succeeding syscall
tracing if seccomp rules want to deny that system call.

On compat task, syscall numbers for system calls allowed in seccomp mode 1
are different from those on normal tasks, and so _NR_seccomp_xxx_32's need
to be redefined.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This regeset is intended to be used to get and set a system call number
while tracing.
There was some discussion about possible approaches to do so:

(1) modify x8 register with ptrace(PTRACE_SETREGSET) indirectly,
    and update regs->syscallno later on in syscall_trace_enter(), or
(2) define a dedicated regset for this purpose as on s390, or
(3) support ptrace(PTRACE_SET_SYSCALL) as on arch/arm

Thinking of the fact that user_pt_regs doesn't expose 'syscallno' to
tracer as well as that secure_computing() expects a changed syscall number,
especially case of -1, to be visible before this function returns in
syscall_trace_enter(), (1) doesn't work well.
We will take (2) since it looks much cleaner.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Pull audit updates from Eric Paris:
 "So this change across a whole bunch of arches really solves one basic
  problem.  We want to audit when seccomp is killing a process.  seccomp
  hooks in before the audit syscall entry code.  audit_syscall_entry
  took as an argument the arch of the given syscall.  Since the arch is
  part of what makes a syscall number meaningful it's an important part
  of the record, but it isn't available when seccomp shoots the
  syscall...

  For most arch's we have a better way to get the arch (syscall_get_arch)
  So the solution was two fold: Implement syscall_get_arch() everywhere
  there is audit which didn't have it.  Use syscall_get_arch() in the
  seccomp audit code.  Having syscall_get_arch() everywhere meant it was
  a useless flag on the stack and we could get rid of it for the typical
  syscall entry.

  The other changes inside the audit system aren't grand, fixed some
  records that had invalid spaces.  Better locking around the task comm
  field.  Removing some dead functions and structs.  Make some things
  static.  Really minor stuff"

* git://git.infradead.org/users/eparis/audit: (31 commits)
  audit: rename audit_log_remove_rule to disambiguate for trees
  audit: cull redundancy in audit_rule_change
  audit: WARN if audit_rule_change called illegally
  audit: put rule existence check in canonical order
  next: openrisc: Fix build
  audit: get comm using lock to avoid race in string printing
  audit: remove open_arg() function that is never used
  audit: correct AUDIT_GET_FEATURE return message type
  audit: set nlmsg_len for multicast messages.
  audit: use union for audit_field values since they are mutually exclusive
  audit: invalid op= values for rules
  audit: use atomic_t to simplify audit_serial()
  kernel/audit.c: use ARRAY_SIZE instead of sizeof/sizeof[0]
  audit: reduce scope of audit_log_fcaps
  audit: reduce scope of audit_net_id
  audit: arm64: Remove the audit arch argument to audit_syscall_entry
  arm64: audit: Add audit hook in syscall_trace_enter/exit()
  audit: x86: drop arch from __audit_syscall_entry() interface
  sparc: implement is_32bit_task
  sparc: properly conditionalize use of TIF_32BIT
  ...

The arm64 tree added calls to audit_syscall_entry() and rightly included
the syscall number.  The interface has since been changed to not need
the syscall number.  As such, arm64 should no longer pass that value.

Signed-off-by: Eric Paris <eparis@redhat.com>

This patch adds auditing functions on entry to or exit from
every system call invocation.

Acked-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

copy_{to,from}_user return the number of bytes remaining on failure, not
an error code.

This patch returns -EFAULT when the copy operation didn't complete,
rather than expose the number of bytes not copied directly to userspace.

Signed-off-by: Will Deacon <will.deacon@arm.com>

I'm not sure what I was on when I wrote this, but when iterating over
the hardware watchpoint array (hbp_watch_array), our index is off by
ARM_MAX_BRP, so we walk off the end of our thread_struct...

... except, a dodgy condition in the loop means that it never executes
at all (bp cannot be NULL).

This patch fixes the code so that we remove the bp check and use the
correct index for accessing the watchpoint structures.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>