Merge PTRACE_SETREGSET leakage fixes from Dave Martin:
"This series is the collection of fixes I proposed on this topic, that
have not yet appeared upstream or in the stable branches,
The issue can leak kernel stack, but doesn't appear to allow userspace
to attack the kernel directly. The affected architectures are c6x,
h8300, metag, mips and sparc.
[ Mark Salter points out that c6x has no MMU or other mechanism to
prevent userspace access to kernel code or data on c6x, but it
doesn't hurt to clean that case up too. ]
The bugs arise from use of user_regset_copyin(). Users of
user_regset_copyin() can work in one of two ways:
1) Copy directly to thread_struct or equivalent. (This seems to be
the design assumption of the regset API, and is the most common
approach.)
2) Copy to a local variable and then transfer to thread_struct. (A
significant minority of cases.)
Buggy code typically involves approach 2"
* emailed patches from Dave Martin <Dave.Martin@arm.com>:
sparc/ptrace: Preserve previous registers for short regset write
mips/ptrace: Preserve previous registers for short regset write
metag/ptrace: Reject partial NT_METAG_RPIPE writes
metag/ptrace: Provide default TXSTATUS for short NT_PRSTATUS
metag/ptrace: Preserve previous registers for short regset write
h8300/ptrace: Fix incorrect register transfer count
c6x/ptrace: Remove useless PTRACE_SETREGSET implementation
gpr_set won't work correctly and can never have been tested, and the
correct behaviour is not clear due to the endianness-dependent task
layout.
So, just remove it. The core code will now return -EOPNOTSUPPORT when
trying to set NT_PRSTATUS on this architecture until/unless a correct
implementation is supplied.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are going to split <linux/sched/task_stack.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/task_stack.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>
Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>
Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Linus Torvalds