Eric Lee / smarc-fsl-linux-kernel

06 Jan, 2017

1 commit

  • 694a95fa6   mm: Add a user_ns owner to mm_struct and fix ptrace permission checks ... Browse Code »

    commit bfedb589252c01fa505ac9f6f2a3d5d68d707ef4 upstream.

    During exec dumpable is cleared if the file that is being executed is
    not readable by the user executing the file. A bug in
    ptrace_may_access allows reading the file if the executable happens to
    enter into a subordinate user namespace (aka clone(CLONE_NEWUSER),
    unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER).

    This problem is fixed with only necessary userspace breakage by adding
    a user namespace owner to mm_struct, captured at the time of exec, so
    it is clear in which user namespace CAP_SYS_PTRACE must be present in
    to be able to safely give read permission to the executable.

    The function ptrace_may_access is modified to verify that the ptracer
    has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns.
    This ensures that if the task changes it's cred into a subordinate
    user namespace it does not become ptraceable.

    The function ptrace_attach is modified to only set PT_PTRACE_CAP when
    CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of
    PT_PTRACE_CAP is to be a flag to note that whatever permission changes
    the task might go through the tracer has sufficient permissions for
    it not to be an issue. task->cred->user_ns is always the same
    as or descendent of mm->user_ns. Which guarantees that having
    CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks
    credentials.

    To prevent regressions mm->dumpable and mm->user_ns are not considered
    when a task has no mm. As simply failing ptrace_may_attach causes
    regressions in privileged applications attempting to read things
    such as /proc//stat

    Acked-by: Kees Cook
    Tested-by: Cyrill Gorcunov
    Fixes: 8409cca70561 ("userns: allow ptrace from non-init user namespaces")
    Signed-off-by: "Eric W. Biederman"
    Signed-off-by: Greg Kroah-Hartman

    Eric W. Biederman
     

27 Jul, 2011

1 commit

  • 60063497a   atomic: use <linux/atomic.h> ... Browse Code »

    This allows us to move duplicated code in
    (atomic_inc_not_zero() for now) to

    Signed-off-by: Arun Sharma
    Reviewed-by: Eric Dumazet
    Cc: Ingo Molnar
    Cc: David Miller
    Cc: Eric Dumazet
    Acked-by: Mike Frysinger
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arun Sharma
     

25 May, 2011

1 commit

  • de03c72cf   mm: convert mm->cpu_vm_cpumask into cpumask_var_t ... Browse Code »

    cpumask_t is very big struct and cpu_vm_mask is placed wrong position.
    It might lead to reduce cache hit ratio.

    This patch has two change.
    1) Move the place of cpumask into last of mm_struct. Because usually cpumask
    is accessed only front bits when the system has cpu-hotplug capability
    2) Convert cpu_vm_mask into cpumask_var_t. It may help to reduce memory
    footprint if cpumask_size() will use nr_cpumask_bits properly in future.

    In addition, this patch change the name of cpu_vm_mask with cpu_vm_mask_var.
    It may help to detect out of tree cpu_vm_mask users.

    This patch has no functional change.

    [akpm@linux-foundation.org: build fix]
    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: KOSAKI Motohiro
    Cc: David Howells
    Cc: Koichi Yasutake
    Cc: Hugh Dickins
    Cc: Chris Metcalf
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     

10 Aug, 2010

1 commit

  • a1b200e27   mm: provide init_mm mm_context initializer ... Browse Code »

    Provide an INIT_MM_CONTEXT intializer macro which can be used to
    statically initialize mm_struct:mm_context of init_mm. This way we can
    get rid of code which will do the initialization at run time (on s390).

    In addition the current code can be found at a place where it is not
    expected. So let's have a common initializer which architectures
    can use if needed.

    This is based on a patch from Suzuki Poulose.

    Signed-off-by: Heiko Carstens
    Cc: Martin Schwidefsky
    Cc: Suzuki Poulose
    Cc: Alexey Dobriyan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Heiko Carstens
     

17 Jun, 2009

1 commit

  • bb1f17b03   mm: consolidate init_mm definition ... Browse Code »

    * create mm/init-mm.c, move init_mm there
    * remove INIT_MM, initialize init_mm with C99 initializer
    * unexport init_mm on all arches:

    init_mm is already unexported on x86.

    One strange place is some OMAP driver (drivers/video/omap/) which
    won't build modular, but it's already wants get_vm_area() export.
    Somebody should look there.

    [akpm@linux-foundation.org: add missing #includes]
    Signed-off-by: Alexey Dobriyan
    Cc: Mike Frysinger
    Cc: Americo Wang
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan