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    Subject[patch 13/16] x86_64: Fix canonical checking for segment registers in ptrace
    [PATCH] x86_64: Fix canonical checking for segment registers in ptrace

    Allowed user programs to set a non canonical segment base, which would cause
    oopses in the kernel later.

    Credit-to: Alexander Nyberg <alexn@dsv.su.se>

    For identifying and reporting this bug.

    Signed-off-by: Andi Kleen <ak@suse.de>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>
    Signed-off-by: Chris Wright <chrisw@osdl.org>
    ---

    ptrace.c | 8 ++++----
    1 files changed, 4 insertions(+), 4 deletions(-)

    Index: release-2.6.11/arch/x86_64/kernel/ptrace.c
    ===================================================================
    --- release-2.6.11.orig/arch/x86_64/kernel/ptrace.c
    +++ release-2.6.11/arch/x86_64/kernel/ptrace.c
    @@ -129,13 +129,13 @@ static int putreg(struct task_struct *ch
    value &= 0xffff;
    return 0;
    case offsetof(struct user_regs_struct,fs_base):
    - if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
    - return -EIO;
    + if (value >= TASK_SIZE)
    + return -EIO;
    child->thread.fs = value;
    return 0;
    case offsetof(struct user_regs_struct,gs_base):
    - if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
    - return -EIO;
    + if (value >= TASK_SIZE)
    + return -EIO;
    child->thread.gs = value;
    return 0;
    case offsetof(struct user_regs_struct, eflags):
    -
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