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    SubjectRe: [Internet]Re: [PATCH] fbcon: Out-Of-Bounds write in sys_imageblit, add range check
    On Tue, Jul 27, 2021 at 01:53:13AM +0000, tcs_kernel(腾讯云内核开发者) wrote:
    > yres and vyres can be controlled by user mode paramaters, and cause p->vrows to become a negative value. While this value be passed to real_y function, the ypos will be out of screen range.
    > This is an out-of-bounds write bug.
    > I think updatescrollmode is the right place to validate values supplied by a user ioctl, because only here makes --operation,and 0 is a legal value before that.

    Please wrap your changelog text.

    > Signed-off-by: Tencent Cloud System

    That is not the name of a person :(

    And the format isn't correct, so there's nothing we can do with this
    patch, and the patch itself is corrupted and could not be applied :(

    Also, what about checking these values earlier? How can the value be 0
    earlier and be acceptable? Putting bounds on the user-provided values
    would be much easier, right?


    greg k-h

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