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    SubjectRe: [PATCH v3] vsprintf: Prevent crash when dereferencing invalid pointers
    On Thu, 15 Mar 2018 17:03:09 +0900
    Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:

    > On (03/15/18 16:58), Sergey Senozhatsky wrote:
    > > On (03/14/18 15:09), Petr Mladek wrote:
    > > [..]
    > > > +static const char *check_pointer_access(const void *ptr)
    > > > +{
    > > > + unsigned char byte;
    > > > +
    > > > + if (!ptr)
    > > > + return "(null)";
    > > > +
    > > > + if (probe_kernel_read(&byte, ptr, 1))
    > > ^^^^^
    > > Why one byte? sizeof(ptr)?
    >
    > I think there is a shorter version - probe_kernel_address(),
    > which, seems, was designed for this particular kind of stuff.
    >
    > void *p;
    >
    > if (probe_kernel_address(ptr, p))
    > ....
    >

    Agreed.

    -- Steve

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