Messages in this thread | | | Date | Mon, 17 Oct 2022 22:25:04 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH] vsprintf: protect kernel from panic due to non-canonical pointer dereference |
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On Mon, Oct 17, 2022 at 01:16:11PM -0600, Jane Chu wrote: > While debugging a separate issue, it was found that an invalid string > pointer could very well contain a non-canical address, such as > 0x7665645f63616465. In that case, this line of defense isn't enough > to protect the kernel from crashing due to general protection fault > > if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr)) > return "(efault)"; > > So instead, use kern_addr_valid() to validate the string pointer.
How did you check that value of the (invalid string) pointer?
-- With Best Regards, Andy Shevchenko
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