Messages in this thread | | | Subject | Re: [PATCH v2] x86/fault: Fix wrong signal when vsyscall fails with pkey | From | Dave Hansen <> | Date | Mon, 23 Aug 2021 07:55:33 -0700 |
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On 7/29/21 8:01 PM, Jiashuo Liang wrote: > The function __bad_area_nosemaphore() calls kernelmode_fixup_or_oops() with > parameter "signal" being "pkey", which will send a signal numbered "pkey". > > This bug appears when the kernel fail to access user-given memory pages > that are protected by pkey, so it can go through the do_user_addr_fault() > path and pass the !user_mode() check in __bad_area_nosemaphore(). Most > cases will simply run the kernel fixup code to make an -EFAULT. But when > another condition current->thread.sig_on_uaccess_err is met, which is > only used to emulate vsyscall, we will generate the wrong signal. > > A new parameter "pkey" is added to kernelmode_fixup_or_oops() to fix it. > > Fixes: 5042d40a264c ("x86/fault: Bypass no_context() for implicit kernel faults from usermode") > Signed-off-by: Jiashuo Liang <liangjs@pku.edu.cn>
This is pretty obscure, only affecting vsyscall emulation, but:
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
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