x86/fault: Fix wrong signal when vsyscall fails with pkey

The function __bad_area_nosemaphore() calls kernelmode_fixup_or_oops()
with the parameter @signal being actually @pkey, which will send a
signal numbered with the argument in @pkey.

This bug can be triggered when the kernel fails to access user-given
memory pages that are protected by a pkey, so it can go down 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, the kernel will generate the wrong
signal.

Add a new parameter @pkey to kernelmode_fixup_or_oops() to fix this.

 [ bp: Massage commit message, fix build error as reported by the 0day
   bot: https://lkml.kernel.org/r/[email protected] ]

Fixes: 5042d40a264c ("x86/fault: Bypass no_context() for implicit kernel faults from usermode")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Jiashuo Liang <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions