x86/fault: Bypass no_context() for implicit kernel faults from usermode
Drop an indentation level and remove the last user_mode(regs) == true caller of no_context() by directly OOPSing for implicit kernel faults from usermode. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/6e3d1129494a8de1e59d28012286e3a292a2296e.1612924255.git.luto@kernel.org
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@ -826,44 +826,49 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
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{
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{
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struct task_struct *tsk = current;
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struct task_struct *tsk = current;
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/* User mode accesses just cause a SIGSEGV */
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if (!user_mode(regs)) {
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if (user_mode(regs) && (error_code & X86_PF_USER)) {
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no_context(regs, error_code, address, pkey, si_code);
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/*
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* It's possible to have interrupts off here:
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*/
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local_irq_enable();
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/*
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* Valid to do another page fault here because this one came
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* from user space:
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*/
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if (is_prefetch(regs, error_code, address))
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return;
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if (is_errata100(regs, address))
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return;
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sanitize_error_code(address, &error_code);
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if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
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return;
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if (likely(show_unhandled_signals))
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show_signal_msg(regs, error_code, address, tsk);
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set_signal_archinfo(address, error_code);
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if (si_code == SEGV_PKUERR)
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force_sig_pkuerr((void __user *)address, pkey);
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force_sig_fault(SIGSEGV, si_code, (void __user *)address);
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local_irq_disable();
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return;
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return;
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}
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}
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no_context(regs, error_code, address, SIGSEGV, si_code);
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if (!(error_code & X86_PF_USER)) {
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/* Implicit user access to kernel memory -- just oops */
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page_fault_oops(regs, error_code, address);
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return;
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}
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/*
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* User mode accesses just cause a SIGSEGV.
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* It's possible to have interrupts off here:
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*/
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local_irq_enable();
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/*
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* Valid to do another page fault here because this one came
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* from user space:
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*/
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if (is_prefetch(regs, error_code, address))
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return;
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if (is_errata100(regs, address))
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return;
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sanitize_error_code(address, &error_code);
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if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
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return;
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if (likely(show_unhandled_signals))
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show_signal_msg(regs, error_code, address, tsk);
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set_signal_archinfo(address, error_code);
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if (si_code == SEGV_PKUERR)
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force_sig_pkuerr((void __user *)address, pkey);
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force_sig_fault(SIGSEGV, si_code, (void __user *)address);
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local_irq_disable();
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}
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}
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static noinline void
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static noinline void
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