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authorAndy Lutomirski <luto@kernel.org>2021-02-09 18:33:42 -0800
committerBorislav Petkov <bp@suse.de>2021-02-10 14:39:52 +0100
commit5042d40a264c8a508d58ed71e4c07b05175b3635 (patch)
treeaeda5b029b741781a0878cd9334ad926f9091cfc /arch/x86/mm/fault.c
parent2cc624b0a7e68ba8957b18600181f7d5b0f3e1b6 (diff)
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
Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c59
1 files changed, 32 insertions, 27 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index dbf6a940b03f..187975b1df66 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -826,44 +826,49 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
{
struct task_struct *tsk = current;
- /* User mode accesses just cause a SIGSEGV */
- if (user_mode(regs) && (error_code & X86_PF_USER)) {
- /*
- * It's possible to have interrupts off here:
- */
- local_irq_enable();
+ if (!user_mode(regs)) {
+ no_context(regs, error_code, address, pkey, si_code);
+ return;
+ }
- /*
- * Valid to do another page fault here because this one came
- * from user space:
- */
- if (is_prefetch(regs, error_code, address))
- return;
+ if (!(error_code & X86_PF_USER)) {
+ /* Implicit user access to kernel memory -- just oops */
+ page_fault_oops(regs, error_code, address);
+ return;
+ }
- if (is_errata100(regs, address))
- return;
+ /*
+ * User mode accesses just cause a SIGSEGV.
+ * It's possible to have interrupts off here:
+ */
+ local_irq_enable();
- sanitize_error_code(address, &error_code);
+ /*
+ * Valid to do another page fault here because this one came
+ * from user space:
+ */
+ if (is_prefetch(regs, error_code, address))
+ return;
- if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
- return;
+ if (is_errata100(regs, address))
+ return;
- if (likely(show_unhandled_signals))
- show_signal_msg(regs, error_code, address, tsk);
+ sanitize_error_code(address, &error_code);
- set_signal_archinfo(address, error_code);
+ if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+ return;
- if (si_code == SEGV_PKUERR)
- force_sig_pkuerr((void __user *)address, pkey);
+ if (likely(show_unhandled_signals))
+ show_signal_msg(regs, error_code, address, tsk);
- force_sig_fault(SIGSEGV, si_code, (void __user *)address);
+ set_signal_archinfo(address, error_code);
- local_irq_disable();
+ if (si_code == SEGV_PKUERR)
+ force_sig_pkuerr((void __user *)address, pkey);
- return;
- }
+ force_sig_fault(SIGSEGV, si_code, (void __user *)address);
- no_context(regs, error_code, address, SIGSEGV, si_code);
+ local_irq_disable();
}
static noinline void