x86/mm: Use lookup_address_in_pgd_attr() in show_fault_oops()

Fix show_fault_oops() to not only look at the leaf PTE for detecting NX violations, but to use the effective NX value returned by lookup_address_in_pgd_attr() instead. Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Link: https://lore.kernel.org/r/[email protected]
torvalds · Apr 14, 2024 · d29dc51 · d29dc51
1 parent ceb647b
commit d29dc51
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
@@ -514,18 +514,19 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
 
  if (error_code & X86_PF_INSTR) {
  unsigned int level;
+ bool nx, rw;
  pgd_t *pgd;
  pte_t *pte;
 
  pgd = __va(read_cr3_pa());
  pgd += pgd_index(address);
 
- pte = lookup_address_in_pgd(pgd, address, &level);
+ pte = lookup_address_in_pgd_attr(pgd, address, &level, &nx, &rw);
 
- if (pte && pte_present(*pte) && !pte_exec(*pte))
+ if (pte && pte_present(*pte) && (!pte_exec(*pte) || nx))
  pr_crit("kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n",
  from_kuid(&init_user_ns, current_uid()));
- if (pte && pte_present(*pte) && pte_exec(*pte) &&
+ if (pte && pte_present(*pte) && pte_exec(*pte) && !nx &&
  (pgd_flags(*pgd) & _PAGE_USER) &&
  (__read_cr4() & X86_CR4_SMEP))
  pr_crit("unable to execute userspace code (SMEP?) (uid: %d)\n",