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authorBrian Norris <computersforpeace@gmail.com>2014-08-19 11:57:23 -0700
committerBrian Norris <computersforpeace@gmail.com>2014-08-19 11:57:23 -0700
commit5b49ab3e03f68eb49db4bce6290e5707b7f6c6f3 (patch)
tree090c7c069bc6c0f2b368ed8d0af861c275525411 /arch/x86/mm/fault.c
parentb25046b1e5e3f1423434da77ccc859f2f779d1ce (diff)
parent54ea17a597b00e46b3720e75dd7595cd5dfa5670 (diff)
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Merge l2-mtd/next into l2-mtd/master
Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 36642793e315..a24194681513 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -577,6 +577,8 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
static const char nx_warning[] = KERN_CRIT
"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n";
+static const char smep_warning[] = KERN_CRIT
+"unable to execute userspace code (SMEP?) (uid: %d)\n";
static void
show_fault_oops(struct pt_regs *regs, unsigned long error_code,
@@ -597,6 +599,10 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
if (pte && pte_present(*pte) && !pte_exec(*pte))
printk(nx_warning, from_kuid(&init_user_ns, current_uid()));
+ if (pte && pte_present(*pte) && pte_exec(*pte) &&
+ (pgd_flags(*pgd) & _PAGE_USER) &&
+ (read_cr4() & X86_CR4_SMEP))
+ printk(smep_warning, from_kuid(&init_user_ns, current_uid()));
}
printk(KERN_ALERT "BUG: unable to handle kernel ");
@@ -1212,7 +1218,8 @@ good_area:
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
- * the fault:
+ * the fault. Since we never set FAULT_FLAG_RETRY_NOWAIT, if
+ * we get VM_FAULT_RETRY back, the mmap_sem has been unlocked.
*/
fault = handle_mm_fault(mm, vma, address, flags);