summaryrefslogtreecommitdiff
path: root/arch/powerpc/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/mm/fault.c')
-rw-r--r--arch/powerpc/mm/fault.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 1697e903bbf2..a6dcfda3e11e 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -226,7 +226,9 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr,
static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
unsigned long address)
{
- if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT))) {
+ /* NX faults set DSISR_PROTFAULT on the 8xx, DSISR_NOEXEC_OR_G on others */
+ if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT |
+ DSISR_PROTFAULT))) {
printk_ratelimited(KERN_CRIT "kernel tried to execute"
" exec-protected page (%lx) -"
"exploit attempt? (uid: %d)\n",
@@ -341,10 +343,21 @@ static inline void cmo_account_page_fault(void)
static inline void cmo_account_page_fault(void) { }
#endif /* CONFIG_PPC_SMLPAR */
-#ifdef CONFIG_PPC_STD_MMU
-static void sanity_check_fault(bool is_write, unsigned long error_code)
+#ifdef CONFIG_PPC_BOOK3S
+static void sanity_check_fault(bool is_write, bool is_user,
+ unsigned long error_code, unsigned long address)
{
/*
+ * Userspace trying to access kernel address, we get PROTFAULT for that.
+ */
+ if (is_user && address >= TASK_SIZE) {
+ pr_crit_ratelimited("%s[%d]: User access of kernel address (%lx) - exploit attempt? (uid: %d)\n",
+ current->comm, current->pid, address,
+ from_kuid(&init_user_ns, current_uid()));
+ return;
+ }
+
+ /*
* For hash translation mode, we should never get a
* PROTFAULT. Any update to pte to reduce access will result in us
* removing the hash page table entry, thus resulting in a DSISR_NOHPTE
@@ -373,12 +386,15 @@ static void sanity_check_fault(bool is_write, unsigned long error_code)
* For radix, we can get prot fault for autonuma case, because radix
* page table will have them marked noaccess for user.
*/
- if (!radix_enabled() && !is_write)
- WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
+ if (radix_enabled() || is_write)
+ return;
+
+ WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
}
#else
-static void sanity_check_fault(bool is_write, unsigned long error_code) { }
-#endif /* CONFIG_PPC_STD_MMU */
+static void sanity_check_fault(bool is_write, bool is_user,
+ unsigned long error_code, unsigned long address) { }
+#endif /* CONFIG_PPC_BOOK3S */
/*
* Define the correct "is_write" bit in error_code based
@@ -435,7 +451,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
}
/* Additional sanity check(s) */
- sanity_check_fault(is_write, error_code);
+ sanity_check_fault(is_write, is_user, error_code, address);
/*
* The kernel should never take an execute fault nor should it
@@ -636,21 +652,23 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
switch (TRAP(regs)) {
case 0x300:
case 0x380:
- printk(KERN_ALERT "Unable to handle kernel paging request for "
- "data at address 0x%08lx\n", regs->dar);
+ case 0xe00:
+ pr_alert("BUG: %s at 0x%08lx\n",
+ regs->dar < PAGE_SIZE ? "Kernel NULL pointer dereference" :
+ "Unable to handle kernel data access", regs->dar);
break;
case 0x400:
case 0x480:
- printk(KERN_ALERT "Unable to handle kernel paging request for "
- "instruction fetch\n");
+ pr_alert("BUG: Unable to handle kernel instruction fetch%s",
+ regs->nip < PAGE_SIZE ? " (NULL pointer?)\n" : "\n");
break;
case 0x600:
- printk(KERN_ALERT "Unable to handle kernel paging request for "
- "unaligned access at address 0x%08lx\n", regs->dar);
+ pr_alert("BUG: Unable to handle kernel unaligned access at 0x%08lx\n",
+ regs->dar);
break;
default:
- printk(KERN_ALERT "Unable to handle kernel paging request for "
- "unknown fault\n");
+ pr_alert("BUG: Unable to handle unknown paging fault at 0x%08lx\n",
+ regs->dar);
break;
}
printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",