Re: [PATCH] tracing/user_events: Don't use %pK through printk

On Wed, Feb 19, 2025 at 09:10:23AM +0900, Masami Hiramatsu wrote:

On Mon, 17 Feb 2025 14:16:12 +0100
Thomas Weißschuh [off-list ref] wrote:

quoted

Restricted pointers ("%pK") are not meant to be used through printk().
It can unintentionally expose security sensitive, raw pointer values.

Use regular pointer formatting instead.

Link: https://lore.kernel.org/lkml/20250113171731-dc10e3c1-da64-4af0-b767-7c7070468023@linutronix.de/ (local)

This is only for the kernel pointer, but the "uaddr" below means it
has a user space address. So I think this does not need to be applied.

"uaddr" is formatted with %llx, which is fine.
"%pK" is used for mm->mm, which is a kernel pointer.

Thank you,

quoted

Signed-off-by: Thomas Weißschuh <redacted>
---
 kernel/trace/trace_events_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 97325fbd62836f4fb477c4a2b2936eff544291ec..3effc6fce20e65a8077de5221eb69db04fb1a775 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c

@@ -455,7 +455,7 @@ static void user_event_enabler_fault_fixup(struct work_struct *work)
 	if (ret && ret != -ENOENT) {
 		struct user_event *user = enabler->event;
 
-		pr_warn("user_events: Fault for mm: 0x%pK @ 0x%llx event: %s\n",
+		pr_warn("user_events: Fault for mm: 0x%p @ 0x%llx event: %s\n",
 			mm->mm, (unsigned long long)uaddr, EVENT_NAME(user));
 	}
 

---
base-commit: 0ad2507d5d93f39619fc42372c347d6006b64319
change-id: 20250217-restricted-pointers-trace-a0fb12707ac6

Best regards,
-- 
Thomas Weißschuh [off-list ref]