From 60f7bb66b88b649433bf700acfc60c3f24953871 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Thu, 2 Jul 2020 15:20:22 -0700
Subject: [PATCH] kprobes: Do not expose probe addresses to non-CAP_SYSLOG
Git-commit: 60f7bb66b88b649433bf700acfc60c3f24953871
References: git-fixes
Patch-mainline: v5.8-rc5

The kprobe show() functions were using "current"'s creds instead
of the file opener's creds for kallsyms visibility. Fix to use
seq_file->file->f_cred.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 81365a947de4 ("kprobes: Show address of kprobes if kallsyms does")
Fixes: ffb9bd68ebdb ("kprobes: Show blacklist addresses as same as kallsyms does")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 kernel/kprobes.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index d4de217e4a91..2e97febeef77 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2448,7 +2448,7 @@ static void report_probe(struct seq_file *pi, struct kprobe *p,
 	else
 		kprobe_type = "k";
 
-	if (!kallsyms_show_value(current_cred()))
+	if (!kallsyms_show_value(pi->file->f_cred))
 		addr = NULL;
 
 	if (sym)
@@ -2540,7 +2540,7 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
 	 * If /proc/kallsyms is not showing kernel address, we won't
 	 * show them here either.
 	 */
-	if (!kallsyms_show_value(current_cred()))
+	if (!kallsyms_show_value(m->file->f_cred))
 		seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
 			   (void *)ent->start_addr);
 	else
-- 
2.26.2