linux-kernel - [PATCH 4.19 50/58] kprobes: Do not expose probe addresses to non-CAP

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Message-Id: <20200714184058.655527155@linuxfoundation.org>
Date:   Tue, 14 Jul 2020 20:44:23 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Masami Hiramatsu <mhiramat@...nel.org>,
        Kees Cook <keescook@...omium.org>
Subject: [PATCH 4.19 50/58] kprobes: Do not expose probe addresses to non-CAP_SYSLOG

From: Kees Cook <keescook@...omium.org>

commit 60f7bb66b88b649433bf700acfc60c3f24953871 upstream.

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@...nel.org>
Cc: stable@...r.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@...omium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 kernel/kprobes.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2334,7 +2334,7 @@ static void report_probe(struct seq_file
 	else
 		kprobe_type = "k";
 
-	if (!kallsyms_show_value(current_cred()))
+	if (!kallsyms_show_value(pi->file->f_cred))
 		addr = NULL;
 
 	if (sym)
@@ -2435,7 +2435,7 @@ static int kprobe_blacklist_seq_show(str
 	 * 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