[PATCH 4/5] kprobes: Do not expose probe addresses to non-CAP_SYSLOG

Kees Cook
2020-07-02T23:27:23Z

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: 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>
---
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
--
2.25.1