From 160251842cd35a75edfb0a1d76afa3eb674ff40a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 2 Jul 2020 11:49:23 -0700 Subject: kallsyms: Refactor kallsyms_show_value() to take cred In order to perform future tests against the cred saved during open(), switch kallsyms_show_value() to operate on a cred, and have all current callers pass current_cred(). This makes it very obvious where callers are checking the wrong credential in their "read" contexts. These will be fixed in the coming patches. Additionally switch return value to bool, since it is always used as a direct permission check, not a 0-on-success, negative-on-error style function return. Cc: stable@vger.kernel.org Signed-off-by: Kees Cook --- kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 4a904cc56d68..d4de217e4a91 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()) + if (!kallsyms_show_value(current_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()) + if (!kallsyms_show_value(current_cred())) seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, (void *)ent->start_addr); else -- cgit v1.2.3-59-g8ed1b From 60f7bb66b88b649433bf700acfc60c3f24953871 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 2 Jul 2020 15:20:22 -0700 Subject: kprobes: Do not expose probe addresses to non-CAP_SYSLOG 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 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 --- kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/kprobes.c') 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 -- cgit v1.2.3-59-g8ed1b