linux-kernel - [PATCH v12 6/6] mm: kasan: Do not panic if both panic_on_warn and kasan

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200811053914.652710-7-davidgow@google.com>
Date:   Mon, 10 Aug 2020 22:39:15 -0700
From:   David Gow <davidgow@...gle.com>
To:     trishalfonso@...gle.com, brendanhiggins@...gle.com,
        aryabinin@...tuozzo.com, dvyukov@...gle.com, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, andreyknvl@...gle.com,
        shuah@...nel.org, akpm@...ux-foundation.org
Cc:     David Gow <davidgow@...gle.com>, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com, kunit-dev@...glegroups.com,
        linux-kselftest@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v12 6/6] mm: kasan: Do not panic if both panic_on_warn and
 kasan_multishot set

KASAN errors will currently trigger a panic when panic_on_warn is set.
This renders kasan_multishot useless, as further KASAN errors won't be
reported if the kernel has already paniced. By making kasan_multishot
disable this behaviour for KASAN errors, we can still have the benefits
of panic_on_warn for non-KASAN warnings, yet be able to use
kasan_multishot.

This is particularly important when running KASAN tests, which need to
trigger multiple KASAN errors: previously these would panic the system
if panic_on_warn was set, now they can run (and will panic the system
should non-KASAN warnings show up).

Signed-off-by: David Gow <davidgow@...gle.com>
Reviewed-by: Andrey Konovalov <andreyknvl@...gle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@...gle.com>
Tested-by: Andrey Konovalov <andreyknvl@...gle.com>
---
 mm/kasan/report.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index e2c14b10bc81..00a53f1355ae 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -95,7 +95,7 @@ static void end_report(unsigned long *flags)
 	pr_err("==================================================================\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irqrestore(&report_lock, *flags);
-	if (panic_on_warn) {
+	if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) {
 		/*
 		 * This thread may hit another WARN() in the panic path.
 		 * Resetting this prevents additional WARN() from panicking the
-- 
2.28.0.236.gb10cc79966-goog