linux-kernel - [PATCH 4.2 100/110] blk-mq: fix use-after-free in blk_mq_free_tag

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20151106191709.195586157@linuxfoundation.org>
Date:	Fri,  6 Nov 2015 11:19:47 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Junichi Nomura <j-nomura@...jp.nec.com>,
	Keith Busch <keith.busch@...el.com>,
	Jeff Moyer <jmoyer@...hat.com>, Jens Axboe <axboe@...com>
Subject: [PATCH 4.2 100/110] blk-mq: fix use-after-free in blk_mq_free_tag_set()

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Junichi Nomura <j-nomura@...jp.nec.com>

commit f42d79ab67322e51b92dd7aa965e310c71352a64 upstream.

tags is freed in blk_mq_free_rq_map() and should not be used after that.
The problem doesn't manifest if CONFIG_CPUMASK_OFFSTACK is false because
free_cpumask_var() is nop.

tags->cpumask is allocated in blk_mq_init_tags() so it's natural to
free cpumask in its counter part, blk_mq_free_tags().

Fixes: f26cdc8536ad ("blk-mq: Shared tag enhancements")
Signed-off-by: Jun'ichi Nomura <j-nomura@...jp.nec.com>
Cc: Keith Busch <keith.busch@...el.com>
Reviewed-by: Jeff Moyer <jmoyer@...hat.com>
Signed-off-by: Jens Axboe <axboe@...com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 block/blk-mq-tag.c |    1 +
 block/blk-mq.c     |    4 +---
 2 files changed, 2 insertions(+), 3 deletions(-)

--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -628,6 +628,7 @@ void blk_mq_free_tags(struct blk_mq_tags
 {
 	bt_free(&tags->bitmap_tags);
 	bt_free(&tags->breserved_tags);
+	free_cpumask_var(tags->cpumask);
 	kfree(tags);
 }
 
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2263,10 +2263,8 @@ void blk_mq_free_tag_set(struct blk_mq_t
 	int i;
 
 	for (i = 0; i < set->nr_hw_queues; i++) {
-		if (set->tags[i]) {
+		if (set->tags[i])
 			blk_mq_free_rq_map(set, set->tags[i], i);
-			free_cpumask_var(set->tags[i]->cpumask);
-		}
 	}
 
 	kfree(set->tags);


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/