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From: Johannes Thumshirn <jthumshirn@suse.de>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
	Linux SCSI Mailinglist <linux-scsi@vger.kernel.org>,
	ard <ard@kwaak.net>, Johannes Thumshirn <jthumshirn@suse.de>
Subject: [PATCH 1/3] fcoe: fix use-after-free in fcoe_ctlr_els_send
Date: Tue, 31 Jul 2018 15:46:01 +0200	[thread overview]
Message-ID: <20180731134603.20089-2-jthumshirn@suse.de> (raw)
In-Reply-To: <20180731134603.20089-1-jthumshirn@suse.de>

KASAN reports a use-after-free in fcoe_ctlr_els_send() when we're
sending a LOGO and have FIP debugging enabled. This is because we're
first freeing the skb and then printing the frame's DID. But the DID
is a member of the FC frame header which in turn is the skb's payload.

Exchange the debug print and kfree_skb() calls so we're not touching
the freed data.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/scsi/fcoe/fcoe_ctlr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c
index ea23c8dffc25..ceb35ebbeb8f 100644
--- a/drivers/scsi/fcoe/fcoe_ctlr.c
+++ b/drivers/scsi/fcoe/fcoe_ctlr.c
@@ -799,9 +799,9 @@ int fcoe_ctlr_els_send(struct fcoe_ctlr *fip, struct fc_lport *lport,
 	fip->send(fip, skb);
 	return -EINPROGRESS;
 drop:
-	kfree_skb(skb);
 	LIBFCOE_FIP_DBG(fip, "drop els_send op %u d_id %x\n",
 			op, ntoh24(fh->fh_d_id));
+	kfree_skb(skb);
 	return -EINVAL;
 }
 EXPORT_SYMBOL(fcoe_ctlr_els_send);
-- 
2.16.4


  reply	other threads:[~2018-07-31 13:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-31 13:46 [PATCH 0/3] scsi: fcoe: memleak fixes Johannes Thumshirn
2018-07-31 13:46 ` Johannes Thumshirn [this message]
2018-08-01  6:30   ` [PATCH 1/3] fcoe: fix use-after-free in fcoe_ctlr_els_send Hannes Reinecke
2018-07-31 13:46 ` [PATCH 2/3] scsi: fcoe: drop frames in ELS LOGO error path Johannes Thumshirn
2018-08-01  6:30   ` Hannes Reinecke
2018-07-31 13:46 ` [PATCH 3/3] scsi: fcoe: clear FC_RP_STARTED flags when receiving a LOGO Johannes Thumshirn
2018-08-01  6:31   ` Hannes Reinecke
2018-08-06  9:25 ` [PATCH 0/3] scsi: fcoe: memleak fixes Johannes Thumshirn
2018-08-06 13:22   ` ard
2018-08-06 13:27     ` Johannes Thumshirn
2018-08-06 14:24       ` ard
2018-08-07  6:54         ` Johannes Thumshirn
2018-08-07  9:26           ` ard
2018-08-07  9:57             ` ard
2018-08-07 16:04             ` ard
2018-08-09 10:01               ` ard
2018-08-09  8:05   ` Johannes Thumshirn
2018-08-09  9:52     ` Martin K. Petersen
2018-08-09  9:56       ` Johannes Thumshirn

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