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From: Peilin Ye <yepeilin.cs@gmail.com>
To: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>
Cc: Peilin Ye <yepeilin.cs@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
	syzkaller-bugs@googlegroups.com,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: [Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()
Date: Thu,  9 Jul 2020 01:18:02 -0400	[thread overview]
Message-ID: <20200709051802.185168-1-yepeilin.cs@gmail.com> (raw)

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it. Also, make `num_rsp` unsigned.

This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
 net/bluetooth/hci_event.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..29aff5e7dec2 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4369,13 +4369,13 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
 	struct inquiry_data data;
-	struct extended_inquiry_info *info = (void *) (skb->data + 1);
-	int num_rsp = *((__u8 *) skb->data);
+	struct extended_inquiry_info *info = (void *)(skb->data + 1);
+	__u8 num_rsp = *((__u8 *)skb->data);
 	size_t eir_len;
 
 	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
 
-	if (!num_rsp)
+	if (!num_rsp || num_rsp * sizeof(*info) > skb->truesize)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Peilin Ye <yepeilin.cs@gmail.com>
To: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>
Cc: netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	Russell King <linux@armlinux.org.uk>,
	"David S . Miller" <davem@davemloft.net>,
	linux-bluetooth@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Peilin Ye <yepeilin.cs@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: [Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()
Date: Thu,  9 Jul 2020 01:18:02 -0400	[thread overview]
Message-ID: <20200709051802.185168-1-yepeilin.cs@gmail.com> (raw)

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it. Also, make `num_rsp` unsigned.

This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
 net/bluetooth/hci_event.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..29aff5e7dec2 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4369,13 +4369,13 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
 	struct inquiry_data data;
-	struct extended_inquiry_info *info = (void *) (skb->data + 1);
-	int num_rsp = *((__u8 *) skb->data);
+	struct extended_inquiry_info *info = (void *)(skb->data + 1);
+	__u8 num_rsp = *((__u8 *)skb->data);
 	size_t eir_len;
 
 	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
 
-	if (!num_rsp)
+	if (!num_rsp || num_rsp * sizeof(*info) > skb->truesize)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
-- 
2.25.1

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

             reply	other threads:[~2020-07-09  5:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09  5:18 Peilin Ye [this message]
2020-07-09  5:18 ` [Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt() Peilin Ye
2020-07-09 13:02 ` [Linux-kernel-mentees] [PATCH v2] " Peilin Ye
2020-07-09 13:02   ` Peilin Ye
2020-07-10 10:43   ` Greg KH
2020-07-10 10:43     ` Greg KH
2020-07-10 16:09   ` [Linux-kernel-mentees] [PATCH v3] " Peilin Ye
2020-07-10 16:09     ` Peilin Ye
2020-07-10 17:08     ` Marcel Holtmann
2020-07-10 17:08       ` Marcel Holtmann
2021-07-01 15:39   ` maybe similar bug exists for HCI_EV_INQUIRY_RESULT* like [Linux-kernel-mentees] [PATCH v2] net/bluetooth: " Alexander Larkin
2021-07-01 15:39     ` Alexander Larkin
2021-07-01 21:06     ` Peilin Ye
2021-07-01 21:06       ` Peilin Ye

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