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Message-ID: <20230712130218.376-1-chris.lu@mediatek.com>
Date: Wed, 12 Jul 2023 21:02:19 +0800
From: Chris Lu <chris.lu@...iatek.com>
To: Marcel Holtmann <marcel@...tmann.org>,
Johan Hedberg <johan.hedberg@...il.com>,
Luiz Von Dentz <luiz.dentz@...il.com>
CC: Sean Wang <sean.wang@...iatek.com>,
Aaron Hou <aaron.hou@...iatek.com>,
Steve Lee <steve.lee@...iatek.com>,
linux-bluetooth <linux-bluetooth@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
linux-mediatek <linux-mediatek@...ts.infradead.org>,
Chris Lu <chris.lu@...iatek.com>
Subject: [PATCH v4] Bluetooth: btmtk: Fix null pointer when processing coredump
There may be a potential null pointer risk if offset value is
less than 0 when doing memcmp in btmtk_process_coredump().
Check offset is valid before doing memcmp.
Signed-off-by: Chris Lu <chris.lu@...iatek.com>
Co-developed-by: Sean Wang <sean.wang@...iatek.com>
Signed-off-by: Sean Wang <sean.wang@...iatek.com>
---
v2: fix typo
v3: fix bot checking error
v4: reduce variable 'offset' declaration in v3
---
drivers/bluetooth/btmtk.c | 12 ++++++------
drivers/bluetooth/btmtk.h | 1 +
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 786f775196ae..9cc789272ab7 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -395,12 +395,12 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
/* Mediatek coredump data would be more than MTK_COREDUMP_NUM */
if (data->cd_info.cnt > MTK_COREDUMP_NUM &&
- skb->len > sizeof(MTK_COREDUMP_END) &&
- !memcmp((char *)&skb->data[skb->len - sizeof(MTK_COREDUMP_END)],
- MTK_COREDUMP_END, sizeof(MTK_COREDUMP_END) - 1)) {
- bt_dev_info(hdev, "Mediatek coredump end");
- hci_devcd_complete(hdev);
- }
+ skb->len > MTK_COREDUMP_END_LEN)
+ if (!memcmp((char *)&skb->data[skb->len - MTK_COREDUMP_END_LEN],
+ MTK_COREDUMP_END, MTK_COREDUMP_END_LEN - 1)) {
+ bt_dev_info(hdev, "Mediatek coredump end");
+ hci_devcd_complete(hdev);
+ }
break;
}
diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
index 68309dfe076a..56f5502baadf 100644
--- a/drivers/bluetooth/btmtk.h
+++ b/drivers/bluetooth/btmtk.h
@@ -24,6 +24,7 @@
#define MTK_COREDUMP_SIZE (1024 * 1000)
#define MTK_COREDUMP_END "coredump end"
+#define MTK_COREDUMP_END_LEN (sizeof(MTK_COREDUMP_END))
#define MTK_COREDUMP_NUM 255
enum {
--
2.18.0
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