Re: [syzbot] [bluetooth?] KASAN: vmalloc-out-of-bounds Read in hci_devcd_dump

Ivan Pravdin
2025-06-08T19:21:43Z

#syz test

diff --git a/net/bluetooth/coredump.c b/net/bluetooth/coredump.c
index 819eacb38762..1232c9a94f95 100644
--- a/net/bluetooth/coredump.c
+++ b/net/bluetooth/coredump.c
@@ -243,6 +243,7 @@ static void hci_devcd_handle_pkt_pattern(struct hci_dev *hdev,
static void hci_devcd_dump(struct hci_dev *hdev)
{
struct sk_buff *skb;
+ char *coredump;
u32 size;

bt_dev_dbg(hdev, "state %d", hdev->dump.state);
@@ -250,7 +251,11 @@ static void hci_devcd_dump(struct hci_dev *hdev)
size = hdev->dump.tail - hdev->dump.head;

/* Emit a devcoredump with the available data */
- dev_coredumpv(&hdev->dev, hdev->dump.head, size, GFP_KERNEL);
+ coredump = vmalloc(size);
+ if (coredump) {
+ memcpy(coredump, hdev->dump.head, size);
+ dev_coredumpv(&hdev->dev, coredump, size, GFP_KERNEL);
+ }

/* Send a copy to monitor as a diagnostic packet */
skb = bt_skb_alloc(size, GFP_ATOMIC);

Ivan Pravdin