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

[Ivan Pravdin <ipravdin.official@gmail.com>]

#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