[23/32] Bluetooth: Use mem_to_flex_dup() with struct hci_op_configure_data_path

Commit Message

Kees Cook May 4, 2022, 1:44 a.m. UTC

As part of the work to perform bounds checking on all memcpy() uses,
replace the open-coded a deserialization of bytes out of memory into a
trailing flexible array by using a flex_array.h helper to perform the
allocation, bounds checking, and copying.

Cc: Marcel Holtmann <[e-mail]>
Cc: Johan Hedberg <[e-mail]>
Cc: Luiz Augusto von Dentz <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Eric Dumazet <[e-mail]>
Cc: Jakub Kicinski <[e-mail]>
Cc: Paolo Abeni <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Kees Cook <[e-mail]>
---
 include/net/bluetooth/hci.h | 4 ++--
 net/bluetooth/hci_request.c | 9 ++-------
 2 files changed, 4 insertions(+), 9 deletions(-)

Patch

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 62a9bb022aed..7b398ef0b46d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1321,8 +1321,8 @@  struct hci_rp_read_local_oob_ext_data {
 struct hci_op_configure_data_path {
 	__u8	direction;
 	__u8	data_path_id;
-	__u8	vnd_len;
-	__u8	vnd_data[];
+	DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(__u8, vnd_len);
+	DECLARE_FLEX_ARRAY_ELEMENTS(__u8, vnd_data);
 } __packed;
 
 #define HCI_OP_READ_LOCAL_VERSION	0x1001
diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index f4afe482e300..e29be3810b93 100644
--- a/net/bluetooth/hci_request.c
+++ b/net/bluetooth/hci_request.c
@@ -2435,19 +2435,14 @@  int hci_req_configure_datapath(struct hci_dev *hdev, struct bt_codec *codec)
 	if (err < 0)
 		goto error;
 
-	cmd = kzalloc(sizeof(*cmd) + vnd_len, GFP_KERNEL);
-	if (!cmd) {
-		err = -ENOMEM;
+	err = mem_to_flex_dup(&cmd, vnd_data, vnd_len, GFP_KERNEL);
+	if (err < 0)
 		goto error;
-	}
 
 	err = hdev->get_data_path_id(hdev, &cmd->data_path_id);
 	if (err < 0)
 		goto error;
 
-	cmd->vnd_len = vnd_len;
-	memcpy(cmd->vnd_data, vnd_data, vnd_len);
-
 	cmd->direction = 0x00;
 	hci_req_add(&req, HCI_CONFIGURE_DATA_PATH, sizeof(*cmd) + vnd_len, cmd);