[PATCH v2 1/3] Bluetooth: btintel: validate version TLV value lengths

[Laxman Acharya Padhya <acharyalaxman8848@gmail.com>]

btintel_parse_version_tlv() verifies that a complete TLV is present in
the response, but it does not ensure that the value is long enough for
the specific TLV type. A short value can therefore cause an
out-of-bounds read through get_unaligned_le16(), get_unaligned_le32(),
or memcpy().

Reject values shorter than the minimum required by each known TLV type.
Also reject responses that do not contain the Command Complete Status
field.

Fixes: 57375beef71a ("Bluetooth: btintel: Add infrastructure to read controller information")
Reviewed-by: Ali Ahmet Memis <ali@iusegentoo.com>
Assisted-by: Codex:gpt-5 sparse
Signed-off-by: Laxman Acharya Padhya <acharyalaxman8848@gmail.com>
---
 drivers/bluetooth/btintel.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index bf567b7c5f00..26435e41f1ce 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c
@@ -570,12 +570,44 @@ int btintel_version_info_tlv(struct hci_dev *hdev,
 }
 EXPORT_SYMBOL_GPL(btintel_version_info_tlv);
 
+static u8 btintel_version_tlv_min_len(u8 type)
+{
+	switch (type) {
+	case INTEL_TLV_CNVI_TOP:
+	case INTEL_TLV_CNVR_TOP:
+	case INTEL_TLV_CNVI_BT:
+	case INTEL_TLV_CNVR_BT:
+	case INTEL_TLV_BUILD_NUM:
+	case INTEL_TLV_GIT_SHA1:
+		return sizeof(u32);
+	case INTEL_TLV_DEV_REV_ID:
+	case INTEL_TLV_TIME_STAMP:
+		return sizeof(u16);
+	case INTEL_TLV_IMAGE_TYPE:
+	case INTEL_TLV_BUILD_TYPE:
+	case INTEL_TLV_SECURE_BOOT:
+	case INTEL_TLV_OTP_LOCK:
+	case INTEL_TLV_API_LOCK:
+	case INTEL_TLV_DEBUG_LOCK:
+	case INTEL_TLV_LIMITED_CCE:
+	case INTEL_TLV_SBE_TYPE:
+		return sizeof(u8);
+	case INTEL_TLV_MIN_FW:
+		return 3;
+	case INTEL_TLV_OTP_BDADDR:
+		return sizeof(bdaddr_t);
+	default:
+		return 0;
+	}
+}
+
 int btintel_parse_version_tlv(struct hci_dev *hdev,
 			      struct intel_version_tlv *version,
 			      struct sk_buff *skb)
 {
 	/* Consume Command Complete Status field */
-	skb_pull(skb, 1);
+	if (!skb_pull(skb, 1))
+		return -EINVAL;
 
 	/* Event parameters contain multiple TLVs. Read each of them
 	 * and only keep the required data. Also, it use existing legacy
@@ -595,6 +627,9 @@ int btintel_parse_version_tlv(struct hci_dev *hdev,
 		if (skb->len < tlv->len + sizeof(*tlv))
 			return -EINVAL;
 
+		if (tlv->len < btintel_version_tlv_min_len(tlv->type))
+			return -EINVAL;
+
 		switch (tlv->type) {
 		case INTEL_TLV_CNVI_TOP:
 			version->cnvi_top = get_unaligned_le32(tlv->val);
-- 
2.51.2