[PATCH 1/5] Bluetooth: qca: fix info leak when fetching fw build id

Johan Hovold
2024-05-01T12:35:14Z

Add the missing sanity checks and move the 255-byte build-id buffer off
the stack to avoid leaking stack data through debugfs in case the
build-info reply is malformed.

Fixes: c0187b0bd3e9 ("Bluetooth: btqca: Add support to read FW build version for WCN3991 BTSoC")
Cc: stable@vger.kernel.org # 5.12
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
drivers/bluetooth/btqca.c | 25 +++++++++++++++++++++----
drivers/bluetooth/btqca.h | 1 -
2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
index 38a770278103..a508d79d9aaa 100644
--- a/drivers/bluetooth/btqca.c
+++ b/drivers/bluetooth/btqca.c
@@ -99,7 +99,8 @@ static int qca_read_fw_build_info(struct hci_dev *hdev)
{
struct sk_buff *skb;
struct edl_event_hdr *edl;
- char cmd, build_label[QCA_FW_BUILD_VER_LEN];
+ char *build_label;
+ char cmd;
int build_lbl_len, err = 0;

bt_dev_dbg(hdev, "QCA read fw build info");
@@ -114,6 +115,11 @@ static int qca_read_fw_build_info(struct hci_dev *hdev)
return err;
}

+ if (skb->len < sizeof(*edl)) {
+ err = -EILSEQ;
+ goto out;
+ }
+
edl = (struct edl_event_hdr *)(skb->data);
if (!edl) {
bt_dev_err(hdev, "QCA read fw build info with no header");
@@ -129,14 +135,25 @@ static int qca_read_fw_build_info(struct hci_dev *hdev)
goto out;
}

+ if (skb->len < sizeof(*edl) + 1) {
+ err = -EILSEQ;
+ goto out;
+ }
+
build_lbl_len = edl->data[0];
- if (build_lbl_len <= QCA_FW_BUILD_VER_LEN - 1) {
- memcpy(build_label, edl->data + 1, build_lbl_len);
- *(build_label + build_lbl_len) = '\0';
+
+ if (skb->len < sizeof(*edl) + 1 + build_lbl_len) {
+ err = -EILSEQ;
+ goto out;
}

+ build_label = kstrndup(&edl->data[1], build_lbl_len, GFP_KERNEL);
+ if (!build_label)
+ goto out;
+
hci_set_fw_info(hdev, "%s", build_label);

+ kfree(build_label);
out:
kfree_skb(skb);
return err;
diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
index 49ad668d0d0b..215433fd76a1 100644
--- a/drivers/bluetooth/btqca.h
+++ b/drivers/bluetooth/btqca.h
@@ -48,7 +48,6 @@
#define get_soc_ver(soc_id, rom_ver) \
((le32_to_cpu(soc_id) << 16) | (le16_to_cpu(rom_ver)))

-#define QCA_FW_BUILD_VER_LEN 255
#define QCA_HSP_GF_SOC_ID 0x1200
#define QCA_HSP_GF_SOC_MASK 0x0000ff00

--
2.43.2