There needs to be a check to verify that we don't read beyond the end
of "buf". This function is called from do_rx(). The "buf" is the USB
transfer_buffer and "len" is "urb->actual_length".
Fixes: 61e121047645 ("staging: gdm7240: adding LTE USB driver")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
The truth is that I don't really understand where the 12 comes from in
(hci_len - 12) but I copy and pasted it. I am a bit tempted to say that
actually hci_len - 12 has to be greater than zero but I didn't do that
because I don't have the hardware to test it.
drivers/staging/gdm724x/gdm_lte.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/gdm724x/gdm_lte.c b/drivers/staging/gdm724x/gdm_lte.c
index 571f47d39484..a41af7aa74ec 100644
--- a/drivers/staging/gdm724x/gdm_lte.c
+++ b/drivers/staging/gdm724x/gdm_lte.c
@@ -677,6 +677,7 @@ static void gdm_lte_multi_sdu_pkt(struct phy_dev *phy_dev, char *buf, int len)
struct sdu *sdu = NULL;
u8 endian = phy_dev->get_endian(phy_dev->priv_dev);
u8 *data = (u8 *)multi_sdu->data;
+ int copied;
u16 i = 0;
u16 num_packet;
u16 hci_len;
@@ -688,6 +689,12 @@ static void gdm_lte_multi_sdu_pkt(struct phy_dev *phy_dev, char *buf, int len)
num_packet = gdm_dev16_to_cpu(endian, multi_sdu->num_packet);
for (i = 0; i < num_packet; i++) {
+ copied = data - multi_sdu->data;
+ if (len < copied + sizeof(*sdu)) {
+ pr_err("rx prevent buffer overflow");
+ return;
+ }
+
sdu = (struct sdu *)data;
cmd_evt = gdm_dev16_to_cpu(endian, sdu->cmd_evt);
@@ -698,7 +705,8 @@ static void gdm_lte_multi_sdu_pkt(struct phy_dev *phy_dev, char *buf, int len)
pr_err("rx sdu wrong hci %04x\n", cmd_evt);
return;
}
- if (hci_len < 12) {
+ if (hci_len < 12 ||
+ len < copied + sizeof(*sdu) + (hci_len - 12)) {
pr_err("rx sdu invalid len %d\n", hci_len);
return;
}
--
2.30.2
