Input: ims-pcu - check record size in ims_pcu_flash_firmware()

commit a95ef0199e80f3384eb992889322957d26c00102 upstream.

The "len" variable comes from the firmware and we generally do
trust firmware, but it's always better to double check.  If the "len"
is too large it could result in memory corruption when we do
"memcpy(fragment->data, rec->data, len);"

Fixes: 628329d52474 ("Input: add IMS Passenger Control Unit driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/131fd1ae92c828ee9f4fa2de03d8c210ae1f3524.1748463049.git.dan.carpenter@linaro.org
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c
index 180d90e46061e70131c68f68b30f638ba15f2dbc..5cfe9b56978da0587b042cbb0096ec6ad2f3bdd8 100644 (file)
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -845,6 +845,12 @@ static int ims_pcu_flash_firmware(struct ims_pcu *pcu,
                addr = be32_to_cpu(rec->addr) / 2;
                len = be16_to_cpu(rec->len);
 
+               if (len > sizeof(pcu->cmd_buf) - 1 - sizeof(*fragment)) {
+                       dev_err(pcu->dev,
+                               "Invalid record length in firmware: %d\n", len);
+                       return -EINVAL;
+               }
+
                fragment = (void *)&pcu->cmd_buf[1];
                put_unaligned_le32(addr, &fragment->addr);
                fragment->len = len;