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 b3215c97ee02d157b6cf238b38b1dd5fee4d5d8e..67636fd217fa8e32b4b4956bec503689c0026417 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;