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 4215f9b9c2b07a85fb2ce6c374afdccbca52d768..fc22cbb854a3852949d102a9d58e40e96d25047a 100644 (file)
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -844,6 +844,12 @@ 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;