firmware: imx: scu: Fix corruption of header

[ Upstream commit f5f27b79eab80de0287c243a22169e4876b08d5e ]

The header of the message to send can be changed if the
response is longer than the request:
 - 1st word, the header is sent
 - the remaining words of the message are sent
 - the response is received asynchronously during the
   execution of the loop, changing the size field in
   the header
 - the for loop test the termination condition using
   the corrupted header

It is the case for the API build_info which has just a
header as request but 3 words in response.

This issue is fixed storing the header locally instead of
using a pointer on it.

Fixes: edbee095fafb (firmware: imx: add SCU firmware driver support)

Signed-off-by: Franck LENORMAND <franck.lenormand@nxp.com>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Cc: stable@vger.kernel.org
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index a92adb9..e48d971 100644 (file)
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -158,7 +158,7 @@ static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 
 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 {
-       struct imx_sc_rpc_msg *hdr = msg;
+       struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
        struct imx_sc_chan *sc_chan;
        u32 *data = msg;
        int ret;
@@ -166,13 +166,13 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
        int i;
 
        /* Check size */
-       if (hdr->size > IMX_SC_RPC_MAX_MSG)
+       if (hdr.size > IMX_SC_RPC_MAX_MSG)
                return -EINVAL;
 
-       dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr->svc,
-               hdr->func, hdr->size);
+       dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
+               hdr.func, hdr.size);
 
-       size = sc_ipc->fast_ipc ? 1 : hdr->size;
+       size = sc_ipc->fast_ipc ? 1 : hdr.size;
        for (i = 0; i < size; i++) {
                sc_chan = &sc_ipc->chans[i % 4];