[PATCH 4.4 056/188] media: siano: Fix out-of-bounds warnings in smscore_load_firmware_family2()

Greg Kroah-Hartman
2021-07-19T14:58:56Z

From: Gustavo A. R. Silva <gustavoars@kernel.org>

[ Upstream commit 13dfead49db07225335d4f587a560a2210391a1a ]

Rename struct sms_msg_data4 to sms_msg_data5 and increase the size of
its msg_data array from 4 to 5 elements. Notice that at some point
the 5th element of msg_data is being accessed in function
smscore_load_firmware_family2():

1006 trigger_msg->msg_data[4] = 4; /* Task ID */

Also, there is no need for the object _trigger_msg_ of type struct
sms_msg_data *, when _msg_ can be used, directly. Notice that msg_data
in struct sms_msg_data is a one-element array, which causes multiple
out-of-bounds warnings when accessing beyond its first element
in function smscore_load_firmware_family2():

992 struct sms_msg_data *trigger_msg =
993 (struct sms_msg_data *) msg;
994
995 pr_debug("sending MSG_SMS_SWDOWNLOAD_TRIGGER_REQ\n");
996 SMS_INIT_MSG(&msg->x_msg_header,
997 MSG_SMS_SWDOWNLOAD_TRIGGER_REQ,
998 sizeof(struct sms_msg_hdr) +
999 sizeof(u32) * 5);
1000
1001 trigger_msg->msg_data[0] = firmware->start_address;
1002 /* Entry point */
1003 trigger_msg->msg_data[1] = 6; /* Priority */
1004 trigger_msg->msg_data[2] = 0x200; /* Stack size */
1005 trigger_msg->msg_data[3] = 0; /* Parameter */
1006 trigger_msg->msg_data[4] = 4; /* Task ID */

even when enough dynamic memory is allocated for _msg_:

929 /* PAGE_SIZE buffer shall be enough and dma aligned */
930 msg = kmalloc(PAGE_SIZE, GFP_KERNEL | coredev->gfp_buf_flags);

but as _msg_ is casted to (struct sms_msg_data *):

992 struct sms_msg_data *trigger_msg =
993 (struct sms_msg_data *) msg;

the out-of-bounds warnings are actually valid and should be addressed.

Fix this by declaring object _msg_ of type struct sms_msg_data5 *,
which contains a 5-elements array, instead of just 4. And use
_msg_ directly, instead of creating object trigger_msg.

This helps with the ongoing efforts to enable -Warray-bounds by fixing
the following warnings:

CC [M] drivers/media/common/siano/smscoreapi.o
drivers/media/common/siano/smscoreapi.c: In function ‘smscore_load_firmware_family2’:
drivers/media/common/siano/smscoreapi.c:1003:24: warning: array subscript 1 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
1003 | trigger_msg->msg_data[1] = 6; /* Priority */
| ~~~~~~~~~~~~~~~~~~~~~^~~
In file included from drivers/media/common/siano/smscoreapi.c:12:
drivers/media/common/siano/smscoreapi.h:619:6: note: while referencing ‘msg_data’
619 | u32 msg_data[1];
| ^~~~~~~~
drivers/media/common/siano/smscoreapi.c:1004:24: warning: array subscript 2 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
1004 | trigger_msg->msg_data[2] = 0x200; /* Stack size */
| ~~~~~~~~~~~~~~~~~~~~~^~~
In file included from drivers/media/common/siano/smscoreapi.c:12:
drivers/media/common/siano/smscoreapi.h:619:6: note: while referencing ‘msg_data’
619 | u32 msg_data[1];
| ^~~~~~~~
drivers/media/common/siano/smscoreapi.c:1005:24: warning: array subscript 3 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
1005 | trigger_msg->msg_data[3] = 0; /* Parameter */
| ~~~~~~~~~~~~~~~~~~~~~^~~
In file included from drivers/media/common/siano/smscoreapi.c:12:
drivers/media/common/siano/smscoreapi.h:619:6: note: while referencing ‘msg_data’
619 | u32 msg_data[1];
| ^~~~~~~~
drivers/media/common/siano/smscoreapi.c:1006:24: warning: array subscript 4 is above array bounds of ‘u32[1]’ {aka ‘unsigned int[1]’} [-Warray-bounds]
1006 | trigger_msg->msg_data[4] = 4; /* Task ID */
| ~~~~~~~~~~~~~~~~~~~~~^~~
In file included from drivers/media/common/siano/smscoreapi.c:12:
drivers/media/common/siano/smscoreapi.h:619:6: note: while referencing ‘msg_data’
619 | u32 msg_data[1];
| ^~~~~~~~

Fixes: 018b0c6f8acb ("[media] siano: make load firmware logic to work with newer firmwares")
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/common/siano/smscoreapi.c | 22 +++++++++-------------
drivers/media/common/siano/smscoreapi.h | 4 ++--
2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/media/common/siano/smscoreapi.c b/drivers/media/common/siano/smscoreapi.c
index 2a8d9a36d6f0..5cc68144771c 100644
--- a/drivers/media/common/siano/smscoreapi.c
+++ b/drivers/media/common/siano/smscoreapi.c
@@ -914,7 +914,7 @@ static int smscore_load_firmware_family2(struct smscore_device_t *coredev,
void *buffer, size_t size)
{
struct sms_firmware *firmware = (struct sms_firmware *) buffer;
- struct sms_msg_data4 *msg;
+ struct sms_msg_data5 *msg;
u32 mem_address, calc_checksum = 0;
u32 i, *ptr;
u8 *payload = firmware->payload;
@@ -995,24 +995,20 @@ static int smscore_load_firmware_family2(struct smscore_device_t *coredev,
goto exit_fw_download;

if (coredev->mode == DEVICE_MODE_NONE) {
- struct sms_msg_data *trigger_msg =
- (struct sms_msg_data *) msg;
-
pr_debug("sending MSG_SMS_SWDOWNLOAD_TRIGGER_REQ\n");
SMS_INIT_MSG(&msg->x_msg_header,
MSG_SMS_SWDOWNLOAD_TRIGGER_REQ,
- sizeof(struct sms_msg_hdr) +
- sizeof(u32) * 5);
+ sizeof(*msg));

- trigger_msg->msg_data[0] = firmware->start_address;
+ msg->msg_data[0] = firmware->start_address;
/* Entry point */
- trigger_msg->msg_data[1] = 6; /* Priority */
- trigger_msg->msg_data[2] = 0x200; /* Stack size */
- trigger_msg->msg_data[3] = 0; /* Parameter */
- trigger_msg->msg_data[4] = 4; /* Task ID */
+ msg->msg_data[1] = 6; /* Priority */
+ msg->msg_data[2] = 0x200; /* Stack size */
+ msg->msg_data[3] = 0; /* Parameter */
+ msg->msg_data[4] = 4; /* Task ID */

- rc = smscore_sendrequest_and_wait(coredev, trigger_msg,
- trigger_msg->x_msg_header.msg_length,
+ rc = smscore_sendrequest_and_wait(coredev, msg,
+ msg->x_msg_header.msg_length,
&coredev->trigger_done);
} else {
SMS_INIT_MSG(&msg->x_msg_header, MSG_SW_RELOAD_EXEC_REQ,
diff --git a/drivers/media/common/siano/smscoreapi.h b/drivers/media/common/siano/smscoreapi.h
index 4cc39e4a8318..55d02c27f124 100644
--- a/drivers/media/common/siano/smscoreapi.h
+++ b/drivers/media/common/siano/smscoreapi.h
@@ -636,9 +636,9 @@ struct sms_msg_data2 {
u32 msg_data[2];
};

-struct sms_msg_data4 {
+struct sms_msg_data5 {
struct sms_msg_hdr x_msg_header;
- u32 msg_data[4];
+ u32 msg_data[5];
};

struct sms_data_download {
--
2.30.2