On 7/4/2023 2:08 PM, Dan Carpenter wrote:
On Tue, Jul 04, 2023 at 11:57:51AM +0530, Pranjal Ramajor Asha Kanojiya wrote:
diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index 5c57f7b4494e..a51b1594dcfa 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -748,7 +748,8 @@ static int encode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
int ret;
int i;
- if (!user_msg->count) {
+ if (!user_msg->count ||
+ user_msg->len < sizeof(*trans_hdr)) {
ret = -EINVAL;
goto out;
}
@@ -765,12 +766,13 @@ static int encode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
}
for (i = 0; i < user_msg->count; ++i) {
- if (user_len >= user_msg->len) {
+ if (user_len >= user_msg->len - sizeof(*trans_hdr)) {
If I understand correctly this check is added to verify if we are left with
trans_hdr size of data. In that case '>' comparison operator should be used.
That was there in the original code and I thought about changing it but
I don't like changing things which aren't necessary and == is also
invalid so I decided to leave it.
I see, I understand your concern about not changing unnecessary things
but '>=' is incorrect for reason mentioned above. We need to change that
to '>'
ret = -EINVAL;
break;
}
trans_hdr = (struct qaic_manage_trans_hdr *)(user_msg->data + user_len);
- if (user_len + trans_hdr->len > user_msg->len) {
+ if (trans_hdr->len < sizeof(trans_hdr) ||
+ size_add(user_len, trans_hdr->len) > user_msg->len) {
If we change to > then the == will be caught by this check. So it
doesn't affect runtime either way.
I fail to see that.
Lets run an example:
user_len is 0
user_msg->len is 8
sizeof(*trans_hdr) is 8
trans_hdr->len is 8
Above instance is correct and should be processed without error.
So user_len > user_msg->len - sizeof(*trans_hdr) translates to
(0 > 8 - 8)
(0 > 0)
false (No error)
.
.
.
trans_hdr->len < sizeof(trans_hdr) ||
size_add(user_len, trans_hdr->len) > user_msg->len, translates to
8 < 8 || size_add(0, 8) > 8
false || 8 > 8
false || false
false (No error)
Am I missing anything?
regards,
dan carpenter
