On 6/21/2023 12:51 PM, Dan Carpenter wrote:
Copy the bounds checking from encode_message() to decode_message().
This patch addresses the following concerns. Ensure that there is
enough space for at least one header so that we don't have a negative
size later.
if (msg_hdr_len < sizeof(*trans_hdr))
Ensure that we have enough space to read the next header from the
msg->data.
if (msg_len >= msg_hdr_len - sizeof(*trans_hdr))
return -EINVAL;
Check that the trans_hdr->len is not below the minimum size:
if (hdr_len < sizeof(*trans_hdr))
This minimum check ensures that we don't corrupt memory in
decode_passthrough() when we do.
memcpy(out_trans->data, in_trans->data, len - sizeof(in_trans->hdr));
And finally, use size_add() to prevent an integer overflow:
if (size_add(msg_len, hdr_len) > msg_hdr_len)
Fixes: 129776ac2e38 ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
drivers/accel/qaic/qaic_control.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index a51b1594dcfa..78f6c3d6380d 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -955,15 +955,23 @@ static int decode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
int ret;
int i;
- if (msg_hdr_len > QAIC_MANAGE_MAX_MSG_LENGTH)
+ if (msg_hdr_len < sizeof(*trans_hdr) ||
+ msg_hdr_len > QAIC_MANAGE_MAX_MSG_LENGTH)
return -EINVAL;
user_msg->len = 0;
user_msg->count = le32_to_cpu(msg->hdr.count);
for (i = 0; i < user_msg->count; ++i) {
+ u32 hdr_len;
+
+ if (msg_len >= msg_hdr_len - sizeof(*trans_hdr))
+ return -EINVAL;
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.
+
trans_hdr = (struct wire_trans_hdr *)(msg->data + msg_len);
- if (msg_len + le32_to_cpu(trans_hdr->len) > msg_hdr_len)
+ hdr_len = le32_to_cpu(trans_hdr->len);
+ if (hdr_len < sizeof(*trans_hdr) ||
+ size_add(msg_len, hdr_len) > msg_hdr_len)
return -EINVAL;
switch (le32_to_cpu(trans_hdr->type)) {
