On 11/15/2017 9:42 PM, Bjorn Andersson wrote:
On Wed 15 Nov 12:10 PST 2017, Bjorn Andersson wrote:
diff --git a/drivers/soc/qcom/qmi_encdec.c b/drivers/soc/qcom/qmi_encdec.c
[..]
+void *qmi_encode_message(int type, unsigned int msg_id, size_t *len,
+                        unsigned int txn_id, struct qmi_elem_info *ei,
+                        const void *c_struct)
+{
+       struct qmi_header *hdr;
+       ssize_t msglen = 0;
+       void *msg;
+       int ret;
+
+       /* Check the possibility of a zero length QMI message */
+       if (!c_struct) {
+               ret = qmi_calc_min_msg_len(ei, 1);
+               if (ret) {
+                       pr_err("%s: Calc. len %d != 0, but NULL c_struct\n",
+                              __func__, ret);
+                       return ERR_PTR(-EINVAL);
+               }
+       }
+
+       msg = kzalloc(sizeof(*hdr) + *len, GFP_KERNEL);
+       if (!msg)
+               return ERR_PTR(-ENOMEM);
+
+       msglen = qmi_encode(ei, msg + sizeof(*hdr), c_struct, *len, 1);
+       if (msglen < 0) {
+               kfree(msg);
+               return ERR_PTR(msglen);
+       }

Talked to Chris Lew about this earlier today;

The check above implies that it's valid to call this function with a
valid ei of minimum message length of 0 and c_struct being NULL. But the
call to qmi_encdec() will dereference c_struct in order to know that the
optional elements described in ei are unset.

So the call to qmi_encode() needs to only be done conditionally on
c_struct being non-NULL, logically interpreting c_struct being NULL as
all optional fields are unset.

Will post an update with this fixed.


I have tested this patch with QMI loopback servers, Qualcomm diag and slimbus ngd.

Tested-By: Chris Lew <c...@codeaurora.org>
+
+       hdr = msg;
+       hdr->type = type;
+       hdr->txn_id = txn_id;
+       hdr->msg_id = msg_id;
+       hdr->msg_len = msglen;
+
+       *len = sizeof(*hdr) + msglen;
+
+       return msg;
+}
+EXPORT_SYMBOL(qmi_encode_message);

Regards,
Bjorn


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