2017-11-16 23:57:45

by Chris Lew

[permalink] [raw]
Subject: Re: [PATCH v3 1/5] soc: qcom: Introduce QMI encoder/decoder



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 <[email protected]>
>> +
>> + 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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a Linux Foundation Collaborative Project

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