On 8/9/2017 11:02 AM, Arend van Spriel wrote:
> On 8/3/2017 9:08 PM, Maya Erez wrote:
>> From: Hamad Kadmany <qca_hkadmany@xxxxxxxxxxxxxxxx>
>>
>> Validate buffer length has the minimum needed size
>> when sending management frame to protect against
>> possible buffer overrun.
>
> I noticed this is already applied, but I saw this subject text which has similar
> sound to a recent patch in our driver so I it made me curious...
>
>> Signed-off-by: Hamad Kadmany <qca_hkadmany@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Lior David <qca_liord@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Maya Erez <qca_merez@xxxxxxxxxxxxxxxx>
>> ---
>> drivers/net/wireless/ath/wil6210/cfg80211.c | 3 +++
>> drivers/net/wireless/ath/wil6210/debugfs.c | 3 +++
>> 2 files changed, 6 insertions(+)
>>
>> diff --git a/drivers/net/wireless/ath/wil6210/cfg80211.c
>> b/drivers/net/wireless/ath/wil6210/cfg80211.c
>> index 0b5383a..77af749 100644
>> --- a/drivers/net/wireless/ath/wil6210/cfg80211.c
>> +++ b/drivers/net/wireless/ath/wil6210/cfg80211.c
>> @@ -884,6 +884,9 @@ int wil_cfg80211_mgmt_tx(struct wiphy *wiphy, struct
>> wireless_dev *wdev,
>> wil_hex_dump_misc("mgmt tx frame ", DUMP_PREFIX_OFFSET, 16, 1, buf,
>> len, true);
>>
>> + if (len < sizeof(struct ieee80211_hdr_3addr))
>> + return -EINVAL;
>
> A similar check is already in net/wireless/cfg80211_mlme_mgmt_tx() which calls
> this function:
>
> if (params->len < 24 + 1)
> return -EINVAL;
>
> So it only makes sense if this is called from some other call site....
>
>> cmd = kmalloc(sizeof(*cmd) + len, GFP_KERNEL);
>> if (!cmd) {
>> rc = -ENOMEM;
>> diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c
>> b/drivers/net/wireless/ath/wil6210/debugfs.c
>> index f82506d..a2b5d59 100644
>> --- a/drivers/net/wireless/ath/wil6210/debugfs.c
>> +++ b/drivers/net/wireless/ath/wil6210/debugfs.c
>> @@ -801,6 +801,9 @@ static ssize_t wil_write_file_txmgmt(struct file *file,
>> const char __user *buf,
>> int rc;
>> void *frame;
>>
>> + if (!len)
>> + return -EINVAL;
>> +
>
> ... which is in this function. Now I wonder why you would need this method in
> the first place. Why not stick with using the nl80211 NL80211_CMD_FRAME api?
>
Using NL80211_CMD_FRAME reaches cfg80211_mlme_mgmt_tx which performs validity
checks such as:
- Fail to send frame types not supported by the driver
- Some strict checks for non-public action frames.
The debugfs file provides a convenient and simple way to send any type of
management frames for debugging and testing. For example, we use it with some
testing scripts, basically turning a station into a "packet injector" and
sending frames into the air for simulating various scenarios.
Thanks,
Lior
