On 8/3/2017 9:08 PM, Maya Erez wrote:
From: Hamad Kadmany <qca_hkadm...@qca.qualcomm.com>

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_hkadm...@qca.qualcomm.com>
Signed-off-by: Lior David <qca_li...@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_me...@qca.qualcomm.com>
---
  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?

Regards,
Arend

        frame = memdup_user(buf, len);
        if (IS_ERR(frame))
                return PTR_ERR(frame);


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