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Date: Sun, 3 Jun 2018 19:16:19 +0300
From: Ivan Safonov <insafonov@...il.com>
To: Dan Carpenter <dan.carpenter@...cle.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
devel@...verdev.osuosl.org,
Santha Meena Ramamoorthy <santhameena13@...il.com>,
Janani Sankara Babu <jananis37@...il.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] staging:r8188eu: Use lib80211 to encrypt (WEP) tx frames
On 05/28/2018 04:53 PM, Dan Carpenter wrote:
> On Mon, May 28, 2018 at 09:18:21AM +0300, Ivan Safonov wrote:
>> Put data to skb, decrypt with lib80211_crypt_wep, and place back to tx buffer.
>>
>> Signed-off-by: Ivan Safonov <insafonov@...il.com>
>> ---
>> drivers/staging/rtl8188eu/core/rtw_security.c | 72 ++++++++++++++++-----------
>> 1 file changed, 43 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/staging/rtl8188eu/core/rtw_security.c b/drivers/staging/rtl8188eu/core/rtw_security.c
>> index bfe0b217e679..80d7569a3108 100644
>> --- a/drivers/staging/rtl8188eu/core/rtw_security.c
>> +++ b/drivers/staging/rtl8188eu/core/rtw_security.c
>> @@ -139,17 +139,11 @@ static __le32 getcrc32(u8 *buf, int len)
>> Need to consider the fragment situation
>> */
>> void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
>> -{ /* exclude ICV */
>> -
>> - unsigned char crc[4];
>> - struct arc4context mycontext;
>> -
>> +{
>> int curfragnum, length;
>> - u32 keylength;
>>
>> - u8 *pframe, *payload, *iv; /* wepkey */
>> - u8 wepkey[16];
>> - u8 hw_hdr_offset = 0;
>> + u8 *pframe;
>> + u8 hw_hdr_offset = 0;
>> struct pkt_attrib *pattrib = &((struct xmit_frame *)pxmitframe)->attrib;
>> struct security_priv *psecuritypriv = &padapter->securitypriv;
>> struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
>> @@ -165,33 +159,53 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
>>
>> /* start to encrypt each fragment */
>> if ((pattrib->encrypt == _WEP40_) || (pattrib->encrypt == _WEP104_)) {
>> - keylength = psecuritypriv->dot11DefKeylen[psecuritypriv->dot11PrivacyKeyIndex];
>> + const int keyindex = psecuritypriv->dot11PrivacyKeyIndex;
>> + void *crypto_private;
>> + struct sk_buff *skb;
>> + struct lib80211_crypto_ops *crypto_ops = try_then_request_module(lib80211_get_crypto_ops("WEP"), "lib80211_crypt_wep");
>> +
>> + if (!crypto_ops)
>> + goto exit;
>> +
>> + crypto_private = crypto_ops->init(keyindex);
>> + if (!crypto_private)
>> + goto exit;
>> +
>> + if (crypto_ops->set_key(psecuritypriv->dot11DefKey[keyindex].skey,
>> + psecuritypriv->dot11DefKeylen[keyindex], NULL, crypto_private) < 0)
>> + goto exit;
>>
>> for (curfragnum = 0; curfragnum < pattrib->nr_frags; curfragnum++) {
>> - iv = pframe+pattrib->hdrlen;
>> - memcpy(&wepkey[0], iv, 3);
>> - memcpy(&wepkey[3], &psecuritypriv->dot11DefKey[psecuritypriv->dot11PrivacyKeyIndex].skey[0], keylength);
>> - payload = pframe+pattrib->iv_len+pattrib->hdrlen;
>> + if (curfragnum + 1 == pattrib->nr_frags)
>> + length = pattrib->last_txcmdsz;
>> + else
>> + length = pxmitpriv->frag_len;
>> + skb = dev_alloc_skb(length);
>> + if (!skb)
>> + goto exit;
>>
>> - if ((curfragnum+1) == pattrib->nr_frags) { /* the last fragment */
>> - length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
>> + skb_put_data(skb, pframe, length);
>>
>> - *((__le32 *)crc) = getcrc32(payload, length);
>> + memmove(skb->data + 4, skb->data, pattrib->hdrlen);
>> + skb_pull(skb, 4);
>> + skb_trim(skb, skb->len - 4);
>>
>> - arcfour_init(&mycontext, wepkey, 3+keylength);
>> - arcfour_encrypt(&mycontext, payload, payload, length);
>> - arcfour_encrypt(&mycontext, payload+length, crc, 4);
>> - } else {
>> - length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
>> - *((__le32 *)crc) = getcrc32(payload, length);
>> - arcfour_init(&mycontext, wepkey, 3+keylength);
>> - arcfour_encrypt(&mycontext, payload, payload, length);
>> - arcfour_encrypt(&mycontext, payload+length, crc, 4);
>> -
>> - pframe += pxmitpriv->frag_len;
>> - pframe = (u8 *)round_up((size_t)(pframe), 4);
>> + if (crypto_ops->encrypt_mpdu(skb, pattrib->hdrlen, crypto_private)) {
>> + kfree_skb(skb);
>> + goto exit;
>> }
>> +
>> + memcpy(pframe, skb->data, skb->len);
>> +
>> + pframe += skb->len;
>> + pframe = (u8 *)round_up((size_t)(pframe), 4);
>> +
>> + kfree_skb(skb);
>> }
>> +
>> +exit:
>> + if (crypto_ops && crypto_private)
>> + crypto_ops->deinit(crypto_private);
>
> One label style error handling is always bugggy. I'm surprised GCC
> doesn't catch that crypto_private can be uninitialized...
This is not a compiler defect. The code
if (a && b) {
...
}
is equal to
if (a) {
if (b) {
...
}
}
>
> Flip the if ((pattrib->encrypt == _WEP40_) || (pattrib->encrypt == _WEP104_)) {
> tests so it's:
>
> if (pattrib->encrypt != _WEP40_ && pattrib->encrypt != _WEP104_)
> return;
The check is superfluous inside this function, it should be
(somewhen) around rtw_wep_encrypt().
>
> The use normal error handling style:
>
> kfree_skb(skb);
> return;
>
> err_free_skb:
> kfree_skb(skb);
> err_deinit:
> crypto_ops->deinit(crypto_private);
> }
>
rtw_(wep|aes|tkip)_(en|de)crypt still need to be rewritten, so I'll
leave this patch as is. In the following patches I'll take your comments
into account, they really simplify reading the code.
> regards,
> dan carpenter
>
Ivan Safonov.
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