Re: [PATCH] staging:r8188eu: Use lib80211 to encrypt (WEP) tx frames
From: Dan Carpenter
Date: Mon Jun 04 2018 - 05:12:02 EST
On Sun, Jun 03, 2018 at 07:16:19PM +0300, Ivan Safonov wrote:
> 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@xxxxxxxxx>
> > > ---
> > > 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) {
> ...
> }
> }
Heh... Oops. Sorry, I misread the code. That's embarrassing.
> 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.
>
Sounds good.
regards,
dan carpenter