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SubjectRe: [PATCH] staging:r8188eu: Use lib80211 to encrypt (WEP) tx frames
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@gmail.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...

Flip the if ((pattrib->encrypt == _WEP40_) || (pattrib->encrypt == _WEP104_)) {
tests so it's:

if (pattrib->encrypt != _WEP40_ && pattrib->encrypt != _WEP104_)
return;

The use normal error handling style:

kfree_skb(skb);
return;

err_free_skb:
kfree_skb(skb);
err_deinit:
crypto_ops->deinit(crypto_private);
}

regards,
dan carpenter

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