Re: [PATCH 13/13] ieee80211: Add TKIP crypt-build_iv

[Johannes Berg]

On Fri, 2006-01-20 at 13:24 +0800, Zhu Yi wrote:

 This patch is based on your patch (mentioned above). It changes the
 build_iv() interface to add two more parameters. Because for TKIP, the
 encryption key is changed everytime an IV is built. Since the IV is
 built by software, we have to return the new key to hardware. So the
 hardware can encryption the packet correctly.

Yeah, makes sense.

 For WEP or even CCMP, the encryption key is not changed together with
 build_iv. So we can simply pass the key and key_len parameters to NULL
 and 0. And your WEP implementation can safetly ignore the two
 parameters. I think it is what I do with the patch. Let me know if it
 doesn't work for you.

Should be fine, but I'll have to try. I somehow got confused about what
this was based on and what it applied against, sorry about that.

johannes


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[PATCH 13/13] ieee80211: Add TKIP crypt-build_iv

[Zhu Yi]

ieee80211: Add TKIP crypt-build_iv

This patch adds ieee80211 TKIP build_iv() method to support hardwares that
can do TKIP encryption but relies on ieee80211 layer to build the IV. It also
changes the build_iv() interface to return the key if possible after the IV
is built (this is required by TKIP).

Signed-off-by: Zhu Yi [EMAIL PROTECTED]
--

diff --git a/include/net/ieee80211_crypt.h b/include/net/ieee80211_crypt.h
index cd82c3e..eb47641 100644
--- a/include/net/ieee80211_crypt.h
+++ b/include/net/ieee80211_crypt.h
@@ -47,7 +47,8 @@ struct ieee80211_crypto_ops {
/* deinitialize crypto context and free allocated private data */
void (*deinit) (void *priv);
 
-   int (*build_iv) (struct sk_buff * skb, int hdr_len, void *priv);
+   int (*build_iv) (struct sk_buff * skb, int hdr_len,
+u8 *key, int keylen, void *priv);
 
/* encrypt/decrypt return  0 on error or = 0 on success. The return
 * value from decrypt_mpdu is passed as the keyidx value for
diff --git a/net/ieee80211/ieee80211_crypt_ccmp.c 
b/net/ieee80211/ieee80211_crypt_ccmp.c
index 4702217..097bcea 100644
--- a/net/ieee80211/ieee80211_crypt_ccmp.c
+++ b/net/ieee80211/ieee80211_crypt_ccmp.c
@@ -190,7 +190,8 @@ static void ccmp_init_blocks(struct cryp
ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 }
 
-static int ieee80211_ccmp_hdr(struct sk_buff *skb, int hdr_len, void *priv)
+static int ieee80211_ccmp_hdr(struct sk_buff *skb, int hdr_len,
+ u8 *aeskey, int keylen, void *priv)
 {
struct ieee80211_ccmp_data *key = priv;
int i;
@@ -199,6 +200,9 @@ static int ieee80211_ccmp_hdr(struct sk_
if (skb_headroom(skb)  CCMP_HDR_LEN || skb-len  hdr_len)
return -1;
 
+   if (aeskey != NULL  keylen = CCMP_TK_LEN)
+   memcpy(aeskey, key-key, CCMP_TK_LEN);
+
pos = skb_push(skb, CCMP_HDR_LEN);
memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
pos += hdr_len;
@@ -238,7 +242,7 @@ static int ieee80211_ccmp_encrypt(struct
return -1;
 
data_len = skb-len - hdr_len;
-   len = ieee80211_ccmp_hdr(skb, hdr_len, priv);
+   len = ieee80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv);
if (len  0)
return -1;
 
diff --git a/net/ieee80211/ieee80211_crypt_tkip.c 
b/net/ieee80211/ieee80211_crypt_tkip.c
index e098832..93def94 100644
--- a/net/ieee80211/ieee80211_crypt_tkip.c
+++ b/net/ieee80211/ieee80211_crypt_tkip.c
@@ -270,34 +270,33 @@ static void tkip_mixing_phase2(u8 * WEPS
 #endif
 }
 
-static u8 *ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len, void *priv)
+static int ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
+ u8 * rc4key, int keylen, void *priv)
 {
struct ieee80211_tkip_data *tkey = priv;
int len;
-   u8 *rc4key, *pos, *icv;
+   u8 *pos;
struct ieee80211_hdr_4addr *hdr;
-   u32 crc;
 
hdr = (struct ieee80211_hdr_4addr *)skb-data;
 
if (skb_headroom(skb)  8 || skb-len  hdr_len)
-   return NULL;
+   return -1;
+
+   if (rc4key == NULL || keylen  16)
+   return -1;
 
if (!tkey-tx_phase1_done) {
tkip_mixing_phase1(tkey-tx_ttak, tkey-key, hdr-addr2,
   tkey-tx_iv32);
tkey-tx_phase1_done = 1;
}
-   rc4key = kmalloc(16, GFP_ATOMIC);
-   if (!rc4key)
-   return NULL;
tkip_mixing_phase2(rc4key, tkey-key, tkey-tx_ttak, tkey-tx_iv16);
 
len = skb-len - hdr_len;
pos = skb_push(skb, 8);
memmove(pos, pos + 8, hdr_len);
pos += hdr_len;
-   icv = skb_put(skb, 4);
 
*pos++ = *rc4key;
*pos++ = *(rc4key + 1);
@@ -308,28 +307,28 @@ static u8 *ieee80211_tkip_hdr(struct sk_
*pos++ = (tkey-tx_iv32  16)  0xff;
*pos++ = (tkey-tx_iv32  24)  0xff;
 
-   crc = ~crc32_le(~0, pos, len);
-   icv[0] = crc;
-   icv[1] = crc  8;
-   icv[2] = crc  16;
-   icv[3] = crc  24;
+   tkey-tx_iv16++;
+   if (tkey-tx_iv16 == 0) {
+   tkey-tx_phase1_done = 0;
+   tkey-tx_iv32++;
+   }
 
-   return rc4key;
+   return 8;
 }
 
 static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 {
struct ieee80211_tkip_data *tkey = priv;
int len;
-   const u8 *rc4key;
-   u8 *pos;
+   u8 rc4key[16], *pos, *icv;
+   u32 crc;
struct scatterlist sg;
 
if (tkey-flags  IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
if (net_ratelimit()) {
struct ieee80211_hdr_4addr *hdr =
(struct ieee80211_hdr_4addr *)skb-data;
-   printk(KERN_DEBUG TKIP countermeasures: dropped 
+   printk(KERN_DEBUG : TKIP countermeasures: dropped 
   TX packet to  MAC_FMT \n,
 

Re: [PATCH 13/13] ieee80211: Add TKIP crypt-build_iv

[Johannes Berg]

On Thu, 2006-01-19 at 16:22 +0800, Zhu Yi wrote:

 This patch adds ieee80211 TKIP build_iv() method to support hardwares that
 can do TKIP encryption but relies on ieee80211 layer to build the IV. It also
 changes the build_iv() interface to return the key if possible after the IV
 is built (this is required by TKIP).

Could you do the same for WEP please (i.e. add build_iv() support)?
Looking at this patch it seems to break my patch
(http://marc.theaimsgroup.com/?l=linux-netdevm=113602540003262w=2)
doing that, but I'm not sure how this ought to be with the new
build_iv() interface.

johannes


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