2009-05-11 18:59:01

by Jouni Malinen

[permalink] [raw]
Subject: [PATCH 4/4] nl80211: Add RSC configuration for new keys

When setting a key with NL80211_CMD_NEW_KEY, we should allow the key
sequence number (RSC) to be set in order to allow replay protection to
work correctly for group keys. This patch documents this use for
nl80211 and adds the couple of missing pieces in nl80211/cfg80211 and
mac80211 to support this. In addition, WEXT SIOCSIWENCODEEXT compat
processing in cfg80211 is extended to handle the RSC (this was already
specified in WEXT, but just not implemented in cfg80211/mac80211).

Signed-off-by: Jouni Malinen <[email protected]>

---
include/linux/nl80211.h | 4 ++--
net/mac80211/cfg.c | 3 ++-
net/mac80211/key.c | 21 ++++++++++++++++++++-
net/mac80211/key.h | 3 ++-
net/wireless/nl80211.c | 5 +++++
net/wireless/wext-compat.c | 5 +++++
6 files changed, 36 insertions(+), 5 deletions(-)

--- uml.orig/include/linux/nl80211.h 2009-05-11 21:39:26.000000000 +0300
+++ uml/include/linux/nl80211.h 2009-05-11 21:39:27.000000000 +0300
@@ -79,8 +79,8 @@
* @NL80211_CMD_SET_KEY: Set key attributes %NL80211_ATTR_KEY_DEFAULT,
* %NL80211_ATTR_KEY_DEFAULT_MGMT, or %NL80211_ATTR_KEY_THRESHOLD.
* @NL80211_CMD_NEW_KEY: add a key with given %NL80211_ATTR_KEY_DATA,
- * %NL80211_ATTR_KEY_IDX, %NL80211_ATTR_MAC and %NL80211_ATTR_KEY_CIPHER
- * attributes.
+ * %NL80211_ATTR_KEY_IDX, %NL80211_ATTR_MAC, %NL80211_ATTR_KEY_CIPHER,
+ * and %NL80211_ATTR_KEY_SEQ attributes.
* @NL80211_CMD_DEL_KEY: delete a key identified by %NL80211_ATTR_KEY_IDX
* or %NL80211_ATTR_MAC.
*
--- uml.orig/net/wireless/nl80211.c 2009-05-11 21:39:26.000000000 +0300
+++ uml/net/wireless/nl80211.c 2009-05-11 21:39:27.000000000 +0300
@@ -1115,6 +1115,11 @@ static int nl80211_new_key(struct sk_buf
params.key_len = nla_len(info->attrs[NL80211_ATTR_KEY_DATA]);
}

+ if (info->attrs[NL80211_ATTR_KEY_SEQ]) {
+ params.seq = nla_data(info->attrs[NL80211_ATTR_KEY_SEQ]);
+ params.seq_len = nla_len(info->attrs[NL80211_ATTR_KEY_SEQ]);
+ }
+
if (info->attrs[NL80211_ATTR_KEY_IDX])
key_idx = nla_get_u8(info->attrs[NL80211_ATTR_KEY_IDX]);

--- uml.orig/net/mac80211/cfg.c 2009-05-11 21:39:26.000000000 +0300
+++ uml/net/mac80211/cfg.c 2009-05-11 21:39:27.000000000 +0300
@@ -141,7 +141,8 @@ static int ieee80211_add_key(struct wiph
return -EINVAL;
}

- key = ieee80211_key_alloc(alg, key_idx, params->key_len, params->key);
+ key = ieee80211_key_alloc(alg, key_idx, params->key_len, params->key,
+ params->seq_len, params->seq);
if (!key)
return -ENOMEM;

--- uml.orig/net/mac80211/key.c 2009-05-11 21:39:08.000000000 +0300
+++ uml/net/mac80211/key.c 2009-05-11 21:39:27.000000000 +0300
@@ -290,9 +290,11 @@ static void __ieee80211_key_replace(stru
struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
int idx,
size_t key_len,
- const u8 *key_data)
+ const u8 *key_data,
+ size_t seq_len, const u8 *seq)
{
struct ieee80211_key *key;
+ int i, j;

BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);

@@ -318,14 +320,31 @@ struct ieee80211_key *ieee80211_key_allo
case ALG_TKIP:
key->conf.iv_len = TKIP_IV_LEN;
key->conf.icv_len = TKIP_ICV_LEN;
+ if (seq && seq_len == 6) {
+ for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
+ key->u.tkip.rx[i].iv32 =
+ get_unaligned_le32(&seq[2]);
+ key->u.tkip.rx[i].iv16 =
+ get_unaligned_le16(seq);
+ }
+ }
break;
case ALG_CCMP:
key->conf.iv_len = CCMP_HDR_LEN;
key->conf.icv_len = CCMP_MIC_LEN;
+ if (seq && seq_len == CCMP_PN_LEN) {
+ for (i = 0; i < NUM_RX_DATA_QUEUES; i++)
+ for (j = 0; j < CCMP_PN_LEN; j++)
+ key->u.ccmp.rx_pn[i][j] =
+ seq[CCMP_PN_LEN - j - 1];
+ }
break;
case ALG_AES_CMAC:
key->conf.iv_len = 0;
key->conf.icv_len = sizeof(struct ieee80211_mmie);
+ if (seq && seq_len == 6)
+ for (j = 0; j < 6; j++)
+ key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
break;
}
memcpy(key->conf.key, key_data, key_len);
--- uml.orig/net/mac80211/key.h 2009-05-11 21:39:08.000000000 +0300
+++ uml/net/mac80211/key.h 2009-05-11 21:39:27.000000000 +0300
@@ -144,7 +144,8 @@ struct ieee80211_key {
struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
int idx,
size_t key_len,
- const u8 *key_data);
+ const u8 *key_data,
+ size_t seq_len, const u8 *seq);
/*
* Insert a key into data structures (sdata, sta if necessary)
* to make it used, free old key.
--- uml.orig/net/wireless/wext-compat.c 2009-05-11 21:39:21.000000000 +0300
+++ uml/net/wireless/wext-compat.c 2009-05-11 21:39:27.000000000 +0300
@@ -655,6 +655,11 @@ int cfg80211_wext_siwencodeext(struct ne
params.key_len = ext->key_len;
params.cipher = cipher;

+ if (ext->ext_flags & IW_ENCODE_EXT_RX_SEQ_VALID) {
+ params.seq = ext->rx_seq;
+ params.seq_len = 6;
+ }
+
return cfg80211_set_encryption(
rdev, dev, addr, remove,
ext->ext_flags & IW_ENCODE_EXT_SET_TX_KEY,

--

--
Jouni Malinen PGP id EFC895FA


2009-05-13 23:39:25

by Johannes Berg

[permalink] [raw]
Subject: Re: [PATCH 4/4] nl80211: Add RSC configuration for new keys

Oops. Now that the patch is in the tree I took another, closer, look...

I think you should add an item to the nl80211 policy for
NL80211_ATTR_KEY_SEQ now, and restrict it to be exactly 6 bytes there
rather than silently ignoring it if it was a different length.

> --- uml.orig/net/wireless/nl80211.c 2009-05-11 21:39:26.000000000 +0300
> +++ uml/net/wireless/nl80211.c 2009-05-11 21:39:27.000000000 +0300
> @@ -1115,6 +1115,11 @@ static int nl80211_new_key(struct sk_buf
> params.key_len = nla_len(info->attrs[NL80211_ATTR_KEY_DATA]);
> }
>
> + if (info->attrs[NL80211_ATTR_KEY_SEQ]) {
> + params.seq = nla_data(info->attrs[NL80211_ATTR_KEY_SEQ]);
> + params.seq_len = nla_len(info->attrs[NL80211_ATTR_KEY_SEQ]);
> + }

Maybe it should also check the key type? At least you haven't
implemented using it with WEP.

> + if (seq && seq_len == 6) {

> + if (seq && seq_len == CCMP_PN_LEN) {

> + if (seq && seq_len == 6)

In any case then you could get rid of those == 6 checks.

johannes


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