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path: root/net/ieee80211/ieee80211_crypt_ccmp.c
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Diffstat (limited to 'net/ieee80211/ieee80211_crypt_ccmp.c')
-rw-r--r--net/ieee80211/ieee80211_crypt_ccmp.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/net/ieee80211/ieee80211_crypt_ccmp.c b/net/ieee80211/ieee80211_crypt_ccmp.c
index fdfe7704a46..35aa3426c3f 100644
--- a/net/ieee80211/ieee80211_crypt_ccmp.c
+++ b/net/ieee80211/ieee80211_crypt_ccmp.c
@@ -263,6 +263,27 @@ static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
return 0;
}
+/*
+ * deal with seq counter wrapping correctly.
+ * refer to timer_after() for jiffies wrapping handling
+ */
+static inline int ccmp_replay_check(u8 *pn_n, u8 *pn_o)
+{
+ u32 iv32_n, iv16_n;
+ u32 iv32_o, iv16_o;
+
+ iv32_n = (pn_n[0] << 24) | (pn_n[1] << 16) | (pn_n[2] << 8) | pn_n[3];
+ iv16_n = (pn_n[4] << 8) | pn_n[5];
+
+ iv32_o = (pn_o[0] << 24) | (pn_o[1] << 16) | (pn_o[2] << 8) | pn_o[3];
+ iv16_o = (pn_o[4] << 8) | pn_o[5];
+
+ if ((s32)iv32_n - (s32)iv32_o < 0 ||
+ (iv32_n == iv32_o && iv16_n <= iv16_o))
+ return 1;
+ return 0;
+}
+
static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
struct ieee80211_ccmp_data *key = priv;
@@ -315,7 +336,7 @@ static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
pn[5] = pos[0];
pos += 8;
- if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
+ if (ccmp_replay_check(pn, key->rx_pn)) {
if (net_ratelimit()) {
printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
" previous PN %02x%02x%02x%02x%02x%02x "