From e4bec827feda76d5e7417a2696a75424834d564f Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 22 Sep 2006 15:17:35 -0700 Subject: [PATCH] [IPSEC] esp: Defer output IV initialization to first use. First of all, if the xfrm_state only gets used for input packets this entropy is a complete waste. Secondly, it is often the case that a configuration loads many rules (perhaps even dynamically) and they don't all necessarily ever get used. This get_random_bytes() call was showing up in the profiles for xfrm_state inserts which is how I noticed this. Signed-off-by: David S. Miller --- include/net/esp.h | 5 +++-- net/ipv4/esp4.c | 9 +++++++-- net/ipv6/esp6.c | 9 +++++++-- 3 files changed, 17 insertions(+), 6 deletions(-) diff --git a/include/net/esp.h b/include/net/esp.h index 064366d66e..713d039f4a 100644 --- a/include/net/esp.h +++ b/include/net/esp.h @@ -15,13 +15,14 @@ struct esp_data struct { u8 *key; /* Key */ int key_len; /* Key length */ - u8 *ivec; /* ivec buffer */ + int padlen; /* 0..255 */ /* ivlen is offset from enc_data, where encrypted data start. * It is logically different of crypto_tfm_alg_ivsize(tfm). * We assume that it is either zero (no ivec), or * >= crypto_tfm_alg_ivsize(tfm). */ int ivlen; - int padlen; /* 0..255 */ + int ivinitted; + u8 *ivec; /* ivec buffer */ struct crypto_blkcipher *tfm; /* crypto handle */ } conf; diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index e87377e1d6..13b29360d1 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -95,8 +95,13 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb) esph->seq_no = htonl(++x->replay.oseq); xfrm_aevent_doreplay(x); - if (esp->conf.ivlen) + if (esp->conf.ivlen) { + if (unlikely(!esp->conf.ivinitted)) { + get_random_bytes(esp->conf.ivec, esp->conf.ivlen); + esp->conf.ivinitted = 1; + } crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); + } do { struct scatterlist *sg = &esp->sgbuf[0]; @@ -378,7 +383,7 @@ static int esp_init_state(struct xfrm_state *x) esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); if (unlikely(esp->conf.ivec == NULL)) goto error; - get_random_bytes(esp->conf.ivec, esp->conf.ivlen); + esp->conf.ivinitted = 0; } if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) goto error; diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index ae50b95111..e78680a998 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -99,8 +99,13 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) esph->seq_no = htonl(++x->replay.oseq); xfrm_aevent_doreplay(x); - if (esp->conf.ivlen) + if (esp->conf.ivlen) { + if (unlikely(!esp->conf.ivinitted)) { + get_random_bytes(esp->conf.ivec, esp->conf.ivlen); + esp->conf.ivinitted = 1; + } crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); + } do { struct scatterlist *sg = &esp->sgbuf[0]; @@ -353,7 +358,7 @@ static int esp6_init_state(struct xfrm_state *x) esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); if (unlikely(esp->conf.ivec == NULL)) goto error; - get_random_bytes(esp->conf.ivec, esp->conf.ivlen); + esp->conf.ivinitted = 0; } if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) goto error; -- 2.39.5