[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 <davem@davemloft.net>
diff --git a/include/net/esp.h b/include/net/esp.h
index 064366d..713d039f 100644
--- a/include/net/esp.h
+++ b/include/net/esp.h
@@ -15,13 +15,14 @@
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 e87377e..13b2936 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -95,8 +95,13 @@
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 @@
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 ae50b95..e78680a 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -99,8 +99,13 @@
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 @@
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;