[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/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;