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Diffstat (limited to 'sys')
-rw-r--r--sys/netipsec/xform_esp.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/sys/netipsec/xform_esp.c b/sys/netipsec/xform_esp.c
index 214df48157c9..8a378c4adaf8 100644
--- a/sys/netipsec/xform_esp.c
+++ b/sys/netipsec/xform_esp.c
@@ -80,6 +80,8 @@
#include <opencrypto/xform.h>
VNET_DEFINE(int, esp_enable) = 1;
+VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1;
+#define V_esp_ctr_compatibility VNET(esp_ctr_compatibility)
VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
VNET_PCPUSTAT_SYSINIT(espstat);
@@ -90,6 +92,9 @@ VNET_PCPUSTAT_SYSUNINIT(espstat);
SYSCTL_DECL(_net_inet_esp);
SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
+SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility,
+ CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0,
+ "Align AES-CTR encrypted transmitted frames to blocksize");
SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
struct espstat, espstat,
"ESP statistics (struct espstat, netipsec/esp_var.h");
@@ -652,8 +657,14 @@ esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
/*
* RFC4303 2.4 Requires 4 byte alignment.
+ * Old versions of FreeBSD can't decrypt partial blocks encrypted
+ * with AES-CTR. Align payload to native_blocksize (16 bytes)
+ * in order to preserve compatibility.
*/
- blks = MAX(4, espx->blocksize); /* Cipher blocksize */
+ if (SAV_ISCTR(sav) && V_esp_ctr_compatibility)
+ blks = MAX(4, espx->native_blocksize); /* Cipher blocksize */
+ else
+ blks = MAX(4, espx->blocksize);
/* XXX clamp padding length a la KAME??? */
padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;