[PATCH] add new_keys argument to esp_setup_keys() and comment clarifying esp.secrets format

[dlenski at gmail.com (Daniel Lenski)]

This is to make esp_setup_keys() usable for both Juniper and GlobalProtect.
Juniper generates a new set of keys on the client side, while GlobalProtect
just needs to set up the keys provided by the server.

Signed-off-by: Daniel Lenski <dlenski at gmail.com>
---
 gnutls-esp.c           | 23 ++++++++++++++---------
 oncp.c                 |  4 ++--
 openconnect-internal.h |  4 ++--
 openssl-esp.c          | 23 ++++++++++++++---------
 4 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/gnutls-esp.c b/gnutls-esp.c
index 1ad4e60..ac58dcd 100644
--- a/gnutls-esp.c
+++ b/gnutls-esp.c
@@ -72,7 +72,7 @@ static int init_esp_ciphers(struct openconnect_info *vpninfo, struct esp *esp,
 	return 0;
 }
 
-int setup_esp_keys(struct openconnect_info *vpninfo)
+int setup_esp_keys(struct openconnect_info *vpninfo, int new_keys)
 {
 	struct esp *esp_in;
 	gnutls_mac_algorithm_t macalg;
@@ -106,16 +106,21 @@ int setup_esp_keys(struct openconnect_info *vpninfo)
 		return -EINVAL;
 	}
 
-	vpninfo->old_esp_maxseq = vpninfo->esp_in[vpninfo->current_esp_in].seq + 32;
-	vpninfo->current_esp_in ^= 1;
+	if (new_keys) {
+		vpninfo->old_esp_maxseq = vpninfo->esp_in[vpninfo->current_esp_in].seq + 32;
+		vpninfo->current_esp_in ^= 1;
+	}
+
 	esp_in = &vpninfo->esp_in[vpninfo->current_esp_in];
 
-	if ((ret = gnutls_rnd(GNUTLS_RND_NONCE, &esp_in->spi, sizeof(esp_in->spi))) ||
-	    (ret = gnutls_rnd(GNUTLS_RND_RANDOM, &esp_in->secrets, sizeof(esp_in->secrets)))) {
-		vpn_progress(vpninfo, PRG_ERR,
-			     _("Failed to generate random keys for ESP: %s\n"),
-			     gnutls_strerror(ret));
-		return -EIO;
+	if (new_keys) {
+		if ((ret = gnutls_rnd(GNUTLS_RND_NONCE, &esp_in->spi, sizeof(esp_in->spi))) ||
+		    (ret = gnutls_rnd(GNUTLS_RND_RANDOM, &esp_in->secrets, sizeof(esp_in->secrets)))) {
+			vpn_progress(vpninfo, PRG_ERR,
+				     _("Failed to generate random keys for ESP: %s\n"),
+				     gnutls_strerror(ret));
+			return -EIO;
+		}
 	}
 
 	ret = init_esp_ciphers(vpninfo, &vpninfo->esp_out, macalg, encalg);
diff --git a/oncp.c b/oncp.c
index b0f6d12..dd79c5a 100644
--- a/oncp.c
+++ b/oncp.c
@@ -778,7 +778,7 @@ int oncp_connect(struct openconnect_info *vpninfo)
 	put_len16(reqbuf, kmp);
 
 #ifdef HAVE_ESP
-	if (!setup_esp_keys(vpninfo)) {
+	if (!setup_esp_keys(vpninfo, TRUE)) {
 		struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
 		/* Since we'll want to do this in the oncp_mainloop too, where it's easier
 		 * *not* to have an oc_text_buf and build it up manually, and since it's
@@ -830,7 +830,7 @@ static int oncp_receive_espkeys(struct openconnect_info *vpninfo, int len)
 	int ret;
 
 	ret = parse_conf_pkt(vpninfo, vpninfo->cstp_pkt->oncp.kmp, len + 20, 301);
-	if (!ret && !setup_esp_keys(vpninfo)) {
+	if (!ret && !setup_esp_keys(vpninfo, TRUE)) {
 		struct esp *esp = &vpninfo->esp_in[vpninfo->current_esp_in];
 		unsigned char *p = vpninfo->cstp_pkt->oncp.kmp;
 
diff --git a/openconnect-internal.h b/openconnect-internal.h
index c8612dd..379156f 100644
--- a/openconnect-internal.h
+++ b/openconnect-internal.h
@@ -337,7 +337,7 @@ struct esp {
 	uint64_t seq_backlog;
 	uint64_t seq;
 	uint32_t spi; /* Stored network-endian */
-	unsigned char secrets[0x40];
+	unsigned char secrets[0x40]; /* Encryption key bytes, then HMAC key bytes */
 };
 
 struct openconnect_info {
@@ -889,7 +889,7 @@ void esp_shutdown(struct openconnect_info *vpninfo);
 int print_esp_keys(struct openconnect_info *vpninfo, const char *name, struct esp *esp);
 
 /* {gnutls,openssl}-esp.c */
-int setup_esp_keys(struct openconnect_info *vpninfo);
+int setup_esp_keys(struct openconnect_info *vpninfo, int new_keys);
 void destroy_esp_ciphers(struct esp *esp);
 int decrypt_esp_packet(struct openconnect_info *vpninfo, struct esp *esp, struct pkt *pkt);
 int encrypt_esp_packet(struct openconnect_info *vpninfo, struct pkt *pkt);
diff --git a/openssl-esp.c b/openssl-esp.c
index e20bde0..e4d5e0c 100644
--- a/openssl-esp.c
+++ b/openssl-esp.c
@@ -112,7 +112,7 @@ static int init_esp_ciphers(struct openconnect_info *vpninfo, struct esp *esp,
 	return 0;
 }
 
-int setup_esp_keys(struct openconnect_info *vpninfo)
+int setup_esp_keys(struct openconnect_info *vpninfo, int new_keys)
 {
 	struct esp *esp_in;
 	const EVP_CIPHER *encalg;
@@ -146,16 +146,21 @@ int setup_esp_keys(struct openconnect_info *vpninfo)
 		return -EINVAL;
 	}
 
-	vpninfo->old_esp_maxseq = vpninfo->esp_in[vpninfo->current_esp_in].seq + 32;
-	vpninfo->current_esp_in ^= 1;
+	if (new_keys) {
+		vpninfo->old_esp_maxseq = vpninfo->esp_in[vpninfo->current_esp_in].seq + 32;
+		vpninfo->current_esp_in ^= 1;
+	}
+
 	esp_in = &vpninfo->esp_in[vpninfo->current_esp_in];
 
-	if (!RAND_bytes((void *)&esp_in->spi, sizeof(esp_in->spi)) ||
-	    !RAND_bytes((void *)&esp_in->secrets, sizeof(esp_in->secrets))) {
-		vpn_progress(vpninfo, PRG_ERR,
-			     _("Failed to generate random keys for ESP:\n"));
-		openconnect_report_ssl_errors(vpninfo);
-		return -EIO;
+	if (new_keys) {
+		if (!RAND_bytes((void *)&esp_in->spi, sizeof(esp_in->spi)) ||
+		    !RAND_bytes((void *)&esp_in->secrets, sizeof(esp_in->secrets))) {
+			vpn_progress(vpninfo, PRG_ERR,
+				     _("Failed to generate random keys for ESP:\n"));
+			openconnect_report_ssl_errors(vpninfo);
+			return -EIO;
+		}
 	}
 
 	ret = init_esp_ciphers(vpninfo, &vpninfo->esp_out, macalg, encalg, 0);
-- 
2.7.4