ppp: implemented mppe

radius: implemented mppe support
various improvements and bug fixes

1 files changed, 132 insertions, 0 deletions

diff --git a/accel-pptpd/radius/auth.c b/accel-pptpd/radius/auth.c
index 9b61ecc..10fdd45 100644
--- a/accel-pptpd/radius/auth.c
+++ b/accel-pptpd/radius/auth.c
@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <openssl/md5.h>
+#include <openssl/sha.h>
 
 #include "triton.h"
 #include "events.h"
@@ -8,9 +9,96 @@
 #include "pwdb.h"
 
 #include "radius_p.h"
+#include "attr_defs.h"
 
 #include "memdebug.h"
 
+static int decrypt_chap_mppe_keys(struct rad_req_t *req, struct rad_attr_t *attr, const uint8_t *challenge, uint8_t *key)
+{
+	MD5_CTX md5_ctx;
+	SHA_CTX sha1_ctx;
+	uint8_t md5[16];
+	uint8_t plain[32];
+	int i;
+	
+	if (attr->len != 32) {
+		log_ppp_warn("radius: %s: incorrect attribute length (%i)\n", attr->attr->name, attr->len);
+		return -1;
+	}
+
+	memcpy(plain, attr->val.octets, 32);
+
+	MD5_Init(&md5_ctx);
+	MD5_Update(&md5_ctx, conf_auth_secret, strlen(conf_auth_secret));
+	MD5_Update(&md5_ctx, req->pack->buf + 4, 16);
+	MD5_Final(md5, &md5_ctx);
+
+	for (i = 0; i < 16; i++)
+		plain[i] ^= md5[i];
+	
+	MD5_Init(&md5_ctx);
+	MD5_Update(&md5_ctx, conf_auth_secret, strlen(conf_auth_secret));
+	MD5_Update(&md5_ctx, attr->val.octets, 16);
+	MD5_Final(md5, &md5_ctx);
+
+	for (i = 0; i < 16; i++)
+		plain[i + 16] ^= md5[i];
+	
+	SHA1_Init(&sha1_ctx);
+	SHA1_Update(&sha1_ctx, plain + 8, 16);
+	SHA1_Update(&sha1_ctx, plain + 8, 16);
+	SHA1_Update(&sha1_ctx, challenge, 8);
+	SHA1_Final(key, &sha1_ctx);
+
+	return 0;
+}
+
+static int decrypt_mppe_key(struct rad_req_t *req, struct rad_attr_t *attr, uint8_t *key)
+{
+	MD5_CTX md5_ctx;
+	uint8_t md5[16];
+	uint8_t plain[32];
+	int i;
+	
+	if (attr->len != 34) {
+		log_ppp_warn("radius: %s: incorrect attribute length (%i)\n", attr->attr->name, attr->len);
+		return -1;
+	}
+
+	if ((attr->val.octets[0] & 0x80) == 0) {
+		log_ppp_warn("radius: %s: incorrect salt value (%x)\n", attr->attr->name, attr->len);
+		return -1;
+	}
+
+	MD5_Init(&md5_ctx);
+	MD5_Update(&md5_ctx, conf_auth_secret, strlen(conf_auth_secret));
+	MD5_Update(&md5_ctx, req->pack->buf + 4, 16);
+	MD5_Update(&md5_ctx, attr->val.octets, 2);
+	MD5_Final(md5, &md5_ctx);
+
+	memcpy(plain, attr->val.octets + 2, 32);
+
+	for (i = 0; i < 16; i++)
+		plain[i] ^= md5[i];
+	
+	if (plain[0] != 16) {
+		log_ppp_warn("radius: %s: incorrect key length (%i)\n", attr->attr->name, plain[0]);
+		return -1;
+	}
+
+	MD5_Init(&md5_ctx);
+	MD5_Update(&md5_ctx, conf_auth_secret, strlen(conf_auth_secret));
+	MD5_Update(&md5_ctx, attr->val.octets + 2, 16);
+	MD5_Final(md5, &md5_ctx);
+
+	plain[16] ^= md5[0];
+
+	memcpy(key, plain + 1, 16);
+
+	return 0;
+}
+
+
 static uint8_t* encrypt_password(const char *passwd, const char *secret, const uint8_t *RA, int *epasswd_len)
 {
 	uint8_t *epasswd;
@@ -160,6 +248,48 @@ out:
 	return r;
 }
 
+static void setup_mppe(struct rad_req_t *req, const uint8_t *challenge)
+{
+	struct rad_attr_t *attr;
+	uint8_t mppe_recv_key[16];
+	uint8_t mppe_send_key[16];
+	struct ev_mppe_keys_t ev_mppe = {
+		.ppp = req->rpd->ppp,
+	};
+
+	list_for_each_entry(attr, &req->reply->attrs, entry) {
+		if (attr->vendor && attr->vendor->id == Vendor_Microsoft) {
+			switch (attr->attr->id) {
+				case MS_CHAP_MPPE_Keys:
+					if (decrypt_chap_mppe_keys(req, attr, challenge, mppe_recv_key))
+						continue;
+					ev_mppe.recv_key = mppe_recv_key;
+					ev_mppe.send_key = mppe_recv_key;
+					break;
+				case MS_MPPE_Recv_Key:
+					if (decrypt_mppe_key(req, attr, mppe_recv_key))
+						continue;
+					ev_mppe.recv_key = mppe_recv_key;
+					break;
+				case MS_MPPE_Send_Key:
+					if (decrypt_mppe_key(req, attr, mppe_send_key))
+						continue;
+					ev_mppe.send_key = mppe_send_key;
+					break;
+				case MS_MPPE_Encryption_Policy:
+					ev_mppe.policy = attr->val.integer;
+					break;
+				case MS_MPPE_Encryption_Type:
+					ev_mppe.type = attr->val.integer;
+					break;
+			}
+		}
+	}
+
+	if (ev_mppe.recv_key && ev_mppe.send_key)
+		triton_event_fire(EV_MPPE_KEYS, &ev_mppe);
+}
+
 int rad_auth_mschap_v1(struct radius_pd_t *rpd, const char *username, va_list args)
 {
 	int r;
@@ -196,6 +326,7 @@ int rad_auth_mschap_v1(struct radius_pd_t *rpd, const char *username, va_list ar
 			.reply = req->reply,
 		};
 		triton_event_fire(EV_RADIUS_ACCESS_ACCEPT, &ev);
+		setup_mppe(req, challenge);
 	}
 
 out:
@@ -251,6 +382,7 @@ int rad_auth_mschap_v2(struct radius_pd_t *rpd, const char *username, va_list ar
 			.reply = req->reply,
 		};
 		triton_event_fire(EV_RADIUS_ACCESS_ACCEPT, &ev);
+		setup_mppe(req, NULL);
 	}
 
 out: