lots of changes to radsrv/reply and use of new radmsg stuff

git-svn-id: https://svn.testnett.uninett.no/radsecproxy/trunk@373 e88ac4ed-0b26-0410-9574-a7f39faa03bf

1 files changed, 238 insertions, 0 deletions

diff --git a/radmsg.c b/radmsg.c
new file mode 100644
index 0000000..26f8fbe
--- /dev/null
+++ b/radmsg.c
@@ -0,0 +1,238 @@
+/*
+ * Copyright (C) 2006-2008 Stig Venaas <venaas@uninett.no>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include "list.h"
+#include "tlv11.h"
+#include "radmsg.h"
+#include "debug.h"
+#include <pthread.h>
+#include <openssl/hmac.h>
+
+#define RADLEN(x) ntohs(((uint16_t *)(x))[1])
+
+void radmsg_free(struct radmsg *msg) {
+    if (msg) {
+        freetlvlist(msg->attrs);
+        free(msg);
+    }
+}
+
+struct radmsg *radmsg_init(uint8_t code, uint8_t id, uint8_t *auth) {
+    struct radmsg *msg;
+    
+    msg = malloc(sizeof(struct radmsg));
+    if (!msg)
+        return NULL;
+    msg->attrs = list_create();
+    if (!msg->attrs) {
+	free(msg);
+        return NULL;
+    }	
+    msg->code = code;
+    msg->id = id;
+    memcpy(msg->auth, auth, 16);
+    return msg;
+}
+
+int radmsg_add(struct radmsg *msg, struct tlv *attr) {
+    if (!msg || !msg->attrs)
+        return 1;
+    if (!attr)
+        return 0;
+    return list_push(msg->attrs, attr);
+}
+
+/* returns first tlv of the given type */
+struct tlv *radmsg_gettype(struct radmsg *msg, uint8_t type) {
+    struct list_node *node;
+    struct tlv *tlv;
+
+    if (!msg)
+        return NULL;
+    for (node = list_first(msg->attrs); node; node = list_next(node)) {
+        tlv = (struct tlv *)node->data;
+        if (tlv->t == type)
+            return tlv;
+    }
+    return NULL;
+}
+
+uint8_t *radmsg2buf(struct radmsg *msg) {
+    struct list_node *node;
+    struct tlv *tlv;
+    int size;
+    uint8_t *buf, *p;
+
+    if (!msg || !msg->attrs)
+        return NULL;
+    size = 20;
+    for (node = list_first(msg->attrs); node; node = list_next(node))
+        size += 2 + ((struct tlv *)node->data)->l;
+    if (size > 65535)
+        return NULL;
+    buf = malloc(size);
+    if (!buf)
+        return NULL;
+    
+    p = buf;
+    *p++ = msg->code;
+    *p++ = msg->id;
+    *(uint16_t *)p = htons(size);
+    p += 2;
+    memcpy(p, msg->auth, 16);
+    p += 16;
+
+    for (node = list_first(msg->attrs); node; node = list_next(node)) {
+        tlv = (struct tlv *)node->data;
+        p = tlv2buf(p, tlv);
+	p[-1] += 2;
+        p += tlv->l;
+    }
+    return buf;
+}
+
+int _checkmsgauth(unsigned char *rad, uint8_t *authattr, uint8_t *secret) {
+    static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+    static unsigned char first = 1;
+    static HMAC_CTX hmacctx;
+    unsigned int md_len;
+    uint8_t auth[16], hash[EVP_MAX_MD_SIZE];
+    
+    pthread_mutex_lock(&lock);
+    if (first) {
+	HMAC_CTX_init(&hmacctx);
+	first = 0;
+    }
+
+    memcpy(auth, authattr, 16);
+    memset(authattr, 0, 16);
+    md_len = 0;
+    HMAC_Init_ex(&hmacctx, secret, strlen((char *)secret), EVP_md5(), NULL);
+    HMAC_Update(&hmacctx, rad, RADLEN(rad));
+    HMAC_Final(&hmacctx, hash, &md_len);
+    memcpy(authattr, auth, 16);
+    if (md_len != 16) {
+	debug(DBG_WARN, "message auth computation failed");
+	pthread_mutex_unlock(&lock);
+	return 0;
+    }
+
+    if (memcmp(auth, hash, 16)) {
+	debug(DBG_WARN, "message authenticator, wrong value");
+	pthread_mutex_unlock(&lock);
+	return 0;
+    }	
+	
+    pthread_mutex_unlock(&lock);
+    return 1;
+}
+
+int _validauth(unsigned char *rad, unsigned char *reqauth, unsigned char *sec) {
+    static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+    static unsigned char first = 1;
+    static EVP_MD_CTX mdctx;
+    unsigned char hash[EVP_MAX_MD_SIZE];
+    unsigned int len;
+    int result;
+    
+    pthread_mutex_lock(&lock);
+    if (first) {
+	EVP_MD_CTX_init(&mdctx);
+	first = 0;
+    }
+
+    len = RADLEN(rad);
+    
+    result = (EVP_DigestInit_ex(&mdctx, EVP_md5(), NULL) &&
+	      EVP_DigestUpdate(&mdctx, rad, 4) &&
+	      EVP_DigestUpdate(&mdctx, reqauth, 16) &&
+	      (len <= 20 || EVP_DigestUpdate(&mdctx, rad + 20, len - 20)) &&
+	      EVP_DigestUpdate(&mdctx, sec, strlen((char *)sec)) &&
+	      EVP_DigestFinal_ex(&mdctx, hash, &len) &&
+	      len == 16 &&
+	      !memcmp(hash, rad + 4, 16));
+    pthread_mutex_unlock(&lock);
+    return result;
+}
+	      
+/* if secret set we also validate message authenticator if present */
+struct radmsg *buf2radmsg(uint8_t *buf, uint8_t *secret, uint8_t *rqauth) {
+    struct radmsg *msg;
+    uint8_t t, l, *v, *p, auth[16];
+    uint16_t len;
+    struct tlv *attr;
+    
+    len = RADLEN(buf);
+    if (len < 20)
+	return NULL;
+
+    if (secret && buf[0] == RAD_Accounting_Request) {
+	memset(auth, 0, 16);
+	if (!_validauth(buf, auth, secret)) {
+	    debug(DBG_WARN, "buf2radmsg: Accounting-Request message authentication failed");
+	    return NULL;
+	}
+    }
+
+    if (rqauth && !_validauth(buf, rqauth, secret)) {
+	debug(DBG_WARN, "buf2radmsg: Invalid auth, ignoring reply");
+	return NULL;
+    }
+	
+    msg = radmsg_init(buf[0], buf[1], (uint8_t *)buf + 4);
+    if (!msg)
+        return NULL;
+
+    p = buf + 20;
+    while (p - buf + 2 <= len) {
+	t = *p++;
+        l = *p++;
+	if (l < 2) {
+	    debug(DBG_WARN, "buf2radmsg: invalid attribute length %d", l);
+	    radmsg_free(msg);
+	    return NULL;
+	}
+	l -= 2;
+        if (l) {
+            if (p - buf + l > len) {
+		debug(DBG_WARN, "buf2radmsg: attribute length %d exceeds packet length", l + 2);
+		radmsg_free(msg);
+		return NULL;
+	    }
+            v = p;
+            p += l;
+        }
+	
+	if (t == RAD_Attr_Message_Authenticator && secret) {
+	    if (rqauth)
+		memcpy(buf + 4, rqauth, 16);
+	    if (l != 16 || !_checkmsgauth(buf, v, secret)) {
+		debug(DBG_WARN, "buf2radmsg: message authentication failed");
+		if (rqauth)
+		    memcpy(buf + 4, msg->auth, 16);
+		radmsg_free(msg);
+		return NULL;
+	    }
+	    if (rqauth)
+		memcpy(buf + 4, msg->auth, 16);
+	    debug(DBG_DBG, "buf2radmsg: message auth ok");
+	}
+
+        attr = maketlv(t, l, v);
+        if (!attr || !radmsg_add(msg, attr)) {
+            freetlv(attr);
+	    radmsg_free(msg);
+	    return NULL;
+        }
+    }
+    return msg;
+}