Fix RADIUS authentication on DAE responses.

[l2tpns.git] / radius.c

diff --git a/radius.c b/radius.c
index 1cdfe7d..0059fcc 100644 (file)
--- a/radius.c
+++ b/radius.c
@@ -1,6 +1,6 @@
 // L2TPNS Radius Stuff
 
-char const *cvs_id_radius = "$Id: radius.c,v 1.42 2005/09/30 13:13:26 bodea Exp $";
+char const *cvs_id_radius = "$Id: radius.c,v 1.43 2005/10/11 02:27:40 foonly Exp $";
 
 #include <time.h>
 #include <stdio.h>
@@ -27,6 +27,20 @@ extern configt *config;
 extern int *radfds;
 extern ip_filtert *ip_filters;
 
+static const hasht zero;
+
+static void calc_auth(const void *buf, size_t len, const uint8_t *in, uint8_t *out)
+{
+       MD5_CTX ctx;
+
+       MD5_Init(&ctx);
+       MD5_Update(&ctx, (void *)buf, 4); // code, id, length
+       MD5_Update(&ctx, (void *)in, 16); // auth
+       MD5_Update(&ctx, (void *)(buf + 20), len - 20);
+       MD5_Update(&ctx, config->radiussecret, strlen(config->radiussecret));
+       MD5_Final(out, &ctx);
+}
+
 // Set up socket for radius requests
 void initrad(void)
 {
@@ -343,18 +357,9 @@ void radiussend(uint16_t r, uint8_t state)
        *(uint16_t *) (b + 2) = htons(p - b);
        if (state != RADIUSAUTH)
        {
-           // Build auth for accounting packet
-           uint8_t z[16] = {0};
-           uint8_t hash[16] = {0};
-           MD5_CTX ctx;
-           MD5_Init(&ctx);
-           MD5_Update(&ctx, b, 4);
-           MD5_Update(&ctx, z, 16);
-           MD5_Update(&ctx, b + 20, (p - b) - 20);
-           MD5_Update(&ctx, config->radiussecret, strlen(config->radiussecret));
-           MD5_Final(hash, &ctx);
-           memcpy(b + 4, hash, 16);
-           memcpy(radius[r].auth, hash, 16);
+               // Build auth for accounting packet
+               calc_auth(b, p - b, zero, b + 4);
+               memcpy(radius[r].auth, b + 4, 16);
        }
        memset(&addr, 0, sizeof(addr));
        addr.sin_family = AF_INET;
@@ -415,7 +420,6 @@ static void handle_avpair(sessionidt s, uint8_t *avp, int len)
 void processrad(uint8_t *buf, int len, char socket_index)
 {
        uint8_t b[MAXETHER];
-       MD5_CTX ctx;
        uint16_t r;
        sessionidt s;
        tunnelidt t = 0;
@@ -454,12 +458,7 @@ void processrad(uint8_t *buf, int len, char socket_index)
                return;
        }
        t = session[s].tunnel;
-       MD5_Init(&ctx);
-       MD5_Update(&ctx, buf, 4);
-       MD5_Update(&ctx, radius[r].auth, 16);
-       MD5_Update(&ctx, buf + 20, len - 20);
-       MD5_Update(&ctx, config->radiussecret, strlen(config->radiussecret));
-       MD5_Final(hash, &ctx);
+       calc_auth(buf, len, radius[r].auth, hash);
        do {
                if (memcmp(hash, buf + 4, 16))
                {
@@ -762,8 +761,8 @@ extern int daefd;
 void processdae(uint8_t *buf, int len, struct sockaddr_in *addr, int alen)
 {
        int i, r_code, r_id, length, attribute_length;
-       uint8_t vector[16], hash[16], *packet, attribute;
-       MD5_CTX ctx;
+       uint8_t *packet, attribute;
+       hasht hash;
        char username[MAXUSER] = "";
        in_addr_t nas = 0;
        in_addr_t ip = 0;
@@ -808,17 +807,8 @@ void processdae(uint8_t *buf, int len, struct sockaddr_in *addr, int alen)
        LOG(3, 0, 0, "Received DAE %s, id %d\n", radius_code(r_code), r_id);
 
        // check authenticator
-       memcpy(vector, buf + 4, 16);
-       memset(buf + 4, 0, 16);
-
-       i = strlen(config->radiussecret);
-       if (i > 16) i = 16;
-
-       MD5_Init(&ctx);
-       MD5_Update(&ctx, buf, len);
-       MD5_Update(&ctx, config->radiussecret, i);
-       MD5_Final(hash, &ctx);
-       if (memcmp(hash, vector, 16) != 0)
+       calc_auth(buf, len, zero, hash);
+       if (memcmp(hash, buf + 4, 16) != 0)
        {
                LOG(1, 0, 0, "Incorrect vector in DAE request (wrong secret in radius config?)\n");
                return;
@@ -1024,10 +1014,9 @@ void processdae(uint8_t *buf, int len, struct sockaddr_in *addr, int alen)
        packet = buf;
        *packet++ = r_code;
        *packet++ = r_id;
-       packet += 2;
-       memset(packet, 0, 16);
-       packet += 16;
-       len = 20;
+       // skip len + auth
+       packet += 2 + 16;
+       len = packet - buf;
 
        // add attributes
        if (error)
@@ -1042,14 +1031,7 @@ void processdae(uint8_t *buf, int len, struct sockaddr_in *addr, int alen)
        *((uint16_t *)(buf + 2)) = htons(len);
 
        // make vector
-       i = strlen(config->radiussecret);
-       if (i > 16) i = 16;
-
-       MD5_Init(&ctx);
-       MD5_Update(&ctx, buf, len);
-       MD5_Update(&ctx, config->radiussecret, i);
-       MD5_Final(hash, &ctx);
-       memcpy(buf + 4, hash, 16);
+       calc_auth(buf, len, hash, buf + 4);
 
        LOG(3, 0, 0, "Sending DAE %s, id=%d\n", radius_code(r_code), r_id);