- markus@cvs.openbsd.org 2002/11/21 22:45:31

[openssh.git] / kex.c

diff --git a/kex.c b/kex.c
index e91b2ee35cd588ac8cd1d3ad781414db9e00e82d..113663598eff617c8ce57734363ff0badb442efa 100644 (file)
--- a/kex.c
+++ b/kex.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.46 2002/02/23 17:59:02 markus Exp $");
+RCSID("$OpenBSD: kex.c,v 1.52 2002/11/21 22:45:31 markus Exp $");
 
 #include <openssl/crypto.h>
 
@@ -40,9 +40,15 @@ RCSID("$OpenBSD: kex.c,v 1.46 2002/02/23 17:59:02 markus Exp $");
 #include "mac.h"
 #include "match.h"
 #include "dispatch.h"
+#include "monitor.h"
 
 #define KEX_COOKIE_LEN 16
 
+/* Use privilege separation for sshd */
+int use_privsep;
+struct monitor *pmonitor;
+
+
 /* prototype */
 static void kex_kexinit_finish(Kex *);
 static void kex_choose_conf(Kex *);
@@ -51,16 +57,15 @@ static void kex_choose_conf(Kex *);
 static void
 kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
 {
-       u_int32_t rand = 0;
        int i;
 
        buffer_clear(b);
-       for (i = 0; i < KEX_COOKIE_LEN; i++) {
-               if (i % 4 == 0)
-                       rand = arc4random();
-               buffer_put_char(b, rand & 0xff);
-               rand >>= 8;
-       }
+       /*
+        * add a dummy cookie, the cookie will be overwritten by
+        * kex_send_kexinit(), each time a kexinit is set
+        */
+       for (i = 0; i < KEX_COOKIE_LEN; i++)
+               buffer_put_char(b, 0);
        for (i = 0; i < PROPOSAL_MAX; i++)
                buffer_put_cstring(b, proposal[i]);
        buffer_put_char(b, 0);                  /* first_kex_packet_follows */
@@ -130,7 +135,7 @@ kex_finish(Kex *kex)
        /* packet_write_wait(); */
        debug("SSH2_MSG_NEWKEYS sent");
 
-       debug("waiting for SSH2_MSG_NEWKEYS");
+       debug("expecting SSH2_MSG_NEWKEYS");
        packet_read_expect(SSH2_MSG_NEWKEYS);
        packet_check_eom();
        debug("SSH2_MSG_NEWKEYS received");
@@ -146,6 +151,10 @@ kex_finish(Kex *kex)
 void
 kex_send_kexinit(Kex *kex)
 {
+       u_int32_t rand = 0;
+       u_char *cookie;
+       int i;
+
        if (kex == NULL) {
                error("kex_send_kexinit: no kex, cannot rekey");
                return;
@@ -155,6 +164,17 @@ kex_send_kexinit(Kex *kex)
                return;
        }
        kex->done = 0;
+
+       /* generate a random cookie */
+       if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
+               fatal("kex_send_kexinit: kex proposal too short");
+       cookie = buffer_ptr(&kex->my);
+       for (i = 0; i < KEX_COOKIE_LEN; i++) {
+               if (i % 4 == 0)
+                       rand = arc4random();
+               cookie[i] = rand;
+               rand >>= 8;
+       }
        packet_start(SSH2_MSG_KEXINIT);
        packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
        packet_send();
@@ -182,8 +202,8 @@ kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
                packet_get_char();
        for (i = 0; i < PROPOSAL_MAX; i++)
                xfree(packet_get_string(NULL));
-       packet_get_char();
-       packet_get_int();
+       (void) packet_get_char();
+       (void) packet_get_int();
        packet_check_eom();
 
        kex_kexinit_finish(kex);
@@ -361,7 +381,7 @@ static u_char *
 derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret)
 {
        Buffer b;
-       EVP_MD *evp_md = EVP_sha1();
+       const EVP_MD *evp_md = EVP_sha1();
        EVP_MD_CTX md;
        char c = id;
        int have;
@@ -413,7 +433,7 @@ kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret)
        for (i = 0; i < NKEYS; i++)
                keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret);
 
-       debug("kex_derive_keys");
+       debug2("kex_derive_keys");
        for (mode = 0; mode < MODE_MAX; mode++) {
                current_keys[mode] = kex->newkeys[mode];
                kex->newkeys[mode] = NULL;