- markus@cvs.openbsd.org 2002/03/18 17:16:38

     [packet.c packet.h]
     export/import cipher state, iv and ssh2 seqnr; needed by ssh-privsep

1 files changed, 109 insertions, 15 deletions

diff --git a/packet.c b/packet.c
index 045d5a105..25de34951 100644
--- a/packet.c
+++ b/packet.c
@@ -37,7 +37,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: packet.c,v 1.90 2002/02/27 21:23:13 stevesk Exp $");
+RCSID("$OpenBSD: packet.c,v 1.91 2002/03/18 17:16:38 markus Exp $");
 
 #include "xmalloc.h"
 #include "buffer.h"
@@ -86,10 +86,10 @@ static CipherContext receive_context;
 static CipherContext send_context;
 
 /* Buffer for raw input data from the socket. */
-static Buffer input;
+Buffer input;
 
 /* Buffer for raw output data going to the socket. */
-static Buffer output;
+Buffer output;
 
 /* Buffer for the partial outgoing packet being constructed. */
 static Buffer outgoing_packet;
@@ -115,6 +115,8 @@ static int interactive_mode = 0;
 
 /* Session key information for Encryption and MAC */
 Newkeys *newkeys[MODE_MAX];
+static u_int32_t read_seqnr = 0;
+static u_int32_t send_seqnr = 0;
 
 /* roundup current message to extra_pad bytes */
 static u_char extra_pad = 0;
@@ -171,6 +173,99 @@ packet_connection_is_on_socket(void)
         return 1;
 }
 
+/* 
+ * Exports an IV from the CipherContext required to export the key
+ * state back from the unprivileged child to the privileged parent
+ * process.
+ */
+
+void
+packet_get_keyiv(int mode, u_char *iv, u_int len)
+{
+        CipherContext *cc;
+
+        if (mode == MODE_OUT)
+                cc = &send_context;
+        else
+                cc = &receive_context;
+
+        cipher_get_keyiv(cc, iv, len);
+}
+
+int
+packet_get_keycontext(int mode, u_char *dat)
+{
+        CipherContext *cc;
+        
+        if (mode == MODE_OUT)
+                cc = &send_context;
+        else
+                cc = &receive_context;
+
+        return (cipher_get_keycontext(cc, dat));
+}
+
+void
+packet_set_keycontext(int mode, u_char *dat)
+{
+        CipherContext *cc;
+        
+        if (mode == MODE_OUT)
+                cc = &send_context;
+        else
+                cc = &receive_context;
+
+        cipher_set_keycontext(cc, dat);
+}
+
+int
+packet_get_keyiv_len(int mode)
+{
+        CipherContext *cc;
+
+        if (mode == MODE_OUT)
+                cc = &send_context;
+        else
+                cc = &receive_context;
+
+        return (cipher_get_keyiv_len(cc));
+}
+void
+packet_set_iv(int mode, u_char *dat)
+{
+        CipherContext *cc;
+
+        if (mode == MODE_OUT)
+                cc = &send_context;
+        else
+                cc = &receive_context;
+
+        cipher_set_keyiv(cc, dat);
+}
+int
+packet_get_ssh1_cipher()
+{
+        return (cipher_get_number(receive_context.cipher));
+}
+
+
+u_int32_t
+packet_get_seqnr(int mode)
+{
+        return (mode == MODE_IN ? read_seqnr : send_seqnr);
+}
+
+void
+packet_set_seqnr(int mode, u_int32_t seqnr)
+{
+        if (mode == MODE_IN)
+                read_seqnr = seqnr;
+        else if (mode == MODE_OUT)
+                send_seqnr = seqnr;
+        else
+                fatal("%s: bad mode %d", __FUNCTION__, mode);
+}
+
 /* returns 1 if connection is via ipv4 */
 
 int
@@ -433,7 +528,7 @@ packet_send1(void)
          */
 }
 
-static void
+void
 set_newkeys(int mode)
 {
         Enc *enc;
@@ -477,8 +572,9 @@ set_newkeys(int mode)
         DBG(debug("cipher_init_context: %d", mode));
         cipher_init(cc, enc->cipher, enc->key, enc->key_len,
             enc->iv, enc->block_size, encrypt);
-        memset(enc->iv,  0, enc->block_size);
-        memset(enc->key, 0, enc->key_len);
+        /* Deleting the keys does not gain extra security */
+        /* memset(enc->iv,  0, enc->block_size);
+           memset(enc->key, 0, enc->key_len); */
         if (comp->type != 0 && comp->enabled == 0) {
                 packet_init_compression();
                 if (mode == MODE_OUT)
@@ -495,7 +591,6 @@ set_newkeys(int mode)
 static void
 packet_send2(void)
 {
-        static u_int32_t seqnr = 0;
         u_char type, *cp, *macbuf = NULL;
         u_char padlen, pad;
         u_int packet_length = 0;
@@ -576,10 +671,10 @@ packet_send2(void)
 
         /* compute MAC over seqnr and packet(length fields, payload, padding) */
         if (mac && mac->enabled) {
-                macbuf = mac_compute(mac, seqnr,
+                macbuf = mac_compute(mac, send_seqnr,
                     buffer_ptr(&outgoing_packet),
                     buffer_len(&outgoing_packet));
-                DBG(debug("done calc MAC out #%d", seqnr));
+                DBG(debug("done calc MAC out #%d", send_seqnr));
         }
         /* encrypt packet and append to output buffer. */
         cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
@@ -593,7 +688,7 @@ packet_send2(void)
         buffer_dump(&output);
 #endif
         /* increment sequence number for outgoing packets */
-        if (++seqnr == 0)
+        if (++send_seqnr == 0)
                 log("outgoing seqnr wraps around");
         buffer_clear(&outgoing_packet);
 
@@ -783,7 +878,6 @@ packet_read_poll1(void)
 static int
 packet_read_poll2(u_int32_t *seqnr_p)
 {
-        static u_int32_t seqnr = 0;
         static u_int packet_length = 0;
         u_int padlen, need;
         u_char *macbuf, *cp, type;
@@ -845,17 +939,17 @@ packet_read_poll2(u_int32_t *seqnr_p)
          * increment sequence number for incoming packet
          */
         if (mac && mac->enabled) {
-                macbuf = mac_compute(mac, seqnr,
+                macbuf = mac_compute(mac, read_seqnr,
                     buffer_ptr(&incoming_packet),
                     buffer_len(&incoming_packet));
                 if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
                         packet_disconnect("Corrupted MAC on input.");
-                DBG(debug("MAC #%d ok", seqnr));
+                DBG(debug("MAC #%d ok", read_seqnr));
                 buffer_consume(&input, mac->mac_len);
         }
         if (seqnr_p != NULL)
-                *seqnr_p = seqnr;
-        if (++seqnr == 0)
+                *seqnr_p = read_seqnr;
+        if (++read_seqnr == 0)
                 log("incoming seqnr wraps around");
 
         /* get padlen */