From 736f370dce614b717193f45d084e9e009de723ce Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Wed, 30 Nov 2005 10:11:24 +0000
Subject: [PATCH] * options.h, common-kex.c: fix support of 4096 byte
host keys
--HG--
extra : convert_revision : 096f29c430c23f0140f0cf272942a13046483ec6
---
common-kex.c | 44 ++++++++++++++++++++++++--------------------
options.h | 12 ++++++++----
2 files changed, 32 insertions(+), 24 deletions(-)
diff --git a/common-kex.c b/common-kex.c
index f3253299..5db8e52e 100644
--- a/common-kex.c
+++ b/common-kex.c
@@ -394,18 +394,28 @@ static void gen_new_zstreams() {
/* Belongs in common_kex.c where it should be moved after review */
void recv_msg_kexinit() {
+ unsigned int kexhashbuf_len = 0;
+ unsigned int remote_ident_len = 0;
+ unsigned int local_ident_len = 0;
+
TRACE(("<- KEXINIT"))
TRACE(("enter recv_msg_kexinit"))
- /* start the kex hash */
- ses.kexhashbuf = buf_new(MAX_KEXHASHBUF);
-
if (!ses.kexstate.sentkexinit) {
/* we need to send a kex packet */
send_msg_kexinit();
TRACE(("continue recv_msg_kexinit: sent kexinit"))
}
+ /* start the kex hash */
+ local_ident_len = strlen(LOCAL_IDENT);
+ remote_ident_len = strlen((char*)ses.remoteident);
+
+ kexhashbuf_len = local_ident_len + remote_ident_len
+ + ses.transkexinit->len + ses.payload->len
+ + KEXHASHBUF_MAX_INTS;
+
+ ses.kexhashbuf = buf_new(kexhashbuf_len);
if (IS_DROPBEAR_CLIENT) {
@@ -414,20 +424,16 @@ void recv_msg_kexinit() {
/* V_C, the client's version string (CR and NL excluded) */
buf_putstring(ses.kexhashbuf,
- (unsigned char*)LOCAL_IDENT, strlen(LOCAL_IDENT));
+ (unsigned char*)LOCAL_IDENT, local_ident_len);
/* V_S, the server's version string (CR and NL excluded) */
- buf_putstring(ses.kexhashbuf,
- ses.remoteident, strlen((char*)ses.remoteident));
+ buf_putstring(ses.kexhashbuf, ses.remoteident, remote_ident_len);
/* I_C, the payload of the client's SSH_MSG_KEXINIT */
buf_putstring(ses.kexhashbuf,
- buf_getptr(ses.transkexinit, ses.transkexinit->len),
- ses.transkexinit->len);
+ ses.transkexinit->data, ses.transkexinit->len);
/* I_S, the payload of the server's SSH_MSG_KEXINIT */
buf_setpos(ses.payload, 0);
- buf_putstring(ses.kexhashbuf,
- buf_getptr(ses.payload, ses.payload->len),
- ses.payload->len);
+ buf_putstring(ses.kexhashbuf, ses.payload->data, ses.payload->len);
} else {
/* SERVER */
@@ -435,21 +441,19 @@ void recv_msg_kexinit() {
/* read the peer's choice of algos */
read_kex_algos();
/* V_C, the client's version string (CR and NL excluded) */
- buf_putstring(ses.kexhashbuf,
- ses.remoteident, strlen((char*)ses.remoteident));
+ buf_putstring(ses.kexhashbuf, ses.remoteident, remote_ident_len);
/* V_S, the server's version string (CR and NL excluded) */
- buf_putstring(ses.kexhashbuf,
- (unsigned char*)LOCAL_IDENT, strlen(LOCAL_IDENT));
+ buf_putstring(ses.kexhashbuf,
+ (unsigned char*)LOCAL_IDENT, local_ident_len);
/* I_C, the payload of the client's SSH_MSG_KEXINIT */
buf_setpos(ses.payload, 0);
- buf_putstring(ses.kexhashbuf,
- buf_getptr(ses.payload, ses.payload->len),
- ses.payload->len);
+ buf_putstring(ses.kexhashbuf, ses.payload->data, ses.payload->len);
+
/* I_S, the payload of the server's SSH_MSG_KEXINIT */
buf_putstring(ses.kexhashbuf,
- buf_getptr(ses.transkexinit, ses.transkexinit->len),
- ses.transkexinit->len);
+ ses.transkexinit->data, ses.transkexinit->len);
+
ses.requirenext = SSH_MSG_KEXDH_INIT;
}
diff --git a/options.h b/options.h
index 62857562..baba472b 100644
--- a/options.h
+++ b/options.h
@@ -306,10 +306,14 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#define MAX_STRING_LEN 1400 /* ~= MAX_PROPOSED_ALGO * MAX_NAME_LEN, also
is the max length for a password etc */
-/* For a 4096 bit DSS key, empirically determined to be 1590 bytes */
-#define MAX_PUBKEY_SIZE 1600
-/* For a 4096 bit DSS key, empirically determined to be 1590 bytes */
-#define MAX_PRIVKEY_SIZE 1600
+/* For a 4096 bit DSS key, empirically determined */
+#define MAX_PUBKEY_SIZE 1700
+/* For a 4096 bit DSS key, empirically determined */
+#define MAX_PRIVKEY_SIZE 1700
+
+/* The maximum size of the bignum portion of the kexhash buffer */
+/* Sect. 8 of the transport draft, K_S + e + f + K */
+#define KEXHASHBUF_MAX_INTS (1700 + 130 + 130 + 130)
#define DROPBEAR_MAX_SOCKS 2 /* IPv4, IPv6 are all we'll get for now. Revisit
in a few years time.... */
--
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