Provide an 'extra' pointer in ssh_signkey and ssh_kex.

This gives families of public key and kex functions (by which I mean
those sharing a set of methods) a place to store parameters that allow
the methods to vary depending on which exact algorithm is in use.

The ssh_kex structure already had a set of parameters specific to
Diffie-Hellman key exchange; I've moved those into sshdh.c and made
them part of the 'extra' structure for that family only, so that
unrelated kex methods don't have to faff about saying NULL,NULL,0,0.
(This required me to write an extra accessor function for ssh.c to ask
whether a DH method was group-exchange style or fixed-group style, but
that doesn't seem too silly.)

diff --git a/ssh.c b/ssh.c
index bd7471fa70a9e8fb01c227994424fa70b344c745..51bfe8c3f03a8edfba19e2c56af8a431ed72f085 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -6740,7 +6740,7 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen,
          * If we're doing Diffie-Hellman group exchange, start by
          * requesting a group.
          */
-        if (!ssh->kex->pdata) {
+        if (dh_is_gex(ssh->kex)) {
             logevent("Doing Diffie-Hellman group exchange");
             ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
             /*
@@ -6828,7 +6828,7 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen,
         set_busy_status(ssh->frontend, BUSY_NOT);
 
         hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
-        if (!ssh->kex->pdata) {
+        if (dh_is_gex(ssh->kex)) {
             if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
                 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
             hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
@@ -6842,7 +6842,7 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen,
 
         dh_cleanup(ssh->kex_ctx);
         freebn(s->f);
-        if (!ssh->kex->pdata) {
+        if (dh_is_gex(ssh->kex)) {
             freebn(s->g);
             freebn(s->p);
         }

diff --git a/ssh.h b/ssh.h
index f23972f0b792172402648b9905a0ab0fb94d63a7..29590c25642c1c9f2c1d6327f8428718ce6858c0 100644 (file)
--- a/ssh.h
+++ b/ssh.h
@@ -344,10 +344,8 @@ struct ssh_hash {
 struct ssh_kex {
     char *name, *groupname;
     enum { KEXTYPE_DH, KEXTYPE_RSA, KEXTYPE_ECDH } main_type;
-    /* For DH */
-    const unsigned char *pdata, *gdata; /* NULL means group exchange */
-    int plen, glen;
     const struct ssh_hash *hash;
+    const void *extra;                 /* private to the kex methods */
 };
 
 struct ssh_kexes {
@@ -385,6 +383,7 @@ struct ssh_signkey {
                            int *siglen);
     const char *name;
     const char *keytype;               /* for host key cache */
+    const void *extra;                 /* private to the public key methods */
 };
 
 struct ssh_compress {
@@ -639,6 +638,7 @@ Bignum bignum_from_decimal(const char *decimal);
 void diagbn(char *prefix, Bignum md);
 #endif
 
+int dh_is_gex(const struct ssh_kex *kex);
 void *dh_setup_group(const struct ssh_kex *kex);
 void *dh_setup_gex(Bignum pval, Bignum gval);
 void dh_cleanup(void *);

diff --git a/sshdh.c b/sshdh.c
index 8f8ab2d26aa6ef9ad7e5fe74710edca473272245..f254bc1de7c3a255f03c53ced7bc9fb5acb31b0c 100644 (file)
--- a/sshdh.c
+++ b/sshdh.c
@@ -50,9 +50,18 @@ static const unsigned char P14[] = {
  */
 static const unsigned char G[] = { 2 };
 
+struct dh_extra {
+    const unsigned char *pdata, *gdata; /* NULL means group exchange */
+    int plen, glen;
+};
+
+static const struct dh_extra extra_group1 = {
+    P1, G, lenof(P1), lenof(G),
+};
+
 static const struct ssh_kex ssh_diffiehellman_group1_sha1 = {
     "diffie-hellman-group1-sha1", "group1",
-    KEXTYPE_DH, P1, G, lenof(P1), lenof(G), &ssh_sha1
+    KEXTYPE_DH, &ssh_sha1, &extra_group1,
 };
 
 static const struct ssh_kex *const group1_list[] = {
@@ -64,9 +73,13 @@ const struct ssh_kexes ssh_diffiehellman_group1 = {
     group1_list
 };
 
+static const struct dh_extra extra_group14 = {
+    P14, G, lenof(P14), lenof(G),
+};
+
 static const struct ssh_kex ssh_diffiehellman_group14_sha1 = {
     "diffie-hellman-group14-sha1", "group14",
-    KEXTYPE_DH, P14, G, lenof(P14), lenof(G), &ssh_sha1
+    KEXTYPE_DH, &ssh_sha1, &extra_group14,
 };
 
 static const struct ssh_kex *const group14_list[] = {
@@ -78,14 +91,18 @@ const struct ssh_kexes ssh_diffiehellman_group14 = {
     group14_list
 };
 
+static const struct dh_extra extra_gex = {
+    NULL, NULL, 0, 0,
+};
+
 static const struct ssh_kex ssh_diffiehellman_gex_sha256 = {
     "diffie-hellman-group-exchange-sha256", NULL,
-    KEXTYPE_DH, NULL, NULL, 0, 0, &ssh_sha256
+    KEXTYPE_DH, &ssh_sha256, &extra_gex,
 };
 
 static const struct ssh_kex ssh_diffiehellman_gex_sha1 = {
     "diffie-hellman-group-exchange-sha1", NULL,
-    KEXTYPE_DH, NULL, NULL, 0, 0, &ssh_sha1
+    KEXTYPE_DH, &ssh_sha1, &extra_gex,
 };
 
 static const struct ssh_kex *const gex_list[] = {
@@ -115,14 +132,21 @@ static void dh_init(struct dh_ctx *ctx)
     ctx->x = ctx->e = NULL;
 }
 
+int dh_is_gex(const struct ssh_kex *kex)
+{
+    const struct dh_extra *extra = (const struct dh_extra *)kex->extra;
+    return extra->pdata == NULL;
+}
+
 /*
  * Initialise DH for a standard group.
  */
 void *dh_setup_group(const struct ssh_kex *kex)
 {
+    const struct dh_extra *extra = (const struct dh_extra *)kex->extra;
     struct dh_ctx *ctx = snew(struct dh_ctx);
-    ctx->p = bignum_from_bytes(kex->pdata, kex->plen);
-    ctx->g = bignum_from_bytes(kex->gdata, kex->glen);
+    ctx->p = bignum_from_bytes(extra->pdata, extra->plen);
+    ctx->g = bignum_from_bytes(extra->gdata, extra->glen);
     dh_init(ctx);
     return ctx;
 }

diff --git a/sshdss.c b/sshdss.c
index bd7e08872f874ed1170aed319e83fa75cdc5334f..20a5e7fa61247742a8d961a2858c213a74dbbbb1 100644 (file)
--- a/sshdss.c
+++ b/sshdss.c
@@ -675,5 +675,6 @@ const struct ssh_signkey ssh_dss = {
     dss_verifysig,
     dss_sign,
     "ssh-dss",
-    "dss"
+    "dss",
+    NULL,
 };

diff --git a/sshecc.c b/sshecc.c
index 84ab2477a71ce527b0bfddb071fe47cf9ca2927b..ec2648b0896bdab6c0a01329bf66aa9ec2c20e9d 100644 (file)
--- a/sshecc.c
+++ b/sshecc.c
@@ -3473,6 +3473,7 @@ const struct ssh_signkey ssh_ecdsa_ed25519 = {
     ecdsa_sign,
     "ssh-ed25519",
     "ssh-ed25519",
+    NULL,
 };
 
 const struct ssh_signkey ssh_ecdsa_nistp256 = {
@@ -3490,6 +3491,7 @@ const struct ssh_signkey ssh_ecdsa_nistp256 = {
     ecdsa_sign,
     "ecdsa-sha2-nistp256",
     "ecdsa-sha2-nistp256",
+    NULL,
 };
 
 const struct ssh_signkey ssh_ecdsa_nistp384 = {
@@ -3507,6 +3509,7 @@ const struct ssh_signkey ssh_ecdsa_nistp384 = {
     ecdsa_sign,
     "ecdsa-sha2-nistp384",
     "ecdsa-sha2-nistp384",
+    NULL,
 };
 
 const struct ssh_signkey ssh_ecdsa_nistp521 = {
@@ -3524,6 +3527,7 @@ const struct ssh_signkey ssh_ecdsa_nistp521 = {
     ecdsa_sign,
     "ecdsa-sha2-nistp521",
     "ecdsa-sha2-nistp521",
+    NULL,
 };
 
 /* ----------------------------------------------------------------------
@@ -3701,19 +3705,19 @@ void ssh_ecdhkex_freekey(void *key)
 }
 
 static const struct ssh_kex ssh_ec_kex_curve25519 = {
-    "curve25519-sha256@libssh.org", NULL, KEXTYPE_ECDH, NULL, NULL, 0, 0, &ssh_sha256
+    "curve25519-sha256@libssh.org", NULL, KEXTYPE_ECDH, &ssh_sha256, NULL
 };
 
 static const struct ssh_kex ssh_ec_kex_nistp256 = {
-    "ecdh-sha2-nistp256", NULL, KEXTYPE_ECDH, NULL, NULL, 0, 0, &ssh_sha256
+    "ecdh-sha2-nistp256", NULL, KEXTYPE_ECDH, &ssh_sha256, NULL
 };
 
 static const struct ssh_kex ssh_ec_kex_nistp384 = {
-    "ecdh-sha2-nistp384", NULL, KEXTYPE_ECDH, NULL, NULL, 0, 0, &ssh_sha384
+    "ecdh-sha2-nistp384", NULL, KEXTYPE_ECDH, &ssh_sha384, NULL
 };
 
 static const struct ssh_kex ssh_ec_kex_nistp521 = {
-    "ecdh-sha2-nistp521", NULL, KEXTYPE_ECDH, NULL, NULL, 0, 0, &ssh_sha512
+    "ecdh-sha2-nistp521", NULL, KEXTYPE_ECDH, &ssh_sha512, NULL
 };
 
 static const struct ssh_kex *const ec_kex_list[] = {

diff --git a/sshrsa.c b/sshrsa.c
index 32694456878fb1d16f42f3b081513ed50ed62409..850204c7ad1fb47f221abbd22c4b9da0a61e7ac9 100644 (file)
--- a/sshrsa.c
+++ b/sshrsa.c
@@ -917,7 +917,8 @@ const struct ssh_signkey ssh_rsa = {
     rsa2_verifysig,
     rsa2_sign,
     "ssh-rsa",
-    "rsa2"
+    "rsa2",
+    NULL,
 };
 
 void *ssh_rsakex_newkey(char *data, int len)
@@ -1057,11 +1058,11 @@ void ssh_rsakex_encrypt(const struct ssh_hash *h, unsigned char *in, int inlen,
 }
 
 static const struct ssh_kex ssh_rsa_kex_sha1 = {
-    "rsa1024-sha1", NULL, KEXTYPE_RSA, NULL, NULL, 0, 0, &ssh_sha1
+    "rsa1024-sha1", NULL, KEXTYPE_RSA, &ssh_sha1, NULL,
 };
 
 static const struct ssh_kex ssh_rsa_kex_sha256 = {
-    "rsa2048-sha256", NULL, KEXTYPE_RSA, NULL, NULL, 0, 0, &ssh_sha256
+    "rsa2048-sha256", NULL, KEXTYPE_RSA, &ssh_sha256, NULL,
 };
 
 static const struct ssh_kex *const rsa_kex_list[] = {