X-Git-Url: https://git.distorted.org.uk/~mdw/tripe/blobdiff_plain/5b9f3d3788bafcba79c893b1afc6a1c77bc77d20..07bdda1fdf877d00dd63d53ebd5159b5edd1df29:/server/dh.c

diff --git a/server/dh.c b/server/dh.c
index bbaa1230..314da5e4 100644
--- a/server/dh.c
+++ b/server/dh.c
@@ -95,6 +95,19 @@ static void pre##_freege(const dhgrp *, dhge *); \
   KLOAD_HALF(pre, ty, TY, priv, PRIV, setgroup, setpriv, setpub)	\
   KLOAD_HALF(pre, ty, TY, pub, PUB, setgroup, { kd->k = 0; }, setpub)
 
+enum { DHSER_V0, DHSER_CONSTLEN };
+
+static int get_serialization(key_file *kf, key *k, dstr *e)
+{
+  const char *p = key_getattr(kf, k, "serialization");
+  if (!p || strcmp(p, "v0") == 0) return (DHSER_V0);
+  else if (strcmp(p, "constlen") == 0) return (DHSER_CONSTLEN);
+  else {
+    a_format(e, "unknown-serialization-format", "%s", p, A_END);
+    return (-1);
+  }
+}
+
 #ifndef NTRACE
 static void setupstr(mptext_stringctx *sc)
   { sc->buf = (char *)buf_u; sc->lim = sc->buf + sizeof(buf_u); }
@@ -132,14 +145,21 @@ typedef struct intdh_grp {
   mpmont mm;
   mp *q, *G;
   size_t gesz;
+  int ser;
 } intdh_grp;
 
 typedef struct intdh_sc { mp *x; } intdh_sc;
 typedef struct intdh_ge { mp *X; } intdh_ge;
 
-static dhgrp *intdh_mkgroup(const dh_param *dp)
+static dhgrp *intdh_mkgroup(key_file *kf, key *k,
+			    const dh_param *dp, dstr *e)
 {
-  intdh_grp *g = CREATE(intdh_grp);
+  intdh_grp *g;
+  int ser;
+
+  if ((ser = get_serialization(kf, k, e)) < 0) return (0);
+  g = CREATE(intdh_grp);
+  g->ser = ser;
   g->_g.scsz = mp_octets(dp->q);
   g->gesz = mp_octets(dp->p);
   mpmont_create(&g->mm, dp->p);
@@ -166,7 +186,7 @@ static dhge *intdh_mptoge(const dhgrp *gg, mp *z)
 }
 
 KLOAD(intdh, dh, DH,
-      { kd->grp = intdh_mkgroup(&p.dp); },
+      { if ((kd->grp = intdh_mkgroup(kf, k, &p.dp, e)) == 0) goto fail; },
       { kd->k = intdh_mptosc(kd->grp, p.x); },
       { kd->K = intdh_mptoge(kd->grp, p.y); })
 
@@ -211,7 +231,9 @@ static void intdh_tracegrp(const dhgrp *gg)
 static int intdh_samegrpp(const dhgrp *gg, const dhgrp *hh)
 {
   const intdh_grp *g = (const intdh_grp *)gg, *h = (const intdh_grp *)hh;
-  return (MP_EQ(g->mm.m, h->mm.m) && MP_EQ(g->q, h->q) && MP_EQ(g->G, h->G));
+  return (MP_EQ(g->mm.m, h->mm.m) &&
+	  MP_EQ(g->q, h->q) && MP_EQ(g->G, h->G) &&
+	  g->ser == h->ser);
 }
 
 static void intdh_freegrp(dhgrp *gg)
@@ -263,10 +285,11 @@ static dhge *intdh_ldge(const dhgrp *gg, buf *b, int fmt)
   const octet *p;
 
   switch (fmt) {
-    case DHFMT_VAR: case DHFMT_HASH:
+    case DHFMT_HASH: if (g->ser == DHSER_CONSTLEN) goto std;
+    case DHFMT_VAR:
       if ((t = buf_getmp(b)) == 0) return (0);
       break;
-    case DHFMT_STD:
+    case DHFMT_STD: std:
       if ((p = buf_get(b, g->gesz)) == 0) return (0);
       t = mp_loadb(MP_NEW, p, g->gesz);
       break;
@@ -289,10 +312,11 @@ static int intdh_stge(const dhgrp *gg, buf *b, const dhge *YY, int fmt)
 
   t = mpmont_reduce(&g->mm, MP_NEW, Y->X);
   switch (fmt) {
-    case DHFMT_VAR: case DHFMT_HASH:
+    case DHFMT_HASH: if (g->ser == DHSER_CONSTLEN) goto std;
+    case DHFMT_VAR:
       rc = buf_putmp(b, t);
       break;
-    case DHFMT_STD:
+    case DHFMT_STD: std:
       if ((p = buf_get(b, g->gesz)) == 0)
 	rc = -1;
       else {
@@ -359,22 +383,26 @@ typedef struct ecdh_grp {
   dhgrp _g;
   ec_info ei;
   ec P;
+  int ser;
 } ecdh_grp;
 
 typedef struct ecdh_sc { mp *x; } ecdh_sc;
 typedef struct ecdh_ge { ec Q; } ecdh_ge;
 
-static dhgrp *ecdh_mkgroup(const char *cstr, dstr *e)
+static dhgrp *ecdh_mkgroup(key_file *kf, key *k, const char *cstr, dstr *e)
 {
   ecdh_grp *g;
   ec_info ei;
+  int ser;
   const char *err;
 
+  if ((ser = get_serialization(kf, k, e)) < 0) return (0);
   if ((err = ec_getinfo(&ei, cstr)) != 0) {
     a_format(e, "decode-failed", "%s", err, A_END);
     return (0);
   }
   g = CREATE(ecdh_grp);
+  g->ser = ser;
   g->ei = ei;
   EC_CREATE(&g->P); EC_IN(g->ei.c, &g->P, &g->ei.g);
   g->_g.scsz = mp_octets(g->ei.r);
@@ -400,7 +428,7 @@ static dhge *ecdh_ectoge(const dhgrp *gg, ec *Q)
 }
 
 KLOAD(ecdh, ec, EC,
-      { if ((kd->grp = ecdh_mkgroup(p.cstr, e)) == 0) goto fail; },
+      { if ((kd->grp = ecdh_mkgroup(kf, k, p.cstr, e)) == 0) goto fail; },
       { kd->k = ecdh_mptosc(kd->grp, p.x); },
       { if ((kd->K = ecdh_ectoge(kd->grp, &p.p)) == 0) {
 	  a_format(e, "bad-public-vector", A_END);
@@ -470,7 +498,8 @@ static void ecdh_tracegrp(const dhgrp *gg)
 static int ecdh_samegrpp(const dhgrp *gg, const dhgrp *hh)
 {
   const ecdh_grp *g = (const ecdh_grp *)gg, *h = (const ecdh_grp *)hh;
-  return (ec_sameinfop(&g->ei, &h->ei));
+  return (ec_sameinfop(&g->ei, &h->ei) &&
+	  g->ser == h->ser);
 }
 
 static void ecdh_freegrp(dhgrp *gg)
@@ -522,8 +551,9 @@ static dhge *ecdh_ldge(const dhgrp *gg, buf *b, int fmt)
   ec T = EC_INIT;
 
   switch (fmt) {
-    case DHFMT_VAR: case DHFMT_HASH: if (buf_getec(b, &T)) return (0); break;
-    case DHFMT_STD: if (ec_getraw(g->ei.c, b, &T)) return (0); break;
+    case DHFMT_HASH: if (g->ser == DHSER_CONSTLEN) goto std;
+    case DHFMT_VAR: if (buf_getec(b, &T)) return (0); break;
+    case DHFMT_STD: std: if (ec_getraw(g->ei.c, b, &T)) return (0); break;
     default:
       abort();
   }
@@ -541,8 +571,9 @@ static int ecdh_stge(const dhgrp *gg, buf *b, const dhge *YY, int fmt)
 
   EC_OUT(g->ei.c, &T, &Y->Q);
   switch (fmt) {
-    case DHFMT_VAR: case DHFMT_HASH: rc = buf_putec(b, &T); break;
-    case DHFMT_STD: rc = ec_putraw(g->ei.c, b, &T); break;
+    case DHFMT_HASH: if (g->ser == DHSER_CONSTLEN) goto std;
+    case DHFMT_VAR: rc = buf_putec(b, &T); break;
+    case DHFMT_STD: std: rc = ec_putraw(g->ei.c, b, &T); break;
     default: abort();
   }
   EC_DESTROY(&T);