chiark / gitweb /
server/, keys/: Support Bernstein's X25519 and Hamburg's X448 algorithms.
[tripe] / server / dh.c
index 314da5e487d36f7955e1f7dc0bc371b26c9b6f78..5c27a079abe4c5abef1c3853b414fe5339a37b5c 100644 (file)
@@ -639,6 +639,172 @@ static const char *ecdh_gestr(const dhgrp *gg, const dhge *YY)
 static void ecdh_freege(const dhgrp *gg, dhge *YY)
   { ecdh_ge *Y = (ecdh_ge *)YY; EC_DESTROY(&Y->Q); DESTROY(Y); }
 
+/*----- The X25519 and similar groups -------------------------------------*/
+
+#define XDHS(_)                                                                \
+  _(x25519, X25519, "curve25519", 252, 255)                            \
+  _(x448, X448, "ed448-goldilocks", 446, 448)
+
+#ifdef NTRACE
+#  define XDHTRACE(xdh, XDH, gname)
+#else
+
+   static const char *binstr(const octet *p, size_t sz)
+   {
+     char *q;
+
+     for (q = (char *)buf_u; sz--; p++, q += 2) sprintf(q, "%02x", *p);
+     return ((const char *)buf_u);
+   }
+
+#  define XDHTRACE(xdh, XDH, gname)                                    \
+     static void xdh##_tracegrp(const dhgrp *g)                                \
+       { trace(T_CRYPTO, "crypto: group type `" gname "'"); }          \
+                                                                       \
+     static const char *xdh##_scstr(const dhgrp *g, const dhsc *xx)    \
+     {                                                                 \
+       const xdh##_sc *x = (const xdh##_sc *)xx;                       \
+       return (binstr(x->x, XDH##_KEYSZ));                             \
+     }                                                                 \
+                                                                       \
+     static const char *xdh##_gestr(const dhgrp *g, const dhge *YY)    \
+     {                                                                 \
+       const xdh##_ge *Y = (const xdh##_ge *)YY;                       \
+       return (binstr(Y->X, XDH##_PUBSZ));                             \
+     }
+#endif
+
+#define XDHDEF(xdh, XDH, gname, groupbits, fieldbits)                  \
+                                                                       \
+  typedef struct xdh##_sc { octet x[XDH##_KEYSZ]; } xdh##_sc;          \
+  typedef struct xdh##_ge { octet X[XDH##_PUBSZ]; } xdh##_ge;          \
+                                                                       \
+  XDHTRACE(xdh, XDH, gname)                                            \
+                                                                       \
+  static dhsc *xdh##_bintosc(const key_bin *b)                         \
+  {                                                                    \
+    xdh##_sc *x;                                                       \
+                                                                       \
+    if (b->sz != XDH##_KEYSZ) return (0);                              \
+    x = CREATE(xdh##_sc);                                              \
+    memcpy(x->x, b->k, XDH##_KEYSZ);                                   \
+    return ((dhsc *)x);                                                        \
+  }                                                                    \
+                                                                       \
+  static dhge *xdh##_bintoge(const key_bin *b)                         \
+  {                                                                    \
+    xdh##_ge *Y;                                                       \
+                                                                       \
+    if (b->sz != XDH##_PUBSZ) return (0);                              \
+    Y = CREATE(xdh##_ge);                                              \
+    memcpy(Y->X, b->k, XDH##_PUBSZ);                                   \
+    return ((dhge *)Y);                                                        \
+  }                                                                    \
+                                                                       \
+  KLOAD(xdh, xdh, XDH,                                                 \
+       { kd->grp = CREATE(dhgrp); kd->grp->scsz = 32; },               \
+       { if ((kd->k = xdh##_bintosc(&p.priv)) == 0) {                  \
+           a_format(e, "bad-private-key", A_END);                      \
+           goto fail;                                                  \
+         }                                                             \
+       },                                                              \
+       { if ((kd->K = xdh##_bintoge(&p.pub)) == 0) {                   \
+           a_format(e, "bad-public-vector", A_END);                    \
+           goto fail;                                                  \
+         }                                                             \
+       })                                                              \
+                                                                       \
+  static const char *xdh##_checkgrp(const dhgrp *g)                    \
+    { return (0); }                                                    \
+                                                                       \
+  static void xdh##_grpinfo(const dhgrp *g, admin *adm)                        \
+  {                                                                    \
+    a_info(adm,                                                                \
+          "kx-group=" gname,                                           \
+          "kx-group-order-bits=%d", (groupbits),                       \
+          "kx-group-elt-bits=%d", (fieldbits),                         \
+          A_END);                                                      \
+  }                                                                    \
+                                                                       \
+  static int xdh##_samegrpp(const dhgrp *g, const dhgrp *hh)           \
+    { return (1); }                                                    \
+                                                                       \
+  static void xdh##_freegrp(dhgrp *g)                                  \
+    { DESTROY(g); }                                                    \
+                                                                       \
+  static dhsc *xdh##_ldsc(const dhgrp *g, const void *p, size_t sz)    \
+  {                                                                    \
+    xdh##_sc *x;                                                       \
+    if (sz != XDH##_KEYSZ) return (0);                                 \
+    x = CREATE(xdh##_sc);                                              \
+    memcpy(x->x, p, XDH##_KEYSZ);                                      \
+    return ((dhsc *)x);                                                        \
+  }                                                                    \
+                                                                       \
+  static int xdh##_stsc(const dhgrp *g, void *p, size_t sz,            \
+                       const dhsc *xx)                                 \
+  {                                                                    \
+    const xdh##_sc *x = (const xdh##_sc *)xx;                          \
+    if (sz != XDH##_KEYSZ) return (-1);                                        \
+    memcpy(p, x->x, XDH##_KEYSZ);                                      \
+    return (0);                                                                \
+  }                                                                    \
+                                                                       \
+  static dhsc *xdh##_randsc(const dhgrp *g)                            \
+  {                                                                    \
+    xdh##_sc *x = CREATE(xdh##_sc);                                    \
+    rand_get(RAND_GLOBAL, x->x, XDH##_KEYSZ);                          \
+    return ((dhsc *)x);                                                        \
+  }                                                                    \
+                                                                       \
+  static void xdh##_freesc(const dhgrp *g, dhsc *xx)                   \
+    { xdh##_sc *x = (xdh##_sc *)xx; DESTROY(x); }                      \
+                                                                       \
+  static dhge *xdh##_ldge(const dhgrp *g, buf *b, int fmt)             \
+  {                                                                    \
+    xdh##_ge *Y;                                                       \
+    const octet *p;                                                    \
+                                                                       \
+    if ((p = buf_get(b, XDH##_PUBSZ)) == 0) return (0);                        \
+    Y = CREATE(xdh##_ge); memcpy(Y->X, p, XDH##_PUBSZ);                        \
+    return ((dhge *)Y);                                                        \
+  }                                                                    \
+                                                                       \
+  static int xdh##_stge(const dhgrp *g, buf *b,                                \
+                       const dhge *YY, int fmt)                        \
+  {                                                                    \
+    const xdh##_ge *Y = (const xdh##_ge *)YY;                          \
+    return (buf_put(b, Y->X, XDH##_PUBSZ));                            \
+  }                                                                    \
+                                                                       \
+  static int xdh##_checkge(const dhgrp *g, const dhge *YY)             \
+    { return (0); }                                                    \
+                                                                       \
+  static int xdh##_eq(const dhgrp *g, const dhge *YY, const dhge *ZZ)  \
+  {                                                                    \
+    const xdh##_ge                                                     \
+      *Y = (const xdh##_ge *)YY, *Z = (const xdh##_ge *)ZZ;            \
+    return (ct_memeq(Y->X, Z->X, XDH##_PUBSZ));                                \
+  }                                                                    \
+                                                                       \
+  static dhge *xdh##_mul(const dhgrp *g,                               \
+                        const dhsc *xx, const dhge *YY)                \
+  {                                                                    \
+    const xdh##_sc *x = (const xdh##_sc *)xx;                          \
+    const xdh##_ge *Y = (const xdh##_ge *)YY;                          \
+    xdh##_ge *Z = CREATE(xdh##_ge);                                    \
+                                                                       \
+    xdh(Z->X, x->x, Y ? Y->X : xdh##_base);                            \
+    return ((dhge *)Z);                                                        \
+  }                                                                    \
+                                                                       \
+  static void xdh##_freege(const dhgrp *g, dhge *YY)                   \
+    { xdh##_ge *Y = (xdh##_ge *)YY; DESTROY(Y); }
+
+XDHS(XDHDEF)
+
+#undef XDHDEF
+
 /*----- Diffie--Hellman group table ---------------------------------------*/
 
 const dhops dhtab[] = {
@@ -657,6 +823,10 @@ const dhops dhtab[] = {
   DH("dh", intdh)
   DH("ec", ecdh)
 
+#define XDHDH(xdh, XDH, gname, groupbits, fieldbits) DH(#xdh, xdh)
+  XDHS(XDHDH)
+#undef XDHDH
+
 #undef DH
 
   { 0 }