Deploy the new <ctype.h> and `foocmp' macros from mLib.
[catacomb] / progs / cc-kem.c
index 6c4d7f3..36dfdb3 100644 (file)
 
 #include <mLib/alloc.h>
 #include <mLib/dstr.h>
+#include <mLib/macros.h>
 #include <mLib/report.h>
 #include <mLib/sub.h>
 
+#include "gaead.h"
 #include "mprand.h"
 #include "rand.h"
 
 #include "ec-keys.h"
 #include "dh.h"
 #include "rsa.h"
+#include "x25519.h"
+#include "x448.h"
 
 #include "rmd160.h"
 #include "blowfish-cbc.h"
+#include "chacha20-poly1305.h"
+#include "poly1305.h"
+#include "salsa20.h"
+#include "chacha.h"
 
 #include "cc.h"
 
 /*----- Bulk crypto -------------------------------------------------------*/
 
+/* --- Authenticated encryption schemes --- */
+
+typedef struct aead_encctx {
+  bulk b;
+  const gcaead *aec;
+  gaead_key *key;
+  union { gaead_enc *enc; gaead_dec *dec; } ed;
+  octet *t;
+  size_t nsz, tsz;
+} aead_encctx;
+
+static bulk *aead_internalinit(key *k, const gcaead *aec)
+{
+  aead_encctx *ctx = CREATE(aead_encctx);
+
+  ctx->key = 0;
+  ctx->aec = aec;
+  if ((ctx->nsz = keysz_pad(4, aec->noncesz)) == 0)
+    die(EXIT_FAILURE, "no suitable nonce size for `%s'", aec->name);
+  ctx->tsz = keysz(0, ctx->aec->tagsz);
+
+  return (&ctx->b);
+}
+
+static bulk *aead_init(key *k, const char *calg, const char *halg)
+{
+  const gcaead *aec;
+  const char *q;
+  dstr t = DSTR_INIT;
+
+  key_fulltag(k, &t);
+
+  if ((q = key_getattr(0, k, "cipher")) != 0) calg = q;
+  if (!calg) aec = &chacha20_poly1305;
+  else if ((aec = gaead_byname(calg)) == 0)
+    die(EXIT_FAILURE, "AEAD scheme `%s' not found in key `%s'",
+       calg, t.buf);
+
+  dstr_destroy(&t);
+  return (aead_internalinit(k, aec));
+}
+
+static int aead_commonsetup(aead_encctx *ctx, gcipher *cx)
+{
+  size_t ksz, n;
+
+  n = ksz = keysz(0, ctx->aec->keysz);
+  if (n < ctx->nsz) n = ctx->nsz;
+  if (n < ctx->tsz) n = ctx->tsz;
+  ctx->t = xmalloc(n);
+
+  GC_ENCRYPT(cx, 0, ctx->t, ksz);
+  ctx->key = GAEAD_KEY(ctx->aec, ctx->t, ksz);
+  return (0);
+}
+
+static size_t aead_overhead(bulk *b)
+  { aead_encctx *ctx = (aead_encctx *)b; return (ctx->aec->ohd + ctx->tsz); }
+
+static void aead_commondestroy(aead_encctx *ctx)
+{
+  if (ctx->key) GAEAD_DESTROY(ctx->key);
+  xfree(ctx->t);
+  DESTROY(ctx);
+}
+
+static int aead_encsetup(bulk *b, gcipher *cx)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  ctx->ed.enc = 0; return (aead_commonsetup(ctx, cx));
+}
+
+static const char *aead_encdoit(bulk *b, uint32 seq, buf *bb,
+                               const void *p, size_t sz)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  octet *t;
+  int rc;
+
+  memset(ctx->t + 4, 0, ctx->nsz - 4); STORE32_B(ctx->t, seq);
+  if (!ctx->ed.enc)
+    ctx->ed.enc = GAEAD_ENC(ctx->key, ctx->t, ctx->nsz, 0, sz, ctx->tsz);
+  else
+    GAEAD_REINIT(ctx->ed.enc, ctx->t, ctx->nsz, 0, sz, ctx->tsz);
+  t = buf_get(bb, ctx->tsz); assert(t);
+  rc = GAEAD_ENCRYPT(ctx->ed.enc, p, sz, bb); assert(rc >= 0);
+  rc = GAEAD_DONE(ctx->ed.enc, 0, bb, t, ctx->tsz); assert(rc >= 0);
+  return (0);
+}
+
+static void aead_encdestroy(bulk *b)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  if (ctx->ed.enc) GAEAD_DESTROY(ctx->ed.enc);
+  aead_commondestroy(ctx);
+}
+
+static int aead_decsetup(bulk *b, gcipher *cx)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  ctx->ed.dec = 0; return (aead_commonsetup(ctx, cx));
+}
+
+static const char *aead_decdoit(bulk *b, uint32 seq, buf *bb,
+                               const void *p, size_t sz)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  buf bin;
+  const octet *t;
+  int rc;
+
+  memset(ctx->t + 4, 0, ctx->nsz - 4); STORE32_B(ctx->t, seq);
+  if (!ctx->ed.dec)
+    ctx->ed.dec = GAEAD_DEC(ctx->key, ctx->t, ctx->nsz, 0, sz, ctx->tsz);
+  else
+    GAEAD_REINIT(ctx->ed.enc, ctx->t, ctx->nsz, 0, sz, ctx->tsz);
+
+  buf_init(&bin, (/*unconst*/ void *)p, sz);
+  t = buf_get(&bin, ctx->tsz); if (!t) return ("no tag");
+  rc = GAEAD_DECRYPT(ctx->ed.dec, BCUR(&bin), BLEFT(&bin), bb);
+  assert(rc >= 0);
+  rc = GAEAD_DONE(ctx->ed.dec, 0, bb, t, ctx->tsz); assert(rc >= 0);
+  if (!rc) return ("authentication failure");
+  return (0);
+}
+
+static void aead_decdestroy(bulk *b)
+{
+  aead_encctx *ctx = (aead_encctx *)b;
+  if (ctx->ed.dec) GAEAD_DESTROY(ctx->ed.dec);
+  aead_commondestroy(ctx);
+}
+
+static const struct bulkops aead_encops = {
+  aead_init, aead_encsetup, aead_overhead,
+  aead_encdoit, aead_encdestroy
+}, aead_decops = {
+  aead_init, aead_decsetup, aead_overhead,
+  aead_decdoit, aead_decdestroy
+};
+
+/* --- NaCl `secretbox' in terms of AEAD --- */
+
+static bulk *naclbox_init(key *k, const char *calg, const char *halg)
+{
+  const gcaead *aec;
+  dstr t = DSTR_INIT;
+  const char *q;
+
+  key_fulltag(k, &t);
+
+  if ((q = key_getattr(0, k, "cipher")) != 0) calg = q;
+  if (!calg || STRCMP(calg, ==, "salsa20")) aec = &salsa20_naclbox;
+  else if (STRCMP(calg, ==, "salsa20/12")) aec = &salsa2012_naclbox;
+  else if (STRCMP(calg, ==, "salsa20/8")) aec = &salsa208_naclbox;
+  else if (STRCMP(calg, ==, "chacha20")) aec = &chacha20_naclbox;
+  else if (STRCMP(calg, ==, "chacha12")) aec = &chacha12_naclbox;
+  else if (STRCMP(calg, ==, "chacha8")) aec = &chacha8_naclbox;
+  else {
+    die(EXIT_FAILURE,
+       "unknown or inappropriate encryption scheme `%s' in key `%s'",
+       calg, t.buf);
+  }
+
+  dstr_destroy(&t);
+  return (aead_internalinit(k, aec));
+}
+
+static const bulkops naclbox_encops = {
+  naclbox_init, aead_encsetup, aead_overhead,
+  aead_encdoit, aead_encdestroy
+}, naclbox_decops = {
+  naclbox_init, aead_decsetup, aead_overhead,
+  aead_decdoit, aead_decdestroy
+};
+
 /* --- Generic composition --- */
 
 typedef struct gencomp_encctx {
@@ -185,6 +369,8 @@ static const bulkops gencomp_encops = {
 
 const struct bulktab bulktab[] = {
   { "gencomp", &gencomp_encops,        &gencomp_decops },
+  { "naclbox", &naclbox_encops,        &naclbox_decops },
+  { "aead",    &aead_encops,           &aead_decops },
   { 0,         0,                      0 }
 };
 
@@ -489,6 +675,80 @@ static const kemops ec_decops = {
   ec_decinit, dh_decdoit, dh_enccheck, dh_encdestroy
 };
 
+/* --- X25519 and similar schemes --- */
+
+#define XDHS(_)                                                                \
+  _(x25519, X25519)                                                    \
+  _(x448, X448)
+
+#define XDHDEF(xdh, XDH)                                               \
+                                                                       \
+  static kem *xdh##_encinit(key *k, void *kd) { return (CREATE(kem)); }        \
+  static void xdh##_encdestroy(kem *k) { DESTROY(k); }                 \
+                                                                       \
+  static const char *xdh##_enccheck(kem *k)                            \
+  {                                                                    \
+    xdh##_pub *kd = k->kd;                                             \
+                                                                       \
+    if (kd->pub.sz != XDH##_PUBSZ)                                     \
+      return ("incorrect " #XDH "public key length");                  \
+    return (0);                                                                \
+  }                                                                    \
+                                                                       \
+  static int xdh##_encdoit(kem *k, dstr *d, ghash *h)                  \
+  {                                                                    \
+    octet t[XDH##_KEYSZ], z[XDH##_OUTSZ];                              \
+    xdh##_pub *kd = k->kd;                                             \
+                                                                       \
+    rand_get(RAND_GLOBAL, t, sizeof(t));                               \
+    dstr_ensure(d, XDH##_PUBSZ);                                       \
+    xdh((octet *)d->buf, t, xdh##_base);                               \
+    xdh(z, t, kd->pub.k);                                              \
+    d->len += XDH##_PUBSZ;                                             \
+    GH_HASH(h, d->buf, XDH##_PUBSZ);                                   \
+    GH_HASH(h, z, XDH##_OUTSZ);                                                \
+    return (0);                                                                \
+  }                                                                    \
+                                                                       \
+  static const char *xdh##_deccheck(kem *k)                            \
+  {                                                                    \
+    xdh##_priv *kd = k->kd;                                            \
+                                                                       \
+    if (kd->priv.sz != XDH##_KEYSZ)                                    \
+      return ("incorrect " #XDH " private key length");                        \
+    if (kd->pub.sz != XDH##_PUBSZ)                                     \
+      return ("incorrect " #XDH " public key length");                 \
+    return (0);                                                                \
+  }                                                                    \
+                                                                       \
+  static int xdh##_decdoit(kem *k, dstr *d, ghash *h)                  \
+  {                                                                    \
+    octet z[XDH##_OUTSZ];                                              \
+    xdh##_priv *kd = k->kd;                                            \
+    int rc = -1;                                                       \
+                                                                       \
+    if (d->len != XDH##_PUBSZ) goto done;                              \
+    xdh(z, kd->priv.k, (const octet *)d->buf);                         \
+    GH_HASH(h, d->buf, XDH##_PUBSZ);                                   \
+    GH_HASH(h, z, XDH##_OUTSZ);                                                \
+    rc = 0;                                                            \
+  done:                                                                        \
+    return (rc);                                                       \
+  }                                                                    \
+                                                                       \
+  static const kemops xdh##_encops = {                                 \
+    xdh##_pubfetch, sizeof(xdh##_pub),                                 \
+    xdh##_encinit, xdh##_encdoit, xdh##_enccheck, xdh##_encdestroy     \
+  };                                                                   \
+                                                                       \
+  static const kemops xdh##_decops = {                                 \
+    xdh##_privfetch, sizeof(xdh##_priv),                               \
+    xdh##_encinit, xdh##_decdoit, xdh##_deccheck, xdh##_encdestroy     \
+  };
+
+XDHS(XDHDEF)
+#undef XDHDEF
+
 /* --- Symmetric --- */
 
 typedef struct symm_ctx {
@@ -557,6 +817,10 @@ const struct kemtab kemtab[] = {
   { "dh",      &dh_encops,     &dh_decops },
   { "bindh",   &bindh_encops,  &bindh_decops },
   { "ec",      &ec_encops,     &ec_decops },
+#define XDHTAB(xdh, XDH)                                               \
+  { #xdh,      &xdh##_encops,  &xdh##_decops },
+  XDHS(XDHTAB)
+#undef XDHTAB
   { "symm",    &symm_encops,   &symm_decops },
   { 0,         0,              0 }
 };
@@ -603,7 +867,7 @@ kem *getkem(key *k, const char *app, int wantpriv, bulk **bc)
   if ((q = key_getattr(0, k, "kem")) != 0) {
     dstr_puts(&d, q);
     p = d.buf;
-  } else if (strncmp(k->type, app, n) == 0 && k->type[n] == '-') {
+  } else if (STRNCMP(k->type, ==, app, n) && k->type[n] == '-') {
     dstr_puts(&d, k->type);
     p = d.buf + n + 1;
   } else
@@ -634,7 +898,7 @@ kem *getkem(key *k, const char *app, int wantpriv, bulk **bc)
   /* --- Instantiate the KEM --- */
 
   for (kt = kemtab; kt->name; kt++) {
-    if (strcmp(kt->name, kalg) == 0)
+    if (STRCMP(kt->name, ==, kalg))
       goto k_found;
   }
   die(EXIT_FAILURE, "key encapsulation mechanism `%s' not found in key `%s'",
@@ -667,24 +931,14 @@ k_found:;
        halg, t.buf);
   }
 
-  dstr_reset(&d);
-  if ((q = key_getattr(0, k, "kdf")) == 0) {
-    dstr_putf(&d, "%s-mgf", kk->hc->name);
-    q = d.buf;
-  }
-  if ((kk->cxc = gcipher_byname(q)) == 0) {
-    die(EXIT_FAILURE, "encryption scheme (KDF) `%s' not found in key `%s'",
-       q, t.buf);
-  }
-
   if (!balg)
     bt = bulktab;
   else {
     for (bt = bulktab, bo = 0; bt->name; bt++) {
-      if (strcmp(balg, bt->name) == 0)
+      if (STRCMP(balg, ==, bt->name))
        { balg = 0; goto b_found; }
       n = strlen(bt->name);
-      if (strncmp(balg, bt->name, n) == 0 && balg[n] == '-')
+      if (STRNCMP(balg, ==, bt->name, n) && balg[n] == '-')
        { balg += n + 1; goto b_found; }
     }
     bt = bulktab;
@@ -694,6 +948,16 @@ k_found:;
   *bc = bo->init(k, balg, kk->hc->name);
   (*bc)->ops = bo;
 
+  dstr_reset(&d);
+  if ((q = key_getattr(0, k, "kdf")) == 0) {
+    dstr_putf(&d, "%s-mgf", kk->hc->name);
+    q = d.buf;
+  }
+  if ((kk->cxc = gcipher_byname(q)) == 0) {
+    die(EXIT_FAILURE, "encryption scheme (KDF) `%s' not found in key `%s'",
+       q, t.buf);
+  }
+
   /* --- Tidy up --- */
 
   dstr_destroy(&d);