X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=rsa.c;h=28a4c1b3225c3caefbb5a296f7582a149b63d245;hb=4a6ee8b677fd7addc97fc0d245f95ddde3b5f8e4;hp=01d97c3e95533ced3757e716b38cb0dfc8476433;hpb=68fd6cd722b62ff32b7f805d49cc9ce08f30f753;p=secnet.git

diff --git a/rsa.c b/rsa.c
index 01d97c3..28a4c1b 100644
--- a/rsa.c
+++ b/rsa.c
@@ -35,15 +35,22 @@
 #include <gmp.h>
 #include "secnet.h"
 #include "util.h"
+#include "unaligned.h"
 
 #define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n"
 
 #define mpp(s,n) do { char *p = mpz_get_str(NULL,16,n); printf("%s 0x%sL\n", s, p); free(p); } while (0)
 
+struct rsacommon {
+    struct hash_if *hashi;
+    uint8_t *hashbuf;
+};
+
 struct rsapriv {
     closure_t cl;
-    struct rsaprivkey_if ops;
+    struct sigprivkey_if ops;
     struct cloc loc;
+    struct rsacommon common;
     MP_INT n;
     MP_INT p, dp;
     MP_INT q, dq;
@@ -51,8 +58,9 @@ struct rsapriv {
 };
 struct rsapub {
     closure_t cl;
-    struct rsapubkey_if ops;
+    struct sigpubkey_if ops;
     struct cloc loc;
+    struct rsacommon common;
     MP_INT e;
     MP_INT n;
 };
@@ -66,6 +74,27 @@ struct rsapub {
 
 static const char *hexchars="0123456789abcdef";
 
+static void rsa_sethash(struct rsacommon *c, struct hash_if *hash)
+{
+    free(c->hashbuf);
+    c->hashbuf=safe_malloc(hash->hlen, "generate_msg");
+    c->hashi=hash;
+}
+static void rsa_pub_sethash(void *sst, struct hash_if *hash)
+{
+    struct rsapub *st=sst;
+    rsa_sethash(&st->common, hash);
+}
+static void rsa_priv_sethash(void *sst, struct hash_if *hash)
+{
+    struct rsapriv *st=sst;
+    rsa_sethash(&st->common, hash);
+}
+static void rsa_hash(struct rsacommon *c, const uint8_t *buf, int32_t len)
+{
+    hash_hash(c->hashi,buf,len,c->hashbuf);
+}
+
 static void emsa_pkcs1(MP_INT *n, MP_INT *m,
 		       const uint8_t *data, int32_t datalen)
 {
@@ -114,17 +143,20 @@ static void emsa_pkcs1(MP_INT *n, MP_INT *m,
     mpz_set_str(m, buff, 16);
 }
 
-static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
+static bool_t rsa_sign(void *sst, uint8_t *data, int32_t datalen,
+		       struct buffer_if *msg)
 {
     struct rsapriv *st=sst;
     MP_INT a, b, u, v, tmp, tmp2;
-    string_t signature;
+    string_t signature = 0;
+    bool_t ok;
 
     mpz_init(&a);
     mpz_init(&b);
 
+    rsa_hash(&st->common,data,datalen);
     /* Construct the message representative. */
-    emsa_pkcs1(&st->n, &a, data, datalen);
+    emsa_pkcs1(&st->n, &a, st->common.hashbuf, st->common.hashi->hlen);
 
     /*
      * Produce an RSA signature (a^d mod n) using the Chinese
@@ -162,14 +194,45 @@ static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
 
     signature=write_mpstring(&b);
 
+    uint8_t *op = buf_append(msg,2);
+    if (!op) { ok=False; goto out; }
+    size_t l = strlen(signature);
+    assert(l < 65536);
+    put_uint16(op, l);
+    op = buf_append(msg,l);
+    if (!op) { ok=False; goto out; }
+    memcpy(op, signature, l);
+
+    ok = True;
+
+ out:
+    free(signature);
     mpz_clear(&b);
     mpz_clear(&a);
-    return signature;
+    return ok;
+}
+
+static bool_t rsa_sig_unpick(void *sst, struct buffer_if *msg,
+			     struct alg_msg_data *sig)
+{
+    uint8_t *lp = buf_unprepend(msg, 2);
+    if (!lp) return False;
+    sig->len = get_uint16(lp);
+    sig->start = buf_unprepend(msg, sig->len);
+    if (!sig->start) return False;
+
+    /* In `rsa_sig_check' below, we assume that we can write a nul
+     * terminator following the signature.  Make sure there's enough space.
+     */
+    if (msg->start >= msg->base + msg->alloclen)
+	return False;
+
+    return True;
 }
 
-static rsa_checksig_fn rsa_sig_check;
+static sig_checksig_fn rsa_sig_check;
 static bool_t rsa_sig_check(void *sst, uint8_t *data, int32_t datalen,
-			    cstring_t signature)
+			    const struct alg_msg_data *sig)
 {
     struct rsapub *st=sst;
     MP_INT a, b, c;
@@ -179,9 +242,14 @@ static bool_t rsa_sig_check(void *sst, uint8_t *data, int32_t datalen,
     mpz_init(&b);
     mpz_init(&c);
 
-    emsa_pkcs1(&st->n, &a, data, datalen);
+    rsa_hash(&st->common,data,datalen);
+    emsa_pkcs1(&st->n, &a, st->common.hashbuf, st->common.hashi->hlen);
 
-    mpz_set_str(&b, signature, 16);
+    /* Terminate signature with a '0' - already checked that this will fit */
+    int save = sig->start[sig->len];
+    sig->start[sig->len] = 0;
+    mpz_set_str(&b, sig->start, 16);
+    sig->start[sig->len] = save;
 
     mpz_powm(&c, &b, &st->e, &st->n);
 
@@ -203,10 +271,13 @@ static list_t *rsapub_apply(closure_t *self, struct cloc loc, dict_t *context,
 
     NEW(st);
     st->cl.description="rsapub";
-    st->cl.type=CL_RSAPUBKEY;
+    st->cl.type=CL_SIGPUBKEY;
     st->cl.apply=NULL;
     st->cl.interface=&st->ops;
     st->ops.st=st;
+    st->ops.sethash=rsa_pub_sethash;
+    st->common.hashbuf=NULL;
+    st->ops.unpick=rsa_sig_unpick;
     st->ops.check=rsa_sig_check;
     st->loc=loc;
 
@@ -281,10 +352,12 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
 
     NEW(st);
     st->cl.description="rsapriv";
-    st->cl.type=CL_RSAPRIVKEY;
+    st->cl.type=CL_SIGPRIVKEY;
     st->cl.apply=NULL;
     st->cl.interface=&st->ops;
     st->ops.st=st;
+    st->ops.sethash=rsa_priv_sethash;
+    st->common.hashbuf=NULL;
     st->ops.sign=rsa_sign;
     st->loc=loc;