autoconf: Update to autoconf 2.69

[secnet.git] / rsa.c

diff --git a/rsa.c b/rsa.c
index fed468dc3ef46f67d9d54dbfa608805cbc8962e4..f7dd69db6f69115e03c94779a2529468b642619f 100644 (file)
--- a/rsa.c
+++ b/rsa.c
@@ -34,18 +34,19 @@ struct rsapub {
 };
 /* Sign data. NB data must be smaller than modulus */
 
 };
 /* Sign data. NB data must be smaller than modulus */
 

+#define RSA_MAX_MODBYTES 2048
+/* The largest modulus I've seen is 15360 bits, which works out at 1920
+ * bytes.  Using keys this big is quite implausible, but it doesn't cost us
+ * much to support them.
+ */
+

 static const char *hexchars="0123456789abcdef";
 
 static const char *hexchars="0123456789abcdef";
 

-static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
+static void emsa_pkcs1(MP_INT *n, MP_INT *m,
+                      const uint8_t *data, int32_t datalen)

 {
 {

-    struct rsapriv *st=sst;
-    MP_INT a, b, u, v, tmp, tmp2;
-    char buff[2048];
+    char buff[2*RSA_MAX_MODBYTES + 1];

     int msize, i;
     int msize, i;

-    string_t signature;
-
-    mpz_init(&a);
-    mpz_init(&b);

 
     /* RSA PKCS#1 v1.5 signature padding:
      *
 
     /* RSA PKCS#1 v1.5 signature padding:
      *


@@ -65,7 +66,7 @@ static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
      * -iwj 17.9.2002
      */
 
      * -iwj 17.9.2002
      */
 

-    msize=mpz_sizeinbase(&st->n, 16);
+    msize=mpz_sizeinbase(n, 16);

 
     if (datalen*2+6>=msize) {
        fatal("rsa_sign: message too big");
 
     if (datalen*2+6>=msize) {
        fatal("rsa_sign: message too big");


@@ -86,7 +87,20 @@ static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
 
     buff[msize]=0;
 
 
     buff[msize]=0;
 

-    mpz_set_str(&a, buff, 16);
+    mpz_set_str(m, buff, 16);
+}
+
+static string_t rsa_sign(void *sst, uint8_t *data, int32_t datalen)
+{
+    struct rsapriv *st=sst;
+    MP_INT a, b, u, v, tmp, tmp2;
+    string_t signature;
+
+    mpz_init(&a);
+    mpz_init(&b);
+
+    /* Construct the message representative. */
+    emsa_pkcs1(&st->n, &a, data, datalen);

 
     /*
      * Produce an RSA signature (a^d mod n) using the Chinese
 
     /*
      * Produce an RSA signature (a^d mod n) using the Chinese


@@ -135,32 +149,13 @@ static bool_t rsa_sig_check(void *sst, uint8_t *data, int32_t datalen,
 {
     struct rsapub *st=sst;
     MP_INT a, b, c;
 {
     struct rsapub *st=sst;
     MP_INT a, b, c;

-    char buff[2048];
-    int msize, i;

     bool_t ok;
 
     mpz_init(&a);
     mpz_init(&b);
     mpz_init(&c);
 
     bool_t ok;
 
     mpz_init(&a);
     mpz_init(&b);
     mpz_init(&c);
 

-    msize=mpz_sizeinbase(&st->n, 16);
-
-    strcpy(buff,"0001");
-
-    for (i=0; i<datalen; i++) {
-       buff[msize+(-datalen+i)*2]=hexchars[(data[i]&0xf0)>>4];
-       buff[msize+(-datalen+i)*2+1]=hexchars[data[i]&0xf];
-    }
-
-    buff[msize-datalen*2-2]= '0';
-    buff[msize-datalen*2-1]= '0';
-
-    for (i=4; i<msize-datalen*2-2; i++)
-       buff[i]='f';
-
-    buff[msize]=0;
-
-    mpz_set_str(&a, buff, 16);
+    emsa_pkcs1(&st->n, &a, data, datalen);

 
     mpz_set_str(&b, signature, 16);
 
 
     mpz_set_str(&b, signature, 16);
 


@@ -204,6 +199,9 @@ static list_t *rsapub_apply(closure_t *self, struct cloc loc, dict_t *context,
     } else {
        cfgfatal(loc,"rsa-public","you must provide an encryption key\n");
     }
     } else {
        cfgfatal(loc,"rsa-public","you must provide an encryption key\n");
     }

+    if (mpz_sizeinbase(&st->e, 256) > RSA_MAX_MODBYTES) {
+       cfgfatal(loc, "rsa-public", "implausibly large public exponent\n");
+    }

     
     i=list_elem(args,1);
     if (i) {
     
     i=list_elem(args,1);
     if (i) {


@@ -218,6 +216,9 @@ static list_t *rsapub_apply(closure_t *self, struct cloc loc, dict_t *context,
     } else {
        cfgfatal(loc,"rsa-public","you must provide a modulus\n");
     }
     } else {
        cfgfatal(loc,"rsa-public","you must provide a modulus\n");
     }

+    if (mpz_sizeinbase(&st->n, 256) > RSA_MAX_MODBYTES) {
+       cfgfatal(loc, "rsa-public", "implausibly large modulus\n");
+    }

     return new_closure(&st->cl);
 }
 
     return new_closure(&st->cl);
 }
 


@@ -307,7 +308,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
     /* Read the public key */
     keyfile_get_int(loc,f); /* Not sure what this is */
     length=(keyfile_get_short(loc,f)+7)/8;
     /* Read the public key */
     keyfile_get_int(loc,f); /* Not sure what this is */
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausible length %ld for modulus\n",
                 length);
     }
        cfgfatal(loc,"rsa-private","implausible length %ld for modulus\n",
                 length);
     }


@@ -319,7 +320,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
     read_mpbin(&st->n,b,length);
     free(b);
     length=(keyfile_get_short(loc,f)+7)/8;
     read_mpbin(&st->n,b,length);
     free(b);
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausible length %ld for e\n",length);
     }
     b=safe_malloc(length,"rsapriv_apply");
        cfgfatal(loc,"rsa-private","implausible length %ld for e\n",length);
     }
     b=safe_malloc(length,"rsapriv_apply");


@@ -350,7 +351,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
 
     /* Read d */
     length=(keyfile_get_short(loc,f)+7)/8;
 
     /* Read d */
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausibly long (%ld) decryption key\n",
                 length);
     }
        cfgfatal(loc,"rsa-private","implausibly long (%ld) decryption key\n",
                 length);
     }


@@ -364,7 +365,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
     free(b);
     /* Read iqmp (inverse of q mod p) */
     length=(keyfile_get_short(loc,f)+7)/8;
     free(b);
     /* Read iqmp (inverse of q mod p) */
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausibly long (%ld)"
                 " iqmp auxiliary value\n", length);
     }
        cfgfatal(loc,"rsa-private","implausibly long (%ld)"
                 " iqmp auxiliary value\n", length);
     }


@@ -378,7 +379,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
     free(b);
     /* Read q (the smaller of the two primes) */
     length=(keyfile_get_short(loc,f)+7)/8;
     free(b);
     /* Read q (the smaller of the two primes) */
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausibly long (%ld) q value\n",
                 length);
     }
        cfgfatal(loc,"rsa-private","implausibly long (%ld) q value\n",
                 length);
     }


@@ -392,7 +393,7 @@ static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
     free(b);
     /* Read p (the larger of the two primes) */
     length=(keyfile_get_short(loc,f)+7)/8;
     free(b);
     /* Read p (the larger of the two primes) */
     length=(keyfile_get_short(loc,f)+7)/8;

-    if (length>1024) {
+    if (length>RSA_MAX_MODBYTES) {

        cfgfatal(loc,"rsa-private","implausibly long (%ld) p value\n",
                 length);
     }
        cfgfatal(loc,"rsa-private","implausibly long (%ld) p value\n",
                 length);
     }