Increase FONT_MAXNO from 0x2f to 0x40, to ensure the fonts[] array

[u/mdw/putty] / sshdss.c

diff --git a/sshdss.c b/sshdss.c
index 7443daf..532c13f 100644 (file)
--- a/sshdss.c
+++ b/sshdss.c
@@ -1,3 +1,7 @@
+/*
+ * Digital Signature Standard implementation for PuTTY.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
@@ -5,18 +9,6 @@
 #include "ssh.h"
 #include "misc.h"
 
-#define GET_32BIT(cp) \
-    (((unsigned long)(unsigned char)(cp)[0] << 24) | \
-    ((unsigned long)(unsigned char)(cp)[1] << 16) | \
-    ((unsigned long)(unsigned char)(cp)[2] << 8) | \
-    ((unsigned long)(unsigned char)(cp)[3]))
-
-#define PUT_32BIT(cp, value) { \
-    (cp)[0] = (unsigned char)((value) >> 24); \
-    (cp)[1] = (unsigned char)((value) >> 16); \
-    (cp)[2] = (unsigned char)((value) >> 8); \
-    (cp)[3] = (unsigned char)(value); }
-
 static void sha_mpint(SHA_State * s, Bignum b)
 {
     unsigned char lenbuf[4];
@@ -28,7 +20,7 @@ static void sha_mpint(SHA_State * s, Bignum b)
        lenbuf[0] = bignum_byte(b, len);
        SHA_Bytes(s, lenbuf, 1);
     }
-    memset(lenbuf, 0, sizeof(lenbuf));
+    smemclr(lenbuf, sizeof(lenbuf));
 }
 
 static void sha512_mpint(SHA512_State * s, Bignum b)
@@ -42,7 +34,7 @@ static void sha512_mpint(SHA512_State * s, Bignum b)
        lenbuf[0] = bignum_byte(b, len);
        SHA512_Bytes(s, lenbuf, 1);
     }
-    memset(lenbuf, 0, sizeof(lenbuf));
+    smemclr(lenbuf, sizeof(lenbuf));
 }
 
 static void getstring(char **data, int *datalen, char **p, int *length)
@@ -50,7 +42,9 @@ static void getstring(char **data, int *datalen, char **p, int *length)
     *p = NULL;
     if (*datalen < 4)
        return;
-    *length = GET_32BIT(*data);
+    *length = toint(GET_32BIT(*data));
+    if (*length < 0)
+        return;
     *datalen -= 4;
     *data += 4;
     if (*datalen < *length)
@@ -91,7 +85,7 @@ static void *dss_newkey(char *data, int len)
     int slen;
     struct dss_key *dss;
 
-    dss = smalloc(sizeof(struct dss_key));
+    dss = snew(struct dss_key);
     if (!dss)
        return NULL;
     getstring(&data, &len, &p, &slen);
@@ -106,7 +100,7 @@ static void *dss_newkey(char *data, int len)
     }
 #endif
 
-    if (!p || memcmp(p, "ssh-dss", 7)) {
+    if (!p || slen != 7 || memcmp(p, "ssh-dss", 7)) {
        sfree(dss);
        return NULL;
     }
@@ -141,7 +135,7 @@ static char *dss_fmtkey(void *key)
     len += 4 * (bignum_bitcount(dss->q) + 15) / 16;
     len += 4 * (bignum_bitcount(dss->g) + 15) / 16;
     len += 4 * (bignum_bitcount(dss->y) + 15) / 16;
-    p = smalloc(len);
+    p = snewn(len, char);
     if (!p)
        return NULL;
 
@@ -209,7 +203,7 @@ static char *dss_fingerprint(void *key)
     for (i = 0; i < 16; i++)
        sprintf(buffer + strlen(buffer), "%s%02x", i ? ":" : "",
                digest[i]);
-    ret = smalloc(strlen(buffer) + 1);
+    ret = snewn(strlen(buffer) + 1, char);
     if (ret)
        strcpy(ret, buffer);
     return ret;
@@ -239,14 +233,14 @@ static int dss_verifysig(void *key, char *sig, int siglen,
 #endif
     /*
      * Commercial SSH (2.0.13) and OpenSSH disagree over the format
-     * of a DSA signature. OpenSSH is in line with the IETF drafts:
+     * of a DSA signature. OpenSSH is in line with RFC 4253:
      * it uses a string "ssh-dss", followed by a 40-byte string
      * containing two 160-bit integers end-to-end. Commercial SSH
      * can't be bothered with the header bit, and considers a DSA
      * signature blob to be _just_ the 40-byte string containing
      * the two 160-bit integers. We tell them apart by measuring
      * the length: length 40 means the commercial-SSH bug, anything
-     * else is assumed to be IETF-compliant.
+     * else is assumed to be RFC-compliant.
      */
     if (siglen != 40) {                       /* bug not present; read admin fields */
        getstring(&sig, &siglen, &p, &slen);
@@ -295,6 +289,8 @@ static int dss_verifysig(void *key, char *sig, int siglen,
 
     freebn(w);
     freebn(sha);
+    freebn(u1);
+    freebn(u2);
     freebn(gu1p);
     freebn(yu2p);
     freebn(gu1yu2p);
@@ -322,7 +318,7 @@ static unsigned char *dss_public_blob(void *key, int *len)
      * 27 + sum of lengths. (five length fields, 20+7=27).
      */
     bloblen = 27 + plen + qlen + glen + ylen;
-    blob = smalloc(bloblen);
+    blob = snewn(bloblen, unsigned char);
     p = blob;
     PUT_32BIT(p, 7);
     p += 4;
@@ -362,7 +358,7 @@ static unsigned char *dss_private_blob(void *key, int *len)
      * mpint x, string[20] the SHA of p||q||g. Total 4 + xlen.
      */
     bloblen = 4 + xlen;
-    blob = smalloc(bloblen);
+    blob = snewn(bloblen, unsigned char);
     p = blob;
     PUT_32BIT(p, xlen);
     p += 4;
@@ -410,6 +406,7 @@ static void *dss_createkey(unsigned char *pub_blob, int pub_len,
     ytest = modpow(dss->g, dss->x, dss->p);
     if (0 != bignum_cmp(ytest, dss->y)) {
        dss_freekey(dss);
+        freebn(ytest);
        return NULL;
     }
     freebn(ytest);
@@ -422,7 +419,7 @@ static void *dss_openssh_createkey(unsigned char **blob, int *len)
     char **b = (char **) blob;
     struct dss_key *dss;
 
-    dss = smalloc(sizeof(struct dss_key));
+    dss = snew(struct dss_key);
     if (!dss)
        return NULL;
 
@@ -473,7 +470,19 @@ static int dss_openssh_fmtkey(void *key, unsigned char *blob, int len)
     return bloblen;
 }
 
-unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
+static int dss_pubkey_bits(void *blob, int len)
+{
+    struct dss_key *dss;
+    int ret;
+
+    dss = dss_newkey((char *) blob, len);
+    ret = bignum_bitcount(dss->p);
+    dss_freekey(dss);
+
+    return ret;
+}
+
+static unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
 {
     /*
      * The basic DSS signing algorithm is:
@@ -571,7 +580,7 @@ unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
     SHA512_Bytes(&ss, digest, sizeof(digest));
     SHA512_Final(&ss, digest512);
 
-    memset(&ss, 0, sizeof(ss));
+    smemclr(&ss, sizeof(ss));
 
     /*
      * Now convert the result into a bignum, and reduce it mod q.
@@ -580,7 +589,7 @@ unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
     k = bigmod(proto_k, dss->q);
     freebn(proto_k);
 
-    memset(digest512, 0, sizeof(digest512));
+    smemclr(digest512, sizeof(digest512));
 
     /*
      * Now we have k, so just go ahead and compute the signature.
@@ -606,7 +615,7 @@ unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen)
      * i.e. 4+7 + 4+40 bytes.
      */
     nbytes = 4 + 7 + 4 + 40;
-    bytes = smalloc(nbytes);
+    bytes = snewn(nbytes, unsigned char);
     PUT_32BIT(bytes, 7);
     memcpy(bytes + 4, "ssh-dss", 7);
     PUT_32BIT(bytes + 4 + 7, 40);
@@ -630,6 +639,7 @@ const struct ssh_signkey ssh_dss = {
     dss_createkey,
     dss_openssh_createkey,
     dss_openssh_fmtkey,
+    dss_pubkey_bits,
     dss_fingerprint,
     dss_verifysig,
     dss_sign,