Merged SSH1 robustness changes from 0.55 release branch on to trunk.

[u/mdw/putty] / sshpubk.c

diff --git a/sshpubk.c b/sshpubk.c
index 3975e0f..13a182a 100644 (file)
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -79,8 +79,8 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     i += 4;
 
     /* Now the serious stuff. An ordinary SSH 1 public key. */
-    i += makekey(buf + i, key, NULL, 1);
-    if (len - i < 0)
+    i += makekey(buf + i, len, key, NULL, 1);
+    if (i < 0)
        goto end;                      /* overran */
 
     if (pub_only) {
@@ -138,18 +138,18 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
      * decryption exponent, and then the three auxiliary values
      * (iqmp, q, p).
      */
-    i += makeprivate(buf + i, key);
-    if (len - i < 0)
-       goto end;
-    i += ssh1_read_bignum(buf + i, &key->iqmp);
-    if (len - i < 0)
-       goto end;
-    i += ssh1_read_bignum(buf + i, &key->q);
-    if (len - i < 0)
-       goto end;
-    i += ssh1_read_bignum(buf + i, &key->p);
-    if (len - i < 0)
-       goto end;
+    j = makeprivate(buf + i, len - i, key);
+    if (j < 0) goto end;
+    i += j;
+    j = ssh1_read_bignum(buf + i, len - i, &key->iqmp);
+    if (j < 0) goto end;
+    i += j;
+    j = ssh1_read_bignum(buf + i, len - i, &key->q);
+    if (j < 0) goto end;
+    i += j;
+    j = ssh1_read_bignum(buf + i, len - i, &key->p);
+    if (j < 0) goto end;
+    i += j;
 
     if (!rsa_verify(key)) {
        *error = "rsa_verify failed";
@@ -182,17 +182,22 @@ int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,
      * key file.
      */
     if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
+       /*
+        * This routine will take care of calling fclose() for us.
+        */
        ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);
+       fp = NULL;
        goto end;
     }
 
     /*
      * Otherwise, we have nothing. Return empty-handed.
      */
-    fclose(fp);
     error = "not an SSH-1 RSA file";
 
   end:
+    if (fp)
+       fclose(fp);
     if ((ret != 1) && errorstr)
        *errorstr = error;
     return ret;
@@ -217,6 +222,9 @@ int rsakey_encrypted(const Filename *filename, char **comment)
      */
     if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
        const char *dummy;
+       /*
+        * This routine will take care of calling fclose() for us.
+        */
        return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);
     }
     fclose(fp);
@@ -258,13 +266,15 @@ int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
            *blob = rsa_public_blob(&key, bloblen);
            freersakey(&key);
            ret = 1;
+           fp = NULL;
        }
     } else {
        error = "not an SSH-1 RSA file";
-        fclose(fp);
     }
 
   end:
+    if (fp)
+       fclose(fp);
     if ((ret != 1) && errorstr)
        *errorstr = error;
     return ret;
@@ -433,8 +443,7 @@ int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)
  *    data    "putty-private-key-file-mac-key"
  *    data    passphrase
  *
- * Encrypted keys should have a MAC, whereas unencrypted ones must
- * have a hash.
+ * (An empty passphrase is used for unencrypted keys.)
  *
  * If the key is encrypted, the encryption key is derived from the
  * passphrase by means of a succession of SHA-1 hashes. Each hash
@@ -606,6 +615,16 @@ struct ssh2_userkey ssh2_wrong_passphrase = {
     NULL, NULL, NULL
 };
 
+const struct ssh_signkey *find_pubkey_alg(const char *name)
+{
+    if (!strcmp(name, "ssh-rsa"))
+       return &ssh_rsa;
+    else if (!strcmp(name, "ssh-dss"))
+       return &ssh_dss;
+    else
+       return NULL;
+}
+
 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
                                       char *passphrase, const char **errorstr)
 {
@@ -647,11 +666,8 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
     if ((b = read_body(fp)) == NULL)
        goto error;
     /* Select key algorithm structure. */
-    if (!strcmp(b, "ssh-rsa"))
-       alg = &ssh_rsa;
-    else if (!strcmp(b, "ssh-dss"))
-       alg = &ssh_dss;
-    else {
+    alg = find_pubkey_alg(b);
+    if (!alg) {
        sfree(b);
        goto error;
     }
@@ -808,6 +824,7 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
            /* An incorrect MAC is an unconditional Error if the key is
             * unencrypted. Otherwise, it means Wrong Passphrase. */
            if (cipher) {
+               error = "wrong passphrase";
                ret = SSH2_WRONG_PASSPHRASE;
            } else {
                error = "MAC failed";
@@ -836,7 +853,8 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
     sfree(public_blob);
     sfree(private_blob);
     sfree(encryption);
-    *errorstr = NULL;
+    if (errorstr)
+       *errorstr = NULL;
     return ret;
 
     /*
@@ -890,11 +908,8 @@ char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
     if ((b = read_body(fp)) == NULL)
        goto error;
     /* Select key algorithm structure. Currently only ssh-rsa. */
-    if (!strcmp(b, "ssh-rsa"))
-       alg = &ssh_rsa;
-    else if (!strcmp(b, "ssh-dss"))
-       alg = &ssh_dss;
-    else {
+    alg = find_pubkey_alg(b);
+    if (!alg) {
        sfree(b);
        goto error;
     }