Fix a couple of code paths on which, if fxp_readdir returned an error,

[sgt/putty] / import.c

diff --git a/import.c b/import.c
index 2ba2f9a..ce957bc 100644 (file)
--- a/import.c
+++ b/import.c
@@ -290,7 +290,7 @@ static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret)
     if (len < 4)
         goto error;
     bytes = GET_32BIT(d);
-    if (len < 4+bytes)
+    if (bytes < 0 || len-4 < bytes)
         goto error;
 
     ret->start = d + 4;
@@ -592,12 +592,13 @@ struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
     
     p = key->keyblob;
 
-    /* Expect the SEQUENCE header. Take its absence as a failure to decrypt. */
+    /* Expect the SEQUENCE header. Take its absence as a failure to
+     * decrypt, if the key was encrypted. */
     ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags);
     p += ret;
     if (ret < 0 || id != 16) {
        errmsg = "ASN.1 decoding failure";
-       retval = SSH2_WRONG_PASSPHRASE;
+        retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
        goto error;
     }
 
@@ -629,7 +630,7 @@ struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
        if (ret < 0 || id != 2 ||
            key->keyblob+key->keyblob_len-p < len) {
            errmsg = "ASN.1 decoding failure";
-           retval = SSH2_WRONG_PASSPHRASE;
+           retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
            goto error;
        }