John Hartnup reports that Apache SSHD's SFTP server responds to

[u/mdw/putty] / import.c

diff --git a/import.c b/import.c
index a3c2405..55e3be2 100644 (file)
--- a/import.c
+++ b/import.c
@@ -308,9 +308,10 @@ static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret)
  */
 
 enum { OSSH_DSA, OSSH_RSA };
+enum { OSSH_ENC_3DES, OSSH_ENC_AES };
 struct openssh_key {
     int type;
-    int encrypted;
+    int encrypted, encryption;
     char iv[32];
     unsigned char *keyblob;
     int keyblob_len, keyblob_size;
@@ -333,7 +334,7 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
     ret->encrypted = 0;
     memset(ret->iv, 0, sizeof(ret->iv));
 
-    fp = f_open(*filename, "r", FALSE);
+    fp = f_open(filename, "r", FALSE);
     if (!fp) {
        errmsg = "unable to open key file";
        goto error;
@@ -387,21 +388,29 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
                if (!strcmp(p, "ENCRYPTED"))
                    ret->encrypted = 1;
            } else if (!strcmp(line, "DEK-Info")) {
-               int i, j;
-
-               if (strncmp(p, "DES-EDE3-CBC,", 13)) {
-                   errmsg = "ciphers other than DES-EDE3-CBC not supported";
+               int i, j, ivlen;
+
+               if (!strncmp(p, "DES-EDE3-CBC,", 13)) {
+                   ret->encryption = OSSH_ENC_3DES;
+                   ivlen = 8;
+               } else if (!strncmp(p, "AES-128-CBC,", 12)) {
+                   ret->encryption = OSSH_ENC_AES;
+                   ivlen = 16;
+               } else {
+                   errmsg = "unsupported cipher";
                    goto error;
                }
-               p += 13;
-               for (i = 0; i < 8; i++) {
-                   if (1 != sscanf(p, "%2x", &j))
-                       break;
+               p = strchr(p, ',') + 1;/* always non-NULL, by above checks */
+               for (i = 0; i < ivlen; i++) {
+                   if (1 != sscanf(p, "%2x", &j)) {
+                       errmsg = "expected more iv data in DEK-Info";
+                       goto error;
+                   }
                    ret->iv[i] = j;
                    p += 2;
                }
-               if (i < 8) {
-                   errmsg = "expected 16-digit iv in DEK-Info";
+               if (*p) {
+                   errmsg = "more iv data than expected in DEK-Info";
                    goto error;
                }
            }
@@ -520,6 +529,10 @@ struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
         *  - let block B equal MD5(A || passphrase || iv)
         *  - block C would be MD5(B || passphrase || iv) and so on
         *  - encryption key is the first N bytes of A || B
+        *
+        * (Note that only 8 bytes of the iv are used for key
+        * derivation, even when the key is encrypted with AES and
+        * hence there are 16 bytes available.)
         */
        struct MD5Context md5c;
        unsigned char keybuf[32];
@@ -538,8 +551,18 @@ struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
        /*
         * Now decrypt the key blob.
         */
-       des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
-                                key->keyblob, key->keyblob_len);
+       if (key->encryption == OSSH_ENC_3DES)
+           des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
+                                    key->keyblob, key->keyblob_len);
+       else {
+           void *ctx;
+           assert(key->encryption == OSSH_ENC_AES);
+           ctx = aes_make_context();
+           aes128_key(ctx, keybuf);
+           aes_iv(ctx, (unsigned char *)key->iv);
+           aes_ssh2_decrypt_blk(ctx, key->keyblob, key->keyblob_len);
+           aes_free_context(ctx);
+       }
 
         memset(&md5c, 0, sizeof(md5c));
         memset(keybuf, 0, sizeof(keybuf));
@@ -853,6 +876,9 @@ int openssh_write(const Filename *filename, struct ssh2_userkey *key,
 
     /*
      * Encrypt the key.
+     *
+     * For the moment, we still encrypt our OpenSSH keys using
+     * old-style 3DES.
      */
     if (passphrase) {
        /*
@@ -893,7 +919,7 @@ int openssh_write(const Filename *filename, struct ssh2_userkey *key,
      * And save it. We'll use Unix line endings just in case it's
      * subsequently transferred in binary mode.
      */
-    fp = f_open(*filename, "wb", TRUE);      /* ensure Unix line endings */
+    fp = f_open(filename, "wb", TRUE);      /* ensure Unix line endings */
     if (!fp)
        goto error;
     fputs(header, fp);
@@ -1027,7 +1053,7 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
     ret->keyblob = NULL;
     ret->keyblob_len = ret->keyblob_size = 0;
 
-    fp = f_open(*filename, "r", FALSE);
+    fp = f_open(filename, "r", FALSE);
     if (!fp) {
        errmsg = "unable to open key file";
        goto error;
@@ -1646,7 +1672,7 @@ int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
      * And save it. We'll use Unix line endings just in case it's
      * subsequently transferred in binary mode.
      */
-    fp = f_open(*filename, "wb", TRUE);      /* ensure Unix line endings */
+    fp = f_open(filename, "wb", TRUE);      /* ensure Unix line endings */
     if (!fp)
        goto error;
     fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp);