upstream: support for RFC4648 base64url encoding; ok markus

OpenBSD-Commit-ID: 0ef22c55e772dda05c112c88412c0797fec66eb4

1 files changed, 44 insertions, 1 deletions

diff --git a/sshbuf-misc.c b/sshbuf-misc.c
index 86e5fa34f..afaab8d61 100644
--- a/sshbuf-misc.c
+++ b/sshbuf-misc.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: sshbuf-misc.c,v 1.15 2020/06/05 03:24:36 djm Exp $    */
+/*      $OpenBSD: sshbuf-misc.c,v 1.16 2020/06/22 05:54:10 djm Exp $    */
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -167,6 +167,49 @@ sshbuf_b64tod(struct sshbuf *buf, const char *b64)
         return 0;
 }
 
+int
+sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap)
+{
+        int r = SSH_ERR_INTERNAL_ERROR;
+        u_char *p;
+        struct sshbuf *b = NULL;
+        size_t i, l;
+
+        if ((b = sshbuf_new()) == NULL)
+                return SSH_ERR_ALLOC_FAIL;
+        /* Encode using regular base64; we'll transform it once done */
+        if ((r = sshbuf_dtob64(d, b, wrap)) != 0)
+                goto out;
+        /* remove padding from end of encoded string*/
+        for (;;) {
+                l = sshbuf_len(b);
+                if (l <= 1 || sshbuf_ptr(b) == NULL) {
+                        r = SSH_ERR_INTERNAL_ERROR;
+                        goto out;
+                }
+                if (sshbuf_ptr(b)[l - 1] != '=')
+                        break;
+                if ((r = sshbuf_consume_end(b, 1)) != 0)
+                        goto out;
+        }
+        /* Replace characters with rfc4648 equivalents */
+        l = sshbuf_len(b);
+        if ((p = sshbuf_mutable_ptr(b)) == NULL) {
+                r = SSH_ERR_INTERNAL_ERROR;
+                goto out;
+        }
+        for (i = 0; i < l; i++) {
+                if (p[i] == '+')
+                        p[i] = '-';
+                else if (p[i] == '/')
+                        p[i] = '_';
+        }
+        r = sshbuf_putb(b64, b);
+ out:
+        sshbuf_free(b);
+        return r;
+}
+
 char *
 sshbuf_dup_string(struct sshbuf *buf)
 {