Mercurial > dropbear

diff libtomcrypt/src/misc/base64/base64_decode.c @ 1712:d885a77b98e0

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avoid zero length array in base64_decode
author Matt Johnston <matt@ucc.asn.au>
date Wed, 10 Jun 2020 23:26:05 +0800
parents 6dba84798cd5
children
line wrap: on
line diff
--- a/libtomcrypt/src/misc/base64/base64_decode.c	Wed Jun 10 23:16:13 2020 +0800
+++ b/libtomcrypt/src/misc/base64/base64_decode.c	Wed Jun 10 23:26:05 2020 +0800
@@ -43,8 +43,8 @@
 255, 255, 255, 255 };
 #endif /* LTC_BASE64 */
 
+#if defined(LTC_BASE64_URL)
 static const unsigned char map_base64url[] = {
-#if defined(LTC_BASE64_URL)
 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
@@ -67,8 +67,8 @@
 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
 255, 255, 255, 255
+};
 #endif /* LTC_BASE64_URL */
-};
 
 enum {
    relaxed = 0,
@@ -117,8 +117,14 @@
    }
 
    if (y != 0) {
+      int allow_b64url = 0;
+#ifdef LTC_BASE64_URL
+      if (map == map_base64url) {
+        allow_b64url = 1;
+      }
+#endif
       if (y == 1) return CRYPT_INVALID_PACKET;
-      if ((y + g) != 4 && is_strict && map != map_base64url) return CRYPT_INVALID_PACKET;
+      if ((y + g) != 4 && is_strict && !allow_b64url) return CRYPT_INVALID_PACKET;
       t = t << (6 * (4 - y));
       if (z + y - 1 > *outlen) return CRYPT_BUFFER_OVERFLOW;
       if (y >= 2) out[z++] = (unsigned char) ((t >> 16) & 255);