MINOR: sample: add ub64dec and ub64enc converters
ub64dec and ub64enc are the base64url equivalent of b64dec and base64
converters. base64url encoding is the "URL and Filename Safe Alphabet"
variant of base64 encoding. It is also used in in JWT (JSON Web Token)
standard.
RFC1421 mention in base64.c file is deprecated so it was replaced with
RFC4648 to which existing converters, base64/b64dec, still apply.
Example:
HAProxy:
http-request return content-type text/plain lf-string %[req.hdr(Authorization),word(2,.),ub64dec]
Client:
Token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjoiZm9vIiwia2V5IjoiY2hhZTZBaFhhaTZlIn0.5VsVj7mdxVvo1wP5c0dVHnr-S_khnIdFkThqvwukmdg
$ curl -H "Authorization: Bearer ${TOKEN}" http://haproxy.local
{"user":"foo","key":"chae6AhXai6e"}
diff --git a/src/base64.c b/src/base64.c
index 53e4d65..5c4ab3a 100644
--- a/src/base64.c
+++ b/src/base64.c
@@ -19,11 +19,14 @@
#define B64BASE '#' /* arbitrary chosen base value */
#define B64CMIN '+'
+#define UB64CMIN '-'
#define B64CMAX 'z'
#define B64PADV 64 /* Base64 chosen special pad value */
const char base64tab[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const char base64rev[]="b###cXYZ[\\]^_`a###d###$%&'()*+,-./0123456789:;<=######>?@ABCDEFGHIJKLMNOPQRSTUVW";
+const char ubase64tab[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+const char ubase64rev[]="b##XYZ[\\]^_`a###c###$%&'()*+,-./0123456789:;<=####c#>?@ABCDEFGHIJKLMNOPQRSTUVW";
/* Encodes <ilen> bytes from <in> to <out> for at most <olen> chars (including
* the trailing zero). Returns the number of bytes written. No check is made
@@ -68,6 +71,48 @@
return convlen;
}
+/* url variant of a2base64 */
+int a2base64url(const char *in, size_t ilen, char *out, size_t olen)
+{
+ int convlen;
+
+ convlen = ((ilen + 2) / 3) * 4;
+
+ if (convlen >= olen)
+ return -1;
+
+ /* we don't need to check olen anymore */
+ while (ilen >= 3) {
+ out[0] = ubase64tab[(((unsigned char)in[0]) >> 2)];
+ out[1] = ubase64tab[(((unsigned char)in[0] & 0x03) << 4) | (((unsigned char)in[1]) >> 4)];
+ out[2] = ubase64tab[(((unsigned char)in[1] & 0x0F) << 2) | (((unsigned char)in[2]) >> 6)];
+ out[3] = ubase64tab[(((unsigned char)in[2] & 0x3F))];
+ out += 4;
+ in += 3;
+ ilen -= 3;
+ }
+
+ if (!ilen) {
+ out[0] = '\0';
+ return convlen;
+ }
+
+ out[0] = ubase64tab[((unsigned char)in[0]) >> 2];
+ if (ilen == 1) {
+ out[1] = ubase64tab[((unsigned char)in[0] & 0x03) << 4];
+ out[2] = '\0';
+ convlen -= 2;
+ } else {
+ out[1] = ubase64tab[(((unsigned char)in[0] & 0x03) << 4) |
+ (((unsigned char)in[1]) >> 4)];
+ out[2] = ubase64tab[((unsigned char)in[1] & 0x0F) << 2];
+ out[3] = '\0';
+ convlen -= 1;
+ }
+
+ return convlen;
+}
+
/* Decodes <ilen> bytes from <in> to <out> for at most <olen> chars.
* Returns the number of bytes converted. No check is made for
* <in> or <out> to be NULL. Returns -1 if <in> is invalid or ilen
@@ -138,6 +183,72 @@
return convlen;
}
+/* url variant of base64dec */
+/* The reverse tab used to decode base64 is generated via /dev/base64/base64rev-gen.c */
+int base64urldec(const char *in, size_t ilen, char *out, size_t olen)
+{
+ unsigned char t[4];
+ signed char b;
+ int convlen = 0, i = 0, pad = 0, padlen = 0;
+
+ if (olen < ((ilen / 4 * 3)))
+ return -2;
+
+ switch (ilen % 4) {
+ case 0:
+ break;
+ case 2:
+ padlen = pad = 2;
+ break;
+ case 3:
+ padlen = pad = 1;
+ break;
+ default:
+ return -1;
+ }
+
+ while (ilen + pad) {
+ if (ilen) {
+ /* if (*p < UB64CMIN || *p > B64CMAX) */
+ b = (signed char) * in - UB64CMIN;
+ if ((unsigned char)b > (B64CMAX - UB64CMIN))
+ return -1;
+
+ b = ubase64rev[b] - B64BASE - 1;
+ /* b == -1: invalid character */
+ if (b < 0)
+ return -1;
+
+ in++;
+ ilen--;
+
+ } else {
+ b = B64PADV;
+ pad--;
+ }
+
+ t[i++] = b;
+
+ if (i == 4) {
+ /*
+ * WARNING: we allow to write little more data than we
+ * should, but the checks from the beginning of the
+ * functions guarantee that we can safely do that.
+ */
+
+ /* xx000000 xx001111 xx111122 xx222222 */
+ out[convlen] = ((t[0] << 2) + (t[1] >> 4));
+ out[convlen + 1] = ((t[1] << 4) + (t[2] >> 2));
+ out[convlen + 2] = ((t[2] << 6) + (t[3] >> 0));
+
+ convlen += 3;
+ i = 0;
+ }
+ }
+ convlen -= padlen;
+
+ return convlen;
+}
/* Converts the lower 30 bits of an integer to a 5-char base64 string. The
* caller is responsible for ensuring that the output buffer can accept 6 bytes