From 17d40a464e7d37a7aa64a731e24c7db5805a9bd8 Mon Sep 17 00:00:00 2001
From: alashkova <n.alashkova@micord.ru>
Date: Fri, 11 Oct 2024 16:15:50 +0300
Subject: [PATCH] =?UTF-8?q?SUPPORT-8592.=20=D0=94=D0=BE=D0=B1=D0=B0=D0=B2?=
 =?UTF-8?q?=D0=BB=D0=B5=D0=BD=D1=8B=20base64=5Fdecoded=5Flength()=20=D0=B8?=
 =?UTF-8?q?=20decode=5Fbase64=5Furl()?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/utils/base64.c | 89 +++++++++++++++++++++++++++++++++++++++++++++-
 src/utils/base64.h |  2 ++
 2 files changed, 90 insertions(+), 1 deletion(-)

diff --git a/src/utils/base64.c b/src/utils/base64.c
index cd4de4f..4c9381e 100644
--- a/src/utils/base64.c
+++ b/src/utils/base64.c
@@ -1,5 +1,7 @@
 #include "base64.h"
 
+#include "logger.h"
+
 #include <assert.h>
 #include <stdint.h>
 
@@ -79,4 +81,89 @@ encode_base64_url(str_t *dst, const str_t *src)
             dst->data[n * 4 + 3] = basis64_url[d];
         }
     }
-}
\ No newline at end of file
+}
+
+static void
+init_decode_base64_url(unsigned char **table)
+{
+    static unsigned char basis64_url[] = {
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x3E, 0xFF, 0xFF,
+    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
+    0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0x3F,
+    0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
+    0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
+    };
+
+    assert(table != NULL);
+
+    *table = basis64_url;
+}
+
+int
+decode_base64_url(str_t *dst, const str_t *src)
+{
+    uint32_t value = 0;
+    unsigned int c;
+    size_t i;
+    size_t n = 0;
+    uint8_t *p = NULL;
+  
+    assert(dst != NULL && !str_t_is_null(*dst));
+    assert(src != NULL && !str_t_is_null(*src));
+  
+    if ((src->len % 4) == 1) {
+        LOG_ERROR("decode_base64_url failed. Desc: invalid src length (%zd)", src->len);
+        goto error;
+    }
+
+    unsigned char *basis64_url;
+    init_decode_base64_url(&basis64_url);
+
+    p = (uint8_t *) dst->data;
+
+    for (i = 0; i < src->len; i++) {
+        c = (unsigned int) src->data[i];
+
+        if (c < 128 && basis64_url[c] < 64) {
+            value = (value << 6) | basis64_url[c];
+
+            if ((i % 4) == 3) {
+                if (p != NULL) {
+                    p[n] = (value >> 16) & 0xFF;
+                    p[n + 1] = (value >> 8) & 0xFF;
+                    p[n + 2] = value & 0xFF;
+                }
+
+                n += 3;
+                value = 0;
+            }
+        } else {
+            LOG_ERROR("decode_base64_url failed. Desc: invalid character: %c", src->data[i]);
+            goto error;
+        }
+    }
+
+    if ((src->len % 4) == 2) {
+        if (p != NULL) {
+            p[n] = (value >> 4) & 0xFF;
+        }
+        n++;
+    } else if ((src->len % 4) == 3) {
+        if (p != NULL) {
+            p[n] = (value >> 10) & 0xFF;
+            p[n + 1] = (value >> 2) & 0xFF;
+        }
+        n += 2;
+    }
+
+    dst->len = n;
+
+    return 0;
+
+error:
+    LOG_ERROR("decode_base64_url exit with error");
+    return -1;
+}
diff --git a/src/utils/base64.h b/src/utils/base64.h
index 55b199d..6ec70e4 100644
--- a/src/utils/base64.h
+++ b/src/utils/base64.h
@@ -4,7 +4,9 @@
 #include "str_t.h"
 
 #define base64_encoded_length(len)  (((len + 2) / 3) * 4)
+#define base64_decoded_length(len)  (((len + 3) / 4) * 3)
 
 void encode_base64_url(str_t *dst, const str_t *src);
+int decode_base64_url(str_t *dst, const str_t *src);
 
 #endif // BASE64_H
\ No newline at end of file