[Rework] Rewrite rfc2047 encoding as it was totally broken

diff --git a/src/libmime/mime_headers.c b/src/libmime/mime_headers.c
index e4bf4db0644b0cbcd5b943f68a6aabc38b89c2a3..9d11210f3762b2bf92fcbd5b384a36671a02c8cb 100644 (file)
--- a/src/libmime/mime_headers.c
+++ b/src/libmime/mime_headers.c
@@ -754,7 +754,7 @@ rspamd_mime_header_decode(rspamd_mempool_t *pool, const char *in,
                                                state = parse_normal;
                                        }
                                } /* qmarks >= 3 */
-                       }     /* p == '=' */
+                       } /* p == '=' */
                        else {
                                state = got_encoded_start;
                        }
@@ -818,86 +818,64 @@ rspamd_mime_header_decode(rspamd_mempool_t *pool, const char *in,
 char *
 rspamd_mime_header_encode(const char *in, gsize len)
 {
-       const char *p = in, *end = in + len;
-       char *out, encode_buf[80 * sizeof(uint32_t)];
-       GString *res;
-       gboolean need_encoding = FALSE;
+       static const size_t max_token_size = 76;
+       GString *outbuf = g_string_sized_new(len);
+       size_t encode_buf_size = max_token_size;
+       char *encode_buf = g_alloca(encode_buf_size + 3);
+       const char *p = in;
+       const char *end = in + len;
 
-       /* Check if we need to encode */
        while (p < end) {
-               if ((((unsigned char) *p) & 0x80) != 0) {
-                       need_encoding = TRUE;
-                       break;
+               if (*p == ' ' || *p == '\r' || *p == '\n' || *p == '(' || *p == ')') {
+                       /* Append the separator as is */
+                       g_string_append_c(outbuf, *p);
+                       p++;
                }
-               p++;
-       }
-
-       if (!need_encoding) {
-               out = g_malloc(len + 1);
-               rspamd_strlcpy(out, in, len + 1);
-       }
-       else {
-               /* Need encode */
-               gsize ulen, pos;
-               int r;
-               const char *prev;
-               /* Choose step: =?UTF-8?Q?<qp>?= should be less than 76 chars */
-               unsigned int step = (76 - 12) / 3 + 1;
-
-               ulen = g_utf8_strlen(in, len);
-               res = g_string_sized_new(len * 2 + 1);
-               pos = 0;
-               prev = in;
-               /* Adjust chunk size for unicode average length */
-               step *= 1.0 * ulen / (double) len;
-
-               while (pos < ulen) {
-                       p = g_utf8_offset_to_pointer(in, pos);
-
-                       if (p > prev) {
-                               /* Encode and print */
-                               r = rspamd_encode_qp2047_buf(prev, p - prev,
-                                                                                        encode_buf, sizeof(encode_buf));
-
-                               if (r != -1) {
-                                       if (res->len > 0) {
-                                               rspamd_printf_gstring(res, " =?UTF-8?Q?%*s?=", r,
-                                                                                         encode_buf);
-                                       }
-                                       else {
-                                               rspamd_printf_gstring(res, "=?UTF-8?Q?%*s?=", r,
-                                                                                         encode_buf);
+               else {
+                       size_t remain = end - p;
+                       gsize next_offset = rspamd_memcspn(p, " \r\n()", MIN(max_token_size, remain));
+                       const char *q = p + next_offset;
+                       size_t piece_len = q - p, encoded_len = 0;
+
+                       /* Check if the piece contains non-ASCII characters */
+                       gboolean has_non_ascii = FALSE;
+                       for (size_t i = 0; i < piece_len; i++) {
+                               if ((unsigned char) p[i] >= 128) {
+                                       has_non_ascii = TRUE;
+                                       encoded_len += 3;
+
+                                       if (encoded_len > max_token_size) {
+                                               piece_len = i - 1;
+                                               q = p + piece_len;
+                                               /* No more space */
+                                               break;
                                        }
                                }
-                       }
-
-                       pos += MIN(step, ulen - pos);
-                       prev = p;
-               }
-
-               /* Leftover */
-               if (prev < end) {
-                       r = rspamd_encode_qp2047_buf(prev, end - prev,
-                                                                                encode_buf, sizeof(encode_buf));
-
-                       if (r != -1) {
-                               if (res->len > 0) {
-                                       rspamd_printf_gstring(res, " =?UTF-8?Q?%*s?=", r,
-                                                                                 encode_buf);
-                               }
                                else {
-                                       rspamd_printf_gstring(res, "=?UTF-8?Q?%*s?=", r,
-                                                                                 encode_buf);
+                                       encoded_len++;
                                }
                        }
-               }
 
-               out = g_string_free(res, FALSE);
+                       if (has_non_ascii) {
+                               g_string_append(outbuf, "=?UTF-8?Q?");
+                               /* Do encode */
+                               gssize encoded_len = rspamd_encode_qp2047_buf(p, piece_len, encode_buf, encode_buf_size);
+                               g_string_append_len(outbuf, encode_buf, encoded_len);
+                               g_string_append(outbuf, "?=");
+                       }
+                       else {
+                               /* No transformation */
+                               g_string_append_len(outbuf, p, piece_len);
+                       }
+                       p = q;
+               }
        }
 
-       return out;
+       /* return the allocated string and free the GString struct */
+       return g_string_free(outbuf, FALSE);
 }
 
+
 char *
 rspamd_mime_message_id_generate(const char *fqdn)
 {