commit 2f3820f: [Fix] Workaround for empty charset in rfc2231 encoding

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2019-07-26 12:49:37 +0100
URL: https://github.com/rspamd/rspamd/commit/2f3820f87e08b2a5ce1c67b59f1d5ef7ea22c99f (HEAD -> master)

[Fix] Workaround for empty charset in rfc2231 encoding

---
 src/libmime/content_type.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/libmime/content_type.c b/src/libmime/content_type.c
index 11fa8cd65..ea48c0373 100644
--- a/src/libmime/content_type.c
+++ b/src/libmime/content_type.c
@@ -48,12 +48,8 @@ rspamd_rfc2231_decode (rspamd_mempool_t *pool,
 		ctok.begin = value_start;
 		ctok.len = quote_pos - value_start;
 
-		charset = rspamd_mime_detect_charset (&ctok, pool);
-
-		if (charset == NULL) {
-			msg_warn_pool ("cannot convert parameter from charset %T", &ctok);
-
-			return FALSE;
+		if (ctok.len > 0) {
+			charset = rspamd_mime_detect_charset (&ctok, pool);
 		}
 
 		/* Now, we can check for either next quote sign or, eh, ignore that */
@@ -71,6 +67,17 @@ rspamd_rfc2231_decode (rspamd_mempool_t *pool,
 				value_end - value_start);
 		GError *err = NULL;
 
+		if (charset == NULL) {
+			/* Try heuristic */
+			charset = rspamd_mime_charset_find_by_content (value_start, r);
+		}
+
+		if (charset == NULL) {
+			msg_warn_pool ("cannot convert parameter from charset %T", &ctok);
+
+			return FALSE;
+		}
+
 		param->value.begin = rspamd_mime_text_to_utf8 (pool,
 				value_start, r,
 				charset, &param->value.len, &err);