From: Vsevolod Stakhov <vsevolod@rspamd.com>
Date: Wed, 20 Mar 2024 17:16:48 +0000 (+0000)
Subject: [Fix] Fix inconsistent nesting in mime parts
X-Git-Tag: 3.9.0~87^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F4882%2Fhead;p=thirdparty%2Frspamd.git

[Fix] Fix inconsistent nesting in mime parts

We should do like MUAs do: imlicitly close incomplete mime parts
and treat them as ususal. It is weird and utterly stupid but that's
what MUA do.

Issue: #4740
Closes: #4740
---

diff --git a/src/libmime/mime_parser.c b/src/libmime/mime_parser.c
index e753f6377c..ac35cffe3b 100644
--- a/src/libmime/mime_parser.c
+++ b/src/libmime/mime_parser.c
@@ -1055,6 +1055,7 @@ rspamd_multipart_boundaries_filter(struct rspamd_task *task,
 	goffset last_offset;
 	unsigned int i, sel = 0;
 	enum rspamd_mime_parse_error ret;
+	bool enforce_closing = false;
 
 	last_offset = (multipart->raw_data.begin - st->start) +
 				  multipart->raw_data.len;
@@ -1099,6 +1100,12 @@ rspamd_multipart_boundaries_filter(struct rspamd_task *task,
 		cur = &g_array_index(st->boundaries, struct rspamd_mime_boundary, i);
 
 		if (cur->boundary > last_offset) {
+			/*
+			 * We have reached the end of the part, so we have to close it implicitly
+			 * like MUA do
+			 */
+			task->flags |= RSPAMD_TASK_FLAG_BROKEN_HEADERS;
+			enforce_closing = true;
 			break;
 		}
 
@@ -1136,7 +1143,7 @@ rspamd_multipart_boundaries_filter(struct rspamd_task *task,
 		}
 	}
 
-	if (i == st->boundaries->len && cb->cur_boundary) {
+	if (enforce_closing || (i == st->boundaries->len && cb->cur_boundary)) {
 		/* Process the last part */
 		struct rspamd_mime_boundary fb;