From 5bfcf8157597f2d327050114fb37ff600004dbcf Mon Sep 17 00:00:00 2001
From: Milan Crha <mcrha@redhat.com>
Date: Tue, 15 Apr 2025 09:03:00 +0200
Subject: [PATCH] multipart: Fix read out of buffer bounds under
 soup_multipart_new_from_message()

This is CVE-2025-32914, special crafted input can cause read out of buffer bounds
of the body argument.

Closes #436

Conflict: Context Adaptation and Test Case Adaptation
Reference: https://gitlab.gnome.org/GNOME/libsoup/-/commit/5bfcf8157597f2d327050114fb37ff600004dbcf

---
 libsoup/soup-multipart.c |  2 +-
 tests/multipart-test.c   | 62 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/libsoup/soup-multipart.c b/libsoup/soup-multipart.c
index a7e550f..dd93973 100644
--- a/libsoup/soup-multipart.c
+++ b/libsoup/soup-multipart.c
@@ -181,7 +181,7 @@ soup_multipart_new_from_message (SoupMessageHeaders *headers,
 			return NULL;
 		}
 
-		split = strstr (start, "\r\n\r\n");
+		split = g_strstr_len (start, body_end - start, "\r\n\r\n");
 		if (!split || split > end) {
 			soup_multipart_free (multipart);
 			soup_buffer_free (flattened);
diff --git a/tests/multipart-test.c b/tests/multipart-test.c
index 64a5ebf..79c2190 100644
--- a/tests/multipart-test.c
+++ b/tests/multipart-test.c
@@ -479,6 +479,66 @@ test_multipart (gconstpointer data)
 	g_main_loop_unref (loop);
 }
 
+static void
+test_multipart_bounds_good (void)
+{
+	#define TEXT "line1\r\nline2"
+	SoupMultipart *multipart;
+	SoupMessageHeaders *headers, *set_headers = NULL;
+	SoupBuffer *set_bytes = NULL;
+	const char *raw_data = "--123\r\nContent-Type: text/plain;\r\n\r\n" TEXT "\r\n--123--\r\n";
+	gboolean success;
+
+	headers = soup_message_headers_new (SOUP_MESSAGE_HEADERS_MULTIPART);
+	soup_message_headers_append (headers, "Content-Type", "multipart/mixed; boundary=\"123\"");
+
+
+	SoupMessageBody *message_body = soup_message_body_new ();
+	SoupBuffer *part_body = soup_buffer_new (SOUP_MEMORY_COPY, raw_data, strlen(raw_data));
+	soup_message_body_append_buffer (message_body, part_body);
+	multipart = soup_multipart_new_from_message (headers, message_body);
+
+	g_assert_nonnull (multipart);
+	g_assert_cmpint (soup_multipart_get_length (multipart), ==, 1);
+	success = soup_multipart_get_part (multipart, 0, &set_headers, &set_bytes);
+	g_assert_true (success);
+	g_assert_nonnull (set_headers);
+	g_assert_nonnull (set_bytes);
+	g_assert_cmpint (strlen (TEXT), ==, set_bytes->length);
+	g_assert_cmpstr ("text/plain", ==, soup_message_headers_get_content_type (set_headers, NULL));
+	g_assert_cmpmem (TEXT, strlen (TEXT), set_bytes->data, set_bytes->length);
+
+	soup_message_headers_free (headers);
+	soup_message_body_free (message_body);
+	soup_buffer_free (part_body);
+	soup_multipart_free (multipart);
+
+	#undef TEXT
+}
+
+static void
+test_multipart_bounds_bad (void)
+{
+	SoupMultipart *multipart;
+	SoupMessageHeaders *headers;
+	const char *raw_data = "--123\r\nContent-Type: text/plain;\r\nline1\r\nline2\r\n--123--\r\n";
+
+	headers = soup_message_headers_new (SOUP_MESSAGE_HEADERS_MULTIPART);
+	soup_message_headers_append (headers, "Content-Type", "multipart/mixed; boundary=\"123\"");
+
+	SoupMessageBody *message_body = soup_message_body_new ();
+	SoupBuffer *part_body = soup_buffer_new (SOUP_MEMORY_COPY, raw_data, strlen(raw_data));
+	soup_message_body_append_buffer (message_body, part_body);
+	/* it did read out of raw_data/bytes bounds */
+	multipart = soup_multipart_new_from_message (headers, message_body);
+
+	g_assert_null (multipart);
+
+	soup_message_headers_free (headers);
+	soup_message_body_free (message_body);
+	soup_buffer_free (part_body);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -508,6 +568,8 @@ main (int argc, char **argv)
 	g_test_add_data_func ("/multipart/sync", GINT_TO_POINTER (SYNC_MULTIPART), test_multipart);
 	g_test_add_data_func ("/multipart/async", GINT_TO_POINTER (ASYNC_MULTIPART), test_multipart);
 	g_test_add_data_func ("/multipart/async-small-reads", GINT_TO_POINTER (ASYNC_MULTIPART_SMALL_READS), test_multipart);
+	g_test_add_func ("/multipart/bounds-good", test_multipart_bounds_good);
+	g_test_add_func ("/multipart/bounds-bad", test_multipart_bounds_bad);
 
 	ret = g_test_run ();
 
-- 
2.33.0