[Feature] Support archive files list extraction

1 files changed, 174 insertions, 0 deletions

diff --git a/src/libmime/archives.c b/src/libmime/archives.c
new file mode 100644
index 000000000..2de9d7176
--- /dev/null
+++ b/src/libmime/archives.c
@@ -0,0 +1,174 @@
+/*-
+ * Copyright 2016 Vsevolod Stakhov
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "config.h"
+#include "message.h"
+#include "task.h"
+#include "archives.h"
+
+static void
+rspamd_archive_dtor (gpointer p)
+{
+	struct rspamd_archive *arch = p;
+	GString *s;
+	guint i;
+
+	for (i = 0; i < arch->files->len; i ++) {
+		s = g_ptr_array_index (arch->files, i);
+
+		g_string_free (s, TRUE);
+	}
+
+	g_ptr_array_free (arch->files, TRUE);
+}
+
+static void
+rspamd_archive_process_zip (struct rspamd_task *task,
+		struct rspamd_mime_part *part)
+{
+	const guchar *p, *start, *end, *eocd = NULL, *cd;
+	const guint32 eocd_magic = 0x06054b50, cd_basic_len = 46;
+	const guchar cd_magic[] = {0x50, 0x4b, 0x01, 0x02};
+	guint32 cd_offset, cd_size;
+	guint16 extra_len, fname_len, comment_len;
+	struct rspamd_archive *arch;
+	GString *fname;
+
+	/* Zip files have interesting data at the end of archive */
+	p = part->content->data + part->content->len - 1;
+	start = part->content->data;
+	end = p;
+
+	/* Search for EOCD:
+	 * 22 bytes is a typical size of eocd without a comment and
+	 * end points one byte after the last character
+	 */
+	p -= 21;
+
+	while (p > start + sizeof (guint32)) {
+		guint32 t;
+
+		/* XXX: not an efficient approach */
+		memcpy (&t, p, sizeof (t));
+
+		if (GUINT32_FROM_LE (t) == eocd_magic) {
+			eocd = p;
+			break;
+		}
+
+		p --;
+	}
+
+
+	if (eocd == NULL) {
+		/* Not a zip file */
+		msg_debug_task ("zip archive is invalid (no EOCD): %s", part->boundary);
+
+		return;
+	}
+
+	if (end - eocd < 21) {
+		msg_debug_task ("zip archive is invalid (short EOCD): %s", part->boundary);
+
+		return;
+	}
+
+
+	memcpy (&cd_size, eocd + 12, sizeof (cd_size));
+	cd_size = GUINT32_FROM_LE (cd_size);
+	memcpy (&cd_offset, eocd + 16, sizeof (cd_offset));
+	cd_offset = GUINT32_FROM_LE (cd_offset);
+
+	/* We need to check sanity as well */
+	if (cd_offset + cd_size != (guint)(eocd - start)) {
+		msg_debug_task ("zip archive is invalid (bad size/offset for CD): %s",
+				part->boundary);
+
+		return;
+	}
+
+	cd = start + cd_offset;
+
+	arch = rspamd_mempool_alloc0 (task->task_pool, sizeof (*arch));
+	arch->files = g_ptr_array_new ();
+	arch->type = RSPAMD_ARCHIVE_ZIP;
+	rspamd_mempool_add_destructor (task->task_pool, rspamd_archive_dtor,
+			arch);
+
+	while (cd < eocd) {
+		/* Read central directory record */
+		if (eocd - cd < cd_basic_len ||
+				memcmp (cd, cd_magic, sizeof (cd_magic)) != 0) {
+			msg_debug_task ("zip archive is invalid (bad cd record): %s",
+					part->boundary);
+
+			return;
+		}
+
+		memcpy (&fname_len, cd + 28, sizeof (fname_len));
+		fname_len = GUINT16_FROM_LE (fname_len);
+		memcpy (&extra_len, cd + 30, sizeof (extra_len));
+		extra_len = GUINT16_FROM_LE (extra_len);
+		memcpy (&comment_len, cd + 32, sizeof (comment_len));
+		comment_len = GUINT16_FROM_LE (comment_len);
+
+		if (cd + fname_len + comment_len + extra_len + cd_basic_len > eocd) {
+			msg_debug_task ("zip archive is invalid (too large cd record): %s",
+					part->boundary);
+
+			return;
+		}
+
+		fname = g_string_new_len (cd + cd_basic_len, fname_len);
+		g_ptr_array_add (arch->files, fname);
+		msg_debug_task ("found file in zip archive: %v", fname);
+
+		cd += fname_len + comment_len + extra_len + cd_basic_len;
+	}
+
+	part->flags |= RSPAMD_MIME_PART_ARCHIVE;
+	part->specific_data = arch;
+}
+
+void
+rspamd_archives_process (struct rspamd_task *task)
+{
+	guint i;
+	struct rspamd_mime_part *part;
+
+	for (i = 0; i < task->parts->len; i ++) {
+		part = g_ptr_array_index (task->parts, i);
+		if (g_mime_content_type_is_type (part->type, "application", "zip") &&
+				part->content->len > 0) {
+			rspamd_archive_process_zip (task, part);
+		}
+	}
+}
+
+
+const gchar *
+rspamd_archive_type_str (enum rspamd_archive_type type)
+{
+	const gchar *ret = "unknown";
+
+	switch (type) {
+	case RSPAMD_ARCHIVE_ZIP:
+		ret = "zip";
+		break;
+	}
+
+	return ret;
+}