X-Git-Url: https://git.notmuchmail.org/git?p=notmuch;a=blobdiff_plain;f=util%2Frepair.c;h=f5cbb14b47f37988108ce12291319eef5a967997;hp=f91c124415516139585b2b48ea00abe5875b7783;hb=5aa60342c86b163848bca6882f34821d4871b849;hpb=1b29822cf55eb53e1d45a71c2a3e4a2c2a4574d1

diff --git a/util/repair.c b/util/repair.c
index f91c1244..f5cbb14b 100644
--- a/util/repair.c
+++ b/util/repair.c
@@ -18,4 +18,195 @@
  * Authors: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
  */
 
+#include <stdbool.h>
 #include "repair.h"
+
+
+static bool
+_notmuch_crypto_payload_has_legacy_display (GMimeObject *payload)
+{
+    GMimeMultipart *mpayload;
+    const char *protected_header_parameter;
+    GMimeTextPart *legacy_display;
+    char *legacy_display_header_text = NULL;
+    GMimeStream *stream = NULL;
+    GMimeParser *parser = NULL;
+    GMimeObject *legacy_header_object = NULL, *first;
+    GMimeHeaderList *legacy_display_headers = NULL, *protected_headers = NULL;
+    bool ret = false;
+
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (payload),
+				       "multipart", "mixed"))
+	return false;
+    protected_header_parameter = g_mime_object_get_content_type_parameter (payload, "protected-headers");
+    if ((! protected_header_parameter) || strcmp (protected_header_parameter, "v1"))
+	return false;
+    if (! GMIME_IS_MULTIPART (payload))
+	return false;
+    mpayload = GMIME_MULTIPART (payload);
+    if (mpayload == NULL)
+	return false;
+    if (g_mime_multipart_get_count (mpayload) != 2)
+	return false;
+    first = g_mime_multipart_get_part (mpayload, 0);
+    /* Early implementations that generated "Legacy Display" parts used
+       Content-Type: text/rfc822-headers, but text/plain is more widely
+       rendered, so it is now the standard choice.  We accept either as a
+       Legacy Display part. */
+    if (! (g_mime_content_type_is_type (g_mime_object_get_content_type (first),
+					"text", "plain") ||
+	   g_mime_content_type_is_type (g_mime_object_get_content_type (first),
+					"text", "rfc822-headers")))
+	return false;
+    protected_header_parameter = g_mime_object_get_content_type_parameter (first, "protected-headers");
+    if ((! protected_header_parameter) || strcmp (protected_header_parameter, "v1"))
+	return false;
+    if (! GMIME_IS_TEXT_PART (first))
+	return false;
+
+    /* ensure that the headers in the first part all match the values
+     * found in the payload's own protected headers!  if they don't,
+     * we should not treat this as a valid "legacy-display" part.
+     *
+     * Crafting a GMimeHeaderList object from the content of the
+     * text/rfc822-headers part is pretty clumsy; we should probably
+     * push something into GMime that makes this a one-shot
+     * operation. */
+    if ((protected_headers = g_mime_object_get_header_list (payload), protected_headers) &&
+	(legacy_display = GMIME_TEXT_PART (first), legacy_display) &&
+	(legacy_display_header_text = g_mime_text_part_get_text (legacy_display), legacy_display_header_text) &&
+	(stream = g_mime_stream_mem_new_with_buffer (legacy_display_header_text, strlen (legacy_display_header_text)), stream) &&
+	(g_mime_stream_write (stream, "\r\n\r\n", 4) == 4) &&
+	(g_mime_stream_seek (stream, 0, GMIME_STREAM_SEEK_SET) == 0) &&
+	(parser = g_mime_parser_new_with_stream (stream), parser) &&
+	(legacy_header_object = g_mime_parser_construct_part (parser, NULL), legacy_header_object) &&
+	(legacy_display_headers = g_mime_object_get_header_list (legacy_header_object), legacy_display_headers)) {
+	/* walk through legacy_display_headers, comparing them against
+	 * their values in the protected_headers: */
+	ret = true;
+	for (int i = 0; i < g_mime_header_list_get_count (legacy_display_headers); i++) {
+	    GMimeHeader *dh = g_mime_header_list_get_header_at (legacy_display_headers, i);
+	    if (dh == NULL) {
+		ret = false;
+		goto DONE;
+	    }
+	    GMimeHeader *ph = g_mime_header_list_get_header (protected_headers, g_mime_header_get_name (dh));
+	    if (ph == NULL) {
+		ret = false;
+		goto DONE;
+	    }
+	    const char *dhv = g_mime_header_get_value (dh);
+	    const char *phv = g_mime_header_get_value (ph);
+	    if (dhv == NULL || phv == NULL || strcmp (dhv, phv)) {
+		ret = false;
+		goto DONE;
+	    }
+	}
+    }
+
+ DONE:
+    if (legacy_display_header_text)
+	g_free (legacy_display_header_text);
+    if (stream)
+	g_object_unref (stream);
+    if (parser)
+	g_object_unref (parser);
+    if (legacy_header_object)
+	g_object_unref (legacy_header_object);
+
+    return ret;
+}
+
+GMimeObject *
+_notmuch_repair_crypto_payload_skip_legacy_display (GMimeObject *payload)
+{
+    if (_notmuch_crypto_payload_has_legacy_display (payload)) {
+	return g_mime_multipart_get_part (GMIME_MULTIPART (payload), 1);
+    } else {
+	return payload;
+    }
+}
+
+/* see
+ * https://tools.ietf.org/html/draft-dkg-openpgp-pgpmime-message-mangling-00#section-4.1.1 */
+static bool
+_notmuch_is_mixed_up_mangled (GMimeObject *part)
+{
+    GMimeMultipart *mpart = NULL;
+    GMimeObject *parts[3] = {NULL, NULL, NULL};
+    GMimeContentType *type = NULL;
+    char *prelude_string = NULL;
+    bool prelude_is_empty;
+
+    if (part == NULL)
+	return false;
+    type = g_mime_object_get_content_type (part);
+    if (type == NULL)
+	return false;
+    if (! g_mime_content_type_is_type (type, "multipart", "mixed"))
+	return false;
+    if (! GMIME_IS_MULTIPART (part)) /* probably impossible */
+	return false;
+    mpart = GMIME_MULTIPART (part);
+    if (mpart == NULL)
+	return false;
+    if (g_mime_multipart_get_count (mpart) != 3)
+	return false;
+    parts[0] = g_mime_multipart_get_part (mpart, 0);
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (parts[0]),
+				       "text", "plain"))
+	return false;
+    if (! GMIME_IS_TEXT_PART (parts[0]))
+	return false;
+    parts[1] = g_mime_multipart_get_part (mpart, 1);
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (parts[1]),
+				       "application", "pgp-encrypted"))
+	return false;
+    parts[2] = g_mime_multipart_get_part (mpart, 2);
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (parts[2]),
+				       "application", "octet-stream"))
+	return false;
+
+    /* Is parts[0] length 0? */
+    prelude_string = g_mime_text_part_get_text (GMIME_TEXT_PART (parts[0]));
+    prelude_is_empty = (prelude_string[0] == '\0');
+    g_free (prelude_string);
+    if (! prelude_is_empty)
+	return false;
+
+    /* FIXME: after decoding and stripping whitespace, is parts[1]
+     * subpart just "Version: 1" ? */
+
+    /* FIXME: can we determine that parts[2] subpart is *only* PGP
+     * encrypted data?  I tried g_mime_part_get_openpgp_data () but
+     * found https://github.com/jstedfast/gmime/issues/60 */
+
+    return true;
+}
+
+
+/* see
+ * https://tools.ietf.org/html/draft-dkg-openpgp-pgpmime-message-mangling-00#section-4.1.2 */
+GMimeObject *
+_notmuch_repair_mixed_up_mangled (GMimeObject *part)
+{
+    GMimeMultipart *mpart = NULL, *mpart_ret = NULL;
+    GMimeObject *ret = NULL;
+
+    if (! _notmuch_is_mixed_up_mangled (part))
+	return NULL;
+    mpart = GMIME_MULTIPART (part);
+    ret = GMIME_OBJECT (g_mime_multipart_encrypted_new ());
+    if (ret == NULL)
+	return NULL;
+    mpart_ret = GMIME_MULTIPART (ret);
+    if (mpart_ret == NULL) {
+	g_object_unref (ret);
+	return NULL;
+    }
+    g_mime_object_set_content_type_parameter (ret, "protocol", "application/pgp-encrypted");
+
+    g_mime_multipart_insert (mpart_ret, 0, g_mime_multipart_get_part (mpart, 1));
+    g_mime_multipart_insert (mpart_ret, 1, g_mime_multipart_get_part (mpart, 2));
+    return ret;
+}