diff options
| -rw-r--r-- | util/repair.c | 101 | ||||
| -rw-r--r-- | util/repair.h | 17 |
2 files changed, 118 insertions, 0 deletions
diff --git a/util/repair.c b/util/repair.c index f91c1244..629e6f23 100644 --- a/util/repair.c +++ b/util/repair.c @@ -18,4 +18,105 @@ * 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); + if (! 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; + } +} diff --git a/util/repair.h b/util/repair.h index 70e2b7bc..9974d693 100644 --- a/util/repair.h +++ b/util/repair.h @@ -11,6 +11,23 @@ extern "C" { * techniques that are designed to improve the user experience of * notmuch */ +/* If payload is a cryptographic payload within an encrypted message, and + * it has a "legacy display" part, then we can skip over it and jump + * to the actual content, because notmuch already handles protected + * headers appropriately. + * + * This function either returns payload directly (if it does not have + * a "legacy display" part), or it returns a pointer to its + * content-bearing subpart, with the "legacy display" part and the + * surrounding multipart/mixed object bypassed. + * + * No new objects are created by calling this function, and the + * returned object will only be released when the original part is + * disposed of. + */ +GMimeObject * +_notmuch_repair_crypto_payload_skip_legacy_display (GMimeObject *payload); + #ifdef __cplusplus } #endif |