From bb189220a323e3140198161234ed54bf98175469 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Sat, 24 Dec 2011 13:52:44 -0500 Subject: [PATCH] Introduce a generic tree-like abstraction for MIME traversal. This wraps all of the complex MIME part handling in a single, simple function that gets part N from *any* MIME object, so traversing a MIME part tree becomes a two-line for loop. Furthermore, the MIME node structure provides easy access to envelopes for message parts as well as cryptographic information. This code is directly derived from the current show_message_body code (much of it is identical), but the control relation is inverted: instead of show_message_body controlling the traversal of the MIME structure and invoking callbacks, the caller controls the traversal of the MIME structure. --- Makefile.local | 1 + mime-node.c | 238 +++++++++++++++++++++++++++++++++++++++++++++++ notmuch-client.h | 83 +++++++++++++++++ 3 files changed, 322 insertions(+) create mode 100644 mime-node.c diff --git a/Makefile.local b/Makefile.local index 97f397ff..516f26e8 100644 --- a/Makefile.local +++ b/Makefile.local @@ -315,6 +315,7 @@ notmuch_client_srcs = \ notmuch-time.c \ query-string.c \ show-message.c \ + mime-node.c \ json.c notmuch_client_modules = $(notmuch_client_srcs:.c=.o) diff --git a/mime-node.c b/mime-node.c new file mode 100644 index 00000000..760c55f6 --- /dev/null +++ b/mime-node.c @@ -0,0 +1,238 @@ +/* notmuch - Not much of an email program, (just index and search) + * + * Copyright © 2009 Carl Worth + * Copyright © 2009 Keith Packard + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see http://www.gnu.org/licenses/ . + * + * Authors: Carl Worth + * Keith Packard + * Austin Clements + */ + +#include "notmuch-client.h" + +/* Context that gets inherited from the root node. */ +typedef struct mime_node_context { + /* Per-message resources. These are allocated internally and must + * be destroyed. */ + FILE *file; + GMimeStream *stream; + GMimeParser *parser; + GMimeMessage *mime_message; + + /* Context provided by the caller. */ + GMimeCipherContext *cryptoctx; + notmuch_bool_t decrypt; +} mime_node_context_t; + +static int +_mime_node_context_free (mime_node_context_t *res) +{ + if (res->mime_message) + g_object_unref (res->mime_message); + + if (res->parser) + g_object_unref (res->parser); + + if (res->stream) + g_object_unref (res->stream); + + if (res->file) + fclose (res->file); + + return 0; +} + +notmuch_status_t +mime_node_open (const void *ctx, notmuch_message_t *message, + GMimeCipherContext *cryptoctx, notmuch_bool_t decrypt, + mime_node_t **root_out) +{ + const char *filename = notmuch_message_get_filename (message); + mime_node_context_t *mctx; + mime_node_t *root; + notmuch_status_t status; + + root = talloc_zero (ctx, mime_node_t); + if (root == NULL) { + fprintf (stderr, "Out of memory.\n"); + status = NOTMUCH_STATUS_OUT_OF_MEMORY; + goto DONE; + } + + /* Create the tree-wide context */ + mctx = talloc_zero (root, mime_node_context_t); + if (mctx == NULL) { + fprintf (stderr, "Out of memory.\n"); + status = NOTMUCH_STATUS_OUT_OF_MEMORY; + goto DONE; + } + talloc_set_destructor (mctx, _mime_node_context_free); + + mctx->file = fopen (filename, "r"); + if (! mctx->file) { + fprintf (stderr, "Error opening %s: %s\n", filename, strerror (errno)); + status = NOTMUCH_STATUS_FILE_ERROR; + goto DONE; + } + + mctx->stream = g_mime_stream_file_new (mctx->file); + g_mime_stream_file_set_owner (GMIME_STREAM_FILE (mctx->stream), FALSE); + + mctx->parser = g_mime_parser_new_with_stream (mctx->stream); + + mctx->mime_message = g_mime_parser_construct_message (mctx->parser); + + mctx->cryptoctx = cryptoctx; + mctx->decrypt = decrypt; + + /* Create the root node */ + root->part = GMIME_OBJECT (mctx->mime_message); + root->envelope_file = message; + root->nchildren = 1; + root->ctx = mctx; + + *root_out = root; + return NOTMUCH_STATUS_SUCCESS; + +DONE: + talloc_free (root); + return status; +} + +static int +_signature_validity_free (GMimeSignatureValidity **proxy) +{ + g_mime_signature_validity_free (*proxy); + return 0; +} + +static mime_node_t * +_mime_node_create (const mime_node_t *parent, GMimeObject *part) +{ + mime_node_t *node = talloc_zero (parent, mime_node_t); + GError *err = NULL; + + /* Set basic node properties */ + node->part = part; + node->ctx = parent->ctx; + if (!talloc_reference (node, node->ctx)) { + fprintf (stderr, "Out of memory.\n"); + talloc_free (node); + return NULL; + } + + /* Deal with the different types of parts */ + if (GMIME_IS_PART (part)) { + node->nchildren = 0; + } else if (GMIME_IS_MULTIPART (part)) { + node->nchildren = g_mime_multipart_get_count (GMIME_MULTIPART (part)); + } else if (GMIME_IS_MESSAGE_PART (part)) { + /* Promote part to an envelope and open it */ + GMimeMessagePart *message_part = GMIME_MESSAGE_PART (part); + GMimeMessage *message = g_mime_message_part_get_message (message_part); + node->envelope_part = message_part; + node->part = GMIME_OBJECT (message); + node->nchildren = 1; + } else { + fprintf (stderr, "Warning: Unknown mime part type: %s.\n", + g_type_name (G_OBJECT_TYPE (part))); + talloc_free (node); + return NULL; + } + + /* Handle PGP/MIME parts */ + if (GMIME_IS_MULTIPART_ENCRYPTED (part) + && node->ctx->cryptoctx && node->ctx->decrypt) { + if (node->nchildren != 2) { + /* this violates RFC 3156 section 4, so we won't bother with it. */ + fprintf (stderr, "Error: %d part(s) for a multipart/encrypted " + "message (must be exactly 2)\n", + node->nchildren); + } else { + GMimeMultipartEncrypted *encrypteddata = + GMIME_MULTIPART_ENCRYPTED (part); + node->decrypt_attempted = TRUE; + node->decrypted_child = g_mime_multipart_encrypted_decrypt + (encrypteddata, node->ctx->cryptoctx, &err); + if (node->decrypted_child) { + node->decrypt_success = node->verify_attempted = TRUE; + node->sig_validity = g_mime_multipart_encrypted_get_signature_validity (encrypteddata); + } else { + fprintf (stderr, "Failed to decrypt part: %s\n", + (err ? err->message : "no error explanation given")); + } + } + } else if (GMIME_IS_MULTIPART_SIGNED (part) && node->ctx->cryptoctx) { + if (node->nchildren != 2) { + /* this violates RFC 3156 section 5, so we won't bother with it. */ + fprintf (stderr, "Error: %d part(s) for a multipart/signed message " + "(must be exactly 2)\n", + node->nchildren); + } else { + /* For some reason the GMimeSignatureValidity returned + * here is not a const (inconsistent with that + * returned by + * g_mime_multipart_encrypted_get_signature_validity, + * and therefore needs to be properly disposed of. + * + * In GMime 2.6, they're both non-const, so we'll be able + * to clean up this asymmetry. */ + GMimeSignatureValidity *sig_validity = g_mime_multipart_signed_verify + (GMIME_MULTIPART_SIGNED (part), node->ctx->cryptoctx, &err); + node->verify_attempted = TRUE; + node->sig_validity = sig_validity; + if (sig_validity) { + GMimeSignatureValidity **proxy = + talloc (node, GMimeSignatureValidity *); + *proxy = sig_validity; + talloc_set_destructor (proxy, _signature_validity_free); + } + } + } + + if (node->verify_attempted && !node->sig_validity) + fprintf (stderr, "Failed to verify signed part: %s\n", + (err ? err->message : "no error explanation given")); + + if (err) + g_error_free (err); + + return node; +} + +mime_node_t * +mime_node_child (const mime_node_t *parent, int child) +{ + GMimeObject *sub; + + if (!parent || child < 0 || child >= parent->nchildren) + return NULL; + + if (GMIME_IS_MULTIPART (parent->part)) { + if (child == 1 && parent->decrypted_child) + sub = parent->decrypted_child; + else + sub = g_mime_multipart_get_part + (GMIME_MULTIPART (parent->part), child); + } else if (GMIME_IS_MESSAGE (parent->part)) { + sub = g_mime_message_get_mime_part (GMIME_MESSAGE (parent->part)); + } else { + /* This should have been caught by message_part_create */ + INTERNAL_ERROR ("Unexpected GMimeObject type: %s", + g_type_name (G_OBJECT_TYPE (parent->part))); + } + return _mime_node_create (parent, sub); +} diff --git a/notmuch-client.h b/notmuch-client.h index c521efa0..64b255c7 100644 --- a/notmuch-client.h +++ b/notmuch-client.h @@ -241,5 +241,88 @@ notmuch_run_hook (const char *db_path, const char *hook); notmuch_bool_t debugger_is_active (void); +/* mime-node.c */ + +/* mime_node_t represents a single node in a MIME tree. A MIME tree + * abstracts the different ways of traversing different types of MIME + * parts, allowing a MIME message to be viewed as a generic tree of + * parts. Message-type parts have one child, multipart-type parts + * have multiple children, and leaf parts have zero children. + */ +typedef struct mime_node { + /* The MIME object of this part. This will be a GMimeMessage, + * GMimePart, GMimeMultipart, or a subclass of one of these. + * + * This will never be a GMimeMessagePart because GMimeMessagePart + * is structurally redundant with GMimeMessage. If this part is a + * message (that is, 'part' is a GMimeMessage), then either + * envelope_file will be set to a notmuch_message_t (for top-level + * messages) or envelope_part will be set to a GMimeMessagePart + * (for embedded message parts). + */ + GMimeObject *part; + + /* If part is a GMimeMessage, these record the envelope of the + * message: either a notmuch_message_t representing a top-level + * message, or a GMimeMessagePart representing a MIME part + * containing a message. + */ + notmuch_message_t *envelope_file; + GMimeMessagePart *envelope_part; + + /* The number of children of this part. */ + int nchildren; + + /* True if decryption of this part was attempted. */ + notmuch_bool_t decrypt_attempted; + /* True if decryption of this part's child succeeded. In this + * case, the decrypted part is substituted for the second child of + * this part (which would usually be the encrypted data). */ + notmuch_bool_t decrypt_success; + + /* True if signature verification on this part was attempted. */ + notmuch_bool_t verify_attempted; + /* For signed or encrypted containers, the validity of the + * signature. May be NULL if signature verification failed. If + * there are simply no signatures, this will be non-NULL with an + * empty signers list. */ + const GMimeSignatureValidity *sig_validity; + + /* Internal: Context inherited from the root iterator. */ + struct mime_node_context *ctx; + + /* Internal: For successfully decrypted multipart parts, the + * decrypted part to substitute for the second child. */ + GMimeObject *decrypted_child; +} mime_node_t; + +/* Construct a new MIME node pointing to the root message part of + * message. If cryptoctx is non-NULL, it will be used to verify + * signatures on any child parts. If decrypt is true, then cryptoctx + * will additionally be used to decrypt any encrypted child parts. + * + * Return value: + * + * NOTMUCH_STATUS_SUCCESS: Root node is returned in *node_out. + * + * NOTMUCH_STATUS_FILE_ERROR: Failed to open message file. + * + * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory. + */ +notmuch_status_t +mime_node_open (const void *ctx, notmuch_message_t *message, + GMimeCipherContext *cryptoctx, notmuch_bool_t decrypt, + mime_node_t **node_out); + +/* Return a new MIME node for the requested child part of parent. + * parent will be used as the talloc context for the returned child + * node. + * + * In case of any failure, this function returns NULL, (after printing + * an error message on stderr). + */ +mime_node_t * +mime_node_child (const mime_node_t *parent, int child); + #include "command-line-arguments.h" #endif