1 files changed, 446 insertions, 0 deletions

diff --git a/src/lib-storage/index/index-attachment.c b/src/lib-storage/index/index-attachment.c
new file mode 100644
index 0000000..6e51fab
--- /dev/null
+++ b/src/lib-storage/index/index-attachment.c
@@ -0,0 +1,446 @@
+/* Copyright (c) 2010-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "safe-mkstemp.h"
+#include "fs-api.h"
+#include "istream.h"
+#include "ostream.h"
+#include "base64.h"
+#include "hash-format.h"
+#include "str.h"
+#include "message-parser.h"
+#include "rfc822-parser.h"
+#include "fs-api.h"
+#include "istream-fs-file.h"
+#include "istream-attachment-connector.h"
+#include "istream-attachment-extractor.h"
+#include "mail-user.h"
+#include "index-mail.h"
+#include "index-attachment.h"
+
+enum mail_attachment_decode_option {
+	MAIL_ATTACHMENT_DECODE_OPTION_NONE = '-',
+	MAIL_ATTACHMENT_DECODE_OPTION_BASE64 = 'B',
+	MAIL_ATTACHMENT_DECODE_OPTION_CRLF = 'C'
+};
+
+struct mail_save_attachment {
+	pool_t pool;
+	struct fs *fs;
+	struct istream *input;
+
+	struct fs_file *cur_file;
+	ARRAY_TYPE(mail_attachment_extref) extrefs;
+};
+
+static const char *index_attachment_dir_get(struct mail_storage *storage)
+{
+	return mail_user_home_expand(storage->user,
+				     storage->set->mail_attachment_dir);
+}
+
+static bool index_attachment_want(const struct istream_attachment_header *hdr,
+				  void *context)
+{
+	struct mail_save_context *ctx = context;
+	struct mail_attachment_part apart;
+
+	i_zero(&apart);
+	apart.part = hdr->part;
+	apart.content_type = hdr->content_type;
+	apart.content_disposition = hdr->content_disposition;
+
+	if (ctx->part_is_attachment != NULL)
+		return ctx->part_is_attachment(ctx, &apart);
+
+	/* don't treat text/ parts as attachments */
+	return hdr->content_type != NULL &&
+		strncasecmp(hdr->content_type, "text/", 5) != 0;
+}
+
+static int index_attachment_open_temp_fd(void *context)
+{
+	struct mail_save_context *ctx = context;
+	struct mail_storage *storage = ctx->transaction->box->storage;
+	string_t *temp_path;
+	int fd;
+
+	temp_path = t_str_new(256);
+	mail_user_set_get_temp_prefix(temp_path, storage->user->set);
+	fd = safe_mkstemp_hostpid(temp_path, 0600, (uid_t)-1, (gid_t)-1);
+	if (fd == -1) {
+		mailbox_set_critical(ctx->transaction->box,
+			"safe_mkstemp(%s) failed: %m", str_c(temp_path));
+		return -1;
+	}
+	if (unlink(str_c(temp_path)) < 0) {
+		mailbox_set_critical(ctx->transaction->box,
+			"unlink(%s) failed: %m", str_c(temp_path));
+		i_close_fd(&fd);
+		return -1;
+	}
+	return fd;
+}
+
+static int
+index_attachment_open_ostream(struct istream_attachment_info *info,
+			      struct ostream **output_r,
+			      const char **error_r ATTR_UNUSED, void *context)
+{
+	struct mail_save_context *ctx = context;
+	struct mail_save_attachment *attach = ctx->data.attach;
+	struct mail_storage *storage = ctx->transaction->box->storage;
+	struct mail_attachment_extref *extref;
+	enum fs_open_flags flags = 0;
+	const char *attachment_dir, *path, *digest = info->hash;
+	guid_128_t guid_128;
+
+	i_assert(attach->cur_file == NULL);
+
+	if (storage->set->parsed_fsync_mode != FSYNC_MODE_NEVER)
+		flags |= FS_OPEN_FLAG_FSYNC;
+
+	if (strlen(digest) < 4) {
+		/* make sure we can access first 4 bytes without accessing
+		   out of bounds memory */
+		digest = t_strconcat(digest, "\0\0\0\0", NULL);
+	}
+
+	guid_128_generate(guid_128);
+	attachment_dir = index_attachment_dir_get(storage);
+	path = t_strdup_printf("%s/%c%c/%c%c/%s-%s", attachment_dir,
+			       digest[0], digest[1],
+			       digest[2], digest[3], digest,
+			       guid_128_to_string(guid_128));
+	attach->cur_file = fs_file_init(attach->fs, path,
+					FS_OPEN_MODE_REPLACE | flags);
+
+	extref = array_append_space(&attach->extrefs);
+	extref->start_offset = info->start_offset;
+	extref->size = info->encoded_size;
+	extref->path = p_strdup(attach->pool,
+				path + strlen(attachment_dir) + 1);
+	extref->base64_blocks_per_line = info->base64_blocks_per_line;
+	extref->base64_have_crlf = info->base64_have_crlf;
+
+	*output_r = fs_write_stream(attach->cur_file);
+	return 0;
+}
+
+static int
+index_attachment_close_ostream(struct ostream *output, bool success,
+			       const char **error, void *context)
+{
+	struct mail_save_context *ctx = context;
+	struct mail_save_attachment *attach = ctx->data.attach;
+	int ret = success ? 0 : -1;
+
+	i_assert(attach->cur_file != NULL);
+
+	if (ret < 0)
+		fs_write_stream_abort_error(attach->cur_file, &output, "%s", *error);
+	else if (fs_write_stream_finish(attach->cur_file, &output) < 0) {
+		*error = t_strdup_printf("Couldn't create attachment %s: %s",
+					 fs_file_path(attach->cur_file),
+					 fs_file_last_error(attach->cur_file));
+		ret = -1;
+	}
+	fs_file_deinit(&attach->cur_file);
+
+	if (ret < 0) {
+		array_pop_back(&attach->extrefs);
+	}
+	return ret;
+}
+
+void index_attachment_save_begin(struct mail_save_context *ctx,
+				 struct fs *fs, struct istream *input)
+{
+	struct mail_storage *storage = ctx->transaction->box->storage;
+	struct mail_save_attachment *attach;
+	struct istream_attachment_settings set;
+	const char *error;
+	pool_t pool;
+
+	i_assert(ctx->data.attach == NULL);
+
+	if (*storage->set->mail_attachment_dir == '\0')
+		return;
+
+	i_zero(&set);
+	set.min_size = storage->set->mail_attachment_min_size;
+	if (hash_format_init(storage->set->mail_attachment_hash,
+			     &set.hash_format, &error) < 0) {
+		/* we already checked this when verifying settings */
+		i_panic("mail_attachment_hash=%s unexpectedly failed: %s",
+			storage->set->mail_attachment_hash, error);
+	}
+	set.want_attachment = index_attachment_want;
+	set.open_temp_fd = index_attachment_open_temp_fd;
+	set.open_attachment_ostream = index_attachment_open_ostream;
+	set.close_attachment_ostream = index_attachment_close_ostream;
+
+	pool = pool_alloconly_create("save attachment", 1024);
+	attach = p_new(pool, struct mail_save_attachment, 1);
+	attach->pool = pool;
+	attach->fs = fs;
+	attach->input = i_stream_create_attachment_extractor(input, &set, ctx);
+	p_array_init(&attach->extrefs, attach->pool, 8);
+	ctx->data.attach = attach;
+}
+
+static int save_check_write_error(struct mail_save_context *ctx,
+				  struct ostream *output)
+{
+	struct mail_storage *storage = ctx->transaction->box->storage;
+
+	if (output->stream_errno == 0)
+		return 0;
+
+	if (!mail_storage_set_error_from_errno(storage)) {
+		mail_set_critical(ctx->dest_mail, "write(%s) failed: %s",
+			o_stream_get_name(output), o_stream_get_error(output));
+	}
+	return -1;
+}
+
+int index_attachment_save_continue(struct mail_save_context *ctx)
+{
+	struct mail_save_attachment *attach = ctx->data.attach;
+	const unsigned char *data;
+	size_t size;
+	ssize_t ret;
+
+	if (attach->input->stream_errno != 0)
+		return -1;
+
+	do {
+		ret = i_stream_read(attach->input);
+		if (ret > 0 || ret == -2) {
+			data = i_stream_get_data(attach->input, &size);
+			o_stream_nsend(ctx->data.output, data, size);
+			i_stream_skip(attach->input, size);
+		}
+		index_mail_cache_parse_continue(ctx->dest_mail);
+		if (ret == 0 && !i_stream_attachment_extractor_can_retry(attach->input)) {
+			/* need more input */
+			return 0;
+		}
+	} while (ret != -1);
+
+	if (attach->input->stream_errno != 0) {
+		mail_set_critical(ctx->dest_mail, "read(%s) failed: %s",
+					  i_stream_get_name(attach->input),
+					  i_stream_get_error(attach->input));
+		return -1;
+	}
+	if (ctx->data.output != NULL) {
+		if (save_check_write_error(ctx, ctx->data.output) < 0)
+			return -1;
+	}
+	return 0;
+}
+
+int index_attachment_save_finish(struct mail_save_context *ctx)
+{
+	struct mail_save_attachment *attach = ctx->data.attach;
+
+	(void)i_stream_read(attach->input);
+	i_assert(attach->input->eof);
+	return attach->input->stream_errno == 0 ? 0 : -1;
+}
+
+void index_attachment_save_free(struct mail_save_context *ctx)
+{
+	struct mail_save_attachment *attach = ctx->data.attach;
+
+	if (attach != NULL) {
+		i_stream_unref(&attach->input);
+		pool_unref(&attach->pool);
+		ctx->data.attach = NULL;
+	}
+}
+
+const ARRAY_TYPE(mail_attachment_extref) *
+index_attachment_save_get_extrefs(struct mail_save_context *ctx)
+{
+	return ctx->data.attach == NULL ? NULL :
+		&ctx->data.attach->extrefs;
+}
+
+static int
+index_attachment_delete_real(struct mail_storage *storage,
+			     struct fs *fs, const char *name)
+{
+	struct fs_file *file;
+	const char *path;
+	int ret;
+
+	path = t_strdup_printf("%s/%s", index_attachment_dir_get(storage), name);
+	file = fs_file_init(fs, path, FS_OPEN_MODE_READONLY);
+	if ((ret = fs_delete(file)) < 0)
+		mail_storage_set_critical(storage, "%s", fs_file_last_error(file));
+	fs_file_deinit(&file);
+	return ret;
+}
+
+int index_attachment_delete(struct mail_storage *storage,
+			    struct fs *fs, const char *name)
+{
+	int ret;
+
+	T_BEGIN {
+		ret = index_attachment_delete_real(storage, fs, name);
+	} T_END;
+	return ret;
+}
+
+void index_attachment_append_extrefs(string_t *str,
+	const ARRAY_TYPE(mail_attachment_extref) *extrefs)
+{
+	const struct mail_attachment_extref *extref;
+	bool add_space = FALSE;
+	unsigned int startpos;
+
+	array_foreach(extrefs, extref) {
+		if (!add_space)
+			add_space = TRUE;
+		else
+			str_append_c(str, ' ');
+		str_printfa(str, "%"PRIuUOFF_T" %"PRIuUOFF_T" ",
+			    extref->start_offset, extref->size);
+
+		startpos = str_len(str);
+		if (extref->base64_have_crlf)
+			str_append_c(str, MAIL_ATTACHMENT_DECODE_OPTION_CRLF);
+		if (extref->base64_blocks_per_line > 0) {
+			str_printfa(str, "%c%u",
+				    MAIL_ATTACHMENT_DECODE_OPTION_BASE64,
+				    extref->base64_blocks_per_line * 4);
+		}
+		if (startpos == str_len(str)) {
+			/* make it clear there are no options */
+			str_append_c(str, MAIL_ATTACHMENT_DECODE_OPTION_NONE);
+		}
+		str_append_c(str, ' ');
+		str_append(str, extref->path);
+	}
+}
+
+static bool
+parse_extref_decode_options(const char *str,
+			    struct mail_attachment_extref *extref)
+{
+	unsigned int num;
+
+	if (*str == MAIL_ATTACHMENT_DECODE_OPTION_NONE)
+		return str[1] == '\0';
+
+	while (*str != '\0') {
+		switch (*str) {
+		case MAIL_ATTACHMENT_DECODE_OPTION_BASE64:
+			str++; num = 0;
+			while (*str >= '0' && *str <= '9') {
+				num = num*10 + (*str-'0');
+				str++;
+			}
+			if (num == 0 || num % 4 != 0)
+				return FALSE;
+
+			extref->base64_blocks_per_line = num/4;
+			break;
+		case MAIL_ATTACHMENT_DECODE_OPTION_CRLF:
+			extref->base64_have_crlf = TRUE;
+			str++;
+			break;
+		default:
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+bool index_attachment_parse_extrefs(const char *line, pool_t pool,
+				    ARRAY_TYPE(mail_attachment_extref) *extrefs)
+{
+	struct mail_attachment_extref extref;
+	const char *const *args;
+	unsigned int i, len;
+	uoff_t last_voffset;
+
+	args = t_strsplit(line, " ");
+	len = str_array_length(args);
+	if ((len % 4) != 0)
+		return FALSE;
+
+	last_voffset = 0;
+	for (i = 0; args[i] != NULL; i += 4) {
+		const char *start_offset_str = args[i+0];
+		const char *size_str = args[i+1];
+		const char *decode_options = args[i+2];
+		const char *path = args[i+3];
+
+		i_zero(&extref);
+		if (str_to_uoff(start_offset_str, &extref.start_offset) < 0 ||
+		    str_to_uoff(size_str, &extref.size) < 0 ||
+		    extref.start_offset < last_voffset ||
+		    !parse_extref_decode_options(decode_options, &extref))
+			return FALSE;
+
+		last_voffset += extref.size +
+			(extref.start_offset - last_voffset);
+
+		extref.path = p_strdup(pool, path);
+		array_push_back(extrefs, &extref);
+	}
+	return TRUE;
+}
+
+int index_attachment_stream_get(struct fs *fs, const char *attachment_dir,
+				const char *path_suffix,
+				struct istream **stream, uoff_t full_size,
+				const char *ext_refs, const char **error_r)
+{
+	ARRAY_TYPE(mail_attachment_extref) extrefs_arr;
+	const struct mail_attachment_extref *extref;
+	struct istream_attachment_connector *conn;
+	struct istream *input;
+	struct fs_file *file;
+	const char *path;
+	int ret;
+
+	*error_r = NULL;
+
+	t_array_init(&extrefs_arr, 16);
+	if (!index_attachment_parse_extrefs(ext_refs, pool_datastack_create(),
+					    &extrefs_arr)) {
+		*error_r = "Broken ext-refs string";
+		return -1;
+	}
+	conn = istream_attachment_connector_begin(*stream, full_size);
+
+	array_foreach(&extrefs_arr, extref) {
+		path = t_strdup_printf("%s/%s%s", attachment_dir,
+				       extref->path, path_suffix);
+		file = fs_file_init(fs, path, FS_OPEN_MODE_READONLY |
+				    FS_OPEN_FLAG_SEEKABLE);
+		input = i_stream_create_fs_file(&file, IO_BLOCK_SIZE);
+
+		ret = istream_attachment_connector_add(conn, input,
+					extref->start_offset, extref->size,
+					extref->base64_blocks_per_line,
+					extref->base64_have_crlf, error_r);
+		i_stream_unref(&input);
+		if (ret < 0) {
+			istream_attachment_connector_abort(&conn);
+			return -1;
+		}
+	}
+
+	input = istream_attachment_connector_finish(&conn);
+	i_stream_set_name(input, t_strdup_printf(
+		"attachments-connector(%s)", i_stream_get_name(*stream)));
+	i_stream_unref(stream);
+	*stream = input;
+	return 0;
+}