commit 7be7cc4530bef333974d95239dfd736695fbeab7
from: Stefan Sperling <stsp@stsp.name>
date: Mon Apr 02 11:48:51 2018 UTC

add a rough outline for privsep support

commit - 5b7e13a71fb6ddb69c2a98e5c8d5192d8805519b
commit + 7be7cc4530bef333974d95239dfd736695fbeab7
blob - /dev/null
blob + 03cc35e32902410a30b98219b774c18a8c3c5665 (mode 644)
--- /dev/null
+++ lib/got_lib_privsep.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * All code runs under the same UID but sensitive code paths are
+ * run in a separate process with tighter pledge(2) promises.
+ * Data is communicated between processes via imsg_read(3)/imsg_compose(3).
+ * This behaviour is transparent to users of the library.
+ *
+ * File descriptor passing is used in cases where sizes exceed MAX_IMSGSIZE.
+ *
+ * We currently do not exec(2) after a fork(2).
+ * To achieve fork+exec, releveant parts of our library functionality could
+ * be made accessible via separate executables in a libexec directory.
+ */
+
+enum got_imsg_type {
+	/*
+	 * Messages concerned with read access to objects in a repository.
+	 * Object and pack files are opened by the main process, where
+	 * data may be read as a byte string but without any interpretation.
+	 * Decompression and parsing of object and pack files occurs in a
+	 * separate process which runs under pledge("stdio").
+	 * This sandboxes our own repository parsing code, as well as zlib.
+	 */
+	GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REQUEST,
+	GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REPLY,
+	GOT_IMSG_DELTA,
+	GOT_IMSG_READ_LOOSE_BLOB_OBJECT_REQUEST,
+	GOT_IMSG_READ_LOOSE_BLOB_OBJECT_REPLY,
+	GOT_IMSG_READ_LOOSE_TREE_OBJECT_REQUEST,
+	GOT_IMSG_READ_LOOSE_TREE_OBJECT_REPLY,
+	GOT_IMSG_READ_LOOSE_COMMIT_OBJECT_REQUEST,
+	GOT_IMSG_READ_LOOSE_COMMIT_OBJECT_REPLY,
+	GOT_IMSG_READ_PACKED_BLOB_OBJECT_REQUEST,
+	GOT_IMSG_READ_PACKED_BLOB_OBJECT_REPLY,
+	GOT_IMSG_READ_PACKED_TREE_OBJECT_REQUEST,
+	GOT_IMSG_READ_PACKED_TREE_OBJECT_REPLY,
+	GOT_IMSG_READ_PACKED_COMMIT_OBJECT_REQUEST,
+	GOT_IMSG_READ_PACKED_COMMIT_OBJECT_REPLY
+};
+
+/* Structure for GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REQUEST data. */
+struct got_imsg_read_loose_object_header_request {
+	/*
+	 * Empty since the following is implied: If imsg fd == -1 then
+	 * read raw object data from imsg buffer, else read from fd.
+	 */
+};
+
+/* Structure for GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REPLY data. */
+struct got_imsg_read_loose_object_header_reply {
+	/* These fields are the same as in struct got_object. */
+	int type;
+	int flags;
+	size_t hdrlen;
+	size_t size;
+	struct got_object_id id;
+
+	int ndeltas; /* this many GOT_IMSG_DELTA messages follow */
+};
+
+/* Structure for GOT_IMSG_DELTA data. */
+struct got_imsg_delta {
+	/* These fields are the same as in struct got_delta. */
+	off_t offset;
+	size_t tslen;
+	int type;
+	size_t size;
+	off_t data_offset;
+	size_t delta_len;
+
+	/*
+	 * Followed by raw delta data: If imsg fd == -1 then read
+	 * delta data from imsg buffer, else read from fd.
+	 */
+};
+
+/* TODO: Implement the above, and then add more message data types here. */