1 /*
2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/uio.h>
20 #include <sys/time.h>
21 
22 #include <stdint.h>
23 #include <limits.h>
24 #include <signal.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29 #include <zlib.h>
30 
31 #include "got_compat.h"
32 
33 #include "got_error.h"
34 #include "got_object.h"
35 #include "got_path.h"
36 
37 #include "got_lib_delta.h"
38 #include "got_lib_inflate.h"
39 #include "got_lib_object.h"
40 #include "got_lib_object_parse.h"
41 #include "got_lib_privsep.h"
42 #include "got_lib_hash.h"
43 
44 static volatile sig_atomic_t sigint_received;
45 
46 static void
47 catch_sigint(int signo)
48 {
49 	sigint_received = 1;
50 }
51 
52 int
53 main(int argc, char *argv[])
54 {
55 	const struct got_error *err = NULL;
56 	struct imsgbuf ibuf;
57 	size_t datalen;
58 	struct got_parsed_tree_entry *entries = NULL;
59 	size_t nentries = 0, nentries_alloc = 0;
60 
61 	signal(SIGINT, catch_sigint);
62 
63 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
64 
65 #ifndef PROFILE
66 	/* revoke access to most system calls */
67 	if (pledge("stdio recvfd", NULL) == -1) {
68 		err = got_error_from_errno("pledge");
69 		got_privsep_send_error(&ibuf, err);
70 		return 1;
71 	}
72 
73 	/* revoke fs access */
74 	if (landlock_no_fs() == -1) {
75 		err = got_error_from_errno("landlock_no_fs");
76 		got_privsep_send_error(&ibuf, err);
77 		return 1;
78 	}
79 	if (cap_enter() == -1) {
80 		err = got_error_from_errno("cap_enter");
81 		got_privsep_send_error(&ibuf, err);
82 		return 1;
83 	}
84 #endif
85 
86 	for (;;) {
87 		struct imsg imsg;
88 		uint8_t *buf = NULL;
89 		struct got_object_id expected_id;
90 		int fd = -1;
91 
92 		if (sigint_received) {
93 			err = got_error(GOT_ERR_CANCELLED);
94 			break;
95 		}
96 
97 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
98 		if (err) {
99 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
100 				err = NULL;
101 			break;
102 		}
103 
104 		if (imsg.hdr.type == GOT_IMSG_STOP)
105 			break;
106 
107 		if (imsg.hdr.type != GOT_IMSG_TREE_REQUEST) {
108 			err = got_error(GOT_ERR_PRIVSEP_MSG);
109 			goto done;
110 		}
111 
112 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
113 		if (datalen != sizeof(expected_id)) {
114 			err = got_error(GOT_ERR_PRIVSEP_LEN);
115 			goto done;
116 		}
117 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
118 
119 		fd = imsg_get_fd(&imsg);
120 		if (fd == -1) {
121 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
122 			goto done;
123 		}
124 
125 		/* Always assume file offset zero. */
126 		err = got_object_read_tree(&entries, &nentries, &nentries_alloc,
127 		    &buf, fd, &expected_id);
128 		if (err)
129 			goto done;
130 
131 		err = got_privsep_send_tree(&ibuf, entries, nentries);
132 done:
133 		free(buf);
134 		if (fd != -1 && close(fd) == -1 && err == NULL)
135 			err = got_error_from_errno("close");
136 		imsg_free(&imsg);
137 		if (err)
138 			break;
139 	}
140 
141 	free(entries);
142 	imsg_clear(&ibuf);
143 	if (err) {
144 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
145 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
146 			got_privsep_send_error(&ibuf, err);
147 		}
148 	}
149 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
150 		err = got_error_from_errno("close");
151 	return err ? 1 : 0;
152 }