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_sha1.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 
91 		if (sigint_received) {
92 			err = got_error(GOT_ERR_CANCELLED);
93 			break;
94 		}
95 
96 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
97 		if (err) {
98 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
99 				err = NULL;
100 			break;
101 		}
102 
103 		if (imsg.hdr.type == GOT_IMSG_STOP)
104 			break;
105 
106 		if (imsg.hdr.type != GOT_IMSG_TREE_REQUEST) {
107 			err = got_error(GOT_ERR_PRIVSEP_MSG);
108 			goto done;
109 		}
110 
111 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
112 		if (datalen != sizeof(expected_id)) {
113 			err = got_error(GOT_ERR_PRIVSEP_LEN);
114 			goto done;
115 		}
116 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
117 
118 		if (imsg.fd == -1) {
119 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
120 			goto done;
121 		}
122 
123 		/* Always assume file offset zero. */
124 		err = got_object_read_tree(&entries, &nentries, &nentries_alloc,
125 		    &buf, imsg.fd, &expected_id);
126 		if (err)
127 			goto done;
128 
129 		err = got_privsep_send_tree(&ibuf, entries, nentries);
130 done:
131 		free(buf);
132 		if (imsg.fd != -1 && close(imsg.fd) == -1 && err == NULL)
133 			err = got_error_from_errno("close");
134 		imsg_free(&imsg);
135 		if (err)
136 			break;
137 	}
138 
139 	free(entries);
140 	imsg_clear(&ibuf);
141 	if (err) {
142 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
143 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
144 			got_privsep_send_error(&ibuf, err);
145 		}
146 	}
147 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
148 		err = got_error_from_errno("close");
149 	return err ? 1 : 0;
150 }