1 /*
2  * Copyright (c) 2018 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 
36 #include "got_lib_delta.h"
37 #include "got_lib_inflate.h"
38 #include "got_lib_object.h"
39 #include "got_lib_object_parse.h"
40 #include "got_lib_privsep.h"
41 #include "got_lib_hash.h"
42 
43 static volatile sig_atomic_t sigint_received;
44 
45 static void
46 catch_sigint(int signo)
47 {
48 	sigint_received = 1;
49 }
50 
51 int
52 main(int argc, char *argv[])
53 {
54 	const struct got_error *err = NULL;
55 	struct imsgbuf ibuf;
56 	size_t datalen;
57 
58 	signal(SIGINT, catch_sigint);
59 
60 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
61 
62 #ifndef PROFILE
63 	/* revoke access to most system calls */
64 	if (pledge("stdio recvfd", NULL) == -1) {
65 		err = got_error_from_errno("pledge");
66 		got_privsep_send_error(&ibuf, err);
67 		return 1;
68 	}
69 
70 	/* revoke fs access */
71 	if (landlock_no_fs() == -1) {
72 		err = got_error_from_errno("landlock_no_fs");
73 		got_privsep_send_error(&ibuf, err);
74 		return 1;
75 	}
76 	if (cap_enter() == -1) {
77 		err = got_error_from_errno("cap_enter");
78 		got_privsep_send_error(&ibuf, err);
79 		return 1;
80 	}
81 #endif
82 
83 	for (;;) {
84 		struct imsg imsg;
85 		struct got_tag_object *tag = NULL;
86 		struct got_object_id expected_id;
87 		int fd = -1;
88 
89 		if (sigint_received) {
90 			err = got_error(GOT_ERR_CANCELLED);
91 			break;
92 		}
93 
94 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
95 		if (err) {
96 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
97 				err = NULL;
98 			break;
99 		}
100 
101 		if (imsg.hdr.type == GOT_IMSG_STOP)
102 			break;
103 
104 		if (imsg.hdr.type != GOT_IMSG_TAG_REQUEST) {
105 			err = got_error(GOT_ERR_PRIVSEP_MSG);
106 			goto done;
107 		}
108 
109 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
110 		if (datalen != sizeof(expected_id)) {
111 			err = got_error(GOT_ERR_PRIVSEP_LEN);
112 			goto done;
113 		}
114 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
115 
116 		fd = imsg_get_fd(&imsg);
117 		if (fd == -1) {
118 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
119 			goto done;
120 		}
121 
122 		/* Always assume file offset zero. */
123 		err = got_object_read_tag(&tag, fd, &expected_id, 0);
124 		if (err)
125 			goto done;
126 
127 		err = got_privsep_send_tag(&ibuf, tag);
128 done:
129 		if (fd != -1 && close(fd) == -1 && err == NULL)
130 			err = got_error_from_errno("close");
131 		imsg_free(&imsg);
132 		if (err)
133 			break;
134 	}
135 
136 	imsg_clear(&ibuf);
137 	if (err) {
138 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
139 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
140 			got_privsep_send_error(&ibuf, err);
141 		}
142 	}
143 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
144 		err = got_error_from_errno("close");
145 	return err ? 1 : 0;
146 }