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 <sha1.h>
29 #include <sha2.h>
30 #include <unistd.h>
31 #include <zlib.h>
32 
33 #include "got_compat.h"
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 
38 #include "got_lib_delta.h"
39 #include "got_lib_inflate.h"
40 #include "got_lib_object.h"
41 #include "got_lib_object_parse.h"
42 #include "got_lib_privsep.h"
43 #include "got_lib_hash.h"
44 
45 #ifndef nitems
46 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
47 #endif
48 
49 #define GOT_OBJ_TAG_COMMIT	"commit"
50 #define GOT_OBJ_TAG_TREE	"tree"
51 #define GOT_OBJ_TAG_BLOB	"blob"
52 #define GOT_OBJ_TAG_TAG		"tag"
53 
54 static volatile sig_atomic_t sigint_received;
55 
56 static void
57 catch_sigint(int signo)
58 {
59 	sigint_received = 1;
60 }
61 
62 static const struct got_error *
63 send_raw_obj(struct imsgbuf *ibuf, struct got_object *obj,
64     struct got_object_id *expected_id,
65     int fd, int outfd)
66 {
67 	const struct got_error *err = NULL;
68 	uint8_t *data = NULL;
69 	off_t size;
70 	size_t hdrlen;
71 
72 	if (lseek(fd, SEEK_SET, 0) == -1) {
73 		err = got_error_from_errno("lseek");
74 		goto done;
75 	}
76 
77 	err = got_object_read_raw(&data, &size, &hdrlen,
78 	    GOT_PRIVSEP_INLINE_BLOB_DATA_MAX, outfd, expected_id, fd);
79 	if (err)
80 		goto done;
81 
82 	err = got_privsep_send_raw_obj(ibuf, size, hdrlen, data);
83 done:
84 	free(data);
85 	if (close(fd) == -1 && err == NULL)
86 		err = got_error_from_errno("close");
87 	return err;
88 }
89 
90 int
91 main(int argc, char *argv[])
92 {
93 	const struct got_error *err = NULL;
94 	struct got_object *obj = NULL;
95 	struct imsg imsg;
96 	struct imsgbuf ibuf;
97 	size_t datalen;
98 	struct got_object_id expected_id;
99 
100 	signal(SIGINT, catch_sigint);
101 
102 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
103 
104 #ifndef PROFILE
105 	/* revoke access to most system calls */
106 	if (pledge("stdio recvfd", NULL) == -1) {
107 		err = got_error_from_errno("pledge");
108 		got_privsep_send_error(&ibuf, err);
109 		return 1;
110 	}
111 
112 	/* revoke fs access */
113 	if (landlock_no_fs() == -1) {
114 		err = got_error_from_errno("landlock_no_fs");
115 		got_privsep_send_error(&ibuf, err);
116 		return 1;
117 	}
118 	if (cap_enter() == -1) {
119 		err = got_error_from_errno("cap_enter");
120 		got_privsep_send_error(&ibuf, err);
121 		return 1;
122 	}
123 #endif
124 
125 	for (;;) {
126 		if (sigint_received) {
127 			err = got_error(GOT_ERR_CANCELLED);
128 			break;
129 		}
130 
131 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
132 		if (err) {
133 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
134 				err = NULL;
135 			break;
136 		}
137 
138 		if (imsg.hdr.type == GOT_IMSG_STOP)
139 			break;
140 
141 		if (imsg.hdr.type != GOT_IMSG_OBJECT_REQUEST &&
142 		    imsg.hdr.type != GOT_IMSG_RAW_OBJECT_REQUEST) {
143 			err = got_error(GOT_ERR_PRIVSEP_MSG);
144 			goto done;
145 		}
146 
147 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
148 		if (datalen != sizeof(expected_id)) {
149 			err = got_error(GOT_ERR_PRIVSEP_LEN);
150 			goto done;
151 		}
152 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
153 
154 		if (imsg.fd == -1) {
155 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
156 			goto done;
157 		}
158 
159 		err = got_object_read_header(&obj, imsg.fd);
160 		if (err)
161 			goto done;
162 
163 		if (imsg.hdr.type == GOT_IMSG_RAW_OBJECT_REQUEST) {
164 			struct imsg imsg_outfd;
165 
166 			err = got_privsep_recv_imsg(&imsg_outfd, &ibuf, 0);
167 			if (err) {
168 				if (imsg_outfd.hdr.len == 0)
169 					err = NULL;
170 				goto done;
171 			}
172 
173 			if (imsg_outfd.hdr.type == GOT_IMSG_STOP) {
174 				imsg_free(&imsg_outfd);
175 				goto done;
176 			}
177 
178 			if (imsg_outfd.hdr.type != GOT_IMSG_RAW_OBJECT_OUTFD) {
179 				err = got_error(GOT_ERR_PRIVSEP_MSG);
180 				imsg_free(&imsg_outfd);
181 				goto done;
182 			}
183 
184 			datalen = imsg_outfd.hdr.len - IMSG_HEADER_SIZE;
185 			if (datalen != 0) {
186 				err = got_error(GOT_ERR_PRIVSEP_LEN);
187 				imsg_free(&imsg_outfd);
188 				goto done;
189 			}
190 			if (imsg_outfd.fd == -1) {
191 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
192 				imsg_free(&imsg_outfd);
193 				goto done;
194 			}
195 			err = send_raw_obj(&ibuf, obj, &expected_id,
196 			    imsg.fd, imsg_outfd.fd);
197 			imsg.fd = -1; /* imsg.fd is owned by send_raw_obj() */
198 			if (close(imsg_outfd.fd) == -1 && err == NULL)
199 				err = got_error_from_errno("close");
200 			imsg_free(&imsg_outfd);
201 			if (err)
202 				goto done;
203 		} else
204 			err = got_privsep_send_obj(&ibuf, obj);
205 done:
206 		if (imsg.fd != -1 && close(imsg.fd) == -1 && err == NULL)
207 			err = got_error_from_errno("close");
208 		imsg_free(&imsg);
209 		if (obj)
210 			got_object_close(obj);
211 		if (err)
212 			break;
213 	}
214 
215 	imsg_clear(&ibuf);
216 	if (err) {
217 		if(!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
218 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
219 			got_privsep_send_error(&ibuf, err);
220 		}
221 	}
222 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
223 		err = got_error_from_errno("close");
224 	return err ? 1 : 0;
225 }