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