1 /*
2  * Copyright (c) 2018, 2019 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_hash.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 
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, imsg_outfd;
85 		FILE *f = NULL;
86 		size_t size;
87 		struct got_object *obj = NULL;
88 		uint8_t *buf = NULL;
89 		struct got_object_id id;
90 		struct got_object_id expected_id;
91 		struct got_inflate_checksum csum;
92 		struct got_hash ctx;
93 
94 		got_hash_init(&ctx, GOT_HASH_SHA1);
95 		memset(&csum, 0, sizeof(csum));
96 		csum.output_ctx = &ctx;
97 
98 		memset(&imsg, 0, sizeof(imsg));
99 		imsg.fd = -1;
100 		memset(&imsg_outfd, 0, sizeof(imsg_outfd));
101 		imsg_outfd.fd = -1;
102 
103 		if (sigint_received) {
104 			err = got_error(GOT_ERR_CANCELLED);
105 			break;
106 		}
107 
108 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
109 		if (err) {
110 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
111 				err = NULL;
112 			break;
113 		}
114 
115 		if (imsg.hdr.type == GOT_IMSG_STOP)
116 			break;
117 
118 		if (imsg.hdr.type != GOT_IMSG_BLOB_REQUEST) {
119 			err = got_error(GOT_ERR_PRIVSEP_MSG);
120 			goto done;
121 		}
122 
123 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
124 		if (datalen != sizeof(expected_id)) {
125 			err = got_error(GOT_ERR_PRIVSEP_LEN);
126 			goto done;
127 		}
128 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
129 
130 		if (imsg.fd == -1) {
131 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
132 			goto done;
133 		}
134 
135 		err = got_privsep_recv_imsg(&imsg_outfd, &ibuf, 0);
136 		if (err) {
137 			if (imsg.hdr.len == 0)
138 				err = NULL;
139 			break;
140 		}
141 
142 		if (imsg_outfd.hdr.type == GOT_IMSG_STOP)
143 			break;
144 
145 		if (imsg_outfd.hdr.type != GOT_IMSG_BLOB_OUTFD) {
146 			err = got_error(GOT_ERR_PRIVSEP_MSG);
147 			goto done;
148 		}
149 
150 		datalen = imsg_outfd.hdr.len - IMSG_HEADER_SIZE;
151 		if (datalen != 0) {
152 			err = got_error(GOT_ERR_PRIVSEP_LEN);
153 			goto done;
154 		}
155 		if (imsg_outfd.fd == -1) {
156 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
157 			goto done;
158 		}
159 
160 		err = got_object_read_header(&obj, imsg.fd);
161 		if (err)
162 			goto done;
163 
164 		if (lseek(imsg.fd, SEEK_SET, 0) == -1) {
165 			err = got_error_from_errno("lseek");
166 			goto done;
167 		}
168 
169 		f = fdopen(imsg.fd, "rb");
170 		if (f == NULL) {
171 			err = got_error_from_errno("fdopen");
172 			goto done;
173 		}
174 
175 		if (obj->size + obj->hdrlen <=
176 		    GOT_PRIVSEP_INLINE_BLOB_DATA_MAX) {
177 			err = got_inflate_to_mem(&buf, &size, NULL, &csum, f);
178 			if (err)
179 				goto done;
180 		} else {
181 			err = got_inflate_to_fd(&size, f, &csum, imsg_outfd.fd);
182 			if (err)
183 				goto done;
184 		}
185 		got_hash_final_object_id(&ctx, &id);
186 		if (got_object_id_cmp(&expected_id, &id) != 0) {
187 			err = got_error_checksum(&expected_id);
188 			goto done;
189 		}
190 
191 		if (size < obj->hdrlen) {
192 			err = got_error(GOT_ERR_BAD_OBJ_HDR);
193 			goto done;
194 		}
195 
196 		err = got_privsep_send_blob(&ibuf, size, obj->hdrlen, buf);
197 done:
198 		free(buf);
199 		if (f) {
200 			if (fclose(f) == EOF && err == NULL)
201 				err = got_error_from_errno("fclose");
202 		} else if (imsg.fd != -1) {
203 			if (close(imsg.fd) == -1 && err == NULL)
204 				err = got_error_from_errno("close");
205 		}
206 		if (imsg_outfd.fd != -1) {
207 			if (close(imsg_outfd.fd) == -1 && err == NULL)
208 				err = got_error_from_errno("close");
209 		}
210 
211 		imsg_free(&imsg);
212 		imsg_free(&imsg_outfd);
213 		if (obj)
214 			got_object_close(obj);
215 		if (err)
216 			break;
217 	}
218 
219 	imsg_clear(&ibuf);
220 	if (err) {
221 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
222 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
223 			got_privsep_send_error(&ibuf, err);
224 		}
225 	}
226 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
227 		err = got_error_from_errno("close");
228 	return err ? 1 : 0;
229 }