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