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/uio.h>
19 #include <sys/time.h>
20 
21 #include <stdint.h>
22 #include <limits.h>
23 #include <signal.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <zlib.h>
29 
30 #include "got_compat.h"
31 
32 #include "got_error.h"
33 #include "got_object.h"
34 
35 #include "got_lib_delta.h"
36 #include "got_lib_inflate.h"
37 #include "got_lib_object.h"
38 #include "got_lib_object_parse.h"
39 #include "got_lib_privsep.h"
40 #include "got_lib_sha1.h"
41 
42 static volatile sig_atomic_t sigint_received;
43 
44 static void
45 catch_sigint(int signo)
46 {
47 	sigint_received = 1;
48 }
49 
50 int
51 main(int argc, char *argv[])
52 {
53 	const struct got_error *err = NULL;
54 	struct imsgbuf ibuf;
55 	size_t datalen;
56 
57 	signal(SIGINT, catch_sigint);
58 
59 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
60 
61 #ifndef PROFILE
62 	/* revoke access to most system calls */
63 	if (pledge("stdio recvfd", NULL) == -1) {
64 		err = got_error_from_errno("pledge");
65 		got_privsep_send_error(&ibuf, err);
66 		return 1;
67 	}
68 
69 	/* revoke fs access */
70 	if (landlock_no_fs() == -1) {
71 		err = got_error_from_errno("landlock_no_fs");
72 		got_privsep_send_error(&ibuf, err);
73 		return 1;
74 	}
75 #endif
76 
77 	for (;;) {
78 		struct imsg imsg, imsg_outfd;
79 		FILE *f = NULL;
80 		size_t size;
81 		struct got_object *obj = NULL;
82 		uint8_t *buf = NULL;
83 		struct got_object_id id;
84 		struct got_object_id expected_id;
85 		struct got_inflate_checksum csum;
86 		SHA1_CTX sha1_ctx;
87 
88 		SHA1Init(&sha1_ctx);
89 		memset(&csum, 0, sizeof(csum));
90 		csum.output_sha1 = &sha1_ctx;
91 
92 		memset(&imsg, 0, sizeof(imsg));
93 		imsg.fd = -1;
94 		memset(&imsg_outfd, 0, sizeof(imsg_outfd));
95 		imsg_outfd.fd = -1;
96 
97 		if (sigint_received) {
98 			err = got_error(GOT_ERR_CANCELLED);
99 			break;
100 		}
101 
102 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
103 		if (err) {
104 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
105 				err = NULL;
106 			break;
107 		}
108 
109 		if (imsg.hdr.type == GOT_IMSG_STOP)
110 			break;
111 
112 		if (imsg.hdr.type != GOT_IMSG_BLOB_REQUEST) {
113 			err = got_error(GOT_ERR_PRIVSEP_MSG);
114 			goto done;
115 		}
116 
117 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
118 		if (datalen != sizeof(expected_id)) {
119 			err = got_error(GOT_ERR_PRIVSEP_LEN);
120 			goto done;
121 		}
122 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
123 
124 		if (imsg.fd == -1) {
125 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
126 			goto done;
127 		}
128 
129 		err = got_privsep_recv_imsg(&imsg_outfd, &ibuf, 0);
130 		if (err) {
131 			if (imsg.hdr.len == 0)
132 				err = NULL;
133 			break;
134 		}
135 
136 		if (imsg_outfd.hdr.type == GOT_IMSG_STOP)
137 			break;
138 
139 		if (imsg_outfd.hdr.type != GOT_IMSG_BLOB_OUTFD) {
140 			err = got_error(GOT_ERR_PRIVSEP_MSG);
141 			goto done;
142 		}
143 
144 		datalen = imsg_outfd.hdr.len - IMSG_HEADER_SIZE;
145 		if (datalen != 0) {
146 			err = got_error(GOT_ERR_PRIVSEP_LEN);
147 			goto done;
148 		}
149 		if (imsg_outfd.fd == -1) {
150 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
151 			goto done;
152 		}
153 
154 		err = got_object_read_header(&obj, imsg.fd);
155 		if (err)
156 			goto done;
157 
158 		if (lseek(imsg.fd, SEEK_SET, 0) == -1) {
159 			err = got_error_from_errno("lseek");
160 			goto done;
161 		}
162 
163 		f = fdopen(imsg.fd, "rb");
164 		if (f == NULL) {
165 			err = got_error_from_errno("fdopen");
166 			goto done;
167 		}
168 
169 		if (obj->size + obj->hdrlen <=
170 		    GOT_PRIVSEP_INLINE_BLOB_DATA_MAX) {
171 			err = got_inflate_to_mem(&buf, &size, NULL, &csum, f);
172 			if (err)
173 				goto done;
174 		} else {
175 			err = got_inflate_to_fd(&size, f, &csum, imsg_outfd.fd);
176 			if (err)
177 				goto done;
178 		}
179 		SHA1Final(id.sha1, &sha1_ctx);
180 		if (memcmp(expected_id.sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
181 			char buf[SHA1_DIGEST_STRING_LENGTH];
182 			err = got_error_fmt(GOT_ERR_OBJ_CSUM,
183 			    "checksum failure for object %s",
184 			    got_sha1_digest_to_str(expected_id.sha1, buf,
185 			    sizeof(buf)));
186 			goto done;
187 		}
188 
189 		if (size < obj->hdrlen) {
190 			err = got_error(GOT_ERR_BAD_OBJ_HDR);
191 			goto done;
192 		}
193 
194 		err = got_privsep_send_blob(&ibuf, size, obj->hdrlen, buf);
195 done:
196 		free(buf);
197 		if (f) {
198 			if (fclose(f) == EOF && err == NULL)
199 				err = got_error_from_errno("fclose");
200 		} else if (imsg.fd != -1) {
201 			if (close(imsg.fd) == -1 && err == NULL)
202 				err = got_error_from_errno("close");
203 		}
204 		if (imsg_outfd.fd != -1) {
205 			if (close(imsg_outfd.fd) == -1 && err == NULL)
206 				err = got_error_from_errno("close");
207 		}
208 
209 		imsg_free(&imsg);
210 		imsg_free(&imsg_outfd);
211 		if (obj)
212 			got_object_close(obj);
213 		if (err)
214 			break;
215 	}
216 
217 	imsg_clear(&ibuf);
218 	if (err) {
219 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
220 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
221 			got_privsep_send_error(&ibuf, err);
222 		}
223 	}
224 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
225 		err = got_error_from_errno("close");
226 	return err ? 1 : 0;
227 }