1 /*
2  * Copyright (c) 2018, 2019, 2020 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 #include "got_path.h"
36 
37 #include "got_lib_delta.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 #include "got_lib_sha1.h"
43 
44 static volatile sig_atomic_t sigint_received;
45 
46 static void
47 catch_sigint(int signo)
48 {
49 	sigint_received = 1;
50 }
51 
52 static const struct got_error *
53 read_tree_object(struct got_parsed_tree_entry **entries, int *nentries,
54     uint8_t **p, FILE *f, struct got_object_id *expected_id)
55 {
56 	const struct got_error *err = NULL;
57 	struct got_object *obj = NULL;
58 	size_t len;
59 	struct got_inflate_checksum csum;
60 	SHA1_CTX sha1_ctx;
61 	struct got_object_id id;
62 
63 	SHA1Init(&sha1_ctx);
64 	memset(&csum, 0, sizeof(csum));
65 	csum.output_sha1 = &sha1_ctx;
66 
67 	err = got_inflate_to_mem(p, &len, NULL, &csum, f);
68 	if (err)
69 		return err;
70 
71 	SHA1Final(id.sha1, &sha1_ctx);
72 	if (memcmp(expected_id->sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
73 		char buf[SHA1_DIGEST_STRING_LENGTH];
74 		err = got_error_fmt(GOT_ERR_OBJ_CSUM,
75 		    "checksum failure for object %s",
76 		    got_sha1_digest_to_str(expected_id->sha1, buf,
77 		    sizeof(buf)));
78 		goto done;
79 	}
80 
81 	err = got_object_parse_header(&obj, *p, len);
82 	if (err)
83 		goto done;
84 
85 	if (len < obj->hdrlen + obj->size) {
86 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
87 		goto done;
88 	}
89 
90 	/* Skip object header. */
91 	len -= obj->hdrlen;
92 	err = got_object_parse_tree(entries, nentries, *p + obj->hdrlen, len);
93 done:
94 	if (obj)
95 		got_object_close(obj);
96 	return err;
97 }
98 
99 int
100 main(int argc, char *argv[])
101 {
102 	const struct got_error *err = NULL;
103 	struct imsgbuf ibuf;
104 	size_t datalen;
105 
106 	signal(SIGINT, catch_sigint);
107 
108 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
109 
110 #ifndef PROFILE
111 	/* revoke access to most system calls */
112 	if (pledge("stdio recvfd", NULL) == -1) {
113 		err = got_error_from_errno("pledge");
114 		got_privsep_send_error(&ibuf, err);
115 		return 1;
116 	}
117 
118 	/* revoke fs access */
119 	if (landlock_no_fs() == -1) {
120 		err = got_error_from_errno("landlock_no_fs");
121 		got_privsep_send_error(&ibuf, err);
122 		return 1;
123 	}
124 	if (cap_enter() == -1) {
125 		err = got_error_from_errno("cap_enter");
126 		got_privsep_send_error(&ibuf, err);
127 		return 1;
128 	}
129 #endif
130 
131 	for (;;) {
132 		struct imsg imsg;
133 		FILE *f = NULL;
134 		struct got_parsed_tree_entry *entries = NULL;
135 		int nentries = 0;
136 		uint8_t *buf = NULL;
137 		struct got_object_id expected_id;
138 
139 		if (sigint_received) {
140 			err = got_error(GOT_ERR_CANCELLED);
141 			break;
142 		}
143 
144 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
145 		if (err) {
146 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
147 				err = NULL;
148 			break;
149 		}
150 
151 		if (imsg.hdr.type == GOT_IMSG_STOP)
152 			break;
153 
154 		if (imsg.hdr.type != GOT_IMSG_TREE_REQUEST) {
155 			err = got_error(GOT_ERR_PRIVSEP_MSG);
156 			goto done;
157 		}
158 
159 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
160 		if (datalen != sizeof(expected_id)) {
161 			err = got_error(GOT_ERR_PRIVSEP_LEN);
162 			goto done;
163 		}
164 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
165 
166 		if (imsg.fd == -1) {
167 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
168 			goto done;
169 		}
170 
171 		/* Always assume file offset zero. */
172 		f = fdopen(imsg.fd, "rb");
173 		if (f == NULL) {
174 			err = got_error_from_errno("fdopen");
175 			goto done;
176 		}
177 
178 		err = read_tree_object(&entries, &nentries, &buf, f,
179 		    &expected_id);
180 		if (err)
181 			goto done;
182 
183 		err = got_privsep_send_tree(&ibuf, entries, nentries);
184 done:
185 		free(entries);
186 		free(buf);
187 		if (f) {
188 			if (fclose(f) == EOF && err == NULL)
189 				err = got_error_from_errno("fclose");
190 		} else if (imsg.fd != -1) {
191 			if (close(imsg.fd) == -1 && err == NULL)
192 				err = got_error_from_errno("close");
193 		}
194 		imsg_free(&imsg);
195 		if (err)
196 			break;
197 	}
198 
199 	imsg_clear(&ibuf);
200 	if (err) {
201 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
202 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
203 			got_privsep_send_error(&ibuf, err);
204 		}
205 	}
206 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
207 		err = got_error_from_errno("close");
208 	return err ? 1 : 0;
209 }