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/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 #include "got_path.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_sha1.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 static const struct got_error *
52 read_tree_object(struct got_parsed_tree_entry **entries, int *nentries,
53     uint8_t **p, FILE *f, struct got_object_id *expected_id)
54 {
55 	const struct got_error *err = NULL;
56 	struct got_object *obj = NULL;
57 	size_t len;
58 	struct got_inflate_checksum csum;
59 	SHA1_CTX sha1_ctx;
60 	struct got_object_id id;
61 
62 	SHA1Init(&sha1_ctx);
63 	memset(&csum, 0, sizeof(csum));
64 	csum.output_sha1 = &sha1_ctx;
65 
66 	err = got_inflate_to_mem(p, &len, NULL, &csum, f);
67 	if (err)
68 		return err;
69 
70 	SHA1Final(id.sha1, &sha1_ctx);
71 	if (memcmp(expected_id->sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
72 		char buf[SHA1_DIGEST_STRING_LENGTH];
73 		err = got_error_fmt(GOT_ERR_OBJ_CSUM,
74 		    "checksum failure for object %s",
75 		    got_sha1_digest_to_str(expected_id->sha1, buf,
76 		    sizeof(buf)));
77 		goto done;
78 	}
79 
80 	err = got_object_parse_header(&obj, *p, len);
81 	if (err)
82 		goto done;
83 
84 	if (len < obj->hdrlen + obj->size) {
85 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
86 		goto done;
87 	}
88 
89 	/* Skip object header. */
90 	len -= obj->hdrlen;
91 	err = got_object_parse_tree(entries, nentries, *p + obj->hdrlen, len);
92 done:
93 	if (obj)
94 		got_object_close(obj);
95 	return err;
96 }
97 
98 int
99 main(int argc, char *argv[])
100 {
101 	const struct got_error *err = NULL;
102 	struct imsgbuf ibuf;
103 	size_t datalen;
104 
105 	signal(SIGINT, catch_sigint);
106 
107 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
108 
109 #ifndef PROFILE
110 	/* revoke access to most system calls */
111 	if (pledge("stdio recvfd", NULL) == -1) {
112 		err = got_error_from_errno("pledge");
113 		got_privsep_send_error(&ibuf, err);
114 		return 1;
115 	}
116 
117 	/* revoke fs access */
118 	if (landlock_no_fs() == -1) {
119 		err = got_error_from_errno("landlock_no_fs");
120 		got_privsep_send_error(&ibuf, err);
121 		return 1;
122 	}
123 	if (cap_enter() == -1) {
124 		err = got_error_from_errno("cap_enter");
125 		got_privsep_send_error(&ibuf, err);
126 		return 1;
127 	}
128 #endif
129 
130 	for (;;) {
131 		struct imsg imsg;
132 		FILE *f = NULL;
133 		struct got_parsed_tree_entry *entries = NULL;
134 		int nentries = 0;
135 		uint8_t *buf = NULL;
136 		struct got_object_id expected_id;
137 
138 		if (sigint_received) {
139 			err = got_error(GOT_ERR_CANCELLED);
140 			break;
141 		}
142 
143 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
144 		if (err) {
145 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
146 				err = NULL;
147 			break;
148 		}
149 
150 		if (imsg.hdr.type == GOT_IMSG_STOP)
151 			break;
152 
153 		if (imsg.hdr.type != GOT_IMSG_TREE_REQUEST) {
154 			err = got_error(GOT_ERR_PRIVSEP_MSG);
155 			goto done;
156 		}
157 
158 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
159 		if (datalen != sizeof(expected_id)) {
160 			err = got_error(GOT_ERR_PRIVSEP_LEN);
161 			goto done;
162 		}
163 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
164 
165 		if (imsg.fd == -1) {
166 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
167 			goto done;
168 		}
169 
170 		/* Always assume file offset zero. */
171 		f = fdopen(imsg.fd, "rb");
172 		if (f == NULL) {
173 			err = got_error_from_errno("fdopen");
174 			goto done;
175 		}
176 
177 		err = read_tree_object(&entries, &nentries, &buf, f,
178 		    &expected_id);
179 		if (err)
180 			goto done;
181 
182 		err = got_privsep_send_tree(&ibuf, entries, nentries);
183 done:
184 		free(entries);
185 		free(buf);
186 		if (f) {
187 			if (fclose(f) == EOF && err == NULL)
188 				err = got_error_from_errno("fclose");
189 		} else if (imsg.fd != -1) {
190 			if (close(imsg.fd) == -1 && err == NULL)
191 				err = got_error_from_errno("close");
192 		}
193 		imsg_free(&imsg);
194 		if (err)
195 			break;
196 	}
197 
198 	imsg_clear(&ibuf);
199 	if (err) {
200 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
201 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
202 			got_privsep_send_error(&ibuf, err);
203 		}
204 	}
205 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
206 		err = got_error_from_errno("close");
207 	return err ? 1 : 0;
208 }