1 /*
2  * Copyright (c) 2018 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 #ifndef nitems
43 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
44 #endif
45 
46 #define GOT_OBJ_TAG_COMMIT	"commit"
47 #define GOT_OBJ_TAG_TREE	"tree"
48 #define GOT_OBJ_TAG_BLOB	"blob"
49 #define GOT_OBJ_TAG_TAG		"tag"
50 
51 static volatile sig_atomic_t sigint_received;
52 
53 static void
54 catch_sigint(int signo)
55 {
56 	sigint_received = 1;
57 }
58 
59 static const struct got_error *
60 send_raw_obj(struct imsgbuf *ibuf, struct got_object *obj,
61     struct got_object_id *expected_id,
62     int fd, int outfd)
63 {
64 	const struct got_error *err = NULL;
65 	uint8_t *data = NULL;
66 	size_t len = 0, consumed;
67 	FILE *f;
68 	struct got_object_id id;
69 	struct got_inflate_checksum csum;
70 	SHA1_CTX sha1_ctx;
71 
72 	SHA1Init(&sha1_ctx);
73 	memset(&csum, 0, sizeof(csum));
74 	csum.output_sha1 = &sha1_ctx;
75 
76 	if (lseek(fd, SEEK_SET, 0) == -1) {
77 		err = got_error_from_errno("lseek");
78 		close(fd);
79 		return err;
80 	}
81 
82 	f = fdopen(fd, "r");
83 	if (f == NULL) {
84 		err = got_error_from_errno("fdopen");
85 		close(fd);
86 		return err;
87 	}
88 
89 	if (obj->size + obj->hdrlen <= GOT_PRIVSEP_INLINE_OBJECT_DATA_MAX)
90 		err = got_inflate_to_mem(&data, &len, &consumed, &csum, f);
91 	else
92 		err = got_inflate_to_fd(&len, f, &csum, outfd);
93 	if (err)
94 		goto done;
95 
96 	if (len < obj->hdrlen || len != obj->hdrlen + obj->size) {
97 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
98 		goto done;
99 	}
100 
101 	SHA1Final(id.sha1, &sha1_ctx);
102 	if (memcmp(expected_id->sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
103 		char buf[SHA1_DIGEST_STRING_LENGTH];
104 		err = got_error_fmt(GOT_ERR_OBJ_CSUM,
105 		    "checksum failure for object %s",
106 		    got_sha1_digest_to_str(expected_id->sha1, buf,
107 		    sizeof(buf)));
108 		goto done;
109 	}
110 
111 
112 	err = got_privsep_send_raw_obj(ibuf, obj->size, obj->hdrlen, data);
113 
114 done:
115 	free(data);
116 	if (fclose(f) == EOF && err == NULL)
117 		err = got_error_from_errno("fclose");
118 
119 	return err;
120 }
121 
122 int
123 main(int argc, char *argv[])
124 {
125 	const struct got_error *err = NULL;
126 	struct got_object *obj = NULL;
127 	struct imsg imsg;
128 	struct imsgbuf ibuf;
129 	size_t datalen;
130 	struct got_object_id expected_id;
131 
132 	signal(SIGINT, catch_sigint);
133 
134 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
135 
136 #ifndef PROFILE
137 	/* revoke access to most system calls */
138 	if (pledge("stdio recvfd", NULL) == -1) {
139 		err = got_error_from_errno("pledge");
140 		got_privsep_send_error(&ibuf, err);
141 		return 1;
142 	}
143 
144 	/* revoke fs access */
145 	if (landlock_no_fs() == -1) {
146 		err = got_error_from_errno("landlock_no_fs");
147 		got_privsep_send_error(&ibuf, err);
148 		return 1;
149 	}
150 	if (cap_enter() == -1) {
151 		err = got_error_from_errno("cap_enter");
152 		got_privsep_send_error(&ibuf, err);
153 		return 1;
154 	}
155 #endif
156 
157 	for (;;) {
158 		if (sigint_received) {
159 			err = got_error(GOT_ERR_CANCELLED);
160 			break;
161 		}
162 
163 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
164 		if (err) {
165 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
166 				err = NULL;
167 			break;
168 		}
169 
170 		if (imsg.hdr.type == GOT_IMSG_STOP)
171 			break;
172 
173 		if (imsg.hdr.type != GOT_IMSG_OBJECT_REQUEST &&
174 		    imsg.hdr.type != GOT_IMSG_RAW_OBJECT_REQUEST) {
175 			err = got_error(GOT_ERR_PRIVSEP_MSG);
176 			goto done;
177 		}
178 
179 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
180 		if (datalen != sizeof(expected_id)) {
181 			err = got_error(GOT_ERR_PRIVSEP_LEN);
182 			goto done;
183 		}
184 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
185 
186 		if (imsg.fd == -1) {
187 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
188 			goto done;
189 		}
190 
191 		err = got_object_read_header(&obj, imsg.fd);
192 		if (err)
193 			goto done;
194 
195 		if (imsg.hdr.type == GOT_IMSG_RAW_OBJECT_REQUEST) {
196 			struct imsg imsg_outfd;
197 
198 			err = got_privsep_recv_imsg(&imsg_outfd, &ibuf, 0);
199 			if (err) {
200 				if (imsg_outfd.hdr.len == 0)
201 					err = NULL;
202 				goto done;
203 			}
204 
205 			if (imsg_outfd.hdr.type == GOT_IMSG_STOP) {
206 				imsg_free(&imsg_outfd);
207 				goto done;
208 			}
209 
210 			if (imsg_outfd.hdr.type != GOT_IMSG_RAW_OBJECT_OUTFD) {
211 				err = got_error(GOT_ERR_PRIVSEP_MSG);
212 				imsg_free(&imsg_outfd);
213 				goto done;
214 			}
215 
216 			datalen = imsg_outfd.hdr.len - IMSG_HEADER_SIZE;
217 			if (datalen != 0) {
218 				err = got_error(GOT_ERR_PRIVSEP_LEN);
219 				imsg_free(&imsg_outfd);
220 				goto done;
221 			}
222 			if (imsg_outfd.fd == -1) {
223 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
224 				imsg_free(&imsg_outfd);
225 				goto done;
226 			}
227 			err = send_raw_obj(&ibuf, obj, &expected_id,
228 			    imsg.fd, imsg_outfd.fd);
229 			imsg.fd = -1; /* imsg.fd is owned by send_raw_obj() */
230 			if (close(imsg_outfd.fd) == -1 && err == NULL)
231 				err = got_error_from_errno("close");
232 			imsg_free(&imsg_outfd);
233 			if (err)
234 				goto done;
235 		} else
236 			err = got_privsep_send_obj(&ibuf, obj);
237 done:
238 		if (imsg.fd != -1 && close(imsg.fd) == -1 && err == NULL)
239 			err = got_error_from_errno("close");
240 		imsg_free(&imsg);
241 		if (obj)
242 			got_object_close(obj);
243 		if (err)
244 			break;
245 	}
246 
247 	imsg_clear(&ibuf);
248 	if (err) {
249 		if(!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
250 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
251 			got_privsep_send_error(&ibuf, err);
252 		}
253 	}
254 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
255 		err = got_error_from_errno("close");
256 	return err ? 1 : 0;
257 }