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 
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_commit_object(struct got_commit_object **commit, FILE *f,
53     struct got_object_id *expected_id)
54 {
55 	struct got_object *obj = NULL;
56 	const struct got_error *err = NULL;
57 	size_t len;
58 	uint8_t *p;
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 	if (obj->type != GOT_OBJ_TYPE_COMMIT) {
91 		err = got_error(GOT_ERR_OBJ_TYPE);
92 		goto done;
93 	}
94 
95 	/* Skip object header. */
96 	len -= obj->hdrlen;
97 	err = got_object_parse_commit(commit, p + obj->hdrlen, len);
98 done:
99 	free(p);
100 	if (obj)
101 		got_object_close(obj);
102 	return err;
103 }
104 
105 int
106 main(int argc, char *argv[])
107 {
108 	const struct got_error *err = NULL;
109 	struct imsgbuf ibuf;
110 	size_t datalen;
111 
112 	signal(SIGINT, catch_sigint);
113 
114 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
115 
116 #ifndef PROFILE
117 	/* revoke access to most system calls */
118 	if (pledge("stdio recvfd", NULL) == -1) {
119 		err = got_error_from_errno("pledge");
120 		got_privsep_send_error(&ibuf, err);
121 		return 1;
122 	}
123 
124 	/* revoke fs access */
125 	if (landlock_no_fs() == -1) {
126 		err = got_error_from_errno("landlock_no_fs");
127 		got_privsep_send_error(&ibuf, err);
128 		return 1;
129 	}
130 	if (cap_enter() == -1) {
131 		err = got_error_from_errno("cap_enter");
132 		got_privsep_send_error(&ibuf, err);
133 		return 1;
134 	}
135 #endif
136 
137 	for (;;) {
138 		struct imsg imsg;
139 		FILE *f = NULL;
140 		struct got_commit_object *commit = NULL;
141 		struct got_object_id expected_id;
142 
143 		if (sigint_received) {
144 			err = got_error(GOT_ERR_CANCELLED);
145 			break;
146 		}
147 
148 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
149 		if (err) {
150 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
151 				err = NULL;
152 			break;
153 		}
154 
155 		if (imsg.hdr.type == GOT_IMSG_STOP)
156 			break;
157 
158 		if (imsg.hdr.type != GOT_IMSG_COMMIT_REQUEST) {
159 			err = got_error(GOT_ERR_PRIVSEP_MSG);
160 			goto done;
161 		}
162 
163 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
164 		if (datalen != sizeof(expected_id)) {
165 			err = got_error(GOT_ERR_PRIVSEP_LEN);
166 			goto done;
167 		}
168 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
169 
170 		if (imsg.fd == -1) {
171 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
172 			goto done;
173 		}
174 
175 		/* Always assume file offset zero. */
176 		f = fdopen(imsg.fd, "rb");
177 		if (f == NULL) {
178 			err = got_error_from_errno("fdopen");
179 			goto done;
180 		}
181 
182 		err = read_commit_object(&commit, f, &expected_id);
183 		if (err)
184 			goto done;
185 
186 		err = got_privsep_send_commit(&ibuf, commit);
187 		got_object_commit_close(commit);
188 done:
189 		if (f) {
190 			if (fclose(f) == EOF && err == NULL)
191 				err = got_error_from_errno("fclose");
192 		} else if (imsg.fd != -1) {
193 			if (close(imsg.fd) == -1 && err == NULL)
194 				err = got_error_from_errno("close");
195 		}
196 		imsg_free(&imsg);
197 		if (err)
198 			break;
199 	}
200 
201 	imsg_clear(&ibuf);
202 	if (err) {
203 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
204 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
205 			got_privsep_send_error(&ibuf, err);
206 		}
207 	}
208 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
209 		err = got_error_from_errno("close");
210 	return err ? 1 : 0;
211 }