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/queue.h>
19 #include <sys/uio.h>
20 #include <sys/time.h>
21 
22 #include <stdint.h>
23 #include <imsg.h>
24 #include <limits.h>
25 #include <signal.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <sha1.h>
30 #include <unistd.h>
31 #include <zlib.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_tag_object(struct got_tag_object **tag, FILE *f,
53     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 	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 	/* Skip object header. */
91 	len -= obj->hdrlen;
92 	err = got_object_parse_tag(tag, p + obj->hdrlen, len);
93 done:
94 	free(p);
95 	if (obj)
96 		got_object_close(obj);
97 	return err;
98 }
99 
100 int
101 main(int argc, char *argv[])
102 {
103 	const struct got_error *err = NULL;
104 	struct imsgbuf ibuf;
105 	size_t datalen;
106 
107 	signal(SIGINT, catch_sigint);
108 
109 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
110 
111 #ifndef PROFILE
112 	/* revoke access to most system calls */
113 	if (pledge("stdio recvfd", NULL) == -1) {
114 		err = got_error_from_errno("pledge");
115 		got_privsep_send_error(&ibuf, err);
116 		return 1;
117 	}
118 #endif
119 
120 	for (;;) {
121 		struct imsg imsg;
122 		FILE *f = NULL;
123 		struct got_tag_object *tag = NULL;
124 		struct got_object_id expected_id;
125 
126 		if (sigint_received) {
127 			err = got_error(GOT_ERR_CANCELLED);
128 			break;
129 		}
130 
131 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
132 		if (err) {
133 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
134 				err = NULL;
135 			break;
136 		}
137 
138 		if (imsg.hdr.type == GOT_IMSG_STOP)
139 			break;
140 
141 		if (imsg.hdr.type != GOT_IMSG_TAG_REQUEST) {
142 			err = got_error(GOT_ERR_PRIVSEP_MSG);
143 			goto done;
144 		}
145 
146 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
147 		if (datalen != sizeof(expected_id)) {
148 			err = got_error(GOT_ERR_PRIVSEP_LEN);
149 			goto done;
150 		}
151 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
152 
153 		if (imsg.fd == -1) {
154 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
155 			goto done;
156 		}
157 
158 		/* Always assume file offset zero. */
159 		f = fdopen(imsg.fd, "rb");
160 		if (f == NULL) {
161 			err = got_error_from_errno("fdopen");
162 			goto done;
163 		}
164 
165 		err = read_tag_object(&tag, f, &expected_id);
166 		if (err)
167 			goto done;
168 
169 		err = got_privsep_send_tag(&ibuf, tag);
170 done:
171 		if (f) {
172 			if (fclose(f) == EOF && err == NULL)
173 				err = got_error_from_errno("fclose");
174 		} else if (imsg.fd != -1) {
175 			if (close(imsg.fd) == -1 && err == NULL)
176 				err = got_error_from_errno("close");
177 		}
178 		imsg_free(&imsg);
179 		if (err)
180 			break;
181 	}
182 
183 	imsg_clear(&ibuf);
184 	if (err) {
185 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
186 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
187 			got_privsep_send_error(&ibuf, err);
188 		}
189 	}
190 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
191 		err = got_error_from_errno("close");
192 	return err ? 1 : 0;
193 }