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 static volatile sig_atomic_t sigint_received;
43 
44 static void
45 catch_sigint(int signo)
46 {
47 	sigint_received = 1;
48 }
49 
50 static const struct got_error *
51 read_tag_object(struct got_tag_object **tag, FILE *f,
52     struct got_object_id *expected_id)
53 {
54 	const struct got_error *err = NULL;
55 	struct got_object *obj = NULL;
56 	size_t len;
57 	uint8_t *p;
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_tag(tag, p + obj->hdrlen, len);
92 done:
93 	free(p);
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 #endif
118 
119 	for (;;) {
120 		struct imsg imsg;
121 		FILE *f = NULL;
122 		struct got_tag_object *tag = NULL;
123 		struct got_object_id expected_id;
124 
125 		if (sigint_received) {
126 			err = got_error(GOT_ERR_CANCELLED);
127 			break;
128 		}
129 
130 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
131 		if (err) {
132 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
133 				err = NULL;
134 			break;
135 		}
136 
137 		if (imsg.hdr.type == GOT_IMSG_STOP)
138 			break;
139 
140 		if (imsg.hdr.type != GOT_IMSG_TAG_REQUEST) {
141 			err = got_error(GOT_ERR_PRIVSEP_MSG);
142 			goto done;
143 		}
144 
145 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
146 		if (datalen != sizeof(expected_id)) {
147 			err = got_error(GOT_ERR_PRIVSEP_LEN);
148 			goto done;
149 		}
150 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
151 
152 		if (imsg.fd == -1) {
153 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
154 			goto done;
155 		}
156 
157 		/* Always assume file offset zero. */
158 		f = fdopen(imsg.fd, "rb");
159 		if (f == NULL) {
160 			err = got_error_from_errno("fdopen");
161 			goto done;
162 		}
163 
164 		err = read_tag_object(&tag, f, &expected_id);
165 		if (err)
166 			goto done;
167 
168 		err = got_privsep_send_tag(&ibuf, tag);
169 done:
170 		if (f) {
171 			if (fclose(f) == EOF && err == NULL)
172 				err = got_error_from_errno("fclose");
173 		} else if (imsg.fd != -1) {
174 			if (close(imsg.fd) == -1 && err == NULL)
175 				err = got_error_from_errno("close");
176 		}
177 		imsg_free(&imsg);
178 		if (err)
179 			break;
180 	}
181 
182 	imsg_clear(&ibuf);
183 	if (err) {
184 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
185 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
186 			got_privsep_send_error(&ibuf, err);
187 		}
188 	}
189 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
190 		err = got_error_from_errno("close");
191 	return err ? 1 : 0;
192 }