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Date:: Thu Jul 8 11:03:29 2021 UTC
Message:: verify object ID checksums while loose objects are being accessed
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  1 28714985 2018-11-17 stsp /*
  2 28714985 2018-11-17 stsp  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
  3 28714985 2018-11-17 stsp  *
  4 28714985 2018-11-17 stsp  * Permission to use, copy, modify, and distribute this software for any
  5 28714985 2018-11-17 stsp  * purpose with or without fee is hereby granted, provided that the above
  6 28714985 2018-11-17 stsp  * copyright notice and this permission notice appear in all copies.
  7 28714985 2018-11-17 stsp  *
  8 28714985 2018-11-17 stsp  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 28714985 2018-11-17 stsp  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 28714985 2018-11-17 stsp  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 28714985 2018-11-17 stsp  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 28714985 2018-11-17 stsp  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 28714985 2018-11-17 stsp  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 28714985 2018-11-17 stsp  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 28714985 2018-11-17 stsp  */
 16 28714985 2018-11-17 stsp 
 17 28714985 2018-11-17 stsp #include <sys/types.h>
 18 28714985 2018-11-17 stsp #include <sys/queue.h>
 19 28714985 2018-11-17 stsp #include <sys/uio.h>
 20 28714985 2018-11-17 stsp #include <sys/time.h>
 21 28714985 2018-11-17 stsp 
 22 28714985 2018-11-17 stsp #include <stdint.h>
 23 28714985 2018-11-17 stsp #include <imsg.h>
 24 12ce7a6c 2019-08-12 stsp #include <limits.h>
 25 28714985 2018-11-17 stsp #include <signal.h>
 26 28714985 2018-11-17 stsp #include <stdio.h>
 27 28714985 2018-11-17 stsp #include <stdlib.h>
 28 28714985 2018-11-17 stsp #include <string.h>
 29 28714985 2018-11-17 stsp #include <sha1.h>
 30 81a12da5 2020-09-09 naddy #include <unistd.h>
 31 28714985 2018-11-17 stsp #include <zlib.h>
 32 28714985 2018-11-17 stsp 
 33 28714985 2018-11-17 stsp #include "got_error.h"
 34 28714985 2018-11-17 stsp #include "got_object.h"
 35 28714985 2018-11-17 stsp 
 36 28714985 2018-11-17 stsp #include "got_lib_delta.h"
 37 28714985 2018-11-17 stsp #include "got_lib_inflate.h"
 38 28714985 2018-11-17 stsp #include "got_lib_object.h"
 39 28714985 2018-11-17 stsp #include "got_lib_object_parse.h"
 40 28714985 2018-11-17 stsp #include "got_lib_privsep.h"
 41 d5c81d44 2021-07-08 stsp #include "got_lib_sha1.h"
 42 28714985 2018-11-17 stsp 
 43 28714985 2018-11-17 stsp static volatile sig_atomic_t sigint_received;
 44 28714985 2018-11-17 stsp 
 45 28714985 2018-11-17 stsp static void
 46 28714985 2018-11-17 stsp catch_sigint(int signo)
 47 28714985 2018-11-17 stsp {
 48 28714985 2018-11-17 stsp 	sigint_received = 1;
 49 28714985 2018-11-17 stsp }
 50 28714985 2018-11-17 stsp 
 51 28714985 2018-11-17 stsp static const struct got_error *
 52 d5c81d44 2021-07-08 stsp read_tag_object(struct got_tag_object **tag, FILE *f,
 53 d5c81d44 2021-07-08 stsp     struct got_object_id *expected_id)
 54 28714985 2018-11-17 stsp {
 55 28714985 2018-11-17 stsp 	const struct got_error *err = NULL;
 56 d5c81d44 2021-07-08 stsp 	struct got_object *obj = NULL;
 57 28714985 2018-11-17 stsp 	size_t len;
 58 28714985 2018-11-17 stsp 	uint8_t *p;
 59 d5c81d44 2021-07-08 stsp 	struct got_inflate_checksum csum;
 60 d5c81d44 2021-07-08 stsp 	SHA1_CTX sha1_ctx;
 61 d5c81d44 2021-07-08 stsp 	struct got_object_id id;
 62 28714985 2018-11-17 stsp 
 63 d5c81d44 2021-07-08 stsp 	SHA1Init(&sha1_ctx);
 64 d5c81d44 2021-07-08 stsp 	memset(&csum, 0, sizeof(csum));
 65 d5c81d44 2021-07-08 stsp 	csum.output_sha1 = &sha1_ctx;
 66 d5c81d44 2021-07-08 stsp 
 67 d5c81d44 2021-07-08 stsp 	err = got_inflate_to_mem(&p, &len, NULL, &csum, f);
 68 28714985 2018-11-17 stsp 	if (err)
 69 28714985 2018-11-17 stsp 		return err;
 70 28714985 2018-11-17 stsp 
 71 d5c81d44 2021-07-08 stsp 	SHA1Final(id.sha1, &sha1_ctx);
 72 d5c81d44 2021-07-08 stsp 	if (memcmp(expected_id->sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
 73 d5c81d44 2021-07-08 stsp 		char buf[SHA1_DIGEST_STRING_LENGTH];
 74 d5c81d44 2021-07-08 stsp 		err = got_error_fmt(GOT_ERR_OBJ_CSUM,
 75 d5c81d44 2021-07-08 stsp 		    "checksum failure for object %s",
 76 d5c81d44 2021-07-08 stsp 		    got_sha1_digest_to_str(expected_id->sha1, buf,
 77 d5c81d44 2021-07-08 stsp 		    sizeof(buf)));
 78 d5c81d44 2021-07-08 stsp 		goto done;
 79 d5c81d44 2021-07-08 stsp 	}
 80 d5c81d44 2021-07-08 stsp 
 81 268f7291 2018-12-24 stsp 	err = got_object_parse_header(&obj, p, len);
 82 268f7291 2018-12-24 stsp 	if (err)
 83 d5c81d44 2021-07-08 stsp 		goto done;
 84 268f7291 2018-12-24 stsp 
 85 28714985 2018-11-17 stsp 	if (len < obj->hdrlen + obj->size) {
 86 28714985 2018-11-17 stsp 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
 87 28714985 2018-11-17 stsp 		goto done;
 88 28714985 2018-11-17 stsp 	}
 89 28714985 2018-11-17 stsp 
 90 28714985 2018-11-17 stsp 	/* Skip object header. */
 91 28714985 2018-11-17 stsp 	len -= obj->hdrlen;
 92 28714985 2018-11-17 stsp 	err = got_object_parse_tag(tag, p + obj->hdrlen, len);
 93 28714985 2018-11-17 stsp done:
 94 268f7291 2018-12-24 stsp 	free(p);
 95 d5c81d44 2021-07-08 stsp 	if (obj)
 96 d5c81d44 2021-07-08 stsp 		got_object_close(obj);
 97 28714985 2018-11-17 stsp 	return err;
 98 28714985 2018-11-17 stsp }
 99 28714985 2018-11-17 stsp 
100 28714985 2018-11-17 stsp int
101 28714985 2018-11-17 stsp main(int argc, char *argv[])
102 28714985 2018-11-17 stsp {
103 28714985 2018-11-17 stsp 	const struct got_error *err = NULL;
104 28714985 2018-11-17 stsp 	struct imsgbuf ibuf;
105 d5c81d44 2021-07-08 stsp 	size_t datalen;
106 28714985 2018-11-17 stsp 
107 28714985 2018-11-17 stsp 	signal(SIGINT, catch_sigint);
108 28714985 2018-11-17 stsp 
109 28714985 2018-11-17 stsp 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
110 28714985 2018-11-17 stsp 
111 28714985 2018-11-17 stsp #ifndef PROFILE
112 28714985 2018-11-17 stsp 	/* revoke access to most system calls */
113 28714985 2018-11-17 stsp 	if (pledge("stdio recvfd", NULL) == -1) {
114 638f9024 2019-05-13 stsp 		err = got_error_from_errno("pledge");
115 28714985 2018-11-17 stsp 		got_privsep_send_error(&ibuf, err);
116 28714985 2018-11-17 stsp 		return 1;
117 28714985 2018-11-17 stsp 	}
118 28714985 2018-11-17 stsp #endif
119 28714985 2018-11-17 stsp 
120 656b1f76 2019-05-11 jcs 	for (;;) {
121 28714985 2018-11-17 stsp 		struct imsg imsg;
122 28714985 2018-11-17 stsp 		FILE *f = NULL;
123 268f7291 2018-12-24 stsp 		struct got_tag_object *tag = NULL;
124 d5c81d44 2021-07-08 stsp 		struct got_object_id expected_id;
125 28714985 2018-11-17 stsp 
126 28714985 2018-11-17 stsp 		if (sigint_received) {
127 28714985 2018-11-17 stsp 			err = got_error(GOT_ERR_CANCELLED);
128 28714985 2018-11-17 stsp 			break;
129 28714985 2018-11-17 stsp 		}
130 28714985 2018-11-17 stsp 
131 28714985 2018-11-17 stsp 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
132 28714985 2018-11-17 stsp 		if (err) {
133 28714985 2018-11-17 stsp 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
134 28714985 2018-11-17 stsp 				err = NULL;
135 28714985 2018-11-17 stsp 			break;
136 28714985 2018-11-17 stsp 		}
137 28714985 2018-11-17 stsp 
138 28714985 2018-11-17 stsp 		if (imsg.hdr.type == GOT_IMSG_STOP)
139 28714985 2018-11-17 stsp 			break;
140 28714985 2018-11-17 stsp 
141 28714985 2018-11-17 stsp 		if (imsg.hdr.type != GOT_IMSG_TAG_REQUEST) {
142 28714985 2018-11-17 stsp 			err = got_error(GOT_ERR_PRIVSEP_MSG);
143 28714985 2018-11-17 stsp 			goto done;
144 28714985 2018-11-17 stsp 		}
145 28714985 2018-11-17 stsp 
146 d5c81d44 2021-07-08 stsp 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
147 d5c81d44 2021-07-08 stsp 		if (datalen != sizeof(expected_id)) {
148 d5c81d44 2021-07-08 stsp 			err = got_error(GOT_ERR_PRIVSEP_LEN);
149 d5c81d44 2021-07-08 stsp 			goto done;
150 d5c81d44 2021-07-08 stsp 		}
151 d5c81d44 2021-07-08 stsp 		memcpy(&expected_id, imsg.data, sizeof(expected_id));
152 d5c81d44 2021-07-08 stsp 
153 28714985 2018-11-17 stsp 		if (imsg.fd == -1) {
154 28714985 2018-11-17 stsp 			err = got_error(GOT_ERR_PRIVSEP_NO_FD);
155 28714985 2018-11-17 stsp 			goto done;
156 28714985 2018-11-17 stsp 		}
157 28714985 2018-11-17 stsp 
158 28714985 2018-11-17 stsp 		/* Always assume file offset zero. */
159 28714985 2018-11-17 stsp 		f = fdopen(imsg.fd, "rb");
160 28714985 2018-11-17 stsp 		if (f == NULL) {
161 638f9024 2019-05-13 stsp 			err = got_error_from_errno("fdopen");
162 28714985 2018-11-17 stsp 			goto done;
163 28714985 2018-11-17 stsp 		}
164 28714985 2018-11-17 stsp 
165 d5c81d44 2021-07-08 stsp 		err = read_tag_object(&tag, f, &expected_id);
166 28714985 2018-11-17 stsp 		if (err)
167 28714985 2018-11-17 stsp 			goto done;
168 28714985 2018-11-17 stsp 
169 28714985 2018-11-17 stsp 		err = got_privsep_send_tag(&ibuf, tag);
170 28714985 2018-11-17 stsp done:
171 fb43ecf1 2019-02-11 stsp 		if (f) {
172 56b63ca4 2021-01-22 stsp 			if (fclose(f) == EOF && err == NULL)
173 638f9024 2019-05-13 stsp 				err = got_error_from_errno("fclose");
174 3a6ce05a 2019-02-11 stsp 		} else if (imsg.fd != -1) {
175 08578a35 2021-01-22 stsp 			if (close(imsg.fd) == -1 && err == NULL)
176 638f9024 2019-05-13 stsp 				err = got_error_from_errno("close");
177 3a6ce05a 2019-02-11 stsp 		}
178 28714985 2018-11-17 stsp 		imsg_free(&imsg);
179 28714985 2018-11-17 stsp 		if (err)
180 28714985 2018-11-17 stsp 			break;
181 28714985 2018-11-17 stsp 	}
182 28714985 2018-11-17 stsp 
183 28714985 2018-11-17 stsp 	imsg_clear(&ibuf);
184 28714985 2018-11-17 stsp 	if (err) {
185 28714985 2018-11-17 stsp 		if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
186 28714985 2018-11-17 stsp 			fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
187 28714985 2018-11-17 stsp 			got_privsep_send_error(&ibuf, err);
188 28714985 2018-11-17 stsp 		}
189 28714985 2018-11-17 stsp 	}
190 08578a35 2021-01-22 stsp 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
191 638f9024 2019-05-13 stsp 		err = got_error_from_errno("close");
192 28714985 2018-11-17 stsp 	return err ? 1 : 0;
193 28714985 2018-11-17 stsp }