2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2014 The FreeBSD Foundation
6 * This software was developed by Edward Tomasz Napierala under sponsorship
7 * from the FreeBSD Foundation.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/capsicum.h>
37 #include <sys/types.h>
40 #include <capsicum_helpers.h>
48 #include <openssl/evp.h>
49 #include <openssl/err.h>
50 #include <openssl/pem.h>
55 load(struct executable *x)
64 error = fstat(fd, &sb);
66 err(1, "%s: fstat", x->x_path);
70 errx(1, "%s: file is empty", x->x_path);
74 err(1, "%s: cannot malloc %zd bytes", x->x_path, len);
76 nread = fread(buf, len, 1, x->x_fp);
78 err(1, "%s: fread", x->x_path);
85 digest_range(struct executable *x, EVP_MD_CTX *mdctx, off_t off, size_t len)
89 range_check(x, off, len, "chunk");
91 ok = EVP_DigestUpdate(mdctx, x->x_buf + off, len);
93 ERR_print_errors_fp(stderr);
94 errx(1, "EVP_DigestUpdate(3) failed");
99 digest(struct executable *x)
103 size_t sum_of_bytes_hashed;
107 * Windows Authenticode Portable Executable Signature Format
108 * spec version 1.0 specifies MD5 and SHA1. However, pesign
109 * and sbsign both use SHA256, so do the same.
111 md = EVP_get_digestbyname(DIGEST);
113 ERR_print_errors_fp(stderr);
114 errx(1, "EVP_get_digestbyname(\"%s\") failed", DIGEST);
117 mdctx = EVP_MD_CTX_create();
119 ERR_print_errors_fp(stderr);
120 errx(1, "EVP_MD_CTX_create(3) failed");
123 ok = EVP_DigestInit_ex(mdctx, md, NULL);
125 ERR_print_errors_fp(stderr);
126 errx(1, "EVP_DigestInit_ex(3) failed");
130 * According to the Authenticode spec, we need to compute
131 * the digest in a rather... specific manner; see "Calculating
132 * the PE Image Hash" part of the spec for details.
134 * First, everything from 0 to before the PE checksum.
136 digest_range(x, mdctx, 0, x->x_checksum_off);
139 * Second, from after the PE checksum to before the Certificate
140 * entry in Data Directory.
142 digest_range(x, mdctx, x->x_checksum_off + x->x_checksum_len,
143 x->x_certificate_entry_off -
144 (x->x_checksum_off + x->x_checksum_len));
147 * Then, from after the Certificate entry to the end of headers.
149 digest_range(x, mdctx,
150 x->x_certificate_entry_off + x->x_certificate_entry_len,
152 (x->x_certificate_entry_off + x->x_certificate_entry_len));
155 * Then, each section in turn, as specified in the PE Section Table.
159 sum_of_bytes_hashed = x->x_headers_len;
160 for (i = 0; i < x->x_nsections; i++) {
161 digest_range(x, mdctx,
162 x->x_section_off[i], x->x_section_len[i]);
163 sum_of_bytes_hashed += x->x_section_len[i];
167 * I believe this can happen with overlapping sections.
169 if (sum_of_bytes_hashed > x->x_len)
170 errx(1, "number of bytes hashed is larger than file size");
173 * I can't really explain this one; just do what the spec says.
175 if (sum_of_bytes_hashed < x->x_len) {
176 digest_range(x, mdctx, sum_of_bytes_hashed,
177 x->x_len - (signature_size(x) + sum_of_bytes_hashed));
180 ok = EVP_DigestFinal_ex(mdctx, x->x_digest, &x->x_digest_len);
182 ERR_print_errors_fp(stderr);
183 errx(1, "EVP_DigestFinal_ex(3) failed");
186 EVP_MD_CTX_destroy(mdctx);
190 show_digest(const struct executable *x)
194 printf("computed %s digest ", DIGEST);
195 for (i = 0; i < (int)x->x_digest_len; i++)
196 printf("%02x", (unsigned char)x->x_digest[i]);
197 printf("; digest len %u\n", x->x_digest_len);
201 send_digest(const struct executable *x, int pipefd)
204 send_chunk(x->x_digest, x->x_digest_len, pipefd);
208 receive_signature(struct executable *x, int pipefd)
211 receive_chunk(&x->x_signature, &x->x_signature_len, pipefd);
215 save(struct executable *x, FILE *fp, const char *path)
220 assert(path != NULL);
222 nwritten = fwrite(x->x_buf, x->x_len, 1, fp);
224 err(1, "%s: fwrite", path);
228 child(const char *inpath, const char *outpath, int pipefd,
229 bool Vflag, bool vflag)
231 FILE *outfp = NULL, *infp = NULL;
232 struct executable *x;
234 infp = checked_fopen(inpath, "r");
236 outfp = checked_fopen(outpath, "w");
238 if (caph_enter() < 0)
241 x = calloc(1, sizeof(*x));
250 if (signature_size(x) == 0)
251 errx(1, "file not signed");
253 printf("file contains signature\n");
260 if (signature_size(x) != 0)
261 errx(1, "file already signed");
266 send_digest(x, pipefd);
267 receive_signature(x, pipefd);
269 save(x, outfp, outpath);