2 * Copyright (c) 2014 The FreeBSD Foundation
5 * This software was developed by Edward Tomasz Napierala under sponsorship
6 * from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/capsicum.h>
36 #include <sys/types.h>
46 #include <openssl/evp.h>
47 #include <openssl/err.h>
48 #include <openssl/pem.h>
53 load(struct executable *x)
62 error = fstat(fd, &sb);
64 err(1, "%s: fstat", x->x_path);
68 errx(1, "%s: file is empty", x->x_path);
72 err(1, "%s: cannot malloc %zd bytes", x->x_path, len);
74 nread = fread(buf, len, 1, x->x_fp);
76 err(1, "%s: fread", x->x_path);
83 digest_range(struct executable *x, EVP_MD_CTX *mdctx, off_t off, size_t len)
87 range_check(x, off, len, "chunk");
89 ok = EVP_DigestUpdate(mdctx, x->x_buf + off, len);
91 ERR_print_errors_fp(stderr);
92 errx(1, "EVP_DigestUpdate(3) failed");
97 digest(struct executable *x)
101 size_t sum_of_bytes_hashed;
105 * Windows Authenticode Portable Executable Signature Format
106 * spec version 1.0 specifies MD5 and SHA1. However, pesign
107 * and sbsign both use SHA256, so do the same.
109 md = EVP_get_digestbyname(DIGEST);
111 ERR_print_errors_fp(stderr);
112 errx(1, "EVP_get_digestbyname(\"%s\") failed", DIGEST);
115 mdctx = EVP_MD_CTX_create();
117 ERR_print_errors_fp(stderr);
118 errx(1, "EVP_MD_CTX_create(3) failed");
121 ok = EVP_DigestInit_ex(mdctx, md, NULL);
123 ERR_print_errors_fp(stderr);
124 errx(1, "EVP_DigestInit_ex(3) failed");
128 * According to the Authenticode spec, we need to compute
129 * the digest in a rather... specific manner; see "Calculating
130 * the PE Image Hash" part of the spec for details.
132 * First, everything from 0 to before the PE checksum.
134 digest_range(x, mdctx, 0, x->x_checksum_off);
137 * Second, from after the PE checksum to before the Certificate
138 * entry in Data Directory.
140 digest_range(x, mdctx, x->x_checksum_off + x->x_checksum_len,
141 x->x_certificate_entry_off -
142 (x->x_checksum_off + x->x_checksum_len));
145 * Then, from after the Certificate entry to the end of headers.
147 digest_range(x, mdctx,
148 x->x_certificate_entry_off + x->x_certificate_entry_len,
150 (x->x_certificate_entry_off + x->x_certificate_entry_len));
153 * Then, each section in turn, as specified in the PE Section Table.
157 sum_of_bytes_hashed = x->x_headers_len;
158 for (i = 0; i < x->x_nsections; i++) {
159 digest_range(x, mdctx,
160 x->x_section_off[i], x->x_section_len[i]);
161 sum_of_bytes_hashed += x->x_section_len[i];
165 * I believe this can happen with overlapping sections.
167 if (sum_of_bytes_hashed > x->x_len)
168 errx(1, "number of bytes hashed is larger than file size");
171 * I can't really explain this one; just do what the spec says.
173 if (sum_of_bytes_hashed < x->x_len) {
174 digest_range(x, mdctx, sum_of_bytes_hashed,
175 x->x_len - (signature_size(x) + sum_of_bytes_hashed));
178 ok = EVP_DigestFinal_ex(mdctx, x->x_digest, &x->x_digest_len);
180 ERR_print_errors_fp(stderr);
181 errx(1, "EVP_DigestFinal_ex(3) failed");
184 EVP_MD_CTX_destroy(mdctx);
188 show_digest(const struct executable *x)
192 printf("computed %s digest ", DIGEST);
193 for (i = 0; i < (int)x->x_digest_len; i++)
194 printf("%02x", (unsigned char)x->x_digest[i]);
195 printf("; digest len %u\n", x->x_digest_len);
199 send_digest(const struct executable *x, int pipefd)
202 send_chunk(x->x_digest, x->x_digest_len, pipefd);
206 receive_signature(struct executable *x, int pipefd)
209 receive_chunk(&x->x_signature, &x->x_signature_len, pipefd);
213 save(struct executable *x, FILE *fp, const char *path)
218 assert(path != NULL);
220 nwritten = fwrite(x->x_buf, x->x_len, 1, fp);
222 err(1, "%s: fwrite", path);
226 child(const char *inpath, const char *outpath, int pipefd,
227 bool Vflag, bool vflag)
230 FILE *outfp = NULL, *infp = NULL;
231 struct executable *x;
233 infp = checked_fopen(inpath, "r");
235 outfp = checked_fopen(outpath, "w");
238 if (error != 0 && errno != ENOSYS)
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);