xref: /freebsd/lib/libsecureboot/openpgp/dearmor.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * Copyright (c) 2018, Juniper Networks, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
14  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
15  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
16  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
17  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
18  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
19  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #define NEED_BRSSL_H
30 #include <libsecureboot.h>
31 #include <brssl.h>
32 
33 #include "decode.h"
34 
35 /**
36  * @brief decode ascii armor
37  *
38  * once we get rid of the trailing checksum
39  * we can treat as PEM.
40  *
41  * @sa rfc4880:6.2
42  */
43 unsigned char *
44 dearmor(char *pem, size_t nbytes, size_t *len)
45 {
46 #ifdef USE_BEARSSL
47 	pem_object *po;
48 	size_t npo;
49 #else
50 	BIO *bp;
51 	char *name = NULL;
52 	char *header = NULL;
53 #endif
54 	unsigned char *data = NULL;
55 	char *cp;
56 	char *ep;
57 
58 	/* we need to remove the Armor tail */
59 	if ((cp = strstr((char *)pem, "\n=")) &&
60 	    (ep = strstr(cp, "\n---"))) {
61 		memmove(cp, ep, nbytes - (size_t)(ep - pem));
62 		nbytes -= (size_t)(ep - cp);
63 		pem[nbytes] = '\0';
64 	}
65 #ifdef USE_BEARSSL
66 	/* we also need to remove any headers */
67 	if ((cp = strstr((char *)pem, "---\n")) &&
68 	    (ep = strstr(cp, "\n\n"))) {
69 		cp += 4;
70 		ep += 2;
71 		memmove(cp, ep, nbytes - (size_t)(ep - pem));
72 		nbytes -= (size_t)(ep - cp);
73 		pem[nbytes] = '\0';
74 	}
75 	if ((po = decode_pem(pem, nbytes, &npo))) {
76 		data = po->data;
77 		*len = po->data_len;
78 	}
79 #else
80 	if ((bp = BIO_new_mem_buf(pem, (int)nbytes))) {
81 		long llen = (long)nbytes;
82 
83 		if (!PEM_read_bio(bp, &name, &header, &data, &llen))
84 			data = NULL;
85 		BIO_free(bp);
86 		*len = (size_t)llen;
87 	}
88 #endif
89 	return (data);
90 }
91 
92 #ifdef MAIN_DEARMOR
93 #include <unistd.h>
94 #include <fcntl.h>
95 #include <err.h>
96 
97 /*
98  * Mostly a unit test.
99  */
100 int
101 main(int argc, char *argv[])
102 {
103 	const char *infile, *outfile;
104 	unsigned char *data;
105 	size_t n, x;
106 	int fd;
107 	int o;
108 
109 	infile = outfile = NULL;
110 	while ((o = getopt(argc, argv, "i:o:")) != -1) {
111 		switch (o) {
112 		case 'i':
113 			infile = optarg;
114 			break;
115 		case 'o':
116 			outfile = optarg;
117 			break;
118 		default:
119 			errx(1, "unknown option: -%c", o);
120 		}
121 	}
122 	if (!infile)
123 		errx(1, "need -i infile");
124 	if (outfile) {
125 		if ((fd = open(outfile, O_WRONLY|O_CREAT|O_TRUNC)) < 0)
126 			err(1, "cannot open %s", outfile);
127 	} else {
128 		fd = 1;			/* stdout */
129 	}
130 	data = read_file(infile, &n);
131 	if (!(data[0] & OPENPGP_TAG_ISTAG))
132 		data = dearmor(data, n, &n);
133 	for (x = 0; x < n; ) {
134 		o = write(fd, &data[x], (n - x));
135 		if (o < 0)
136 			err(1, "cannot write");
137 		x += o;
138 	}
139 	if (fd != 1)
140 		close(fd);
141 	free(data);
142 	return (0);
143 }
144 #endif
145