Annotation of src/usr.bin/signify/zsig.c, Revision 1.8
1.8 ! tedu 1: /* $OpenBSD: zsig.c,v 1.7 2016/09/03 12:59:33 espie Exp $ */
1.1 espie 2: /*
3: * Copyright (c) 2016 Marc Espie <espie@openbsd.org>
4: *
5: * Permission to use, copy, modify, and distribute this software for any
6: * purpose with or without fee is hereby granted, provided that the above
7: * copyright notice and this permission notice appear in all copies.
8: *
9: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16: */
17:
18: #ifndef VERIFYONLY
19: #include <stdint.h>
20: #include <err.h>
21: #include <stdio.h>
22: #include <stdlib.h>
23: #include <unistd.h>
24: #include <sha2.h>
25: #include <string.h>
26: #include <sys/stat.h>
1.6 espie 27: #include <time.h>
1.1 espie 28: #include <fcntl.h>
29: #include "signify.h"
30:
31: struct gzheader {
32: uint8_t flg;
33: uint32_t mtime;
34: uint8_t xflg;
35: uint8_t os;
36: uint8_t *name;
37: uint8_t *comment;
38: uint8_t *endcomment;
39: unsigned long long headerlength;
1.5 espie 40: uint8_t *buffer;
1.1 espie 41: };
42:
43: #define FTEXT_FLAG 1
44: #define FHCRC_FLAG 2
45: #define FEXTRA_FLAG 4
46: #define FNAME_FLAG 8
47: #define FCOMMENT_FLAG 16
48:
1.5 espie 49: #define GZHEADERLENGTH 10
1.1 espie 50: #define MYBUFSIZE 65536LU
51:
52:
1.6 espie 53: static uint8_t fake[10] = { 0x1f, 0x8b, 8, FCOMMENT_FLAG, 0, 0, 0, 0, 0, 3 };
1.1 espie 54:
55: /* XXX no static there, confuses the hell out of gcc which displays
56: * non-existent warnings.
57: */
58: uint8_t *
59: readgz_header(struct gzheader *h, int fd)
60: {
61: size_t sz = 1024;
62: uint8_t *p;
63: size_t pos = 0;
64: size_t len = 0;
65: int state = 0;
66: ssize_t n;
1.4 tedu 67: uint8_t *buf;
1.1 espie 68:
1.4 tedu 69: buf = xmalloc(sz);
1.1 espie 70:
71: while (1) {
72: if (len == sz) {
73: sz *= 2;
74: buf = realloc(buf, sz);
75: if (!buf)
1.3 tedu 76: err(1, "realloc");
1.1 espie 77: }
78: n = read(fd, buf+len, sz-len);
79: if (n == -1)
1.3 tedu 80: err(1, "read");
1.1 espie 81: /* incomplete info */
82: if (n == 0)
1.3 tedu 83: errx(1, "gzheader truncated");
1.1 espie 84: len += n;
85: h->comment = NULL;
86: h->name = NULL;
87:
88: switch(state) {
89: case 0: /* check header proper */
90: /* need ten bytes */
1.5 espie 91: if (len < GZHEADERLENGTH)
1.1 espie 92: continue;
93: h->flg = buf[3];
1.4 tedu 94: h->mtime = buf[4] | (buf[5] << 8U) | (buf[6] << 16U) |
1.1 espie 95: (buf[7] << 24U);
96: h->xflg = buf[8];
97: h->os = buf[9];
98: /* magic gzip header */
99: if (buf[0] != 0x1f || buf[1] != 0x8b || buf[2] != 8)
1.3 tedu 100: err(1, "invalud magic in gzheader");
1.1 espie 101: /* XXX special code that only caters to our needs */
102: if (h->flg & ~ (FCOMMENT_FLAG | FNAME_FLAG))
1.3 tedu 103: err(1, "invalid flags in gzheader");
1.5 espie 104: pos = GZHEADERLENGTH;
1.1 espie 105: state++;
106: /*FALLTHRU*/
107: case 1:
108: if (h->flg & FNAME_FLAG) {
109: p = memchr(buf+pos, 0, len - pos);
110: if (!p)
111: continue;
112: pos = (p - buf) + 1;
113: }
114: state++;
115: /*FALLTHRU*/
116: case 2:
117: if (h->flg & FCOMMENT_FLAG) {
118: p = memchr(buf+pos, 0, len - pos);
119: if (!p)
120: continue;
121: h->comment = buf + pos;
122: h->endcomment = p;
123: pos = (p - buf) + 1;
124: }
1.5 espie 125: if (h->flg & FNAME_FLAG)
126: h->name = buf + GZHEADERLENGTH;
1.1 espie 127: h->headerlength = pos;
1.5 espie 128: h->buffer = buf;
1.1 espie 129: return buf + len;
130: }
131:
132: }
133: }
134:
1.4 tedu 135: static void
1.1 espie 136: copy_blocks(int fdout, int fdin, const char *sha, const char *endsha,
1.4 tedu 137: size_t bufsize, uint8_t *bufend)
1.1 espie 138: {
1.4 tedu 139: uint8_t *buffer;
140: uint8_t *residual;
1.8 ! tedu 141: uint8_t output[SHA512_256_DIGEST_STRING_LENGTH];
1.4 tedu 142:
143: buffer = xmalloc(bufsize);
144: residual = (uint8_t *)endsha + 1;
1.1 espie 145:
146: while (1) {
147: /* get the next block */
148: size_t n = 0;
149: /* if we have residual data, we use it */
150: if (residual != bufend) {
151: /* how much can we copy */
152: size_t len = bufend - residual;
153: if (len >= bufsize) {
154: memcpy(buffer, residual, bufsize);
155: n = bufsize;
156: residual += bufsize;
157: } else {
158: memcpy(buffer, residual, len);
159: residual += len;
160: n = len;
161: }
1.4 tedu 162: }
1.1 espie 163: /* if we're not done yet, try to obtain more until EOF */
164: while (n != bufsize) {
165: ssize_t more = read(fdin, buffer+n, bufsize-n);
166: if (more == -1)
1.3 tedu 167: err(1, "read");
1.1 espie 168: n += more;
169: if (more == 0)
170: break;
171: }
1.8 ! tedu 172: SHA512_256Data(buffer, n, output);
! 173: if (endsha - sha < SHA512_256_DIGEST_STRING_LENGTH-1)
1.1 espie 174: errx(4, "signature truncated");
1.8 ! tedu 175: if (memcmp(output, sha, SHA512_256_DIGEST_STRING_LENGTH-1) != 0)
1.1 espie 176: errx(4, "signature mismatch");
1.8 ! tedu 177: if (sha[SHA512_256_DIGEST_STRING_LENGTH-1] != '\n')
1.1 espie 178: errx(4, "signature mismatch");
1.8 ! tedu 179: sha += SHA512_256_DIGEST_STRING_LENGTH;
1.1 espie 180: writeall(fdout, buffer, n, "stdout");
181: if (n != bufsize)
182: break;
1.4 tedu 183: }
1.1 espie 184: free(buffer);
185: }
186:
187: void
188: zverify(const char *pubkeyfile, const char *msgfile, const char *sigfile,
189: const char *keytype)
190: {
191: struct gzheader h;
192: size_t bufsize;
1.6 espie 193: char *p, *meta;
1.1 espie 194: uint8_t *bufend;
195: int fdin, fdout;
1.4 tedu 196:
1.1 espie 197: /* by default, verification will love pipes */
198: if (!sigfile)
199: sigfile = "-";
200: if (!msgfile)
201: msgfile = "-";
202:
203: fdin = xopen(sigfile, O_RDONLY | O_NOFOLLOW, 0);
204:
205: bufend = readgz_header(&h, fdin);
206: if (!(h.flg & FCOMMENT_FLAG))
207: errx(1, "%s is an unsigned archive", sigfile);
208: fake[8] = h.xflg;
209:
1.4 tedu 210: p = verifyzdata(h.comment, h.endcomment-h.comment, sigfile,
1.1 espie 211: pubkeyfile, keytype);
212:
213: bufsize = MYBUFSIZE;
214:
1.6 espie 215: meta = p;
216: #define BEGINS_WITH(x, y) memcmp((x), (y), sizeof(y)-1) == 0
217:
1.8 ! tedu 218: while (BEGINS_WITH(p, "algorithm=SHA512/256") ||
1.6 espie 219: BEGINS_WITH(p, "date=") ||
220: sscanf(p, "blocksize=%zu\n", &bufsize) > 0) {
1.1 espie 221: while (*(p++) != '\n')
222: continue;
223: }
1.6 espie 224:
225: if (*p != '\n')
226: errx(1, "invalid signature");
227: *(p++) = 0;
228:
1.1 espie 229: fdout = xopen(msgfile, O_CREAT|O_TRUNC|O_NOFOLLOW|O_WRONLY, 0666);
230: /* we don't actually copy the header, but put in a fake one with about
231: * zero useful information.
232: */
233: writeall(fdout, fake, sizeof fake, msgfile);
1.6 espie 234: writeall(fdout, meta, p - meta, msgfile);
1.1 espie 235: copy_blocks(fdout, fdin, p, h.endcomment, bufsize, bufend);
1.5 espie 236: free(h.buffer);
1.1 espie 237: close(fdout);
238: close(fdin);
239: }
240:
241: void
242: zsign(const char *seckeyfile, const char *msgfile, const char *sigfile)
243: {
244: size_t bufsize = MYBUFSIZE;
245: int fdin, fdout;
246: struct gzheader h;
247: struct stat sb;
248: size_t space;
249: char *msg;
250: char *p;
251: uint8_t *buffer;
252: uint8_t *sighdr;
1.6 espie 253: char date[80];
254: time_t clock;
1.1 espie 255:
256: fdin = xopen(msgfile, O_RDONLY, 0);
257: if (fstat(fdin, &sb) == -1 || !S_ISREG(sb.st_mode))
258: errx(1, "Sorry can only sign regular files");
259:
260: readgz_header(&h, fdin);
1.5 espie 261: /* we don't care about the header, actually */
262: free(h.buffer);
1.1 espie 263:
264: if (lseek(fdin, h.headerlength, SEEK_SET) == -1)
265: err(1, "seek in %s", msgfile);
266:
1.8 ! tedu 267: space = (sb.st_size / MYBUFSIZE+1) * SHA512_256_DIGEST_STRING_LENGTH +
1.6 espie 268: 1024; /* long enough for extra header information */
1.1 espie 269:
270: msg = xmalloc(space);
271: buffer = xmalloc(bufsize);
1.6 espie 272: time(&clock);
273: strftime(date, sizeof date, "%Y-%m-%dT%H:%M:%SZ", gmtime(&clock));
274: snprintf(msg, space,
275: "date=%s\n"
1.8 ! tedu 276: "algorithm=SHA512/256\n"
1.6 espie 277: "blocksize=%zu\n\n",
278: date, bufsize);
1.1 espie 279: p = strchr(msg, 0);
280:
281: while (1) {
282: size_t n = read(fdin, buffer, bufsize);
283: if (n == -1)
284: err(1, "read from %s", msgfile);
285: if (n == 0)
286: break;
1.8 ! tedu 287: SHA512_256Data(buffer, n, p);
! 288: p += SHA512_256_DIGEST_STRING_LENGTH;
1.1 espie 289: p[-1] = '\n';
290: if (msg + space < p)
291: errx(1, "file too long %s", msgfile);
292: }
293: *p = 0;
294:
295: fdout = xopen(sigfile, O_CREAT|O_TRUNC|O_NOFOLLOW|O_WRONLY, 0666);
296: sighdr = createsig(seckeyfile, msgfile, msg, p-msg);
297: fake[8] = h.xflg;
298:
299: writeall(fdout, fake, sizeof fake, sigfile);
300: writeall(fdout, sighdr, strlen(sighdr), sigfile);
301: free(sighdr);
302: /* need the 0 ! */
303: writeall(fdout, msg, p - msg + 1, sigfile);
304: free(msg);
305:
306: if (lseek(fdin, h.headerlength, SEEK_SET) == -1)
307: err(1, "seek in %s", msgfile);
308:
309: while (1) {
310: size_t n = read(fdin, buffer, bufsize);
311: if (n == -1)
312: err(1, "read from %s", msgfile);
313: if (n == 0)
314: break;
315: writeall(fdout, buffer, n, sigfile);
316: }
317: free(buffer);
318: close(fdout);
319: }
320: #endif
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