Annotation of src/usr.bin/ssh/authfile.c, Revision 1.127
1.127 ! djm 1: /* $OpenBSD: authfile.c,v 1.126 2017/05/31 09:15:42 deraadt Exp $ */
1.1 deraadt 2: /*
1.99 markus 3: * Copyright (c) 2000, 2013 Markus Friedl. All rights reserved.
1.19 deraadt 4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT 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 OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.9 deraadt 24: */
1.1 deraadt 25:
1.62 stevesk 26:
27: #include <sys/types.h>
28: #include <sys/stat.h>
1.76 deraadt 29: #include <sys/uio.h>
1.1 deraadt 30:
1.69 stevesk 31: #include <errno.h>
1.68 stevesk 32: #include <fcntl.h>
1.74 stevesk 33: #include <stdio.h>
1.73 stevesk 34: #include <stdlib.h>
1.71 stevesk 35: #include <string.h>
1.70 stevesk 36: #include <unistd.h>
1.110 deraadt 37: #include <limits.h>
1.15 markus 38:
1.25 markus 39: #include "cipher.h"
1.1 deraadt 40: #include "ssh.h"
1.25 markus 41: #include "log.h"
1.27 itojun 42: #include "authfile.h"
1.60 dtucker 43: #include "misc.h"
1.61 djm 44: #include "atomicio.h"
1.116 markus 45: #include "sshkey.h"
1.107 djm 46: #include "sshbuf.h"
47: #include "ssherr.h"
1.108 djm 48: #include "krl.h"
1.1 deraadt 49:
1.88 djm 50: #define MAX_KEY_FILE_SIZE (1024 * 1024)
51:
1.86 djm 52: /* Save a key blob to a file */
53: static int
1.107 djm 54: sshkey_save_private_blob(struct sshbuf *keybuf, const char *filename)
1.86 djm 55: {
1.107 djm 56: int fd, oerrno;
1.86 djm 57:
1.107 djm 58: if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0)
59: return SSH_ERR_SYSTEM_ERROR;
60: if (atomicio(vwrite, fd, (u_char *)sshbuf_ptr(keybuf),
61: sshbuf_len(keybuf)) != sshbuf_len(keybuf)) {
62: oerrno = errno;
1.86 djm 63: close(fd);
64: unlink(filename);
1.107 djm 65: errno = oerrno;
66: return SSH_ERR_SYSTEM_ERROR;
1.86 djm 67: }
68: close(fd);
1.107 djm 69: return 0;
1.86 djm 70: }
71:
72: int
1.107 djm 73: sshkey_save_private(struct sshkey *key, const char *filename,
74: const char *passphrase, const char *comment,
75: int force_new_format, const char *new_format_cipher, int new_format_rounds)
1.86 djm 76: {
1.107 djm 77: struct sshbuf *keyblob = NULL;
78: int r;
1.86 djm 79:
1.107 djm 80: if ((keyblob = sshbuf_new()) == NULL)
81: return SSH_ERR_ALLOC_FAIL;
82: if ((r = sshkey_private_to_fileblob(key, keyblob, passphrase, comment,
83: force_new_format, new_format_cipher, new_format_rounds)) != 0)
1.86 djm 84: goto out;
1.107 djm 85: if ((r = sshkey_save_private_blob(keyblob, filename)) != 0)
1.86 djm 86: goto out;
1.107 djm 87: r = 0;
1.86 djm 88: out:
1.107 djm 89: sshbuf_free(keyblob);
90: return r;
1.86 djm 91: }
92:
1.88 djm 93: /* Load a key from a fd into a buffer */
94: int
1.109 djm 95: sshkey_load_file(int fd, struct sshbuf *blob)
1.86 djm 96: {
1.88 djm 97: u_char buf[1024];
1.86 djm 98: size_t len;
1.51 fgsch 99: struct stat st;
1.126 deraadt 100: int r;
1.8 markus 101:
1.107 djm 102: if (fstat(fd, &st) < 0)
103: return SSH_ERR_SYSTEM_ERROR;
1.88 djm 104: if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
1.107 djm 105: st.st_size > MAX_KEY_FILE_SIZE)
106: return SSH_ERR_INVALID_FORMAT;
1.88 djm 107: for (;;) {
108: if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
109: if (errno == EPIPE)
110: break;
1.107 djm 111: r = SSH_ERR_SYSTEM_ERROR;
112: goto out;
1.88 djm 113: }
1.107 djm 114: if ((r = sshbuf_put(blob, buf, len)) != 0)
115: goto out;
116: if (sshbuf_len(blob) > MAX_KEY_FILE_SIZE) {
117: r = SSH_ERR_INVALID_FORMAT;
118: goto out;
1.88 djm 119: }
120: }
121: if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
1.107 djm 122: st.st_size != (off_t)sshbuf_len(blob)) {
123: r = SSH_ERR_FILE_CHANGED;
124: goto out;
1.8 markus 125: }
1.107 djm 126: r = 0;
1.88 djm 127:
1.107 djm 128: out:
129: explicit_bzero(buf, sizeof(buf));
130: if (r != 0)
131: sshbuf_reset(blob);
132: return r;
1.86 djm 133: }
1.8 markus 134:
1.1 deraadt 135:
1.107 djm 136: /* XXX remove error() calls from here? */
1.63 dtucker 137: int
1.107 djm 138: sshkey_perm_ok(int fd, const char *filename)
1.15 markus 139: {
140: struct stat st;
141:
1.38 markus 142: if (fstat(fd, &st) < 0)
1.107 djm 143: return SSH_ERR_SYSTEM_ERROR;
1.38 markus 144: /*
145: * if a key owned by the user is accessed, then we check the
146: * permissions of the file. if the key owned by a different user,
147: * then we don't care.
148: */
149: if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
1.15 markus 150: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
151: error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
152: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.38 markus 153: error("Permissions 0%3.3o for '%s' are too open.",
1.54 djm 154: (u_int)st.st_mode & 0777, filename);
1.114 djm 155: error("It is required that your private key files are NOT accessible by others.");
1.29 markus 156: error("This private key will be ignored.");
1.107 djm 157: return SSH_ERR_KEY_BAD_PERMISSIONS;
1.15 markus 158: }
1.107 djm 159: return 0;
1.29 markus 160: }
161:
1.107 djm 162: /* XXX kill perm_ok now that we have SSH_ERR_KEY_BAD_PERMISSIONS? */
163: int
164: sshkey_load_private_type(int type, const char *filename, const char *passphrase,
165: struct sshkey **keyp, char **commentp, int *perm_ok)
1.86 djm 166: {
1.107 djm 167: int fd, r;
1.99 markus 168:
1.121 djm 169: if (keyp != NULL)
170: *keyp = NULL;
1.107 djm 171: if (commentp != NULL)
172: *commentp = NULL;
1.86 djm 173:
1.107 djm 174: if ((fd = open(filename, O_RDONLY)) < 0) {
1.78 dtucker 175: if (perm_ok != NULL)
176: *perm_ok = 0;
1.107 djm 177: return SSH_ERR_SYSTEM_ERROR;
1.78 dtucker 178: }
1.107 djm 179: if (sshkey_perm_ok(fd, filename) != 0) {
1.67 dtucker 180: if (perm_ok != NULL)
181: *perm_ok = 0;
1.107 djm 182: r = SSH_ERR_KEY_BAD_PERMISSIONS;
183: goto out;
1.29 markus 184: }
1.67 dtucker 185: if (perm_ok != NULL)
186: *perm_ok = 1;
1.86 djm 187:
1.109 djm 188: r = sshkey_load_private_type_fd(fd, type, passphrase, keyp, commentp);
189: out:
190: close(fd);
191: return r;
192: }
193:
194: int
195: sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
196: struct sshkey **keyp, char **commentp)
197: {
198: struct sshbuf *buffer = NULL;
199: int r;
200:
1.121 djm 201: if (keyp != NULL)
202: *keyp = NULL;
1.107 djm 203: if ((buffer = sshbuf_new()) == NULL) {
204: r = SSH_ERR_ALLOC_FAIL;
205: goto out;
1.15 markus 206: }
1.109 djm 207: if ((r = sshkey_load_file(fd, buffer)) != 0 ||
208: (r = sshkey_parse_private_fileblob_type(buffer, type,
209: passphrase, keyp, commentp)) != 0)
1.107 djm 210: goto out;
1.109 djm 211:
212: /* success */
1.107 djm 213: r = 0;
214: out:
1.120 mmcc 215: sshbuf_free(buffer);
1.107 djm 216: return r;
1.29 markus 217: }
218:
1.107 djm 219: /* XXX this is almost identical to sshkey_load_private_type() */
220: int
221: sshkey_load_private(const char *filename, const char *passphrase,
222: struct sshkey **keyp, char **commentp)
1.88 djm 223: {
1.107 djm 224: struct sshbuf *buffer = NULL;
225: int r, fd;
1.88 djm 226:
1.121 djm 227: if (keyp != NULL)
228: *keyp = NULL;
1.107 djm 229: if (commentp != NULL)
230: *commentp = NULL;
1.88 djm 231:
1.107 djm 232: if ((fd = open(filename, O_RDONLY)) < 0)
233: return SSH_ERR_SYSTEM_ERROR;
234: if (sshkey_perm_ok(fd, filename) != 0) {
235: r = SSH_ERR_KEY_BAD_PERMISSIONS;
236: goto out;
1.29 markus 237: }
1.86 djm 238:
1.107 djm 239: if ((buffer = sshbuf_new()) == NULL) {
240: r = SSH_ERR_ALLOC_FAIL;
241: goto out;
1.86 djm 242: }
1.109 djm 243: if ((r = sshkey_load_file(fd, buffer)) != 0 ||
1.117 tim 244: (r = sshkey_parse_private_fileblob(buffer, passphrase, keyp,
245: commentp)) != 0)
1.107 djm 246: goto out;
247: r = 0;
248: out:
1.86 djm 249: close(fd);
1.120 mmcc 250: sshbuf_free(buffer);
1.107 djm 251: return r;
1.18 markus 252: }
253:
1.37 itojun 254: static int
1.107 djm 255: sshkey_try_load_public(struct sshkey *k, const char *filename, char **commentp)
1.18 markus 256: {
257: FILE *f;
1.59 dtucker 258: char line[SSH_MAX_PUBKEY_BYTES];
1.18 markus 259: char *cp;
1.60 dtucker 260: u_long linenum = 0;
1.107 djm 261: int r;
1.18 markus 262:
1.107 djm 263: if (commentp != NULL)
264: *commentp = NULL;
265: if ((f = fopen(filename, "r")) == NULL)
266: return SSH_ERR_SYSTEM_ERROR;
267: while (read_keyfile_line(f, filename, line, sizeof(line),
268: &linenum) != -1) {
269: cp = line;
270: switch (*cp) {
271: case '#':
272: case '\n':
273: case '\0':
274: continue;
275: }
276: /* Abort loading if this looks like a private key */
277: if (strncmp(cp, "-----BEGIN", 10) == 0 ||
278: strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
279: break;
280: /* Skip leading whitespace. */
281: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
282: ;
283: if (*cp) {
284: if ((r = sshkey_read(k, &cp)) == 0) {
285: cp[strcspn(cp, "\r\n")] = '\0';
286: if (commentp) {
287: *commentp = strdup(*cp ?
288: cp : filename);
289: if (*commentp == NULL)
290: r = SSH_ERR_ALLOC_FAIL;
1.18 markus 291: }
1.107 djm 292: fclose(f);
293: return r;
1.18 markus 294: }
295: }
296: }
1.107 djm 297: fclose(f);
298: return SSH_ERR_INVALID_FORMAT;
1.18 markus 299: }
300:
1.125 markus 301: /* load public key from any pubkey file */
1.107 djm 302: int
303: sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
1.18 markus 304: {
1.107 djm 305: struct sshkey *pub = NULL;
1.125 markus 306: char *file = NULL;
307: int r;
1.18 markus 308:
1.107 djm 309: if (keyp != NULL)
310: *keyp = NULL;
311: if (commentp != NULL)
312: *commentp = NULL;
313:
314: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
315: return SSH_ERR_ALLOC_FAIL;
316: if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
1.125 markus 317: if (keyp != NULL) {
1.107 djm 318: *keyp = pub;
1.125 markus 319: pub = NULL;
320: }
321: r = 0;
322: goto out;
1.107 djm 323: }
324: sshkey_free(pub);
1.53 markus 325:
1.107 djm 326: /* try .pub suffix */
1.125 markus 327: if (asprintf(&file, "%s.pub", filename) == -1)
1.107 djm 328: return SSH_ERR_ALLOC_FAIL;
1.125 markus 329: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
330: r = SSH_ERR_ALLOC_FAIL;
331: goto out;
332: }
333: if ((r = sshkey_try_load_public(pub, file, commentp)) == 0) {
334: if (keyp != NULL) {
1.107 djm 335: *keyp = pub;
1.125 markus 336: pub = NULL;
337: }
338: r = 0;
1.107 djm 339: }
1.125 markus 340: out:
341: free(file);
1.107 djm 342: sshkey_free(pub);
343: return r;
1.81 djm 344: }
345:
346: /* Load the certificate associated with the named private key */
1.107 djm 347: int
348: sshkey_load_cert(const char *filename, struct sshkey **keyp)
1.81 djm 349: {
1.107 djm 350: struct sshkey *pub = NULL;
351: char *file = NULL;
352: int r = SSH_ERR_INTERNAL_ERROR;
353:
1.121 djm 354: if (keyp != NULL)
355: *keyp = NULL;
1.81 djm 356:
1.107 djm 357: if (asprintf(&file, "%s-cert.pub", filename) == -1)
358: return SSH_ERR_ALLOC_FAIL;
359:
360: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
361: goto out;
362: }
363: if ((r = sshkey_try_load_public(pub, file, NULL)) != 0)
364: goto out;
1.121 djm 365: /* success */
366: if (keyp != NULL) {
367: *keyp = pub;
368: pub = NULL;
369: }
1.107 djm 370: r = 0;
371: out:
1.118 mmcc 372: free(file);
1.119 mmcc 373: sshkey_free(pub);
1.107 djm 374: return r;
1.81 djm 375: }
376:
377: /* Load private key and certificate */
1.107 djm 378: int
379: sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
380: struct sshkey **keyp, int *perm_ok)
1.81 djm 381: {
1.107 djm 382: struct sshkey *key = NULL, *cert = NULL;
383: int r;
384:
1.121 djm 385: if (keyp != NULL)
386: *keyp = NULL;
1.81 djm 387:
388: switch (type) {
1.106 markus 389: #ifdef WITH_OPENSSL
1.81 djm 390: case KEY_RSA:
391: case KEY_DSA:
1.83 djm 392: case KEY_ECDSA:
1.116 markus 393: #endif /* WITH_OPENSSL */
1.101 djm 394: case KEY_ED25519:
1.107 djm 395: case KEY_UNSPEC:
1.81 djm 396: break;
397: default:
1.107 djm 398: return SSH_ERR_KEY_TYPE_UNKNOWN;
1.81 djm 399: }
400:
1.107 djm 401: if ((r = sshkey_load_private_type(type, filename,
402: passphrase, &key, NULL, perm_ok)) != 0 ||
403: (r = sshkey_load_cert(filename, &cert)) != 0)
404: goto out;
1.81 djm 405:
406: /* Make sure the private key matches the certificate */
1.107 djm 407: if (sshkey_equal_public(key, cert) == 0) {
408: r = SSH_ERR_KEY_CERT_MISMATCH;
409: goto out;
1.81 djm 410: }
411:
1.115 djm 412: if ((r = sshkey_to_certified(key)) != 0 ||
1.107 djm 413: (r = sshkey_cert_copy(cert, key)) != 0)
414: goto out;
415: r = 0;
1.121 djm 416: if (keyp != NULL) {
417: *keyp = key;
418: key = NULL;
419: }
1.107 djm 420: out:
1.119 mmcc 421: sshkey_free(key);
422: sshkey_free(cert);
1.107 djm 423: return r;
1.1 deraadt 424: }
1.80 djm 425:
426: /*
1.107 djm 427: * Returns success if the specified "key" is listed in the file "filename",
428: * SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
1.108 djm 429: * If "strict_type" is set then the key type must match exactly,
1.80 djm 430: * otherwise a comparison that ignores certficiate data is performed.
1.108 djm 431: * If "check_ca" is set and "key" is a certificate, then its CA key is
432: * also checked and sshkey_in_file() will return success if either is found.
1.80 djm 433: */
434: int
1.108 djm 435: sshkey_in_file(struct sshkey *key, const char *filename, int strict_type,
436: int check_ca)
1.80 djm 437: {
438: FILE *f;
439: char line[SSH_MAX_PUBKEY_BYTES];
440: char *cp;
441: u_long linenum = 0;
1.107 djm 442: int r = 0;
443: struct sshkey *pub = NULL;
444: int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
445: strict_type ? sshkey_equal : sshkey_equal_public;
1.80 djm 446:
1.108 djm 447: if ((f = fopen(filename, "r")) == NULL)
448: return SSH_ERR_SYSTEM_ERROR;
1.80 djm 449:
450: while (read_keyfile_line(f, filename, line, sizeof(line),
1.107 djm 451: &linenum) != -1) {
1.80 djm 452: cp = line;
453:
454: /* Skip leading whitespace. */
455: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
456: ;
457:
458: /* Skip comments and empty lines */
459: switch (*cp) {
460: case '#':
461: case '\n':
462: case '\0':
463: continue;
464: }
465:
1.107 djm 466: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
467: r = SSH_ERR_ALLOC_FAIL;
468: goto out;
1.80 djm 469: }
1.107 djm 470: if ((r = sshkey_read(pub, &cp)) != 0)
471: goto out;
1.108 djm 472: if (sshkey_compare(key, pub) ||
473: (check_ca && sshkey_is_cert(key) &&
474: sshkey_compare(key->cert->signature_key, pub))) {
1.107 djm 475: r = 0;
476: goto out;
1.80 djm 477: }
1.107 djm 478: sshkey_free(pub);
479: pub = NULL;
1.80 djm 480: }
1.107 djm 481: r = SSH_ERR_KEY_NOT_FOUND;
482: out:
1.119 mmcc 483: sshkey_free(pub);
1.80 djm 484: fclose(f);
1.107 djm 485: return r;
1.108 djm 486: }
487:
488: /*
489: * Checks whether the specified key is revoked, returning 0 if not,
490: * SSH_ERR_KEY_REVOKED if it is or another error code if something
491: * unexpected happened.
492: * This will check both the key and, if it is a certificate, its CA key too.
493: * "revoked_keys_file" may be a KRL or a one-per-line list of public keys.
494: */
495: int
496: sshkey_check_revoked(struct sshkey *key, const char *revoked_keys_file)
497: {
498: int r;
499:
500: r = ssh_krl_file_contains_key(revoked_keys_file, key);
501: /* If this was not a KRL to begin with then continue below */
502: if (r != SSH_ERR_KRL_BAD_MAGIC)
503: return r;
504:
505: /*
506: * If the file is not a KRL or we can't handle KRLs then attempt to
507: * parse the file as a flat list of keys.
508: */
509: switch ((r = sshkey_in_file(key, revoked_keys_file, 0, 1))) {
510: case 0:
511: /* Key found => revoked */
512: return SSH_ERR_KEY_REVOKED;
513: case SSH_ERR_KEY_NOT_FOUND:
514: /* Key not found => not revoked */
515: return 0;
516: default:
517: /* Some other error occurred */
518: return r;
519: }
1.80 djm 520: }
1.107 djm 521:
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