Annotation of src/usr.bin/ssh/authfile.c, Revision 1.134
1.134 ! dtucker 1: /* $OpenBSD: authfile.c,v 1.133 2019/07/15 13:16:29 djm 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:
1.132 deraadt 58: if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) == -1)
1.107 djm 59: return SSH_ERR_SYSTEM_ERROR;
1.130 markus 60: if (atomicio(vwrite, fd, sshbuf_mutable_ptr(keybuf),
1.107 djm 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,
1.133 djm 75: int format, const char *openssh_format_cipher, int openssh_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,
1.133 djm 83: format, openssh_format_cipher, openssh_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:
1.132 deraadt 102: if (fstat(fd, &st) == -1)
1.107 djm 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:
1.132 deraadt 142: if (fstat(fd, &st) == -1)
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: int
163: sshkey_load_private_type(int type, const char *filename, const char *passphrase,
1.134 ! dtucker 164: struct sshkey **keyp, char **commentp)
1.86 djm 165: {
1.107 djm 166: int fd, r;
1.99 markus 167:
1.121 djm 168: if (keyp != NULL)
169: *keyp = NULL;
1.107 djm 170: if (commentp != NULL)
171: *commentp = NULL;
1.86 djm 172:
1.134 ! dtucker 173: if ((fd = open(filename, O_RDONLY)) == -1)
1.107 djm 174: return SSH_ERR_SYSTEM_ERROR;
1.134 ! dtucker 175:
! 176: r = sshkey_perm_ok(fd, filename);
! 177: if (r != 0)
1.107 djm 178: goto out;
1.86 djm 179:
1.109 djm 180: r = sshkey_load_private_type_fd(fd, type, passphrase, keyp, commentp);
1.128 markus 181: if (r == 0 && keyp && *keyp)
182: r = sshkey_set_filename(*keyp, filename);
1.109 djm 183: out:
184: close(fd);
185: return r;
186: }
187:
188: int
189: sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
190: struct sshkey **keyp, char **commentp)
191: {
192: struct sshbuf *buffer = NULL;
193: int r;
194:
1.121 djm 195: if (keyp != NULL)
196: *keyp = NULL;
1.107 djm 197: if ((buffer = sshbuf_new()) == NULL) {
198: r = SSH_ERR_ALLOC_FAIL;
199: goto out;
1.15 markus 200: }
1.109 djm 201: if ((r = sshkey_load_file(fd, buffer)) != 0 ||
202: (r = sshkey_parse_private_fileblob_type(buffer, type,
203: passphrase, keyp, commentp)) != 0)
1.107 djm 204: goto out;
1.109 djm 205:
206: /* success */
1.107 djm 207: r = 0;
208: out:
1.120 mmcc 209: sshbuf_free(buffer);
1.107 djm 210: return r;
1.29 markus 211: }
212:
1.107 djm 213: /* XXX this is almost identical to sshkey_load_private_type() */
214: int
215: sshkey_load_private(const char *filename, const char *passphrase,
216: struct sshkey **keyp, char **commentp)
1.88 djm 217: {
1.107 djm 218: struct sshbuf *buffer = NULL;
219: int r, fd;
1.88 djm 220:
1.121 djm 221: if (keyp != NULL)
222: *keyp = NULL;
1.107 djm 223: if (commentp != NULL)
224: *commentp = NULL;
1.88 djm 225:
1.132 deraadt 226: if ((fd = open(filename, O_RDONLY)) == -1)
1.107 djm 227: return SSH_ERR_SYSTEM_ERROR;
228: if (sshkey_perm_ok(fd, filename) != 0) {
229: r = SSH_ERR_KEY_BAD_PERMISSIONS;
230: goto out;
1.29 markus 231: }
1.86 djm 232:
1.107 djm 233: if ((buffer = sshbuf_new()) == NULL) {
234: r = SSH_ERR_ALLOC_FAIL;
235: goto out;
1.86 djm 236: }
1.109 djm 237: if ((r = sshkey_load_file(fd, buffer)) != 0 ||
1.117 tim 238: (r = sshkey_parse_private_fileblob(buffer, passphrase, keyp,
239: commentp)) != 0)
1.107 djm 240: goto out;
1.128 markus 241: if (keyp && *keyp &&
242: (r = sshkey_set_filename(*keyp, filename)) != 0)
243: goto out;
1.107 djm 244: r = 0;
245: out:
1.86 djm 246: close(fd);
1.120 mmcc 247: sshbuf_free(buffer);
1.107 djm 248: return r;
1.18 markus 249: }
250:
1.37 itojun 251: static int
1.107 djm 252: sshkey_try_load_public(struct sshkey *k, const char *filename, char **commentp)
1.18 markus 253: {
254: FILE *f;
1.129 markus 255: char *line = NULL, *cp;
256: size_t linesize = 0;
1.107 djm 257: int r;
1.18 markus 258:
1.107 djm 259: if (commentp != NULL)
260: *commentp = NULL;
261: if ((f = fopen(filename, "r")) == NULL)
262: return SSH_ERR_SYSTEM_ERROR;
1.129 markus 263: while (getline(&line, &linesize, f) != -1) {
1.107 djm 264: cp = line;
265: switch (*cp) {
266: case '#':
267: case '\n':
268: case '\0':
269: continue;
270: }
271: /* Abort loading if this looks like a private key */
272: if (strncmp(cp, "-----BEGIN", 10) == 0 ||
273: strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
274: break;
275: /* Skip leading whitespace. */
276: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
277: ;
278: if (*cp) {
279: if ((r = sshkey_read(k, &cp)) == 0) {
280: cp[strcspn(cp, "\r\n")] = '\0';
281: if (commentp) {
282: *commentp = strdup(*cp ?
283: cp : filename);
284: if (*commentp == NULL)
285: r = SSH_ERR_ALLOC_FAIL;
1.18 markus 286: }
1.129 markus 287: free(line);
1.107 djm 288: fclose(f);
289: return r;
1.18 markus 290: }
291: }
292: }
1.129 markus 293: free(line);
1.107 djm 294: fclose(f);
295: return SSH_ERR_INVALID_FORMAT;
1.18 markus 296: }
297:
1.125 markus 298: /* load public key from any pubkey file */
1.107 djm 299: int
300: sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
1.18 markus 301: {
1.107 djm 302: struct sshkey *pub = NULL;
1.125 markus 303: char *file = NULL;
304: int r;
1.18 markus 305:
1.107 djm 306: if (keyp != NULL)
307: *keyp = NULL;
308: if (commentp != NULL)
309: *commentp = NULL;
310:
311: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
312: return SSH_ERR_ALLOC_FAIL;
313: if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
1.125 markus 314: if (keyp != NULL) {
1.107 djm 315: *keyp = pub;
1.125 markus 316: pub = NULL;
317: }
318: r = 0;
319: goto out;
1.107 djm 320: }
321: sshkey_free(pub);
1.53 markus 322:
1.107 djm 323: /* try .pub suffix */
1.125 markus 324: if (asprintf(&file, "%s.pub", filename) == -1)
1.107 djm 325: return SSH_ERR_ALLOC_FAIL;
1.125 markus 326: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
327: r = SSH_ERR_ALLOC_FAIL;
328: goto out;
329: }
330: if ((r = sshkey_try_load_public(pub, file, commentp)) == 0) {
331: if (keyp != NULL) {
1.107 djm 332: *keyp = pub;
1.125 markus 333: pub = NULL;
334: }
335: r = 0;
1.107 djm 336: }
1.125 markus 337: out:
338: free(file);
1.107 djm 339: sshkey_free(pub);
340: return r;
1.81 djm 341: }
342:
343: /* Load the certificate associated with the named private key */
1.107 djm 344: int
345: sshkey_load_cert(const char *filename, struct sshkey **keyp)
1.81 djm 346: {
1.107 djm 347: struct sshkey *pub = NULL;
348: char *file = NULL;
349: int r = SSH_ERR_INTERNAL_ERROR;
350:
1.121 djm 351: if (keyp != NULL)
352: *keyp = NULL;
1.81 djm 353:
1.107 djm 354: if (asprintf(&file, "%s-cert.pub", filename) == -1)
355: return SSH_ERR_ALLOC_FAIL;
356:
357: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
358: goto out;
359: }
360: if ((r = sshkey_try_load_public(pub, file, NULL)) != 0)
361: goto out;
1.121 djm 362: /* success */
363: if (keyp != NULL) {
364: *keyp = pub;
365: pub = NULL;
366: }
1.107 djm 367: r = 0;
368: out:
1.118 mmcc 369: free(file);
1.119 mmcc 370: sshkey_free(pub);
1.107 djm 371: return r;
1.81 djm 372: }
373:
374: /* Load private key and certificate */
1.107 djm 375: int
376: sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
1.134 ! dtucker 377: struct sshkey **keyp)
1.81 djm 378: {
1.107 djm 379: struct sshkey *key = NULL, *cert = NULL;
380: int r;
381:
1.121 djm 382: if (keyp != NULL)
383: *keyp = NULL;
1.81 djm 384:
385: switch (type) {
1.106 markus 386: #ifdef WITH_OPENSSL
1.81 djm 387: case KEY_RSA:
388: case KEY_DSA:
1.83 djm 389: case KEY_ECDSA:
1.116 markus 390: #endif /* WITH_OPENSSL */
1.101 djm 391: case KEY_ED25519:
1.128 markus 392: case KEY_XMSS:
1.107 djm 393: case KEY_UNSPEC:
1.81 djm 394: break;
395: default:
1.107 djm 396: return SSH_ERR_KEY_TYPE_UNKNOWN;
1.81 djm 397: }
398:
1.107 djm 399: if ((r = sshkey_load_private_type(type, filename,
1.134 ! dtucker 400: passphrase, &key, NULL)) != 0 ||
1.107 djm 401: (r = sshkey_load_cert(filename, &cert)) != 0)
402: goto out;
1.81 djm 403:
404: /* Make sure the private key matches the certificate */
1.107 djm 405: if (sshkey_equal_public(key, cert) == 0) {
406: r = SSH_ERR_KEY_CERT_MISMATCH;
407: goto out;
1.81 djm 408: }
409:
1.115 djm 410: if ((r = sshkey_to_certified(key)) != 0 ||
1.107 djm 411: (r = sshkey_cert_copy(cert, key)) != 0)
412: goto out;
413: r = 0;
1.121 djm 414: if (keyp != NULL) {
415: *keyp = key;
416: key = NULL;
417: }
1.107 djm 418: out:
1.119 mmcc 419: sshkey_free(key);
420: sshkey_free(cert);
1.107 djm 421: return r;
1.1 deraadt 422: }
1.80 djm 423:
424: /*
1.107 djm 425: * Returns success if the specified "key" is listed in the file "filename",
426: * SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
1.108 djm 427: * If "strict_type" is set then the key type must match exactly,
1.80 djm 428: * otherwise a comparison that ignores certficiate data is performed.
1.108 djm 429: * If "check_ca" is set and "key" is a certificate, then its CA key is
430: * also checked and sshkey_in_file() will return success if either is found.
1.80 djm 431: */
432: int
1.108 djm 433: sshkey_in_file(struct sshkey *key, const char *filename, int strict_type,
434: int check_ca)
1.80 djm 435: {
436: FILE *f;
1.129 markus 437: char *line = NULL, *cp;
438: size_t linesize = 0;
1.107 djm 439: int r = 0;
440: struct sshkey *pub = NULL;
1.129 markus 441:
1.107 djm 442: int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
443: strict_type ? sshkey_equal : sshkey_equal_public;
1.80 djm 444:
1.108 djm 445: if ((f = fopen(filename, "r")) == NULL)
446: return SSH_ERR_SYSTEM_ERROR;
1.80 djm 447:
1.129 markus 448: while (getline(&line, &linesize, f) != -1) {
1.131 djm 449: sshkey_free(pub);
450: pub = NULL;
1.80 djm 451: cp = line;
452:
453: /* Skip leading whitespace. */
454: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
455: ;
456:
457: /* Skip comments and empty lines */
458: switch (*cp) {
459: case '#':
460: case '\n':
461: case '\0':
462: continue;
463: }
464:
1.107 djm 465: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
466: r = SSH_ERR_ALLOC_FAIL;
467: goto out;
1.80 djm 468: }
1.131 djm 469: switch (r = sshkey_read(pub, &cp)) {
470: case 0:
471: break;
472: case SSH_ERR_KEY_LENGTH:
473: continue;
474: default:
1.107 djm 475: goto out;
1.131 djm 476: }
1.108 djm 477: if (sshkey_compare(key, pub) ||
478: (check_ca && sshkey_is_cert(key) &&
479: sshkey_compare(key->cert->signature_key, pub))) {
1.107 djm 480: r = 0;
481: goto out;
1.80 djm 482: }
483: }
1.107 djm 484: r = SSH_ERR_KEY_NOT_FOUND;
485: out:
1.129 markus 486: free(line);
1.119 mmcc 487: sshkey_free(pub);
1.80 djm 488: fclose(f);
1.107 djm 489: return r;
1.108 djm 490: }
491:
492: /*
493: * Checks whether the specified key is revoked, returning 0 if not,
494: * SSH_ERR_KEY_REVOKED if it is or another error code if something
495: * unexpected happened.
496: * This will check both the key and, if it is a certificate, its CA key too.
497: * "revoked_keys_file" may be a KRL or a one-per-line list of public keys.
498: */
499: int
500: sshkey_check_revoked(struct sshkey *key, const char *revoked_keys_file)
501: {
502: int r;
503:
504: r = ssh_krl_file_contains_key(revoked_keys_file, key);
505: /* If this was not a KRL to begin with then continue below */
506: if (r != SSH_ERR_KRL_BAD_MAGIC)
507: return r;
508:
509: /*
510: * If the file is not a KRL or we can't handle KRLs then attempt to
511: * parse the file as a flat list of keys.
512: */
513: switch ((r = sshkey_in_file(key, revoked_keys_file, 0, 1))) {
514: case 0:
515: /* Key found => revoked */
516: return SSH_ERR_KEY_REVOKED;
517: case SSH_ERR_KEY_NOT_FOUND:
518: /* Key not found => not revoked */
519: return 0;
520: default:
521: /* Some other error occurred */
522: return r;
523: }
1.80 djm 524: }
1.107 djm 525:
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