Annotation of src/usr.bin/ssh/authfile.c, Revision 1.142
1.142 ! jsg 1: /* $OpenBSD: authfile.c,v 1.141 2020/06/18 23:33:38 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: {
1.137 djm 56: int r;
57: mode_t omask;
1.86 djm 58:
1.137 djm 59: omask = umask(077);
60: r = sshbuf_write_file(filename, keybuf);
61: umask(omask);
62: return r;
1.86 djm 63: }
64:
65: int
1.107 djm 66: sshkey_save_private(struct sshkey *key, const char *filename,
67: const char *passphrase, const char *comment,
1.133 djm 68: int format, const char *openssh_format_cipher, int openssh_format_rounds)
1.86 djm 69: {
1.107 djm 70: struct sshbuf *keyblob = NULL;
71: int r;
1.86 djm 72:
1.107 djm 73: if ((keyblob = sshbuf_new()) == NULL)
74: return SSH_ERR_ALLOC_FAIL;
75: if ((r = sshkey_private_to_fileblob(key, keyblob, passphrase, comment,
1.133 djm 76: format, openssh_format_cipher, openssh_format_rounds)) != 0)
1.86 djm 77: goto out;
1.107 djm 78: if ((r = sshkey_save_private_blob(keyblob, filename)) != 0)
1.86 djm 79: goto out;
1.107 djm 80: r = 0;
1.86 djm 81: out:
1.107 djm 82: sshbuf_free(keyblob);
83: return r;
1.86 djm 84: }
85:
1.107 djm 86: /* XXX remove error() calls from here? */
1.63 dtucker 87: int
1.107 djm 88: sshkey_perm_ok(int fd, const char *filename)
1.15 markus 89: {
90: struct stat st;
91:
1.132 deraadt 92: if (fstat(fd, &st) == -1)
1.107 djm 93: return SSH_ERR_SYSTEM_ERROR;
1.38 markus 94: /*
95: * if a key owned by the user is accessed, then we check the
96: * permissions of the file. if the key owned by a different user,
97: * then we don't care.
98: */
99: if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
1.15 markus 100: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
101: error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
102: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.38 markus 103: error("Permissions 0%3.3o for '%s' are too open.",
1.54 djm 104: (u_int)st.st_mode & 0777, filename);
1.114 djm 105: error("It is required that your private key files are NOT accessible by others.");
1.29 markus 106: error("This private key will be ignored.");
1.107 djm 107: return SSH_ERR_KEY_BAD_PERMISSIONS;
1.15 markus 108: }
1.107 djm 109: return 0;
1.29 markus 110: }
111:
1.107 djm 112: int
113: sshkey_load_private_type(int type, const char *filename, const char *passphrase,
1.134 dtucker 114: struct sshkey **keyp, char **commentp)
1.86 djm 115: {
1.107 djm 116: int fd, r;
1.99 markus 117:
1.121 djm 118: if (keyp != NULL)
119: *keyp = NULL;
1.107 djm 120: if (commentp != NULL)
121: *commentp = NULL;
1.86 djm 122:
1.134 dtucker 123: if ((fd = open(filename, O_RDONLY)) == -1)
1.107 djm 124: return SSH_ERR_SYSTEM_ERROR;
1.134 dtucker 125:
126: r = sshkey_perm_ok(fd, filename);
127: if (r != 0)
1.107 djm 128: goto out;
1.86 djm 129:
1.109 djm 130: r = sshkey_load_private_type_fd(fd, type, passphrase, keyp, commentp);
1.128 markus 131: if (r == 0 && keyp && *keyp)
132: r = sshkey_set_filename(*keyp, filename);
1.109 djm 133: out:
134: close(fd);
135: return r;
136: }
137:
138: int
1.140 djm 139: sshkey_load_private(const char *filename, const char *passphrase,
140: struct sshkey **keyp, char **commentp)
141: {
142: return sshkey_load_private_type(KEY_UNSPEC, filename, passphrase,
143: keyp, commentp);
144: }
145:
146: int
1.109 djm 147: sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
148: struct sshkey **keyp, char **commentp)
149: {
150: struct sshbuf *buffer = NULL;
151: int r;
152:
1.121 djm 153: if (keyp != NULL)
154: *keyp = NULL;
1.137 djm 155: if ((r = sshbuf_load_fd(fd, &buffer)) != 0 ||
1.109 djm 156: (r = sshkey_parse_private_fileblob_type(buffer, type,
157: passphrase, keyp, commentp)) != 0)
1.107 djm 158: goto out;
1.109 djm 159:
160: /* success */
1.107 djm 161: r = 0;
162: out:
1.120 mmcc 163: sshbuf_free(buffer);
1.107 djm 164: return r;
1.18 markus 165: }
166:
1.139 djm 167: /* Load a pubkey from the unencrypted envelope of a new-format private key */
168: static int
169: sshkey_load_pubkey_from_private(const char *filename, struct sshkey **pubkeyp)
170: {
171: struct sshbuf *buffer = NULL;
172: struct sshkey *pubkey = NULL;
173: int r, fd;
174:
175: if (pubkeyp != NULL)
176: *pubkeyp = NULL;
177:
178: if ((fd = open(filename, O_RDONLY)) == -1)
179: return SSH_ERR_SYSTEM_ERROR;
180: if ((r = sshbuf_load_fd(fd, &buffer)) != 0 ||
181: (r = sshkey_parse_pubkey_from_private_fileblob_type(buffer,
182: KEY_UNSPEC, &pubkey)) != 0)
183: goto out;
184: if ((r = sshkey_set_filename(pubkey, filename)) != 0)
185: goto out;
186: /* success */
187: if (pubkeyp != NULL) {
188: *pubkeyp = pubkey;
189: pubkey = NULL;
190: }
191: r = 0;
192: out:
193: close(fd);
194: sshbuf_free(buffer);
195: sshkey_free(pubkey);
196: return r;
197: }
198:
1.37 itojun 199: static int
1.138 djm 200: sshkey_try_load_public(struct sshkey **kp, const char *filename,
201: char **commentp)
1.18 markus 202: {
203: FILE *f;
1.129 markus 204: char *line = NULL, *cp;
205: size_t linesize = 0;
1.107 djm 206: int r;
1.138 djm 207: struct sshkey *k = NULL;
1.18 markus 208:
1.138 djm 209: *kp = NULL;
1.107 djm 210: if (commentp != NULL)
211: *commentp = NULL;
212: if ((f = fopen(filename, "r")) == NULL)
213: return SSH_ERR_SYSTEM_ERROR;
1.138 djm 214: if ((k = sshkey_new(KEY_UNSPEC)) == NULL) {
215: fclose(f);
216: return SSH_ERR_ALLOC_FAIL;
217: }
1.129 markus 218: while (getline(&line, &linesize, f) != -1) {
1.107 djm 219: cp = line;
220: switch (*cp) {
221: case '#':
222: case '\n':
223: case '\0':
224: continue;
225: }
226: /* Abort loading if this looks like a private key */
227: if (strncmp(cp, "-----BEGIN", 10) == 0 ||
228: strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
229: break;
230: /* Skip leading whitespace. */
231: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
232: ;
233: if (*cp) {
234: if ((r = sshkey_read(k, &cp)) == 0) {
235: cp[strcspn(cp, "\r\n")] = '\0';
236: if (commentp) {
237: *commentp = strdup(*cp ?
238: cp : filename);
239: if (*commentp == NULL)
240: r = SSH_ERR_ALLOC_FAIL;
1.18 markus 241: }
1.138 djm 242: /* success */
243: *kp = k;
1.129 markus 244: free(line);
1.107 djm 245: fclose(f);
246: return r;
1.18 markus 247: }
248: }
249: }
1.138 djm 250: free(k);
1.129 markus 251: free(line);
1.107 djm 252: fclose(f);
253: return SSH_ERR_INVALID_FORMAT;
1.18 markus 254: }
255:
1.125 markus 256: /* load public key from any pubkey file */
1.107 djm 257: int
258: sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
1.18 markus 259: {
1.138 djm 260: char *pubfile = NULL;
1.141 djm 261: int r, oerrno;
1.18 markus 262:
1.107 djm 263: if (keyp != NULL)
264: *keyp = NULL;
265: if (commentp != NULL)
266: *commentp = NULL;
267:
1.138 djm 268: if ((r = sshkey_try_load_public(keyp, filename, commentp)) == 0)
1.125 markus 269: goto out;
1.53 markus 270:
1.107 djm 271: /* try .pub suffix */
1.138 djm 272: if (asprintf(&pubfile, "%s.pub", filename) == -1)
1.107 djm 273: return SSH_ERR_ALLOC_FAIL;
1.138 djm 274: if ((r = sshkey_try_load_public(keyp, pubfile, commentp)) == 0)
1.139 djm 275: goto out;
276:
277: /* finally, try to extract public key from private key file */
278: if ((r = sshkey_load_pubkey_from_private(filename, keyp)) == 0)
1.125 markus 279: goto out;
1.138 djm 280:
1.141 djm 281: /* Pretend we couldn't find the key */
282: r = SSH_ERR_SYSTEM_ERROR;
283: errno = ENOENT;
284:
1.125 markus 285: out:
1.141 djm 286: oerrno = errno;
1.138 djm 287: free(pubfile);
1.141 djm 288: errno = oerrno;
1.107 djm 289: return r;
1.81 djm 290: }
291:
292: /* Load the certificate associated with the named private key */
1.107 djm 293: int
294: sshkey_load_cert(const char *filename, struct sshkey **keyp)
1.81 djm 295: {
1.107 djm 296: struct sshkey *pub = NULL;
297: char *file = NULL;
298: int r = SSH_ERR_INTERNAL_ERROR;
299:
1.121 djm 300: if (keyp != NULL)
301: *keyp = NULL;
1.81 djm 302:
1.107 djm 303: if (asprintf(&file, "%s-cert.pub", filename) == -1)
304: return SSH_ERR_ALLOC_FAIL;
305:
1.138 djm 306: r = sshkey_try_load_public(keyp, file, NULL);
1.118 mmcc 307: free(file);
1.119 mmcc 308: sshkey_free(pub);
1.107 djm 309: return r;
1.81 djm 310: }
311:
312: /* Load private key and certificate */
1.107 djm 313: int
314: sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
1.134 dtucker 315: struct sshkey **keyp)
1.81 djm 316: {
1.107 djm 317: struct sshkey *key = NULL, *cert = NULL;
318: int r;
319:
1.121 djm 320: if (keyp != NULL)
321: *keyp = NULL;
1.81 djm 322:
323: switch (type) {
1.106 markus 324: #ifdef WITH_OPENSSL
1.81 djm 325: case KEY_RSA:
326: case KEY_DSA:
1.83 djm 327: case KEY_ECDSA:
1.116 markus 328: #endif /* WITH_OPENSSL */
1.101 djm 329: case KEY_ED25519:
1.128 markus 330: case KEY_XMSS:
1.107 djm 331: case KEY_UNSPEC:
1.81 djm 332: break;
333: default:
1.107 djm 334: return SSH_ERR_KEY_TYPE_UNKNOWN;
1.81 djm 335: }
336:
1.107 djm 337: if ((r = sshkey_load_private_type(type, filename,
1.134 dtucker 338: passphrase, &key, NULL)) != 0 ||
1.107 djm 339: (r = sshkey_load_cert(filename, &cert)) != 0)
340: goto out;
1.81 djm 341:
342: /* Make sure the private key matches the certificate */
1.107 djm 343: if (sshkey_equal_public(key, cert) == 0) {
344: r = SSH_ERR_KEY_CERT_MISMATCH;
345: goto out;
1.81 djm 346: }
347:
1.115 djm 348: if ((r = sshkey_to_certified(key)) != 0 ||
1.107 djm 349: (r = sshkey_cert_copy(cert, key)) != 0)
350: goto out;
351: r = 0;
1.121 djm 352: if (keyp != NULL) {
353: *keyp = key;
354: key = NULL;
355: }
1.107 djm 356: out:
1.119 mmcc 357: sshkey_free(key);
358: sshkey_free(cert);
1.107 djm 359: return r;
1.1 deraadt 360: }
1.80 djm 361:
362: /*
1.107 djm 363: * Returns success if the specified "key" is listed in the file "filename",
364: * SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
1.108 djm 365: * If "strict_type" is set then the key type must match exactly,
1.142 ! jsg 366: * otherwise a comparison that ignores certificate data is performed.
1.108 djm 367: * If "check_ca" is set and "key" is a certificate, then its CA key is
368: * also checked and sshkey_in_file() will return success if either is found.
1.80 djm 369: */
370: int
1.108 djm 371: sshkey_in_file(struct sshkey *key, const char *filename, int strict_type,
372: int check_ca)
1.80 djm 373: {
374: FILE *f;
1.129 markus 375: char *line = NULL, *cp;
376: size_t linesize = 0;
1.107 djm 377: int r = 0;
378: struct sshkey *pub = NULL;
1.129 markus 379:
1.107 djm 380: int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
381: strict_type ? sshkey_equal : sshkey_equal_public;
1.80 djm 382:
1.108 djm 383: if ((f = fopen(filename, "r")) == NULL)
384: return SSH_ERR_SYSTEM_ERROR;
1.80 djm 385:
1.129 markus 386: while (getline(&line, &linesize, f) != -1) {
1.131 djm 387: sshkey_free(pub);
388: pub = NULL;
1.80 djm 389: cp = line;
390:
391: /* Skip leading whitespace. */
392: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
393: ;
394:
395: /* Skip comments and empty lines */
396: switch (*cp) {
397: case '#':
398: case '\n':
399: case '\0':
400: continue;
401: }
402:
1.107 djm 403: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
404: r = SSH_ERR_ALLOC_FAIL;
405: goto out;
1.80 djm 406: }
1.131 djm 407: switch (r = sshkey_read(pub, &cp)) {
408: case 0:
409: break;
410: case SSH_ERR_KEY_LENGTH:
411: continue;
412: default:
1.107 djm 413: goto out;
1.131 djm 414: }
1.108 djm 415: if (sshkey_compare(key, pub) ||
416: (check_ca && sshkey_is_cert(key) &&
417: sshkey_compare(key->cert->signature_key, pub))) {
1.107 djm 418: r = 0;
419: goto out;
1.80 djm 420: }
421: }
1.107 djm 422: r = SSH_ERR_KEY_NOT_FOUND;
423: out:
1.129 markus 424: free(line);
1.119 mmcc 425: sshkey_free(pub);
1.80 djm 426: fclose(f);
1.107 djm 427: return r;
1.108 djm 428: }
429:
430: /*
431: * Checks whether the specified key is revoked, returning 0 if not,
432: * SSH_ERR_KEY_REVOKED if it is or another error code if something
433: * unexpected happened.
434: * This will check both the key and, if it is a certificate, its CA key too.
435: * "revoked_keys_file" may be a KRL or a one-per-line list of public keys.
436: */
437: int
438: sshkey_check_revoked(struct sshkey *key, const char *revoked_keys_file)
439: {
440: int r;
441:
442: r = ssh_krl_file_contains_key(revoked_keys_file, key);
443: /* If this was not a KRL to begin with then continue below */
444: if (r != SSH_ERR_KRL_BAD_MAGIC)
445: return r;
446:
447: /*
448: * If the file is not a KRL or we can't handle KRLs then attempt to
449: * parse the file as a flat list of keys.
450: */
451: switch ((r = sshkey_in_file(key, revoked_keys_file, 0, 1))) {
452: case 0:
453: /* Key found => revoked */
454: return SSH_ERR_KEY_REVOKED;
455: case SSH_ERR_KEY_NOT_FOUND:
456: /* Key not found => not revoked */
457: return 0;
458: default:
459: /* Some other error occurred */
460: return r;
461: }
1.135 djm 462: }
463:
464: /*
465: * Advanced *cpp past the end of key options, defined as the first unquoted
466: * whitespace character. Returns 0 on success or -1 on failure (e.g.
467: * unterminated quotes).
468: */
469: int
470: sshkey_advance_past_options(char **cpp)
471: {
472: char *cp = *cpp;
473: int quoted = 0;
474:
475: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
476: if (*cp == '\\' && cp[1] == '"')
477: cp++; /* Skip both */
478: else if (*cp == '"')
479: quoted = !quoted;
480: }
481: *cpp = cp;
482: /* return failure for unterminated quotes */
483: return (*cp == '\0' && quoted) ? -1 : 0;
1.80 djm 484: }
1.107 djm 485:
1.136 djm 486: /* Save a public key */
487: int
488: sshkey_save_public(const struct sshkey *key, const char *path,
489: const char *comment)
490: {
491: int fd, oerrno;
492: FILE *f = NULL;
493: int r = SSH_ERR_INTERNAL_ERROR;
494:
495: if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
496: return SSH_ERR_SYSTEM_ERROR;
497: if ((f = fdopen(fd, "w")) == NULL) {
498: r = SSH_ERR_SYSTEM_ERROR;
499: goto fail;
500: }
501: if ((r = sshkey_write(key, f)) != 0)
502: goto fail;
503: fprintf(f, " %s\n", comment);
504: if (ferror(f) || fclose(f) != 0) {
505: r = SSH_ERR_SYSTEM_ERROR;
506: fail:
507: oerrno = errno;
508: if (f != NULL)
509: fclose(f);
510: else
511: close(fd);
512: errno = oerrno;
513: return r;
514: }
515: return 0;
516: }
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