Annotation of src/usr.bin/ssh/authfile.c, Revision 1.138
1.138 ! djm 1: /* $OpenBSD: authfile.c,v 1.137 2020/01/25 23:02:13 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
139: sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
140: struct sshkey **keyp, char **commentp)
141: {
142: struct sshbuf *buffer = NULL;
143: int r;
144:
1.121 djm 145: if (keyp != NULL)
146: *keyp = NULL;
1.137 djm 147: if ((r = sshbuf_load_fd(fd, &buffer)) != 0 ||
1.109 djm 148: (r = sshkey_parse_private_fileblob_type(buffer, type,
149: passphrase, keyp, commentp)) != 0)
1.107 djm 150: goto out;
1.109 djm 151:
152: /* success */
1.107 djm 153: r = 0;
154: out:
1.120 mmcc 155: sshbuf_free(buffer);
1.107 djm 156: return r;
1.29 markus 157: }
158:
1.107 djm 159: /* XXX this is almost identical to sshkey_load_private_type() */
160: int
161: sshkey_load_private(const char *filename, const char *passphrase,
162: struct sshkey **keyp, char **commentp)
1.88 djm 163: {
1.107 djm 164: struct sshbuf *buffer = NULL;
165: int r, fd;
1.88 djm 166:
1.121 djm 167: if (keyp != NULL)
168: *keyp = NULL;
1.107 djm 169: if (commentp != NULL)
170: *commentp = NULL;
1.88 djm 171:
1.132 deraadt 172: if ((fd = open(filename, O_RDONLY)) == -1)
1.107 djm 173: return SSH_ERR_SYSTEM_ERROR;
174: if (sshkey_perm_ok(fd, filename) != 0) {
175: r = SSH_ERR_KEY_BAD_PERMISSIONS;
176: goto out;
1.29 markus 177: }
1.137 djm 178: if ((r = sshbuf_load_fd(fd, &buffer)) != 0 ||
1.117 tim 179: (r = sshkey_parse_private_fileblob(buffer, passphrase, keyp,
180: commentp)) != 0)
1.107 djm 181: goto out;
1.128 markus 182: if (keyp && *keyp &&
183: (r = sshkey_set_filename(*keyp, filename)) != 0)
184: goto out;
1.107 djm 185: r = 0;
186: out:
1.86 djm 187: close(fd);
1.120 mmcc 188: sshbuf_free(buffer);
1.107 djm 189: return r;
1.18 markus 190: }
191:
1.37 itojun 192: static int
1.138 ! djm 193: sshkey_try_load_public(struct sshkey **kp, const char *filename,
! 194: char **commentp)
1.18 markus 195: {
196: FILE *f;
1.129 markus 197: char *line = NULL, *cp;
198: size_t linesize = 0;
1.107 djm 199: int r;
1.138 ! djm 200: struct sshkey *k = NULL;
1.18 markus 201:
1.138 ! djm 202: *kp = NULL;
1.107 djm 203: if (commentp != NULL)
204: *commentp = NULL;
205: if ((f = fopen(filename, "r")) == NULL)
206: return SSH_ERR_SYSTEM_ERROR;
1.138 ! djm 207: if ((k = sshkey_new(KEY_UNSPEC)) == NULL) {
! 208: fclose(f);
! 209: return SSH_ERR_ALLOC_FAIL;
! 210: }
1.129 markus 211: while (getline(&line, &linesize, f) != -1) {
1.107 djm 212: cp = line;
213: switch (*cp) {
214: case '#':
215: case '\n':
216: case '\0':
217: continue;
218: }
219: /* Abort loading if this looks like a private key */
220: if (strncmp(cp, "-----BEGIN", 10) == 0 ||
221: strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
222: break;
223: /* Skip leading whitespace. */
224: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
225: ;
226: if (*cp) {
227: if ((r = sshkey_read(k, &cp)) == 0) {
228: cp[strcspn(cp, "\r\n")] = '\0';
229: if (commentp) {
230: *commentp = strdup(*cp ?
231: cp : filename);
232: if (*commentp == NULL)
233: r = SSH_ERR_ALLOC_FAIL;
1.18 markus 234: }
1.138 ! djm 235: /* success */
! 236: *kp = k;
1.129 markus 237: free(line);
1.107 djm 238: fclose(f);
239: return r;
1.18 markus 240: }
241: }
242: }
1.138 ! djm 243: free(k);
1.129 markus 244: free(line);
1.107 djm 245: fclose(f);
246: return SSH_ERR_INVALID_FORMAT;
1.18 markus 247: }
248:
1.125 markus 249: /* load public key from any pubkey file */
1.107 djm 250: int
251: sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
1.18 markus 252: {
1.138 ! djm 253: char *pubfile = NULL;
1.125 markus 254: int r;
1.18 markus 255:
1.107 djm 256: if (keyp != NULL)
257: *keyp = NULL;
258: if (commentp != NULL)
259: *commentp = NULL;
260:
1.138 ! djm 261: if ((r = sshkey_try_load_public(keyp, filename, commentp)) == 0)
1.125 markus 262: goto out;
1.53 markus 263:
1.107 djm 264: /* try .pub suffix */
1.138 ! djm 265: if (asprintf(&pubfile, "%s.pub", filename) == -1)
1.107 djm 266: return SSH_ERR_ALLOC_FAIL;
1.138 ! djm 267: if ((r = sshkey_try_load_public(keyp, pubfile, commentp)) == 0)
1.125 markus 268: goto out;
1.138 ! djm 269:
1.125 markus 270: out:
1.138 ! djm 271: free(pubfile);
1.107 djm 272: return r;
1.81 djm 273: }
274:
275: /* Load the certificate associated with the named private key */
1.107 djm 276: int
277: sshkey_load_cert(const char *filename, struct sshkey **keyp)
1.81 djm 278: {
1.107 djm 279: struct sshkey *pub = NULL;
280: char *file = NULL;
281: int r = SSH_ERR_INTERNAL_ERROR;
282:
1.121 djm 283: if (keyp != NULL)
284: *keyp = NULL;
1.81 djm 285:
1.107 djm 286: if (asprintf(&file, "%s-cert.pub", filename) == -1)
287: return SSH_ERR_ALLOC_FAIL;
288:
1.138 ! djm 289: r = sshkey_try_load_public(keyp, file, NULL);
1.118 mmcc 290: free(file);
1.119 mmcc 291: sshkey_free(pub);
1.107 djm 292: return r;
1.81 djm 293: }
294:
295: /* Load private key and certificate */
1.107 djm 296: int
297: sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
1.134 dtucker 298: struct sshkey **keyp)
1.81 djm 299: {
1.107 djm 300: struct sshkey *key = NULL, *cert = NULL;
301: int r;
302:
1.121 djm 303: if (keyp != NULL)
304: *keyp = NULL;
1.81 djm 305:
306: switch (type) {
1.106 markus 307: #ifdef WITH_OPENSSL
1.81 djm 308: case KEY_RSA:
309: case KEY_DSA:
1.83 djm 310: case KEY_ECDSA:
1.116 markus 311: #endif /* WITH_OPENSSL */
1.101 djm 312: case KEY_ED25519:
1.128 markus 313: case KEY_XMSS:
1.107 djm 314: case KEY_UNSPEC:
1.81 djm 315: break;
316: default:
1.107 djm 317: return SSH_ERR_KEY_TYPE_UNKNOWN;
1.81 djm 318: }
319:
1.107 djm 320: if ((r = sshkey_load_private_type(type, filename,
1.134 dtucker 321: passphrase, &key, NULL)) != 0 ||
1.107 djm 322: (r = sshkey_load_cert(filename, &cert)) != 0)
323: goto out;
1.81 djm 324:
325: /* Make sure the private key matches the certificate */
1.107 djm 326: if (sshkey_equal_public(key, cert) == 0) {
327: r = SSH_ERR_KEY_CERT_MISMATCH;
328: goto out;
1.81 djm 329: }
330:
1.115 djm 331: if ((r = sshkey_to_certified(key)) != 0 ||
1.107 djm 332: (r = sshkey_cert_copy(cert, key)) != 0)
333: goto out;
334: r = 0;
1.121 djm 335: if (keyp != NULL) {
336: *keyp = key;
337: key = NULL;
338: }
1.107 djm 339: out:
1.119 mmcc 340: sshkey_free(key);
341: sshkey_free(cert);
1.107 djm 342: return r;
1.1 deraadt 343: }
1.80 djm 344:
345: /*
1.107 djm 346: * Returns success if the specified "key" is listed in the file "filename",
347: * SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
1.108 djm 348: * If "strict_type" is set then the key type must match exactly,
1.80 djm 349: * otherwise a comparison that ignores certficiate data is performed.
1.108 djm 350: * If "check_ca" is set and "key" is a certificate, then its CA key is
351: * also checked and sshkey_in_file() will return success if either is found.
1.80 djm 352: */
353: int
1.108 djm 354: sshkey_in_file(struct sshkey *key, const char *filename, int strict_type,
355: int check_ca)
1.80 djm 356: {
357: FILE *f;
1.129 markus 358: char *line = NULL, *cp;
359: size_t linesize = 0;
1.107 djm 360: int r = 0;
361: struct sshkey *pub = NULL;
1.129 markus 362:
1.107 djm 363: int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
364: strict_type ? sshkey_equal : sshkey_equal_public;
1.80 djm 365:
1.108 djm 366: if ((f = fopen(filename, "r")) == NULL)
367: return SSH_ERR_SYSTEM_ERROR;
1.80 djm 368:
1.129 markus 369: while (getline(&line, &linesize, f) != -1) {
1.131 djm 370: sshkey_free(pub);
371: pub = NULL;
1.80 djm 372: cp = line;
373:
374: /* Skip leading whitespace. */
375: for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
376: ;
377:
378: /* Skip comments and empty lines */
379: switch (*cp) {
380: case '#':
381: case '\n':
382: case '\0':
383: continue;
384: }
385:
1.107 djm 386: if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
387: r = SSH_ERR_ALLOC_FAIL;
388: goto out;
1.80 djm 389: }
1.131 djm 390: switch (r = sshkey_read(pub, &cp)) {
391: case 0:
392: break;
393: case SSH_ERR_KEY_LENGTH:
394: continue;
395: default:
1.107 djm 396: goto out;
1.131 djm 397: }
1.108 djm 398: if (sshkey_compare(key, pub) ||
399: (check_ca && sshkey_is_cert(key) &&
400: sshkey_compare(key->cert->signature_key, pub))) {
1.107 djm 401: r = 0;
402: goto out;
1.80 djm 403: }
404: }
1.107 djm 405: r = SSH_ERR_KEY_NOT_FOUND;
406: out:
1.129 markus 407: free(line);
1.119 mmcc 408: sshkey_free(pub);
1.80 djm 409: fclose(f);
1.107 djm 410: return r;
1.108 djm 411: }
412:
413: /*
414: * Checks whether the specified key is revoked, returning 0 if not,
415: * SSH_ERR_KEY_REVOKED if it is or another error code if something
416: * unexpected happened.
417: * This will check both the key and, if it is a certificate, its CA key too.
418: * "revoked_keys_file" may be a KRL or a one-per-line list of public keys.
419: */
420: int
421: sshkey_check_revoked(struct sshkey *key, const char *revoked_keys_file)
422: {
423: int r;
424:
425: r = ssh_krl_file_contains_key(revoked_keys_file, key);
426: /* If this was not a KRL to begin with then continue below */
427: if (r != SSH_ERR_KRL_BAD_MAGIC)
428: return r;
429:
430: /*
431: * If the file is not a KRL or we can't handle KRLs then attempt to
432: * parse the file as a flat list of keys.
433: */
434: switch ((r = sshkey_in_file(key, revoked_keys_file, 0, 1))) {
435: case 0:
436: /* Key found => revoked */
437: return SSH_ERR_KEY_REVOKED;
438: case SSH_ERR_KEY_NOT_FOUND:
439: /* Key not found => not revoked */
440: return 0;
441: default:
442: /* Some other error occurred */
443: return r;
444: }
1.135 djm 445: }
446:
447: /*
448: * Advanced *cpp past the end of key options, defined as the first unquoted
449: * whitespace character. Returns 0 on success or -1 on failure (e.g.
450: * unterminated quotes).
451: */
452: int
453: sshkey_advance_past_options(char **cpp)
454: {
455: char *cp = *cpp;
456: int quoted = 0;
457:
458: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
459: if (*cp == '\\' && cp[1] == '"')
460: cp++; /* Skip both */
461: else if (*cp == '"')
462: quoted = !quoted;
463: }
464: *cpp = cp;
465: /* return failure for unterminated quotes */
466: return (*cp == '\0' && quoted) ? -1 : 0;
1.80 djm 467: }
1.107 djm 468:
1.136 djm 469: /* Save a public key */
470: int
471: sshkey_save_public(const struct sshkey *key, const char *path,
472: const char *comment)
473: {
474: int fd, oerrno;
475: FILE *f = NULL;
476: int r = SSH_ERR_INTERNAL_ERROR;
477:
478: if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
479: return SSH_ERR_SYSTEM_ERROR;
480: if ((f = fdopen(fd, "w")) == NULL) {
481: r = SSH_ERR_SYSTEM_ERROR;
482: goto fail;
483: }
484: if ((r = sshkey_write(key, f)) != 0)
485: goto fail;
486: fprintf(f, " %s\n", comment);
487: if (ferror(f) || fclose(f) != 0) {
488: r = SSH_ERR_SYSTEM_ERROR;
489: fail:
490: oerrno = errno;
491: if (f != NULL)
492: fclose(f);
493: else
494: close(fd);
495: errno = oerrno;
496: return r;
497: }
498: return 0;
499: }
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