diff options
Diffstat (limited to 'usr.bin/ssh/dh.c')
| -rw-r--r-- | usr.bin/ssh/dh.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/usr.bin/ssh/dh.c b/usr.bin/ssh/dh.c new file mode 100644 index 00000000000..8f1ad19dd42 --- /dev/null +++ b/usr.bin/ssh/dh.c @@ -0,0 +1,158 @@ +/* + * Copyright (c) 2000 Niels Provos. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" +RCSID("$OpenBSD: dh.c,v 1.1 2000/10/11 04:02:16 provos Exp $"); + +#include "xmalloc.h" + +#include <openssl/bn.h> +#include <openssl/dh.h> +#include <openssl/evp.h> + +#include "ssh.h" +#include "buffer.h" +#include "kex.h" +#include "dh.h" + +int +parse_prime(int linenum, char *line, struct dhgroup *dhg) +{ + char *cp, *arg; + char *strsize, *gen, *prime; + + cp = line; + arg = strdelim(&cp); + /* Ignore leading whitespace */ + if (*arg == '\0') + arg = strdelim(&cp); + if (!*arg || *arg == '#') + return 0; + + /* time */ + if (cp == NULL || *arg == '\0') + goto fail; + arg = strsep(&cp, " "); /* type */ + if (cp == NULL || *arg == '\0') + goto fail; + arg = strsep(&cp, " "); /* tests */ + if (cp == NULL || *arg == '\0') + goto fail; + arg = strsep(&cp, " "); /* tries */ + if (cp == NULL || *arg == '\0') + goto fail; + strsize = strsep(&cp, " "); /* size */ + if (cp == NULL || *strsize == '\0' || + (dhg->size = atoi(strsize)) == 0) + goto fail; + gen = strsep(&cp, " "); /* gen */ + if (cp == NULL || *gen == '\0') + goto fail; + prime = strsep(&cp, " "); /* prime */ + if (cp != NULL || *prime == '\0') + goto fail; + + dhg->g = BN_new(); + if (BN_hex2bn(&dhg->g, gen) < 0) { + BN_free(dhg->g); + goto fail; + } + dhg->p = BN_new(); + if (BN_hex2bn(&dhg->p, prime) < 0) { + BN_free(dhg->g); + BN_free(dhg->p); + goto fail; + } + + return (1); + fail: + fprintf(stderr, "Bad prime description in line %d\n", linenum); + return (0); +} + +DH * +choose_dh(int minbits) +{ + FILE *f; + char line[1024]; + char *cp, *arg; + int best, bestcount, which; + int linenum; + struct dhgroup dhg; + + f = fopen(DH_PRIMES, "r"); + if (!f) { + perror(DH_PRIMES); + log("WARNING: %s does not exist, using old prime", DH_PRIMES); + return (dh_new_group1()); + } + + linenum = 0; + best = bestcount = 0; + while (fgets(line, sizeof(line), f)) { + linenum++; + if (!parse_prime(linenum, line, &dhg)) + continue; + BN_free(dhg.g); + BN_free(dhg.p); + + if ((dhg.size > minbits && dhg.size < best) || + (dhg.size > best && best < minbits)) { + best = dhg.size; + bestcount = 0; + } + if (dhg.size == best) + bestcount++; + } + fclose (f); + + if (bestcount == 0) { + log("WARNING: no primes in %s, using old prime", DH_PRIMES); + return (dh_new_group1()); + } + + f = fopen(DH_PRIMES, "r"); + if (!f) { + perror(DH_PRIMES); + exit(1); + } + + linenum = 0; + which = arc4random() % bestcount; + while (fgets(line, sizeof(line), f)) { + if (!parse_prime(linenum, line, &dhg)) + continue; + if (dhg.size != best) + continue; + if (linenum++ != which) { + BN_free(dhg.g); + BN_free(dhg.p); + continue; + } + break; + } + fclose(f); + + return (dh_new_group(dhg.g, dhg.p)); +} |