diff options
| author | Niels Provos <provos@cvs.openbsd.org> | 2001-03-27 17:46:51 +0000 |
|---|---|---|
| committer | Niels Provos <provos@cvs.openbsd.org> | 2001-03-27 17:46:51 +0000 |
| commit | 6184a97d2bbb6c2b11ce9a90994b814cf4bb85b4 (patch) | |
| tree | 40585dac26ba6cf1d1d311328dc6e401f5995b71 /usr.bin/ssh/sshconnect2.c | |
| parent | acb804f2fba02b2a7159852bcd5b347b3416ab32 (diff) | |
make dh group exchange more flexible, allow min and max group size,
okay markus@, deraadt@
Diffstat (limited to 'usr.bin/ssh/sshconnect2.c')
| -rw-r--r-- | usr.bin/ssh/sshconnect2.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c index f636fb3d92f..da8c8229ca0 100644 --- a/usr.bin/ssh/sshconnect2.c +++ b/usr.bin/ssh/sshconnect2.c @@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect2.c,v 1.56 2001/03/26 08:07:09 markus Exp $"); +RCSID("$OpenBSD: sshconnect2.c,v 1.57 2001/03/27 17:46:49 provos Exp $"); #include <openssl/bn.h> #include <openssl/md5.h> @@ -46,6 +46,7 @@ RCSID("$OpenBSD: sshconnect2.c,v 1.56 2001/03/26 08:07:09 markus Exp $"); #include "sshconnect.h" #include "authfile.h" #include "cli.h" +#include "dh.h" #include "dispatch.h" #include "authfd.h" #include "log.h" @@ -309,7 +310,7 @@ ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, int plen, dlen; u_int klen, kout; char *signature = NULL; - u_int slen, nbits; + u_int slen, nbits, min, max; char *server_host_key_blob = NULL; Key *server_host_key; u_int sbloblen; @@ -322,14 +323,31 @@ ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, nbits = dh_estimate(kex->we_need * 8); - debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); - packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); - packet_put_int(nbits); + if (datafellows & SSH_OLD_DHGEX) { + debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST_OLD."); + + /* Old GEX request */ + packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD); + packet_put_int(nbits); + min = DH_GRP_MIN; + max = DH_GRP_MAX; + } else { + debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); + + /* New GEX request */ + min = DH_GRP_MIN; + max = MIN(DH_GRP_MAX, nbits * 1.25); + + packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); + packet_put_int(min); + packet_put_int(nbits); + packet_put_int(max); + } packet_send(); packet_write_wait(); #ifdef DEBUG_KEXDH - fprintf(stderr, "\nnbits = %d", nbits); + fprintf(stderr, "\nmin = %d, nbits = %d, max = %d", min, nbits, max); #endif debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); @@ -344,6 +362,11 @@ ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, if ((g = BN_new()) == NULL) fatal("BN_new"); packet_get_bignum2(g, &dlen); + + if (BN_num_bits(p) < min || BN_num_bits(p) > max) + fatal("DH_GEX group out of range: %d !< %d !< %d", + min, BN_num_bits(p), max); + dh = dh_new_group(g, p); dh_gen_key(dh, kex->we_need * 8); |