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author | Aris Adamantiadis <aris@0xbadc0de.be> | 2016-02-09 15:09:27 +0100 |
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committer | Andreas Schneider <asn@cryptomilk.org> | 2016-02-23 08:17:43 +0100 |
commit | f8d0026c65fc8a55748ae481758e2cf376c26c86 (patch) | |
tree | cb678aa20a0d2a864dd6de1b59247a928bd91112 | |
parent | 6b608e70ee61919f5cc23af5072bc7d3cc44c787 (diff) | |
download | libssh-f8d0026c65fc8a55748ae481758e2cf376c26c86.tar.gz libssh-f8d0026c65fc8a55748ae481758e2cf376c26c86.tar.xz libssh-f8d0026c65fc8a55748ae481758e2cf376c26c86.zip |
dh: Fix CVE-2016-0739
Due to a byte/bit confusion, the DH secret was too short. This file was
completely reworked and will be commited in a future version.
Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
-rw-r--r-- | src/dh.c | 22 |
1 files changed, 17 insertions, 5 deletions
@@ -227,15 +227,21 @@ void ssh_crypto_finalize(void) { } int dh_generate_x(ssh_session session) { + int keysize; + if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1) { + keysize = 1023; + } else { + keysize = 2047; + } session->next_crypto->x = bignum_new(); if (session->next_crypto->x == NULL) { return -1; } #ifdef HAVE_LIBGCRYPT - bignum_rand(session->next_crypto->x, 128); + bignum_rand(session->next_crypto->x, keysize); #elif defined HAVE_LIBCRYPTO - bignum_rand(session->next_crypto->x, 128, 0, -1); + bignum_rand(session->next_crypto->x, keysize, -1, 0); #endif /* not harder than this */ @@ -248,15 +254,21 @@ int dh_generate_x(ssh_session session) { /* used by server */ int dh_generate_y(ssh_session session) { - session->next_crypto->y = bignum_new(); + int keysize; + if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1) { + keysize = 1023; + } else { + keysize = 2047; + } + session->next_crypto->y = bignum_new(); if (session->next_crypto->y == NULL) { return -1; } #ifdef HAVE_LIBGCRYPT - bignum_rand(session->next_crypto->y, 128); + bignum_rand(session->next_crypto->y, keysize); #elif defined HAVE_LIBCRYPTO - bignum_rand(session->next_crypto->y, 128, 0, -1); + bignum_rand(session->next_crypto->y, keysize, -1, 0); #endif /* not harder than this */ |