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mirror of https://git.libssh.org/projects/libssh.git synced 2025-12-05 01:02:39 +03:00

CVE-2021-3634: Create a separate length for session_id

Normally, the length of session_id and secret_hash is the same,
but if we will get into rekeying with a peer that changes preference
of key exchange algorithm, the new secret hash can be larger or
smaller than the previous session_id causing invalid reads or writes.

Resolves https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35485

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
This commit is contained in:
Jakub Jelen
2021-06-23 13:16:33 +02:00
parent a3b2229a4e
commit f5211239f9
10 changed files with 23 additions and 18 deletions

View File

@@ -465,8 +465,8 @@ static ssh_buffer ssh_gssapi_build_mic(ssh_session session)
rc = ssh_buffer_pack(mic_buffer,
"dPbsss",
crypto->digest_len,
(size_t)crypto->digest_len, crypto->session_id,
crypto->session_id_len,
crypto->session_id_len, crypto->session_id,
SSH2_MSG_USERAUTH_REQUEST,
session->gssapi->user,
"ssh-connection",