diff options
| author | Dr. Stephen Henson <steve@openssl.org> | 2014-10-24 12:30:33 +0100 |
|---|---|---|
| committer | Dr. Stephen Henson <steve@openssl.org> | 2015-01-05 23:34:57 +0000 |
| commit | 4aaf1e493cb86efa64f6a486a27d38da6bce23af (patch) | |
| tree | 201d689030a5f9faa5c2acaba8f60e89cd35bdfa /ssl/s3_clnt.c | |
| parent | d96c24926d74aacbabe70f9ef49a0d260d9e2fad (diff) | |
ECDH downgrade bug fix.
Fix bug where an OpenSSL client would accept a handshake using an
ephemeral ECDH ciphersuites with the server key exchange message omitted.
Thanks to Karthikeyan Bhargavan for reporting this issue.
CVE-2014-3572
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit b15f8769644b00ef7283521593360b7b2135cb63)
Diffstat (limited to 'ssl/s3_clnt.c')
| -rw-r--r-- | ssl/s3_clnt.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c index 47cb93d8a1..6de971b226 100644 --- a/ssl/s3_clnt.c +++ b/ssl/s3_clnt.c @@ -1363,6 +1363,8 @@ int ssl3_get_key_exchange(SSL *s) int encoded_pt_len = 0; #endif + EVP_MD_CTX_init(&md_ctx); + /* use same message size as in ssl3_get_certificate_request() * as ServerKeyExchange message may be skipped */ n=s->method->ssl_get_message(s, @@ -1373,14 +1375,26 @@ int ssl3_get_key_exchange(SSL *s) &ok); if (!ok) return((int)n); + alg_k=s->s3->tmp.new_cipher->algorithm_mkey; + if (s->s3->tmp.message_type != SSL3_MT_SERVER_KEY_EXCHANGE) { + /* + * Can't skip server key exchange if this is an ephemeral + * ciphersuite. + */ + if (alg_k & (SSL_kDHE|SSL_kECDHE)) + { + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_UNEXPECTED_MESSAGE); + al = SSL_AD_UNEXPECTED_MESSAGE; + goto f_err; + } #ifndef OPENSSL_NO_PSK /* In plain PSK ciphersuite, ServerKeyExchange can be omitted if no identity hint is sent. Set session->sess_cert anyway to avoid problems later.*/ - if (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK) + if (alg_k & SSL_kPSK) { s->session->sess_cert=ssl_sess_cert_new(); if (s->ctx->psk_identity_hint) @@ -1425,9 +1439,7 @@ int ssl3_get_key_exchange(SSL *s) /* Total length of the parameters including the length prefix */ param_len=0; - alg_k=s->s3->tmp.new_cipher->algorithm_mkey; alg_a=s->s3->tmp.new_cipher->algorithm_auth; - EVP_MD_CTX_init(&md_ctx); al=SSL_AD_DECODE_ERROR; |