diff options
| -rw-r--r-- | lib/vtls/nss.c | 78 | ||||
| -rw-r--r-- | lib/vtls/nssg.h | 3 |
2 files changed, 81 insertions, 0 deletions
diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c index 841d6b75d..22d3730a8 100644 --- a/lib/vtls/nss.c +++ b/lib/vtls/nss.c @@ -728,6 +728,64 @@ static void HandshakeCallback(PRFileDesc *sock, void *arg) } } +static SECStatus CanFalseStartCallback(PRFileDesc *sock, void *client_data, + PRBool *canFalseStart) +{ + struct connectdata *conn = client_data; + struct SessionHandle *data = conn->data; + + SSLChannelInfo channelInfo; + SSLCipherSuiteInfo cipherInfo; + + SECStatus rv; + PRBool negotiatedExtension; + + *canFalseStart = PR_FALSE; + + if(SSL_GetChannelInfo(sock, &channelInfo, sizeof(channelInfo)) != SECSuccess) + return SECFailure; + + if(SSL_GetCipherSuiteInfo(channelInfo.cipherSuite, &cipherInfo, + sizeof(cipherInfo)) != SECSuccess) + return SECFailure; + + /* Prevent version downgrade attacks from TLS 1.2, and avoid False Start for + * TLS 1.3 and later. See https://bugzilla.mozilla.org/show_bug.cgi?id=861310 + */ + if(channelInfo.protocolVersion != SSL_LIBRARY_VERSION_TLS_1_2) + goto end; + + /* Only allow ECDHE key exchange algorithm. + * See https://bugzilla.mozilla.org/show_bug.cgi?id=952863 */ + if(cipherInfo.keaType != ssl_kea_ecdh) + goto end; + + /* Prevent downgrade attacks on the symmetric cipher. We do not allow CBC + * mode due to BEAST, POODLE, and other attacks on the MAC-then-Encrypt + * design. See https://bugzilla.mozilla.org/show_bug.cgi?id=1109766 */ + if(cipherInfo.symCipher != ssl_calg_aes_gcm) + goto end; + + /* Enforce ALPN or NPN to do False Start, as an indicator of server + * compatibility. */ + rv = SSL_HandshakeNegotiatedExtension(sock, ssl_app_layer_protocol_xtn, + &negotiatedExtension); + if(rv != SECSuccess || !negotiatedExtension) { + rv = SSL_HandshakeNegotiatedExtension(sock, ssl_next_proto_nego_xtn, + &negotiatedExtension); + } + + if(rv != SECSuccess || !negotiatedExtension) + goto end; + + *canFalseStart = PR_TRUE; + + infof(data, "Trying TLS False Start\n"); + +end: + return SECSuccess; +} + static void display_cert_info(struct SessionHandle *data, CERTCertificate *cert) { @@ -1652,6 +1710,18 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex) goto error; #endif +#ifdef SSL_ENABLE_FALSE_START + if(data->set.ssl.falsestart) { + if(SSL_OptionSet(connssl->handle, SSL_ENABLE_FALSE_START, PR_TRUE) + != SECSuccess) + goto error; + + if(SSL_SetCanFalseStartCallback(connssl->handle, CanFalseStartCallback, + conn) != SECSuccess) + goto error; + } +#endif + #if defined(SSL_ENABLE_NPN) || defined(SSL_ENABLE_ALPN) if(data->set.ssl_enable_npn || data->set.ssl_enable_alpn) { int cur = 0; @@ -1929,4 +1999,12 @@ bool Curl_nss_cert_status_request(void) #endif } +bool Curl_nss_false_start(void) { +#ifdef SSL_ENABLE_FALSE_START + return TRUE; +#else + return FALSE; +#endif +} + #endif /* USE_NSS */ diff --git a/lib/vtls/nssg.h b/lib/vtls/nssg.h index 38e75456f..d0e74124e 100644 --- a/lib/vtls/nssg.h +++ b/lib/vtls/nssg.h @@ -58,6 +58,8 @@ void Curl_nss_md5sum(unsigned char *tmp, /* input */ bool Curl_nss_cert_status_request(void); +bool Curl_nss_false_start(void); + /* Set the API backend definition to NSS */ #define CURL_SSL_BACKEND CURLSSLBACKEND_NSS @@ -88,6 +90,7 @@ bool Curl_nss_cert_status_request(void); #define curlssl_random(x,y,z) Curl_nss_random(x,y,z) #define curlssl_md5sum(a,b,c,d) Curl_nss_md5sum(a,b,c,d) #define curlssl_cert_status_request() Curl_nss_cert_status_request() +#define curlssl_false_start() Curl_nss_false_start() #endif /* USE_NSS */ #endif /* HEADER_CURL_NSSG_H */ |