From 2a699bc6e94b8223d900e8880ad628aebf17ab6d Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Mon, 6 Feb 2012 22:12:06 +0100 Subject: [PATCH] CURLOPT_SSL_OPTIONS: added Allow an appliction to set libcurl specific SSL options. The first and only options supported right now is CURLSSLOPT_ALLOW_BEAST. It will make libcurl to disable any work-arounds the underlying SSL library may have to address a known security flaw in the SSL3 and TLS1.0 protocol versions. This is a reaction to us unconditionally removing that behavior after this security advisory: http://curl.haxx.se/docs/adv_20120124B.html ... it did however cause a lot of programs to fail because of old servers not liking this work-around. Now programs can opt to decrease the security in order to interoperate with old servers better. --- docs/libcurl/curl_easy_setopt.3 | 10 ++++++++++ docs/libcurl/symbols-in-versions | 2 ++ include/curl/curl.h | 12 ++++++++++++ lib/ssluse.c | 5 ++++- lib/url.c | 15 ++++++++++----- lib/urldata.h | 2 ++ 6 files changed, 40 insertions(+), 6 deletions(-) diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3 index a7688a7d0..571fe742a 100644 --- a/docs/libcurl/curl_easy_setopt.3 +++ b/docs/libcurl/curl_easy_setopt.3 @@ -2313,6 +2313,16 @@ this to 1 to enable it. By default all transfers are done using the cache. While nothing ever should get hurt by attempting to reuse SSL session-IDs, there seem to be broken SSL implementations in the wild that may require you to disable this in order for you to succeed. (Added in 7.16.0) +.IP CURLOPT_SSL_OPTIONS +Pass a long with a bitmask to tell libcurl about specific SSL behaviors. + +CURLSSLOPT_ALLOW_BEAST is the only supported bit and by setting this the user +will tell libcurl to not attempt to use any work-arounds for a security flaw +in the SSL3 and TLS1.0 protocols. If this option isn't used or this bit is +set to 0, the SSL layer libcurl uses may use a work-around for this flaw +although it might cause interoperability problems with some (older) SSL +implementations. WARNING: avoiding this work-around loosens the security, and +by setting this option to 1 you ask for exactly that. (Added in 7.25.0) .IP CURLOPT_KRBLEVEL Pass a char * as parameter. Set the kerberos security level for FTP; this also enables kerberos awareness. This is a string, \&'clear', \&'safe', diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions index a9f8a9d6e..010ebc6fe 100644 --- a/docs/libcurl/symbols-in-versions +++ b/docs/libcurl/symbols-in-versions @@ -482,6 +482,7 @@ CURLOPT_SSLVERSION 7.1 CURLOPT_SSL_CIPHER_LIST 7.9 CURLOPT_SSL_CTX_DATA 7.10.6 CURLOPT_SSL_CTX_FUNCTION 7.10.6 +CURLOPT_SSL_OPTIONS 7.25.0 CURLOPT_SSL_SESSIONID_CACHE 7.16.0 CURLOPT_SSL_VERIFYHOST 7.8.1 CURLOPT_SSL_VERIFYPEER 7.4.2 @@ -573,6 +574,7 @@ CURLSSH_AUTH_KEYBOARD 7.16.1 CURLSSH_AUTH_NONE 7.16.1 CURLSSH_AUTH_PASSWORD 7.16.1 CURLSSH_AUTH_PUBLICKEY 7.16.1 +CURLSSLOPT_ALLOW_BEAST 7.25.0 CURLUSESSL_ALL 7.17.0 CURLUSESSL_CONTROL 7.17.0 CURLUSESSL_NONE 7.17.0 diff --git a/include/curl/curl.h b/include/curl/curl.h index 2a9957e9c..3c9c41d8a 100644 --- a/include/curl/curl.h +++ b/include/curl/curl.h @@ -673,6 +673,15 @@ typedef enum { CURLUSESSL_LAST /* not an option, never use */ } curl_usessl; +/* Definition of bits for the CURLOPT_SSL_OPTIONS argument: */ + +/* - ALLOW_BEAST tells libcurl to allow the BEAST SSL vulnerability in the + name of improving interoperability with older servers. Some SSL libraries + have introduced work-arounds for this flaw but those work-arounds sometimes + make the SSL communication fail. To regain functionality with those broken + servers, a user can this way allow the vulnerability back. */ +#define CURLSSLOPT_ALLOW_BEAST (1<<0) + #ifndef CURL_NO_OLDIES /* define this to test if your app builds with all the obsolete stuff removed! */ @@ -1506,6 +1515,9 @@ typedef enum { CINIT(TCP_KEEPIDLE, LONG, 214), CINIT(TCP_KEEPINTVL, LONG, 215), + /* Enable/disable specific SSL features with a bitmask, see CURLSSLOPT_* */ + CINIT(SSL_OPTIONS, LONG, 216), + CURLOPT_LASTENTRY /* the last unused */ } CURLoption; diff --git a/lib/ssluse.c b/lib/ssluse.c index 014d5b56a..c3d5ec4c7 100644 --- a/lib/ssluse.c +++ b/lib/ssluse.c @@ -1566,7 +1566,10 @@ ossl_connect_step1(struct connectdata *conn, #endif #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS - ctx_options &= ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; + /* unless the user explicitly ask to allow the protocol vulnerability we + use the work-around */ + if(!conn->data->set.ssl_enable_beast) + ctx_options &= ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; #endif /* disable SSLv2 in the default case (i.e. allow SSLv3 and TLSv1) */ diff --git a/lib/url.c b/lib/url.c index c89234d74..b3040b26d 100644 --- a/lib/url.c +++ b/lib/url.c @@ -838,6 +838,7 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, { char *argptr; CURLcode result = CURLE_OK; + long arg; #ifndef CURL_DISABLE_HTTP curl_off_t bigsize; #endif @@ -847,12 +848,10 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, data->set.dns_cache_timeout = va_arg(param, long); break; case CURLOPT_DNS_USE_GLOBAL_CACHE: - { /* remember we want this enabled */ - long use_cache = va_arg(param, long); - data->set.global_dns_cache = (0 != use_cache)?TRUE:FALSE; - } - break; + arg = va_arg(param, long); + data->set.global_dns_cache = (0 != arg)?TRUE:FALSE; + break; case CURLOPT_SSL_CIPHER_LIST: /* set a list of cipher we want to use in the SSL connection */ result = setstropt(&data->set.str[STRING_SSL_CIPHER_LIST], @@ -2189,6 +2188,12 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, */ data->set.use_ssl = (curl_usessl)va_arg(param, long); break; + + case CURLOPT_SSL_OPTIONS: + arg = va_arg(param, long); + data->set.ssl_enable_beast = arg&CURLSSLOPT_ALLOW_BEAST?TRUE:FALSE; + break; + #endif case CURLOPT_FTPSSLAUTH: /* diff --git a/lib/urldata.h b/lib/urldata.h index a959bc716..5725ba86b 100644 --- a/lib/urldata.h +++ b/lib/urldata.h @@ -1508,6 +1508,8 @@ struct UserDefined { bool ftp_skip_ip; /* skip the IP address the FTP server passes on to us */ bool connect_only; /* make connection, let application use the socket */ + bool ssl_enable_beast; /* especially allow this flaw for interoperability's + sake*/ long ssh_auth_types; /* allowed SSH auth types */ bool http_te_skip; /* pass the raw body data to the user, even when transfer-encoded (chunked, compressed) */