src/ssl/bio.h

   1 /*
   2  * Copyright (C) 1996-2016 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_SSL_BIO_H
  10 #define SQUID_SSL_BIO_H
  11
  12 #include "fd.h"
  13 #include "security/Handshake.h"
  14
  15 #include <iosfwd>
  16 #include <list>
  17 #if HAVE_OPENSSL_BIO_H
  18 #include <openssl/bio.h>
  19 #endif
  20 #include <string>
  21 #include <type_traits>
  22
  23 namespace Ssl
  24 {
  25
  26 /// BIO source and sink node, handling socket I/O and monitoring SSL state
  27 class Bio
  28 {
  29 public:
  30     enum Type {
  31         BIO_TO_CLIENT = 6000,
  32         BIO_TO_SERVER
  33     };
  34
  35     explicit Bio(const int anFd);
  36     virtual ~Bio();
  37
  38     /// Writes the given data to socket
  39     virtual int write(const char *buf, int size, BIO *table);
  40
  41     /// Reads data from socket
  42     virtual int read(char *buf, int size, BIO *table);
  43
  44     /// Flushes any buffered data to socket.
  45     /// The Ssl::Bio does not buffer any data, so this method has nothing to do
  46     virtual void flush(BIO *table) {}
  47
  48     int fd() const { return fd_; } ///< The SSL socket descriptor
  49
  50     /// Called by linked SSL connection whenever state changes, an alert
  51     /// appears, or an error occurs. See SSL_set_info_callback().
  52     virtual void stateChanged(const SSL *ssl, int where, int ret);
  53
  54     /// Creates a low-level BIO table, creates a high-level Ssl::Bio object
  55     /// for a given socket, and then links the two together via BIO_C_SET_FD.
  56     static BIO *Create(const int fd, Type type);
  57     /// Tells ssl connection to use BIO and monitor state via stateChanged()
  58     static void Link(SSL *ssl, BIO *bio);
  59
  60     const SBuf &rBufData() {return rbuf;} ///< The buffered input data
  61 protected:
  62     const int fd_; ///< the SSL socket we are reading and writing
  63     SBuf rbuf;  ///< Used to buffer input data.
  64 };
  65
  66 /// BIO node to handle socket IO for squid client side
  67 /// If bumping is enabled  this Bio detects and analyses client hello message
  68 /// to retrieve the SSL features supported by the client
  69 class ClientBio: public Bio
  70 {
  71 public:
  72     explicit ClientBio(const int anFd): Bio(anFd), holdRead_(false), holdWrite_(false), helloSize(0) {}
  73
  74     /// The ClientBio version of the Ssl::Bio::stateChanged method
  75     /// When the client hello message retrieved, fill the
  76     /// "features" member with the client provided informations.
  77     virtual void stateChanged(const SSL *ssl, int where, int ret);
  78     /// The ClientBio version of the Ssl::Bio::write method
  79     virtual int write(const char *buf, int size, BIO *table);
  80     /// The ClientBio version of the Ssl::Bio::read method
  81     /// If the holdRead flag is true then it does not write any data
  82     /// to socket and sets the "read retry" flag of the BIO to true
  83     virtual int read(char *buf, int size, BIO *table);
  84     /// Prevents or allow writting on socket.
  85     void hold(bool h) {holdRead_ = holdWrite_ = h;}
  86
  87     /// Sets the buffered input data (Bio::rbuf).
  88     /// Used to pass payload data (normally client HELLO data) retrieved
  89     /// by the caller.
  90     void setReadBufData(SBuf &data) {rbuf = data;}
  91 private:
  92     /// True if the SSL state corresponds to a hello message
  93     bool isClientHello(int state);
  94     bool holdRead_; ///< The read hold state of the bio.
  95     bool holdWrite_;  ///< The write hold state of the bio.
  96     int helloSize; ///< The SSL hello message sent by client size
  97 };
  98
  99 /// BIO node to handle socket IO for squid server side
 100 /// If bumping is enabled, analyses the SSL hello message sent by squid OpenSSL
 101 /// subsystem (step3 bumping step) against bumping mode:
 102 ///   * Peek mode:  Send client hello message instead of the openSSL generated
 103 ///                 hello message and normaly denies bumping and allow only
 104 ///                 splice or terminate the SSL connection
 105 ///   * Stare mode: Sends the openSSL generated hello message and normaly
 106 ///                 denies splicing and allow bump or terminate the SSL
 107 ///                 connection
 108 ///  If SQUID_USE_OPENSSL_HELLO_OVERWRITE_HACK is enabled also checks if the
 109 ///  openSSL library features are compatible with the features reported in
 110 ///  web client SSL hello message and if it is, overwrites the openSSL SSL
 111 ///  object members to replace hello message with web client hello message.
 112 ///  This is may allow bumping in peek mode and splicing in stare mode after
 113 ///  the server hello message received.
 114 class ServerBio: public Bio
 115 {
 116 public:
 117     explicit ServerBio(const int anFd);
 118
 119     /// The ServerBio version of the Ssl::Bio::stateChanged method
 120     virtual void stateChanged(const SSL *ssl, int where, int ret);
 121     /// The ServerBio version of the Ssl::Bio::write method
 122     /// If a clientRandom number is set then rewrites the raw hello message
 123     /// "client random" field with the provided random number.
 124     /// It may buffer the output packets.
 125     virtual int write(const char *buf, int size, BIO *table);
 126     /// The ServerBio version of the Ssl::Bio::read method
 127     /// If the record flag is set then append the data to the rbuf member
 128     virtual int read(char *buf, int size, BIO *table);
 129     /// The ServerBio version of the Ssl::Bio::flush method.
 130     /// Flushes any buffered data
 131     virtual void flush(BIO *table);
 132     /// Sets the random number to use in client SSL HELLO message
 133     void setClientFeatures(Security::TlsDetails::Pointer const &details, SBuf const &hello);
 134
 135     bool resumingSession();
 136
 137     /// The write hold state
 138     bool holdWrite() const {return holdWrite_;}
 139     /// Enables or disables the write hold state
 140     void holdWrite(bool h) {holdWrite_ = h;}
 141     /// The read hold state
 142     bool holdRead() const {return holdRead_;}
 143     /// Enables or disables the read hold state
 144     void holdRead(bool h) {holdRead_ = h;}
 145     /// Enables or disables the input data recording, for internal analysis.
 146     void recordInput(bool r) {record_ = r;}
 147     /// Whether we can splice or not the SSL stream
 148     bool canSplice() {return allowSplice;}
 149     /// Whether we can bump or not the SSL stream
 150     bool canBump() {return allowBump;}
 151     /// The bumping mode
 152     void mode(Ssl::BumpMode m) {bumpMode_ = m;}
 153     Ssl::BumpMode bumpMode() {return bumpMode_;} ///< return the bumping mode
 154
 155     /// \retval true if the Server hello message received
 156     bool gotHello() const { return (parsedHandshake && !parseError); }
 157
 158     /// Return true if the Server Hello parsing failed
 159     bool gotHelloFailed() const { return (parsedHandshake && parseError); }
 160
 161     /// \return the server certificates list if received and parsed correctly
 162     const Security::CertList &serverCertificatesIfAny() { return parser_.serverCertificates; }
 163
 164     /// \return the TLS Details advertised by TLS server.
 165     const Security::TlsDetails::Pointer &receivedHelloDetails() const {return parser_.details;}
 166
 167 private:
 168     int readAndGive(char *buf, const int size, BIO *table);
 169     int readAndParse(char *buf, const int size, BIO *table);
 170     int readAndBuffer(BIO *table);
 171     int giveBuffered(char *buf, const int size);
 172
 173     /// SSL client features extracted from ClientHello message or SSL object
 174     Security::TlsDetails::Pointer clientTlsDetails;
 175     /// TLS client hello message, used to adapt our tls Hello message to the server
 176     SBuf clientHelloMessage;
 177     SBuf helloMsg; ///< Used to buffer output data.
 178     mb_size_t  helloMsgSize;
 179     bool helloBuild; ///< True if the client hello message sent to the server
 180     bool allowSplice; ///< True if the SSL stream can be spliced
 181     bool allowBump;  ///< True if the SSL stream can be bumped
 182     bool holdWrite_;  ///< The write hold state of the bio.
 183     bool holdRead_;  ///< The read hold state of the bio.
 184     bool record_; ///< If true the input data recorded to rbuf for internal use
 185     bool parsedHandshake; ///< whether we are done parsing TLS Hello
 186     bool parseError; ///< error while parsing server hello message
 187     Ssl::BumpMode bumpMode_;
 188
 189     /// The size of data stored in rbuf which passed to the openSSL
 190     size_t rbufConsumePos;
 191     Security::HandshakeParser parser_; ///< The TLS/SSL messages parser.
 192 };
 193
 194 } // namespace Ssl
 195
 196 void
 197 applyTlsDetailsToSSL(SSL *ssl, Security::TlsDetails::Pointer const &details, Ssl::BumpMode bumpMode);
 198
 199 #endif /* SQUID_SSL_BIO_H */
 200