Botan 2.19.3
Crypto and TLS for C&
Public Member Functions | List of all members
Botan::TLS::Session_Manager_SQL Class Reference

#include <tls_session_manager_sql.h>

Inheritance diagram for Botan::TLS::Session_Manager_SQL:
Botan::TLS::Session_Manager Botan::TLS::Session_Manager_SQLite

Public Member Functions

bool load_from_server_info (const Server_Information &info, Session &session) override
 
bool load_from_session_id (const std::vector< uint8_t > &session_id, Session &session) override
 
Session_Manager_SQLoperator= (const Session_Manager_SQL &)=delete
 
size_t remove_all () override
 
void remove_entry (const std::vector< uint8_t > &session_id) override
 
void save (const Session &session_data) override
 
std::chrono::seconds session_lifetime () const override
 
 Session_Manager_SQL (const Session_Manager_SQL &)=delete
 
 Session_Manager_SQL (std::shared_ptr< SQL_Database > db, const std::string &passphrase, RandomNumberGenerator &rng, size_t max_sessions=1000, std::chrono::seconds session_lifetime=std::chrono::seconds(7200))
 

Detailed Description

An implementation of Session_Manager that saves values in a SQL database file, with the session data encrypted using a passphrase.

Warning
For clients, the hostnames associated with the saved sessions are stored in the database in plaintext. This may be a serious privacy risk in some situations.

Definition at line 28 of file tls_session_manager_sql.h.

Constructor & Destructor Documentation

◆ Session_Manager_SQL() [1/2]

Botan::TLS::Session_Manager_SQL::Session_Manager_SQL ( std::shared_ptr< SQL_Database db,
const std::string &  passphrase,
RandomNumberGenerator rng,
size_t  max_sessions = 1000,
std::chrono::seconds  session_lifetime = std::chrono::seconds(7200) 
)
Parameters
dbA connection to the database to use The table names botan_tls_sessions and botan_tls_sessions_metadata will be used
passphraseused to encrypt the session data
rnga random number generator
max_sessionsa hint on the maximum number of sessions to keep in memory at any one time. (If zero, don't cap)
session_lifetimesessions are expired after this many seconds have elapsed from initial handshake.

Definition at line 20 of file tls_session_manager_sql.cpp.

24 :
25 m_db(db),
26 m_rng(rng),
27 m_max_sessions(max_sessions),
28 m_session_lifetime(session_lifetime)
29 {
30 m_db->create_table(
31 "create table if not exists tls_sessions "
32 "("
33 "session_id TEXT PRIMARY KEY, "
34 "session_start INTEGER, "
35 "hostname TEXT, "
36 "hostport INTEGER, "
37 "session BLOB"
38 ")");
39
40 m_db->create_table(
41 "create table if not exists tls_sessions_metadata "
42 "("
43 "passphrase_salt BLOB, "
44 "passphrase_iterations INTEGER, "
45 "passphrase_check INTEGER "
46 ")");
47
48 const size_t salts = m_db->row_count("tls_sessions_metadata");
49
50 std::unique_ptr<PBKDF> pbkdf(get_pbkdf("PBKDF2(SHA-512)"));
51
52 if(salts == 1)
53 {
54 // existing db
55 auto stmt = m_db->new_statement("select * from tls_sessions_metadata");
56
57 if(stmt->step())
58 {
59 std::pair<const uint8_t*, size_t> salt = stmt->get_blob(0);
60 const size_t iterations = stmt->get_size_t(1);
61 const size_t check_val_db = stmt->get_size_t(2);
62
63 secure_vector<uint8_t> x = pbkdf->pbkdf_iterations(32 + 2,
64 passphrase,
65 salt.first, salt.second,
66 iterations);
67
68 const size_t check_val_created = make_uint16(x[0], x[1]);
69 m_session_key.assign(x.begin() + 2, x.end());
70
71 if(check_val_created != check_val_db)
72 throw Invalid_Argument("Session database password not valid");
73 }
74 }
75 else
76 {
77 // maybe just zap the salts + sessions tables in this case?
78 if(salts != 0)
79 throw Internal_Error("Seemingly corrupted TLS session db, multiple salts found");
80
81 // new database case
82
83 std::vector<uint8_t> salt;
84 rng.random_vec(salt, 16);
85 size_t iterations = 0;
86
87 secure_vector<uint8_t> x = pbkdf->pbkdf_timed(32 + 2,
88 passphrase,
89 salt.data(), salt.size(),
90 std::chrono::milliseconds(100),
91 iterations);
92
93 size_t check_val = make_uint16(x[0], x[1]);
94 m_session_key.assign(x.begin() + 2, x.end());
95
96 auto stmt = m_db->new_statement("insert into tls_sessions_metadata values(?1, ?2, ?3)");
97
98 stmt->bind(1, salt);
99 stmt->bind(2, iterations);
100 stmt->bind(3, check_val);
101
102 stmt->spin();
103 }
104 }
std::chrono::seconds session_lifetime() const override
PBKDF * get_pbkdf(const std::string &algo_spec, const std::string &provider="")
Definition pbkdf.h:232
constexpr uint16_t make_uint16(uint8_t i0, uint8_t i1)
Definition loadstor.h:54

References Botan::get_pbkdf(), Botan::make_uint16(), and Botan::RandomNumberGenerator::random_vec().

◆ Session_Manager_SQL() [2/2]

Botan::TLS::Session_Manager_SQL::Session_Manager_SQL ( const Session_Manager_SQL )
delete

Member Function Documentation

◆ load_from_server_info()

bool Botan::TLS::Session_Manager_SQL::load_from_server_info ( const Server_Information info,
Session session 
)
overridevirtual

Try to load a saved session (using info about server)

Parameters
infothe information about the server
sessionwill be set to the saved session data (if found), or not modified if not found
Returns
true if session was modified

Implements Botan::TLS::Session_Manager.

Definition at line 130 of file tls_session_manager_sql.cpp.

132 {
133 auto stmt = m_db->new_statement("select session from tls_sessions"
134 " where hostname = ?1 and hostport = ?2"
135 " order by session_start desc");
136
137 stmt->bind(1, server.hostname());
138 stmt->bind(2, server.port());
139
140 while(stmt->step())
141 {
142 std::pair<const uint8_t*, size_t> blob = stmt->get_blob(0);
143
144 try
145 {
146 session = Session::decrypt(blob.first, blob.second, m_session_key);
147 return true;
148 }
149 catch(...)
150 {
151 }
152 }
153
154 return false;
155 }
static Session decrypt(const uint8_t ctext[], size_t ctext_size, const SymmetricKey &key)

References Botan::TLS::Session::decrypt(), Botan::TLS::Server_Information::hostname(), and Botan::TLS::Server_Information::port().

◆ load_from_session_id()

bool Botan::TLS::Session_Manager_SQL::load_from_session_id ( const std::vector< uint8_t > &  session_id,
Session session 
)
overridevirtual

Try to load a saved session (using session ID)

Parameters
session_idthe session identifier we are trying to resume
sessionwill be set to the saved session data (if found), or not modified if not found
Returns
true if session was modified

Implements Botan::TLS::Session_Manager.

Definition at line 106 of file tls_session_manager_sql.cpp.

108 {
109 auto stmt = m_db->new_statement("select session from tls_sessions where session_id = ?1");
110
111 stmt->bind(1, hex_encode(session_id));
112
113 while(stmt->step())
114 {
115 std::pair<const uint8_t*, size_t> blob = stmt->get_blob(0);
116
117 try
118 {
119 session = Session::decrypt(blob.first, blob.second, m_session_key);
120 return true;
121 }
122 catch(...)
123 {
124 }
125 }
126
127 return false;
128 }
void hex_encode(char output[], const uint8_t input[], size_t input_length, bool uppercase)
Definition hex.cpp:31

References Botan::TLS::Session::decrypt(), and Botan::hex_encode().

◆ operator=()

Session_Manager_SQL & Botan::TLS::Session_Manager_SQL::operator= ( const Session_Manager_SQL )
delete

◆ remove_all()

size_t Botan::TLS::Session_Manager_SQL::remove_all ( )
overridevirtual

Remove all sessions from the cache, return number of sessions deleted

Implements Botan::TLS::Session_Manager.

Definition at line 166 of file tls_session_manager_sql.cpp.

167 {
168 auto stmt = m_db->new_statement("delete from tls_sessions");
169 return stmt->spin();
170 }

◆ remove_entry()

void Botan::TLS::Session_Manager_SQL::remove_entry ( const std::vector< uint8_t > &  session_id)
overridevirtual

Remove this session id from the cache, if it exists

Implements Botan::TLS::Session_Manager.

Definition at line 157 of file tls_session_manager_sql.cpp.

158 {
159 auto stmt = m_db->new_statement("delete from tls_sessions where session_id = ?1");
160
161 stmt->bind(1, hex_encode(session_id));
162
163 stmt->spin();
164 }

References Botan::hex_encode().

◆ save()

void Botan::TLS::Session_Manager_SQL::save ( const Session session)
overridevirtual

Save a session on a best effort basis; the manager may not in fact be able to save the session for whatever reason; this is not an error. Caller cannot assume that calling save followed immediately by load_from_* will result in a successful lookup.

Parameters
sessionto save

Implements Botan::TLS::Session_Manager.

Definition at line 172 of file tls_session_manager_sql.cpp.

173 {
174 if(session.server_info().hostname().empty())
175 return;
176
177 auto stmt = m_db->new_statement("insert or replace into tls_sessions"
178 " values(?1, ?2, ?3, ?4, ?5)");
179
180 stmt->bind(1, hex_encode(session.session_id()));
181 stmt->bind(2, session.start_time());
182 stmt->bind(3, session.server_info().hostname());
183 stmt->bind(4, session.server_info().port());
184 stmt->bind(5, session.encrypt(m_session_key, m_rng));
185
186 stmt->spin();
187
188 prune_session_cache();
189 }

References Botan::TLS::Session::encrypt(), Botan::hex_encode(), Botan::TLS::Server_Information::hostname(), Botan::TLS::Server_Information::port(), Botan::TLS::Session::server_info(), Botan::TLS::Session::session_id(), and Botan::TLS::Session::start_time().

◆ session_lifetime()

std::chrono::seconds Botan::TLS::Session_Manager_SQL::session_lifetime ( ) const
inlineoverridevirtual

Return the allowed lifetime of a session; beyond this time, sessions are not resumed. Returns 0 if unknown/no explicit expiration policy.

Implements Botan::TLS::Session_Manager.

Definition at line 64 of file tls_session_manager_sql.h.

65 { return m_session_lifetime; }

The documentation for this class was generated from the following files: