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mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 09:27:59 +00:00
putty-source/defs.h
Simon Tatham 320bf8479f Replace PuTTY's PRNG with a Fortuna-like system.
This tears out the entire previous random-pool system in sshrand.c. In
its place is a system pretty close to Ferguson and Schneier's
'Fortuna' generator, with the main difference being that I use SHA-256
instead of AES for the generation side of the system (rationale given
in comment).

The PRNG implementation lives in sshprng.c, and defines a self-
contained data type with no state stored outside the object, so you
can instantiate however many of them you like. The old sshrand.c still
exists, but in place of the previous random pool system, it's just
become a client of sshprng.c, whose job is to hold a single global
instance of the PRNG type, and manage its reference count, save file,
noise-collection timers and similar administrative business.

Advantages of this change include:

 - Fortuna is designed with a more varied threat model in mind than my
   old home-grown random pool. For example, after any request for
   random numbers, it automatically re-seeds itself, so that if the
   state of the PRNG should be leaked, it won't give enough
   information to find out what past outputs _were_.

 - The PRNG type can be instantiated with any hash function; the
   instance used by the main tools is based on SHA-256, an improvement
   on the old pool's use of SHA-1.

 - The new PRNG only uses the completely standard interface to the
   hash function API, instead of having to have privileged access to
   the internal SHA-1 block transform function. This will make it
   easier to revamp the hash code in general, and also it means that
   hardware-accelerated versions of SHA-256 will automatically be used
   for the PRNG as well as for everything else.

 - The new PRNG can be _tested_! Because it has an actual (if not
   quite explicit) specification for exactly what the output numbers
   _ought_ to be derived from the hashes of, I can (and have) put
   tests in cryptsuite that ensure the output really is being derived
   in the way I think it is. The old pool could have been returning
   any old nonsense and it would have been very hard to tell for sure.
2019-01-23 22:36:17 +00:00

182 lines
5.7 KiB
C

/*
* defs.h: initial definitions for PuTTY.
*
* The rule about this header file is that it can't depend on any
* other header file in this code base. This is where we define
* things, as much as we can, that other headers will want to refer
* to, such as opaque structure types and their associated typedefs,
* or macros that are used by other headers.
*/
#ifndef PUTTY_DEFS_H
#define PUTTY_DEFS_H
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#if defined _MSC_VER && _MSC_VER < 1800
/* Work around lack of inttypes.h in older MSVC */
#define PRIx32 "x"
#define PRIu64 "I64u"
#define PRIdMAX "I64d"
#define PRIXMAX "I64X"
#define SCNu64 "I64u"
#else
#include <inttypes.h>
#endif
typedef struct conf_tag Conf;
typedef struct terminal_tag Terminal;
typedef struct Filename Filename;
typedef struct FontSpec FontSpec;
typedef struct bufchain_tag bufchain;
typedef struct strbuf strbuf;
typedef struct RSAKey RSAKey;
typedef struct BinarySink BinarySink;
typedef struct BinarySource BinarySource;
typedef struct IdempotentCallback IdempotentCallback;
typedef struct SockAddr SockAddr;
typedef struct Socket Socket;
typedef struct Plug Plug;
typedef struct SocketPeerInfo SocketPeerInfo;
typedef struct Backend Backend;
typedef struct BackendVtable BackendVtable;
typedef struct Ldisc_tag Ldisc;
typedef struct LogContext LogContext;
typedef struct LogPolicy LogPolicy;
typedef struct LogPolicyVtable LogPolicyVtable;
typedef struct Seat Seat;
typedef struct SeatVtable SeatVtable;
typedef struct TermWin TermWin;
typedef struct TermWinVtable TermWinVtable;
typedef struct Ssh Ssh;
typedef struct mp_int mp_int;
typedef struct MontyContext MontyContext;
typedef struct WeierstrassCurve WeierstrassCurve;
typedef struct WeierstrassPoint WeierstrassPoint;
typedef struct MontgomeryCurve MontgomeryCurve;
typedef struct MontgomeryPoint MontgomeryPoint;
typedef struct EdwardsCurve EdwardsCurve;
typedef struct EdwardsPoint EdwardsPoint;
typedef struct SftpServer SftpServer;
typedef struct SftpServerVtable SftpServerVtable;
typedef struct Channel Channel;
typedef struct SshChannel SshChannel;
typedef struct mainchan mainchan;
typedef struct ssh_sharing_state ssh_sharing_state;
typedef struct ssh_sharing_connstate ssh_sharing_connstate;
typedef struct share_channel share_channel;
typedef struct PortFwdManager PortFwdManager;
typedef struct PortFwdRecord PortFwdRecord;
typedef struct ConnectionLayer ConnectionLayer;
typedef struct prng prng;
typedef struct ssh_hashalg ssh_hashalg;
typedef struct ssh_hash ssh_hash;
typedef struct ssh_kex ssh_kex;
typedef struct ssh_kexes ssh_kexes;
typedef struct ssh_keyalg ssh_keyalg;
typedef struct ssh_key ssh_key;
typedef struct ssh_compressor ssh_compressor;
typedef struct ssh_decompressor ssh_decompressor;
typedef struct ssh_compression_alg ssh_compression_alg;
typedef struct ssh2_userkey ssh2_userkey;
typedef struct ssh2_macalg ssh2_macalg;
typedef struct ssh2_mac ssh2_mac;
typedef struct ssh_cipheralg ssh_cipheralg;
typedef struct ssh_cipher ssh_cipher;
typedef struct ssh2_ciphers ssh2_ciphers;
typedef struct dh_ctx dh_ctx;
typedef struct ecdh_key ecdh_key;
typedef struct dlgparam dlgparam;
typedef struct settings_w settings_w;
typedef struct settings_r settings_r;
typedef struct settings_e settings_e;
typedef struct SessionSpecial SessionSpecial;
/*
* A small structure wrapping up a (pointer, length) pair so that it
* can be conveniently passed to or from a function.
*/
typedef struct ptrlen {
const void *ptr;
size_t len;
} ptrlen;
typedef struct logblank_t logblank_t;
typedef struct BinaryPacketProtocol BinaryPacketProtocol;
typedef struct PacketProtocolLayer PacketProtocolLayer;
/* Do a compile-time type-check of 'to_check' (without evaluating it),
* as a side effect of returning the value 'to_return'. Note that
* although this macro double-*expands* to_return, it always
* *evaluates* exactly one copy of it, so it's side-effect safe. */
#define TYPECHECK(to_check, to_return) \
(sizeof(to_check) ? (to_return) : (to_return))
/* Return a pointer to the object of structure type 'type' whose field
* with name 'field' is pointed at by 'object'. */
#define container_of(object, type, field) \
TYPECHECK(object == &((type *)0)->field, \
((type *)(((char *)(object)) - offsetof(type, field))))
#if defined __GNUC__ || defined __clang__
#define NORETURN __attribute__((__noreturn__))
#else
#define NORETURN
#endif
/* ----------------------------------------------------------------------
* Platform-specific definitions.
*
* Most of these live in the per-platform header files, of which
* puttyps.h selects the appropriate one. But some of the sources
* (particularly standalone test applications) would prefer not to
* have to include a per-platform header at all, because that makes it
* more portable to platforms not supported by the code base as a
* whole (for example, compiling purely computational parts of the
* code for specialist platforms for test and analysis purposes). So
* any definition that has to affect even _those_ modules will have to
* go here, with the key constraint being that this code has to come
* to _some_ decision even if the compilation platform is not a
* recognised one at all.
*/
/* Purely computational code uses smemclr(), so we have to make the
* decision here about whether that's provided by utils.c or by a
* platform implementation. We define PLATFORM_HAS_SMEMCLR to suppress
* utils.c's definition. */
#ifdef _WINDOWS
/* Windows provides the API function 'SecureZeroMemory', which we use
* unless the user has told us not to by defining NO_SECUREZEROMEMORY. */
#ifndef NO_SECUREZEROMEMORY
#define PLATFORM_HAS_SMEMCLR
#endif
#endif
#endif /* PUTTY_DEFS_H */