X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/c8e02c8a4947afa4f9ac20e78a3c8808b3945804..add23883a6378567be6b7866bc2ff2c32400a346:/server/tripe.h diff --git a/server/tripe.h b/server/tripe.h index bf599774..de3e016c 100644 --- a/server/tripe.h +++ b/server/tripe.h @@ -52,6 +52,7 @@ #include #include #include +#include #include #include @@ -70,9 +71,11 @@ #include #include #include +#include #include #include #include +#include #include #include #include @@ -86,6 +89,7 @@ #include #include +#include #include #include @@ -103,7 +107,9 @@ #include #include +#include "priv.h" #include "protocol.h" +#include "slip.h" #include "util.h" #undef sun @@ -121,37 +127,91 @@ #define T_KEYEXCH 64u #define T_KEYMGMT 128u #define T_CHAL 256u +/* T_PRIVSEP in priv.h */ -#define T_ALL 511u +#define T_ALL 1023u /* --- Units --- */ #define SEC(n) (n##u) #define MIN(n) (n##u * 60u) +#define F_2P32 (65536.0*65536.0) #define MEG(n) (n##ul * 1024ul * 1024ul) +/* --- Timing parameters --- */ + +#define T_EXP MIN(60) /* Expiry time for a key */ +#define T_REGEN MIN(40) /* Regeneration time for a key */ + +#define T_VALID SEC(20) /* Challenge validity period */ +#define T_RETRYMIN SEC(2) /* Minimum retry interval */ +#define T_RETRYMAX MIN(5) /* Maximum retry interval */ +#define T_RETRYGROW (5.0/4.0) /* Retry interval growth factor */ + +#define T_WOBBLE (1.0/3.0) /* Relative timer randomness */ + /* --- Other things --- */ #define PKBUFSZ 65536 /*----- Cipher selections -------------------------------------------------*/ -typedef struct algswitch { - const gccipher *c; /* Symmetric encryption scheme */ - const gccipher *mgf; /* Mask-generation function */ +typedef struct keyset keyset; +typedef struct algswitch algswitch; + +typedef struct bulkcrypto { + const char *name; + unsigned prim; + int (*check)(const algswitch */*a*/, dstr */*e*/); + size_t (*overhead)(const algswitch */*a*/); + int (*encrypt)(keyset */*ks*/, unsigned /*ty*/, buf */*b*/, buf */*bb*/); + int (*decrypt)(keyset */*ks*/, unsigned /*ty*/, + buf */*b*/, buf */*bb*/, uint32 */*seq*/); +} bulkcrypto; + +#define BCP_CIPHER 1 +#define BCP_MAC 2 +#define BCP_BLKC 4 + +struct algswitch { const gchash *h; /* Hash function */ + const gccipher *mgf; /* Mask-generation function */ + const struct bulkcrypto *bulk; /* Bulk crypto transformation */ + const gccipher *c; /* Symmetric encryption scheme */ const gcmac *m; /* Message authentication code */ + const gccipher *b; /* Block cipher */ size_t hashsz; /* Hash output size */ size_t tagsz; /* Length to truncate MAC tags */ - size_t cksz, mksz; /* Key lengths for @c@ and @m@ */ -} algswitch; + size_t expsz; /* Size of data to process */ + size_t cksz, mksz, bksz; /* Key lengths for things */ +}; -extern algswitch algs; +typedef struct kdata { + unsigned ref; /* Reference counter */ + struct knode *kn; /* Pointer to cache entry */ + char *tag; /* Full tag name of the key */ + group *g; /* The group we work in */ + size_t indexsz; /* Size of exponent for the group */ + mp *kpriv; /* The private key (or null) */ + ge *kpub; /* The public key */ + time_t t_exp; /* Expiry time of the key */ + algswitch algs; /* Collection of algorithms */ +} kdata; + +typedef struct knode { + sym_base _b; /* Symbol table intrusion */ + unsigned f; /* Various flags */ +#define KNF_BROKEN 1u /* Don't use this key any more */ + struct keyhalf *kh; /* Pointer to the home keyhalf */ + kdata *kd; /* Pointer to the key data */ +} knode; #define MAXHASHSZ 64 /* Largest possible hash size */ #define HASH_STRING(h, s) GH_HASH((h), (s), sizeof(s)) +extern const struct bulkcrypto bulktab[]; + /*----- Data structures ---------------------------------------------------*/ /* --- Socket addresses --- * @@ -198,24 +258,34 @@ typedef struct seqwin { * expiry. */ -typedef struct keyset { +struct keyset { struct keyset *next; /* Next active keyset in the list */ unsigned ref; /* Reference count for keyset */ struct peer *p; /* Pointer to peer structure */ time_t t_exp; /* Expiry time for this keyset */ - unsigned long sz_exp; /* Data limit for the keyset */ + unsigned long sz_exp, sz_regen; /* Data limits for the keyset */ T( unsigned seq; ) /* Sequence number for tracing */ unsigned f; /* Various useful flags */ - gcipher *cin, *cout; /* Keyset ciphers for encryption */ + const bulkcrypto *bulk; /* Bulk crypto transform */ size_t tagsz; /* Length to truncate MAC tags */ - gmac *min, *mout; /* Keyset MACs for integrity */ + struct ksdir { + gcipher *c; /* Keyset cipher for encryption */ + gmac *m; /* Keyset MAC for integrity */ + gcipher *b; /* Block cipher, just in case */ + } in, out; uint32 oseq; /* Outbound sequence number */ seqwin iseq; /* Inbound sequence number */ -} keyset; +}; #define KSF_LISTEN 1u /* Don't encrypt packets yet */ #define KSF_LINK 2u /* Key is in a linked list */ +#define KSERR_REGEN -1 /* Regenerate keys */ +#define KSERR_NOKEYS -2 /* No keys left */ +#define KSERR_DECRYPT -3 /* Unable to decrypt message */ +#define KSERR_SEQ -4 /* Incorrect sequence number */ +#define KSERR_MALFORMED -5 /* Input ciphertext is broken */ + /* --- Key exchange --- * * * TrIPE uses the Wrestlers Protocol for its key exchange. The Wrestlers @@ -225,6 +295,10 @@ typedef struct keyset { * Clive Jones. */ +typedef struct retry { + double t; /* Current retry time */ +} retry; + #define KX_NCHAL 16u typedef struct kxchal { @@ -234,6 +308,7 @@ typedef struct kxchal { keyset *ks; /* Pointer to temporary keyset */ unsigned f; /* Various useful flags */ sel_timer t; /* Response timer for challenge */ + retry rs; /* Retry state */ octet hc[MAXHASHSZ]; /* Hash of his challenge */ octet ck[MAXHASHSZ]; /* His magical check value */ octet hswrq_in[MAXHASHSZ]; /* Inbound switch request message */ @@ -244,12 +319,13 @@ typedef struct kxchal { typedef struct keyexch { struct peer *p; /* Pointer back to the peer */ + kdata *kpriv; /* Private key and related info */ + kdata *kpub; /* Peer's public key */ keyset **ks; /* Peer's list of keysets */ unsigned f; /* Various useful flags */ unsigned s; /* Current state in exchange */ sel_timer t; /* Timer for next exchange */ - ge *kpub; /* Peer's public key */ - time_t texp_kpub; /* Expiry time for public key */ + retry rs; /* Retry state */ mp *alpha; /* My temporary secret */ ge *c; /* My challenge */ ge *rx; /* The expected response */ @@ -281,8 +357,10 @@ struct peer; typedef struct tunnel_ops { const char *name; /* Name of this tunnel driver */ + unsigned flags; /* Various interesting flags */ +#define TUNF_PRIVOPEN 1u /* Need helper to open file */ void (*init)(void); /* Initializes the system */ - tunnel *(*create)(struct peer */*p*/, char **/*ifn*/); + tunnel *(*create)(struct peer */*p*/, int /*fd*/, char **/*ifn*/); /* Initializes a new tunnel */ void (*setifname)(tunnel */*t*/, const char */*ifn*/); /* Notifies ifname change */ @@ -320,11 +398,15 @@ typedef struct stats { typedef struct peerspec { char *name; /* Peer's name */ + char *privtag; /* Private key tag */ + char *tag; /* Public key tag */ const tunnel_ops *tops; /* Tunnel operations */ unsigned long t_ka; /* Keep alive interval */ addr sa; /* Socket address to speak to */ size_t sasz; /* Socket address size */ - unsigned kxf; /* Key exchange flags to set */ + unsigned f; /* Flags for the peer */ +#define PSF_KXMASK 255u /* Key-exchange flags to set */ +#define PSF_MOBILE 256u /* Address may change rapidly */ } peerspec; typedef struct peer_byname { @@ -412,12 +494,6 @@ typedef struct admin_addop { peerspec peer; /* Peer pending creation */ } admin_addop; -typedef struct admin_greetop { - admin_resop r; /* Name resolution header */ - void *c; /* Challenge block */ - size_t sz; /* Length of challenge */ -} admin_greetop; - typedef struct admin_pingop { admin_bgop bg; /* Background operation header */ ping ping; /* Ping pending response */ @@ -434,7 +510,7 @@ typedef struct admin_service { typedef struct admin_svcop { admin_bgop bg; /* Background operation header */ struct admin *prov; /* Client servicing this job */ - unsigned short index; /* This job's index */ + unsigned index; /* This job's index */ struct admin_svcop *next, *prev; /* Links for provider's jobs */ } admin_svcop; @@ -476,6 +552,7 @@ typedef struct admin { #ifndef NTRACE #define AF_TRACE 16u /* Catch tracing */ #endif +#define AF_FOREGROUND 32u /* Quit server when client closes */ #ifndef NTRACE # define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN) @@ -486,13 +563,11 @@ typedef struct admin { /*----- Global variables --------------------------------------------------*/ extern sel_state sel; /* Global I/O event state */ -extern group *gg; /* The group we work in */ -extern size_t indexsz; /* Size of exponent for the group */ -extern mp *kpriv; /* Our private key */ -extern ge *kpub; /* Our public key */ -extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ]; +extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ], buf_u[PKBUFSZ]; extern const tunnel_ops *tunnels[]; /* Table of tunnels (0-term) */ extern const tunnel_ops *tun_default; /* Default tunnel to use */ +extern kdata *master; /* Default private key */ +extern const char *tag_priv; /* Default private key tag */ #ifndef NTRACE extern const trace_opt tr_opts[]; /* Trace options array */ @@ -505,6 +580,21 @@ extern unsigned tr_flags; /* Trace options flags */ /*----- Key management ----------------------------------------------------*/ +/* --- @km_init@ --- * + * + * Arguments: @const char *privkr@ = private keyring file + * @const char *pubkr@ = public keyring file + * @const char *ptag@ = default private-key tag + * + * Returns: --- + * + * Use: Initializes the key-management machinery, loading the + * keyrings and so on. + */ + +extern void km_init(const char */*privkr*/, const char */*pubkr*/, + const char */*ptag*/); + /* --- @km_reload@ --- * * * Arguments: --- @@ -516,33 +606,60 @@ extern unsigned tr_flags; /* Trace options flags */ extern int km_reload(void); -/* --- @km_init@ --- * +/* --- @km_findpub@, @km_findpriv@ --- * * - * Arguments: @const char *kr_priv@ = private keyring file - * @const char *kr_pub@ = public keyring file - * @const char *tag@ = tag to load + * Arguments: @const char *tag@ = key tag to load + * + * Returns: Pointer to the kdata object if successful, or null on error. + * + * Use: Fetches a public or private key from the keyring. + */ + +extern kdata *km_findpub(const char */*tag*/); +extern kdata *km_findpriv(const char */*tag*/); + +/* --- @km_samealgsp@ --- * + * + * Arguments: @const kdata *kdx, *kdy@ = two key data objects + * + * Returns: Nonzero if their two algorithm selections are the same. + * + * Use: Checks sameness of algorithm selections: used to ensure that + * peers are using sensible algorithms. + */ + +extern int km_samealgsp(const kdata */*kdx*/, const kdata */*kdy*/); + +/* --- @km_ref@ --- * + * + * Arguments: @kdata *kd@ = pointer to the kdata object * * Returns: --- * - * Use: Initializes, and loads the private key. + * Use: Claim a new reference to a kdata object. */ -extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/, - const char */*tag*/); +extern void km_ref(kdata */*kd*/); -/* --- @km_getpubkey@ --- * +/* --- @km_unref@ --- * * - * Arguments: @const char *tag@ = public key tag to load - * @ge *kpub@ = where to put the public key - * @time_t *t_exp@ = where to put the expiry time + * Arguments: @kdata *kd@ = pointer to the kdata object * - * Returns: Zero if OK, nonzero if it failed. + * Returns: --- + * + * Use: Releases a reference to a kdata object. + */ + +extern void km_unref(kdata */*kd*/); + +/* --- @km_tag@ --- * * - * Use: Fetches a public key from the keyring. + * Arguments: @kdata *kd@ - pointer to the kdata object + * + * Returns: A pointer to the short tag by which the kdata was loaded. */ -extern int km_getpubkey(const char */*tag*/, ge */*kpub*/, - time_t */*t_exp*/); +extern const char *km_tag(kdata */*kd*/); /*----- Key exchange ------------------------------------------------------*/ @@ -657,15 +774,6 @@ extern keyset *ks_gen(const void */*k*/, size_t /*x*/, size_t /*y*/, size_t /*z*/, peer */*p*/); -/* --- @ks_tregen@ --- * - * - * Arguments: @keyset *ks@ = pointer to a keyset - * - * Returns: The time at which moves ought to be made to replace this key. - */ - -extern time_t ks_tregen(keyset */*ks*/); - /* --- @ks_activate@ --- * * * Arguments: @keyset *ks@ = pointer to a keyset @@ -685,14 +793,20 @@ extern void ks_activate(keyset */*ks*/); * @buf *b@ = pointer to input buffer * @buf *bb@ = pointer to output buffer * - * Returns: Zero if OK, nonzero if the key needs replacing. If the - * encryption failed, the output buffer is broken and zero is - * returned. + * Returns: Zero if successful; @KSERR_REGEN@ if we should negotiate a + * new key; @KSERR_NOKEYS@ if the key is not usable. Also + * returns zero if there was insufficient buffer (but the output + * buffer is broken in this case). * * Use: Encrypts a block of data using the key. Note that the `key * ought to be replaced' notification is only ever given once * for each key. Also note that this call forces a keyset to be * used even if it's marked as not for data output. + * + * The encryption transform is permitted to corrupt @buf_u@ for + * its own purposes. Neither the source nor destination should + * be within @buf_u@; and callers mustn't expect anything stored + * in @buf_u@ to still */ extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/, @@ -705,11 +819,18 @@ extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/, * @buf *b@ = pointer to an input buffer * @buf *bb@ = pointer to an output buffer * - * Returns: Zero on success, or nonzero if there was some problem. + * Returns: Zero on success; @KSERR_DECRYPT@ on failure. Also returns + * zero if there was insufficient buffer (but the output buffer + * is broken in this case). * * Use: Attempts to decrypt a message using a given key. Note that * requesting decryption with a key directly won't clear a * marking that it's not for encryption. + * + * The decryption transform is permitted to corrupt @buf_u@ for + * its own purposes. Neither the source nor destination should + * be within @buf_u@; and callers mustn't expect anything stored + * in @buf_u@ to still */ extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/, @@ -758,7 +879,10 @@ extern void ksl_prune(keyset **/*ksroot*/); * @buf *b@ = pointer to input buffer * @buf *bb@ = pointer to output buffer * - * Returns: Nonzero if a new key is needed. + * Returns: Zero if successful; @KSERR_REGEN@ if it's time to negotiate a + * new key; @KSERR_NOKEYS@ if there are no suitable keys + * available. Also returns zero if there was insufficient + * buffer space (but the output buffer is broken in this case). * * Use: Encrypts a packet. */ @@ -773,7 +897,9 @@ extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/, * @buf *b@ = pointer to input buffer * @buf *bb@ = pointer to output buffer * - * Returns: Nonzero if the packet couldn't be decrypted. + * Returns: Zero on success; @KSERR_DECRYPT@ on failure. Also returns + * zero if there was insufficient buffer (but the output buffer + * is broken in this case). * * Use: Decrypts a packet. */ @@ -809,6 +935,50 @@ extern int c_check(buf */*b*/); #define A_END ((char *)0) +/* --- @a_vformat@ --- * + * + * Arguments: @dstr *d@ = where to leave the formatted message + * @const char *fmt@ = pointer to format string + * @va_list ap@ = arguments in list + * + * Returns: --- + * + * Use: Main message token formatting driver. The arguments are + * interleaved formatting tokens and their parameters, finally + * terminated by an entry @A_END@. + * + * Tokens recognized: + * + * * "*..." ... -- pretokenized @dstr_putf@-like string + * + * * "?ADDR" SOCKADDR -- a socket address, to be converted + * + * * "?B64" BUFFER SIZE -- binary data to be base64-encoded + * + * * "?TOKENS" VECTOR -- null-terminated vector of tokens + * + * * "?PEER" PEER -- peer's name + * + * * "?ERRNO" ERRNO -- system error code + * + * * "[!]..." ... -- @dstr_putf@-like string as single token + */ + +extern void a_vformat(dstr */*d*/, const char */*fmt*/, va_list /*ap*/); + +/* --- @a_format@ --- * + * + * Arguments: @dstr *d@ = where to leave the formatted message + * @const char *fmt@ = pointer to format string + * + * Returns: --- + * + * Use: Writes a tokenized message into a string, for later + * presentation. + */ + +extern void EXECL_LIKE(0) a_format(dstr */*d*/, const char */*fmt*/, ...); + /* --- @a_warn@ --- * * * Arguments: @const char *fmt@ = pointer to format string @@ -819,7 +989,7 @@ extern int c_check(buf */*b*/); * Use: Informs all admin connections of a warning. */ -extern void a_warn(const char */*fmt*/, ...); +extern void EXECL_LIKE(0) a_warn(const char */*fmt*/, ...); /* --- @a_notify@ --- * * @@ -831,7 +1001,7 @@ extern void a_warn(const char */*fmt*/, ...); * Use: Sends a notification to interested admin connections. */ -extern void a_notify(const char */*fmt*/, ...); +extern void EXECL_LIKE(0) a_notify(const char */*fmt*/, ...); /* --- @a_create@ --- * * @@ -883,13 +1053,17 @@ extern void a_daemon(void); /* --- @a_init@ --- * * * Arguments: @const char *sock@ = socket name to create + * @uid_t u@ = user to own the socket + * @gid_t g@ = group to own the socket + * @mode_t m@ = permissions to set on the socket * * Returns: --- * * Use: Creates the admin listening socket. */ -extern void a_init(const char */*sock*/); +extern void a_init(const char */*sock*/, + uid_t /*u*/, gid_t /*g*/, mode_t /*m*/); /*----- Mapping with addresses as keys ------------------------------------*/ @@ -945,6 +1119,69 @@ extern void *am_find(addrmap */*m*/, const addr */*a*/, extern void am_remove(addrmap */*m*/, void */*i*/); +/*----- Privilege separation ----------------------------------------------*/ + +/* --- @ps_trace@ --- * + * + * Arguments: @unsigned mask@ = trace mask to check + * @const char *fmt@ = message format + * @...@ = values for placeholders + * + * Returns: --- + * + * Use: Writes a trace message. + */ + +T( extern void PRINTF_LIKE(2, 3) + ps_trace(unsigned /*mask*/, const char */*fmt*/, ...); ) + +/* --- @ps_warn@ --- * + * + * Arguments: @const char *fmt@ = message format + * @...@ = values for placeholders + * + * Returns: --- + * + * Use: Writes a warning message. + */ + +extern void PRINTF_LIKE(1, 2) ps_warn(const char */*fmt*/, ...); + +/* --- @ps_tunfd@ --- * + * + * Arguments: @const tunnel_ops *tops@ = pointer to tunnel operations + * @char **ifn@ = where to put the interface name + * + * Returns: The file descriptor, or @-1@ on error. + * + * Use: Fetches a file descriptor for a tunnel driver. + */ + +extern int ps_tunfd(const tunnel_ops */*tops*/, char **/*ifn*/); + +/* --- @ps_split@ --- * + * + * Arguments: @int detachp@ = whether to detach the child from its terminal + * + * Returns: --- + * + * Use: Separates off the privileged tunnel-opening service from the + * rest of the server. + */ + +extern void ps_split(int /*detachp*/); + +/* --- @ps_quit@ --- * + * + * Arguments: --- + * + * Returns: --- + * + * Use: Detaches from the helper process. + */ + +extern void ps_quit(void); + /*----- Peer management ---------------------------------------------------*/ /* --- @p_txstart@ --- * @@ -1132,6 +1369,24 @@ extern peer *p_create(peerspec */*spec*/); extern const char *p_name(peer */*p*/); +/* --- @p_tag@ --- * + * + * Arguments: @peer *p@ = pointer to a peer block + * + * Returns: A pointer to the peer's public key tag. + */ + +extern const char *p_tag(peer */*p*/); + +/* --- @p_privtag@ --- * + * + * Arguments: @peer *p@ = pointer to a peer block + * + * Returns: A pointer to the peer's private key tag. + */ + +extern const char *p_privtag(peer */*p*/); + /* --- @p_spec@ --- * * * Arguments: @peer *p@ = pointer to a peer block @@ -1185,7 +1440,7 @@ extern void p_destroy(peer */*p*/); #define FOREACH_PEER(p, stuff) do { \ peer_iter i_; \ peer *p; \ - for (p_mkiter(&i_); (p = p_next(&i_)) != 0; ) do stuff while (0); \ + for (p_mkiter(&i_); (p = p_next(&i_)) != 0; ) stuff \ } while (0) /* --- @p_mkiter@ --- * @@ -1235,7 +1490,7 @@ extern const tunnel_ops tun_slip; * Returns: A pointer to the integer's textual representation. * * Use: Converts a multiprecision integer to a string. Corrupts - * @buf_t@. + * @buf_u@. */ extern const char *mpstr(mp */*m*/); @@ -1248,7 +1503,7 @@ extern const char *mpstr(mp */*m*/); * Returns: A pointer to the element's textual representation. * * Use: Converts a group element to a string. Corrupts - * @buf_t@. + * @buf_u@. */ extern const char *gestr(group */*g*/, ge */*x*/); @@ -1260,7 +1515,7 @@ extern const char *gestr(group */*g*/, ge */*x*/); * Returns: A pointer to a textual representation of the time. * * Use: Converts a time to a textual representation. Corrupts - * @buf_t@. + * @buf_u@. */ extern const char *timestr(time_t /*t*/);