diff options
Diffstat (limited to 'libotr/libotr-4.1.1/src/privkey.c')
| -rw-r--r-- | libotr/libotr-4.1.1/src/privkey.c | 938 |
1 files changed, 938 insertions, 0 deletions
diff --git a/libotr/libotr-4.1.1/src/privkey.c b/libotr/libotr-4.1.1/src/privkey.c new file mode 100644 index 0000000..6e4bbe4 --- /dev/null +++ b/libotr/libotr-4.1.1/src/privkey.c @@ -0,0 +1,938 @@ +/* + * Off-the-Record Messaging library + * Copyright (C) 2004-2012 Ian Goldberg, Rob Smits, Chris Alexander, + * Willy Lew, Lisa Du, Nikita Borisov + * <otr@cypherpunks.ca> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of version 2.1 of the GNU Lesser General + * Public License as published by the Free Software Foundation. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* system headers */ +#include <stdio.h> +#include <stdlib.h> +#include <errno.h> +#include <sys/stat.h> + +/* libgcrypt headers */ +#include <gcrypt.h> + +/* libotr headers */ +#include "privkey.h" +#include "serial.h" + +/* Convert a 20-byte hash value to a 45-byte human-readable value */ +void otrl_privkey_hash_to_human( + char human[OTRL_PRIVKEY_FPRINT_HUMAN_LEN], + const unsigned char hash[20]) +{ + int word, byte; + char *p = human; + + for(word=0; word<5; ++word) { + for(byte=0; byte<4; ++byte) { + sprintf(p, "%02X", hash[word*4+byte]); + p += 2; + } + *(p++) = ' '; + } + /* Change that last ' ' to a '\0' */ + --p; + *p = '\0'; +} + +/* Calculate a human-readable hash of our DSA public key. Return it in + * the passed fingerprint buffer. Return NULL on error, or a pointer to + * the given buffer on success. */ +char *otrl_privkey_fingerprint(OtrlUserState us, + char fingerprint[OTRL_PRIVKEY_FPRINT_HUMAN_LEN], + const char *accountname, const char *protocol) +{ + unsigned char hash[20]; + OtrlPrivKey *p = otrl_privkey_find(us, accountname, protocol); + + if (p) { + /* Calculate the hash */ + gcry_md_hash_buffer(GCRY_MD_SHA1, hash, p->pubkey_data, + p->pubkey_datalen); + + /* Now convert it to a human-readable format */ + otrl_privkey_hash_to_human(fingerprint, hash); + } else { + return NULL; + } + + return fingerprint; +} + +/* Calculate a raw hash of our DSA public key. Return it in the passed + * fingerprint buffer. Return NULL on error, or a pointer to the given + * buffer on success. */ +unsigned char *otrl_privkey_fingerprint_raw(OtrlUserState us, + unsigned char hash[20], const char *accountname, const char *protocol) +{ + OtrlPrivKey *p = otrl_privkey_find(us, accountname, protocol); + + if (p) { + /* Calculate the hash */ + gcry_md_hash_buffer(GCRY_MD_SHA1, hash, p->pubkey_data, + p->pubkey_datalen); + } else { + return NULL; + } + + return hash; +} + +/* Create a public key block from a private key */ +static gcry_error_t make_pubkey(unsigned char **pubbufp, size_t *publenp, + gcry_sexp_t privkey) +{ + gcry_mpi_t p,q,g,y; + gcry_sexp_t dsas,ps,qs,gs,ys; + size_t np,nq,ng,ny; + enum gcry_mpi_format format = GCRYMPI_FMT_USG; + unsigned char *bufp; + size_t lenp; + + *pubbufp = NULL; + *publenp = 0; + + /* Extract the public parameters */ + dsas = gcry_sexp_find_token(privkey, "dsa", 0); + if (dsas == NULL) { + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + ps = gcry_sexp_find_token(dsas, "p", 0); + qs = gcry_sexp_find_token(dsas, "q", 0); + gs = gcry_sexp_find_token(dsas, "g", 0); + ys = gcry_sexp_find_token(dsas, "y", 0); + gcry_sexp_release(dsas); + if (!ps || !qs || !gs || !ys) { + gcry_sexp_release(ps); + gcry_sexp_release(qs); + gcry_sexp_release(gs); + gcry_sexp_release(ys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + p = gcry_sexp_nth_mpi(ps, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(ps); + q = gcry_sexp_nth_mpi(qs, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(qs); + g = gcry_sexp_nth_mpi(gs, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(gs); + y = gcry_sexp_nth_mpi(ys, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(ys); + if (!p || !q || !g || !y) { + gcry_mpi_release(p); + gcry_mpi_release(q); + gcry_mpi_release(g); + gcry_mpi_release(y); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + + *publenp = 0; + gcry_mpi_print(format, NULL, 0, &np, p); + *publenp += np + 4; + gcry_mpi_print(format, NULL, 0, &nq, q); + *publenp += nq + 4; + gcry_mpi_print(format, NULL, 0, &ng, g); + *publenp += ng + 4; + gcry_mpi_print(format, NULL, 0, &ny, y); + *publenp += ny + 4; + + *pubbufp = malloc(*publenp); + if (*pubbufp == NULL) { + gcry_mpi_release(p); + gcry_mpi_release(q); + gcry_mpi_release(g); + gcry_mpi_release(y); + return gcry_error(GPG_ERR_ENOMEM); + } + bufp = *pubbufp; + lenp = *publenp; + + write_mpi(p,np,"P"); + write_mpi(q,nq,"Q"); + write_mpi(g,ng,"G"); + write_mpi(y,ny,"Y"); + + gcry_mpi_release(p); + gcry_mpi_release(q); + gcry_mpi_release(g); + gcry_mpi_release(y); + + return gcry_error(GPG_ERR_NO_ERROR); +} + +/* Read a sets of private DSA keys from a file on disk into the given + * OtrlUserState. */ +gcry_error_t otrl_privkey_read(OtrlUserState us, const char *filename) +{ + FILE *privf; + gcry_error_t err; + + /* Open the privkey file. We use rb mode so that on WIN32, fread() + * reads the same number of bytes that fstat() indicates are in the + * file. */ + privf = fopen(filename, "rb"); + if (!privf) { + err = gcry_error_from_errno(errno); + return err; + } + + err = otrl_privkey_read_FILEp(us, privf); + + fclose(privf); + return err; +} + +/* Read a sets of private DSA keys from a FILE* into the given + * OtrlUserState. The FILE* must be open for reading. */ +gcry_error_t otrl_privkey_read_FILEp(OtrlUserState us, FILE *privf) +{ + int privfd; + struct stat st; + char *buf; + const char *token; + size_t tokenlen; + gcry_error_t err; + gcry_sexp_t allkeys; + int i; + + if (!privf) return gcry_error(GPG_ERR_NO_ERROR); + + /* Release any old ideas we had about our keys */ + otrl_privkey_forget_all(us); + + /* Load the data into a buffer */ + privfd = fileno(privf); + if (fstat(privfd, &st)) { + err = gcry_error_from_errno(errno); + return err; + } + buf = malloc(st.st_size); + if (!buf && st.st_size > 0) { + return gcry_error(GPG_ERR_ENOMEM); + } + if (fread(buf, st.st_size, 1, privf) != 1) { + err = gcry_error_from_errno(errno); + free(buf); + return err; + } + + err = gcry_sexp_new(&allkeys, buf, st.st_size, 0); + free(buf); + if (err) { + return err; + } + + token = gcry_sexp_nth_data(allkeys, 0, &tokenlen); + if (tokenlen != 8 || strncmp(token, "privkeys", 8)) { + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + + /* Get each account */ + for(i=1; i<gcry_sexp_length(allkeys); ++i) { + gcry_sexp_t names, protos, privs; + char *name, *proto; + gcry_sexp_t accounts; + OtrlPrivKey *p; + + /* Get the ith "account" S-exp */ + accounts = gcry_sexp_nth(allkeys, i); + + /* It's really an "account" S-exp? */ + token = gcry_sexp_nth_data(accounts, 0, &tokenlen); + if (tokenlen != 7 || strncmp(token, "account", 7)) { + gcry_sexp_release(accounts); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + /* Extract the name, protocol, and privkey S-exps */ + names = gcry_sexp_find_token(accounts, "name", 0); + protos = gcry_sexp_find_token(accounts, "protocol", 0); + privs = gcry_sexp_find_token(accounts, "private-key", 0); + gcry_sexp_release(accounts); + if (!names || !protos || !privs) { + gcry_sexp_release(names); + gcry_sexp_release(protos); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + /* Extract the actual name and protocol */ + token = gcry_sexp_nth_data(names, 1, &tokenlen); + if (!token) { + gcry_sexp_release(names); + gcry_sexp_release(protos); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + name = malloc(tokenlen + 1); + if (!name) { + gcry_sexp_release(names); + gcry_sexp_release(protos); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_ENOMEM); + } + memmove(name, token, tokenlen); + name[tokenlen] = '\0'; + gcry_sexp_release(names); + + token = gcry_sexp_nth_data(protos, 1, &tokenlen); + if (!token) { + free(name); + gcry_sexp_release(protos); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + proto = malloc(tokenlen + 1); + if (!proto) { + free(name); + gcry_sexp_release(protos); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_ENOMEM); + } + memmove(proto, token, tokenlen); + proto[tokenlen] = '\0'; + gcry_sexp_release(protos); + + /* Make a new OtrlPrivKey entry */ + p = malloc(sizeof(*p)); + if (!p) { + free(name); + free(proto); + gcry_sexp_release(privs); + gcry_sexp_release(allkeys); + return gcry_error(GPG_ERR_ENOMEM); + } + + /* Fill it in and link it up */ + p->accountname = name; + p->protocol = proto; + p->pubkey_type = OTRL_PUBKEY_TYPE_DSA; + p->privkey = privs; + p->next = us->privkey_root; + if (p->next) { + p->next->tous = &(p->next); + } + p->tous = &(us->privkey_root); + us->privkey_root = p; + err = make_pubkey(&(p->pubkey_data), &(p->pubkey_datalen), p->privkey); + if (err) { + gcry_sexp_release(allkeys); + otrl_privkey_forget(p); + return gcry_error(GPG_ERR_UNUSABLE_SECKEY); + } + } + gcry_sexp_release(allkeys); + + return gcry_error(GPG_ERR_NO_ERROR); +} + +static OtrlPendingPrivKey *pending_find(OtrlUserState us, + const char *accountname, const char *protocol) +{ + OtrlPendingPrivKey *search = us->pending_root; + + while (search) { + if (!strcmp(search->accountname, accountname) && + !strcmp(search->protocol, protocol)) { + /* Found it */ + return search; + } + search = search->next; + } + return NULL; +} + +/* Insert an account/protocol pair into the pending privkey list of the + * given OtrlUserState and return a pointer to the new + * OtrlPendingPrivKey, or return NULL if it's already there. */ +static OtrlPendingPrivKey *pending_insert(OtrlUserState us, + const char *accountname, const char *protocol) +{ + /* See if it's already there */ + OtrlPendingPrivKey *search = pending_find(us, accountname, protocol); + + if (search) { + /* It is */ + return NULL; + } + + /* We'll insert it at the beginning of the list */ + search = malloc(sizeof(*search)); + if (!search) return NULL; + + search->accountname = strdup(accountname); + search->protocol = strdup(protocol); + + search->next = us->pending_root; + us->pending_root = search; + if (search->next) { + search->next->tous = &(search->next); + } + search->tous = &(us->pending_root); + return search; +} + +static void pending_forget(OtrlPendingPrivKey *ppk) +{ + if (ppk) { + free(ppk->accountname); + free(ppk->protocol); + + /* Re-link the list */ + *(ppk->tous) = ppk->next; + if (ppk->next) { + ppk->next->tous = ppk->tous; + } + + free(ppk); + } +} + +/* Free the memory associated with the pending privkey list */ +void otrl_privkey_pending_forget_all(OtrlUserState us) +{ + while(us->pending_root) { + pending_forget(us->pending_root); + } +} + +static gcry_error_t sexp_write(FILE *privf, gcry_sexp_t sexp) +{ + size_t buflen; + char *buf; + + buflen = gcry_sexp_sprint(sexp, GCRYSEXP_FMT_ADVANCED, NULL, 0); + buf = malloc(buflen); + if (buf == NULL && buflen > 0) { + return gcry_error(GPG_ERR_ENOMEM); + } + gcry_sexp_sprint(sexp, GCRYSEXP_FMT_ADVANCED, buf, buflen); + + fprintf(privf, "%s", buf); + free(buf); + + return gcry_error(GPG_ERR_NO_ERROR); +} + +static gcry_error_t account_write(FILE *privf, const char *accountname, + const char *protocol, gcry_sexp_t privkey) +{ + gcry_error_t err; + gcry_sexp_t names, protos; + + fprintf(privf, " (account\n"); + + err = gcry_sexp_build(&names, NULL, "(name %s)", accountname); + if (!err) { + err = sexp_write(privf, names); + gcry_sexp_release(names); + } + if (!err) err = gcry_sexp_build(&protos, NULL, "(protocol %s)", protocol); + if (!err) { + err = sexp_write(privf, protos); + gcry_sexp_release(protos); + } + if (!err) err = sexp_write(privf, privkey); + + fprintf(privf, " )\n"); + + return err; +} + +struct s_pending_privkey_calc { + char *accountname; + char *protocol; + gcry_sexp_t privkey; +}; + +/* Begin a private key generation that will potentially take place in + * a background thread. This routine must be called from the main + * thread. It will set *newkeyp, which you can pass to + * otrl_privkey_generate_calculate in a background thread. If it + * returns gcry_error(GPG_ERR_EEXIST), then a privkey creation for + * this accountname/protocol is already in progress, and *newkeyp will + * be set to NULL. */ +gcry_error_t otrl_privkey_generate_start(OtrlUserState us, + const char *accountname, const char *protocol, void **newkeyp) +{ + OtrlPendingPrivKey *found = pending_find(us, accountname, protocol); + struct s_pending_privkey_calc *ppc; + + if (found) { + if (newkeyp) *newkeyp = NULL; + return gcry_error(GPG_ERR_EEXIST); + } + + /* We're not already creating this key. Mark it as in progress. */ + pending_insert(us, accountname, protocol); + + /* Allocate the working structure */ + ppc = malloc(sizeof(*ppc)); + ppc->accountname = strdup(accountname); + ppc->protocol = strdup(protocol); + ppc->privkey = NULL; + + *newkeyp = ppc; + + return gcry_error(GPG_ERR_NO_ERROR); +} + +/* Do the private key generation calculation. You may call this from a + * background thread. When it completes, call + * otrl_privkey_generate_finish from the _main_ thread. */ +gcry_error_t otrl_privkey_generate_calculate(void *newkey) +{ + struct s_pending_privkey_calc *ppc = + (struct s_pending_privkey_calc *)newkey; + gcry_error_t err; + gcry_sexp_t key, parms; + static const char *parmstr = "(genkey (dsa (nbits 4:1024)))"; + + /* Create a DSA key */ + err = gcry_sexp_new(&parms, parmstr, strlen(parmstr), 0); + if (err) { + return err; + } + err = gcry_pk_genkey(&key, parms); + gcry_sexp_release(parms); + if (err) { + return err; + } + + /* Extract the privkey */ + ppc->privkey = gcry_sexp_find_token(key, "private-key", 0); + gcry_sexp_release(key); + + return gcry_error(GPG_ERR_NO_ERROR); +} + +static FILE* privkey_fopen(const char *filename, gcry_error_t *errp) +{ + FILE *privf; +#ifndef WIN32 + mode_t oldmask; +#endif + +#ifndef WIN32 + oldmask = umask(077); +#endif + privf = fopen(filename, "w+b"); + if (!privf && errp) { + *errp = gcry_error_from_errno(errno); + } +#ifndef WIN32 + umask(oldmask); +#endif + return privf; +} + +/* Call this from the main thread only, in the event that the background + * thread generating the key is cancelled. The newkey is deallocated, + * and must not be used further. */ +void otrl_privkey_generate_cancelled(OtrlUserState us, void *newkey) +{ + struct s_pending_privkey_calc *ppc = + (struct s_pending_privkey_calc *)newkey; + + if (us) { + pending_forget(pending_find(us, ppc->accountname, ppc->protocol)); + } + + /* Deallocate ppc */ + free(ppc->accountname); + free(ppc->protocol); + gcry_sexp_release(ppc->privkey); + free(ppc); +} + +/* Call this from the main thread only. It will write the newly created + * private key into the given file and store it in the OtrlUserState. */ +gcry_error_t otrl_privkey_generate_finish(OtrlUserState us, + void *newkey, const char *filename) +{ + gcry_error_t err; + FILE *privf = privkey_fopen(filename, &err); + if (!privf) { + return err; + } + + err = otrl_privkey_generate_finish_FILEp(us, newkey, privf); + + fclose(privf); + return err; +} + +/* Call this from the main thread only. It will write the newly created + * private key into the given FILE* (which must be open for reading and + * writing) and store it in the OtrlUserState. */ +gcry_error_t otrl_privkey_generate_finish_FILEp(OtrlUserState us, + void *newkey, FILE *privf) +{ + struct s_pending_privkey_calc *ppc = + (struct s_pending_privkey_calc *)newkey; + gcry_error_t ret = gcry_error(GPG_ERR_INV_VALUE); + + if (ppc && us && privf) { + OtrlPrivKey *p; + + /* Output the other keys we know */ + fprintf(privf, "(privkeys\n"); + + for (p=us->privkey_root; p; p=p->next) { + /* Skip this one if our new key replaces it */ + if (!strcmp(p->accountname, ppc->accountname) && + !strcmp(p->protocol, ppc->protocol)) { + continue; + } + + account_write(privf, p->accountname, p->protocol, p->privkey); + } + account_write(privf, ppc->accountname, ppc->protocol, ppc->privkey); + fprintf(privf, ")\n"); + + fseek(privf, 0, SEEK_SET); + + ret = otrl_privkey_read_FILEp(us, privf); + } + + otrl_privkey_generate_cancelled(us, newkey); + + return ret; +} + +/* Generate a private DSA key for a given account, storing it into a + * file on disk, and loading it into the given OtrlUserState. Overwrite any + * previously generated keys for that account in that OtrlUserState. */ +gcry_error_t otrl_privkey_generate(OtrlUserState us, const char *filename, + const char *accountname, const char *protocol) +{ + gcry_error_t err; + FILE *privf = privkey_fopen(filename, &err); + if (!privf) { + return err; + } + + err = otrl_privkey_generate_FILEp(us, privf, accountname, protocol); + + fclose(privf); + return err; +} + +/* Generate a private DSA key for a given account, storing it into a + * FILE*, and loading it into the given OtrlUserState. Overwrite any + * previously generated keys for that account in that OtrlUserState. + * The FILE* must be open for reading and writing. */ +gcry_error_t otrl_privkey_generate_FILEp(OtrlUserState us, FILE *privf, + const char *accountname, const char *protocol) +{ + void *newkey = NULL; + gcry_error_t err; + + err = otrl_privkey_generate_start(us, accountname, protocol, &newkey); + if (newkey) { + otrl_privkey_generate_calculate(newkey); + err = otrl_privkey_generate_finish_FILEp(us, newkey, privf); + } + + return err; +} + +/* Convert a hex character to a value */ +static unsigned int ctoh(char c) +{ + if (c >= '0' && c <= '9') return c-'0'; + if (c >= 'a' && c <= 'f') return c-'a'+10; + if (c >= 'A' && c <= 'F') return c-'A'+10; + return 0; /* Unknown hex char */ +} + +/* Read the fingerprint store from a file on disk into the given + * OtrlUserState. Use add_app_data to add application data to each + * ConnContext so created. */ +gcry_error_t otrl_privkey_read_fingerprints(OtrlUserState us, + const char *filename, + void (*add_app_data)(void *data, ConnContext *context), + void *data) +{ + gcry_error_t err; + FILE *storef; + + storef = fopen(filename, "rb"); + if (!storef) { + err = gcry_error_from_errno(errno); + return err; + } + + err = otrl_privkey_read_fingerprints_FILEp(us, storef, add_app_data, data); + + fclose(storef); + return err; +} + +/* Read the fingerprint store from a FILE* into the given + * OtrlUserState. Use add_app_data to add application data to each + * ConnContext so created. The FILE* must be open for reading. */ +gcry_error_t otrl_privkey_read_fingerprints_FILEp(OtrlUserState us, + FILE *storef, + void (*add_app_data)(void *data, ConnContext *context), + void *data) +{ + ConnContext *context; + char storeline[1000]; + unsigned char fingerprint[20]; + size_t maxsize = sizeof(storeline); + + if (!storef) return gcry_error(GPG_ERR_NO_ERROR); + + while(fgets(storeline, maxsize, storef)) { + char *username; + char *accountname; + char *protocol; + char *hex; + char *trust; + char *tab; + char *eol; + Fingerprint *fng; + int i, j; + /* Parse the line, which should be of the form: + * username\taccountname\tprotocol\t40_hex_nybbles\n */ + username = storeline; + tab = strchr(username, '\t'); + if (!tab) continue; + *tab = '\0'; + + accountname = tab + 1; + tab = strchr(accountname, '\t'); + if (!tab) continue; + *tab = '\0'; + + protocol = tab + 1; + tab = strchr(protocol, '\t'); + if (!tab) continue; + *tab = '\0'; + + hex = tab + 1; + tab = strchr(hex, '\t'); + if (!tab) { + eol = strchr(hex, '\r'); + if (!eol) eol = strchr(hex, '\n'); + if (!eol) continue; + *eol = '\0'; + trust = NULL; + } else { + *tab = '\0'; + trust = tab + 1; + eol = strchr(trust, '\r'); + if (!eol) eol = strchr(trust, '\n'); + if (!eol) continue; + *eol = '\0'; + } + + if (strlen(hex) != 40) continue; + for(j=0, i=0; i<40; i+=2) { + fingerprint[j++] = (ctoh(hex[i]) << 4) + (ctoh(hex[i+1])); + } + /* Get the context for this user, adding if not yet present */ + context = otrl_context_find(us, username, accountname, protocol, + OTRL_INSTAG_MASTER, 1, NULL, add_app_data, data); + /* Add the fingerprint if not already there */ + fng = otrl_context_find_fingerprint(context, fingerprint, 1, NULL); + otrl_context_set_trust(fng, trust); + } + + return gcry_error(GPG_ERR_NO_ERROR); +} + +/* Write the fingerprint store from a given OtrlUserState to a file on disk. */ +gcry_error_t otrl_privkey_write_fingerprints(OtrlUserState us, + const char *filename) +{ + gcry_error_t err; + FILE *storef; + + storef = fopen(filename, "wb"); + if (!storef) { + err = gcry_error_from_errno(errno); + return err; + } + + err = otrl_privkey_write_fingerprints_FILEp(us, storef); + + fclose(storef); + return err; +} + +/* Write the fingerprint store from a given OtrlUserState to a FILE*. + * The FILE* must be open for writing. */ +gcry_error_t otrl_privkey_write_fingerprints_FILEp(OtrlUserState us, + FILE *storef) +{ + ConnContext *context; + Fingerprint *fprint; + + if (!storef) return gcry_error(GPG_ERR_NO_ERROR); + + for(context = us->context_root; context; context = context->next) { + /* Fingerprints are only stored in the master contexts */ + if (context->their_instance != OTRL_INSTAG_MASTER) continue; + + /* Don't bother with the first (fingerprintless) entry. */ + for (fprint = context->fingerprint_root.next; fprint; + fprint = fprint->next) { + int i; + fprintf(storef, "%s\t%s\t%s\t", context->username, + context->accountname, context->protocol); + for(i=0;i<20;++i) { + fprintf(storef, "%02x", fprint->fingerprint[i]); + } + fprintf(storef, "\t%s\n", fprint->trust ? fprint->trust : ""); + } + } + + return gcry_error(GPG_ERR_NO_ERROR); +} + +/* Fetch the private key from the given OtrlUserState associated with + * the given account */ +OtrlPrivKey *otrl_privkey_find(OtrlUserState us, const char *accountname, + const char *protocol) +{ + OtrlPrivKey *p; + if (!accountname || !protocol) return NULL; + + for(p=us->privkey_root; p; p=p->next) { + if (!strcmp(p->accountname, accountname) && + !strcmp(p->protocol, protocol)) { + return p; + } + } + return NULL; +} + +/* Forget a private key */ +void otrl_privkey_forget(OtrlPrivKey *privkey) +{ + free(privkey->accountname); + free(privkey->protocol); + gcry_sexp_release(privkey->privkey); + free(privkey->pubkey_data); + + /* Re-link the list */ + *(privkey->tous) = privkey->next; + if (privkey->next) { + privkey->next->tous = privkey->tous; + } + + /* Free the privkey struct */ + free(privkey); +} + +/* Forget all private keys in a given OtrlUserState. */ +void otrl_privkey_forget_all(OtrlUserState us) +{ + while (us->privkey_root) { + otrl_privkey_forget(us->privkey_root); + } +} + +/* Sign data using a private key. The data must be small enough to be + * signed (i.e. already hashed, if necessary). The signature will be + * returned in *sigp, which the caller must free(). Its length will be + * returned in *siglenp. */ +gcry_error_t otrl_privkey_sign(unsigned char **sigp, size_t *siglenp, + OtrlPrivKey *privkey, const unsigned char *data, size_t len) +{ + gcry_mpi_t r,s, datampi; + gcry_sexp_t dsas, rs, ss, sigs, datas; + size_t nr, ns; + const enum gcry_mpi_format format = GCRYMPI_FMT_USG; + + if (privkey->pubkey_type != OTRL_PUBKEY_TYPE_DSA) + return gcry_error(GPG_ERR_INV_VALUE); + + *sigp = malloc(40); + if (*sigp == NULL) return gcry_error(GPG_ERR_ENOMEM); + *siglenp = 40; + + if (len) { + gcry_mpi_scan(&datampi, GCRYMPI_FMT_USG, data, len, NULL); + } else { + datampi = gcry_mpi_set_ui(NULL, 0); + } + gcry_sexp_build(&datas, NULL, "(%m)", datampi); + gcry_mpi_release(datampi); + gcry_pk_sign(&sigs, datas, privkey->privkey); + gcry_sexp_release(datas); + dsas = gcry_sexp_find_token(sigs, "dsa", 0); + gcry_sexp_release(sigs); + rs = gcry_sexp_find_token(dsas, "r", 0); + ss = gcry_sexp_find_token(dsas, "s", 0); + gcry_sexp_release(dsas); + r = gcry_sexp_nth_mpi(rs, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(rs); + s = gcry_sexp_nth_mpi(ss, 1, GCRYMPI_FMT_USG); + gcry_sexp_release(ss); + gcry_mpi_print(format, NULL, 0, &nr, r); + gcry_mpi_print(format, NULL, 0, &ns, s); + memset(*sigp, 0, 40); + gcry_mpi_print(format, (*sigp)+(20-nr), nr, NULL, r); + gcry_mpi_print(format, (*sigp)+20+(20-ns), ns, NULL, s); + gcry_mpi_release(r); + gcry_mpi_release(s); + + return gcry_error(GPG_ERR_NO_ERROR); +} + +/* Verify a signature on data using a public key. The data must be + * small enough to be signed (i.e. already hashed, if necessary). */ +gcry_error_t otrl_privkey_verify(const unsigned char *sigbuf, size_t siglen, + unsigned short pubkey_type, gcry_sexp_t pubs, + const unsigned char *data, size_t len) +{ + gcry_error_t err; + gcry_mpi_t datampi,r,s; + gcry_sexp_t datas, sigs; + + if (pubkey_type != OTRL_PUBKEY_TYPE_DSA || siglen != 40) + return gcry_error(GPG_ERR_INV_VALUE); + + if (len) { + gcry_mpi_scan(&datampi, GCRYMPI_FMT_USG, data, len, NULL); + } else { + datampi = gcry_mpi_set_ui(NULL, 0); + } + gcry_sexp_build(&datas, NULL, "(%m)", datampi); + gcry_mpi_release(datampi); + gcry_mpi_scan(&r, GCRYMPI_FMT_USG, sigbuf, 20, NULL); + gcry_mpi_scan(&s, GCRYMPI_FMT_USG, sigbuf+20, 20, NULL); + gcry_sexp_build(&sigs, NULL, "(sig-val (dsa (r %m)(s %m)))", r, s); + gcry_mpi_release(r); + gcry_mpi_release(s); + + err = gcry_pk_verify(sigs, datas, pubs); + gcry_sexp_release(datas); + gcry_sexp_release(sigs); + + return err; +} + |