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/*
* wrapper functions around the usign executable
* Copyright (C) 2018 Daniel Golle <daniel@makrotopia.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3
* as published by the Free Software Foundation
*
* This program 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 General Public License for more details.
*/
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include "usign.h"
#ifdef UCERT_HOST_BUILD
#define USIGN_EXEC "usign"
#else
#define USIGN_EXEC "/usr/bin/usign"
#endif
/*
* check for revoker deadlink in pubkeydir
* return true if a revoker exists, false otherwise
*/
int _usign_key_is_revoked(const char *fingerprint, const char *pubkeydir) {
char tml[64] = {0};
char rfname[256] = {0};
snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
if (readlink(rfname, tml, sizeof(tml)) > 0 &&
!strcmp(tml, ".revoked.")) {
return true;
};
return false;
}
#ifdef UCERT_FULL
/*
* call usign -S ...
* return WEXITSTATUS or -1 if fork fails
*/
int usign_s(const char *msgfile, const char *seckeyfile, const char *sigfile, bool quiet) {
pid_t pid;
int status;
const char *usign_argv[16] = {0};
unsigned int usign_argc = 0;
usign_argv[usign_argc++] = USIGN_EXEC;
usign_argv[usign_argc++] = "-S";
usign_argv[usign_argc++] = "-m";
usign_argv[usign_argc++] = msgfile;
usign_argv[usign_argc++] = "-s";
usign_argv[usign_argc++] = seckeyfile;
usign_argv[usign_argc++] = "-x";
usign_argv[usign_argc++] = sigfile;
if (quiet)
usign_argv[usign_argc++] = "-q";
pid = fork();
switch (pid) {
case -1:
return -1;
case 0:
execvp(usign_argv[0], (char *const *)usign_argv);
if (!quiet)
perror("Failed to execute usign");
_exit(1);
}
waitpid(pid, &status, 0);
return WIFEXITED(status) ? WEXITSTATUS(status) : -1;
}
#else
int usign_s(const char *msgfile, const char *seckeyfile, const char *sigfile, bool quiet) {
return -1;
};
#endif
/*
* call usign -F ... and set fingerprint returned
* return WEXITSTATUS or -1 if fork fails
*/
static int usign_f(char fingerprint[17], const char *pubkeyfile, const char *seckeyfile, const char *sigfile, bool quiet) {
int fds[2];
FILE *f;
pid_t pid;
int status;
const char *usign_argv[16] = {0};
unsigned int usign_argc = 0;
if (pipe(fds))
return -1;
usign_argv[usign_argc++] = USIGN_EXEC;
usign_argv[usign_argc++] = "-F";
if (pubkeyfile) {
usign_argv[usign_argc++] = "-p";
usign_argv[usign_argc++] = pubkeyfile;
}
if (seckeyfile) {
usign_argv[usign_argc++] = "-s";
usign_argv[usign_argc++] = seckeyfile;
}
if (sigfile) {
usign_argv[usign_argc++] = "-x";
usign_argv[usign_argc++] = sigfile;
}
pid = fork();
switch (pid) {
case -1:
return -1;
case 0:
dup2(fds[1], 1);
close(fds[0]);
close(fds[1]);
execvp(usign_argv[0], (char *const *)usign_argv);
if (!quiet)
perror("Failed to execute usign");
_exit(1);
}
close(fds[1]);
waitpid(pid, &status, 0);
status = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
if (!fingerprint || status) {
close(fds[0]);
return status;
}
f = fdopen(fds[0], "r");
if (fread(fingerprint, 1, 16, f) != 16)
status = -1;
fclose(f);
if (status)
return status;
fingerprint[16] = '\0';
if (strspn(fingerprint, "0123456789abcdefABCDEF") != 16)
status = -1;
return status;
}
/*
* call usign -F -p ...
*/
int usign_f_pubkey(char fingerprint[17], const char *pubkeyfile, bool quiet) {
return usign_f(fingerprint, pubkeyfile, NULL, NULL, quiet);
}
/*
* call usign -F -s ...
*/
int usign_f_seckey(char fingerprint[17], const char *seckeyfile, bool quiet) {
return usign_f(fingerprint, NULL, seckeyfile, NULL, quiet);
}
/*
* call usign -F -x ...
*/
int usign_f_sig(char fingerprint[17], const char *sigfile, bool quiet) {
return usign_f(fingerprint, NULL, NULL, sigfile, quiet);
}
/*
* call usign -V ...
* return WEXITSTATUS or -1 if fork fails
*/
int usign_v(const char *msgfile, const char *pubkeyfile,
const char *pubkeydir, const char *sigfile, bool quiet) {
pid_t pid;
int status;
const char *usign_argv[16] = {0};
unsigned int usign_argc = 0;
char fingerprint[17];
if (usign_f_sig(fingerprint, sigfile, quiet)) {
if (!quiet)
fprintf(stderr, "cannot get signing key fingerprint\n");
return 1;
}
if (pubkeydir && _usign_key_is_revoked(fingerprint, pubkeydir)) {
if (!quiet)
fprintf(stderr, "key %s has been revoked!\n", fingerprint);
return 1;
}
usign_argv[usign_argc++] = USIGN_EXEC;
usign_argv[usign_argc++] = "-V";
usign_argv[usign_argc++] = "-m";
usign_argv[usign_argc++] = msgfile;
if (quiet)
usign_argv[usign_argc++] = "-q";
if (pubkeyfile) {
usign_argv[usign_argc++] = "-p";
usign_argv[usign_argc++] = pubkeyfile;
}
if (pubkeydir) {
usign_argv[usign_argc++] = "-P";
usign_argv[usign_argc++] = pubkeydir;
}
if (sigfile) {
usign_argv[usign_argc++] = "-x";
usign_argv[usign_argc++] = sigfile;
}
pid = fork();
switch (pid) {
case -1:
return -1;
case 0:
execvp(usign_argv[0], (char *const *)usign_argv);
if (!quiet)
perror("Failed to execute usign");
_exit(1);
}
waitpid(pid, &status, 0);
return WIFEXITED(status) ? WEXITSTATUS(status) : -1;
}
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