mirror of https://github.com/rd235/cado
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
/*
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* cado: execute a command in a capability ambient
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* Copyright (C) 2016 Renzo Davoli, University of Bologna
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*
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* This file is part of cado.
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*
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* Cado is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <read_conf.h>
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#include <set_ambient_cap.h>
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#include <capset_from_namelist.h>
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#ifndef CONFDIR
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#define CONFDIR "/etc"
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#endif
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#define CADO_CONF CONFDIR "/cado.conf"
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static int groupmatch (char *group, char **grouplist) {
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for (;*grouplist; grouplist++) {
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//printf("%s %s\n",group, *grouplist);
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if (strcmp(group, *grouplist) == 0)
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return 1;
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}
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return 0;
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}
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uint64_t get_authorized_caps(char **user_groups) {
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uint64_t ok_caps=0;
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FILE *f;
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if (user_groups) raise_cap_dac_read_search();
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f=fopen(CADO_CONF, "r");
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if (f) {
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char *line=NULL;
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ssize_t len,n=0;
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while ((len=getline(&line, &n, f)) > 0) {
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//printf("%s",line);
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char *scan=line;
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char *tok;
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uint64_t capset;
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char *tmptok;
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while (isspace(*scan)) scan++;
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if (*scan == 0 || *scan == '#') //comment
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continue;
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tok=strtok_r(scan, ":", &tmptok);
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//printf("%s\n",tok);
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capset=0;
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if (capset_from_namelist(tok, &capset) < 0)
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continue;
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if (user_groups == NULL) {
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ok_caps |= capset;
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continue;
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}
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//printf("CAP %s %d\n",tok,thiscap);
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while ((tok=strtok_r(NULL, ",\n ",&tmptok)) != NULL) {
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//printf("XX %s\n",tok);
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if (*tok=='@') {
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if (groupmatch(tok+1, user_groups+1)) {
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ok_caps |= capset;
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break;
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}
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} else if (strcmp(tok, user_groups[0]) == 0) {
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ok_caps |= capset;
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break;
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}
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}
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}
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fclose(f);
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if (line)
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free(line);
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}
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if (user_groups) lower_cap_dac_read_search();
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return ok_caps;
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}
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int set_self_capability(uint64_t capset) {
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cap_value_t cap;
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cap_t caps=cap_init();
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int f,rv=-1;
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for (cap = 0; cap <= CAP_LAST_CAP; cap++) {
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if (capset & (1ULL << cap)) {
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/*if (cap_set_flag(caps, CAP_PERMITTED, 1, &cap, CAP_SET) ||
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cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap, CAP_SET)) {*/
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if (cap_set_flag(caps, CAP_PERMITTED, 1, &cap, CAP_SET)) {
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fprintf(stderr, "Cannot set permitted cap %s\n",cap_to_name(cap));
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exit(2);
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}
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}
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}
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if ((f=open("/proc/self/exe",O_RDONLY)) >= 0) {
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if (cap_set_fd(f,caps) >= 0)
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rv=0;
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close(f);
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}
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cap_free(caps);
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return rv;
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}
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