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/*
* Copyright (C) 2014-2018 Firejail Authors
*
* This file is part of firejail project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_SECCOMP
#include "firejail.h"
#include "../include/seccomp.h"
void protocol_filter_save(void) {
// save protocol filter configuration in PROTOCOL_CFG
FILE *fp = fopen(RUN_PROTOCOL_CFG, "w");
if (!fp)
errExit("fopen");
fprintf(fp, "%s\n", cfg.protocol);
SET_PERMS_STREAM(fp, 0, 0, 0600);
fclose(fp);
}
void protocol_filter_load(const char *fname) {
assert(fname);
// read protocol filter configuration from PROTOCOL_CFG
FILE *fp = fopen(fname, "r");
if (!fp)
return;
const int MAXBUF = 4098;
char buf[MAXBUF];
if (fgets(buf, MAXBUF, fp) == NULL) {
// empty file
fclose(fp);
return;
}
fclose(fp);
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
cfg.protocol = strdup(buf);
if (!cfg.protocol)
errExit("strdup");
}
// --protocol.print
void protocol_print_filter(pid_t pid) {
EUID_ASSERT();
(void) pid;
#ifdef SYS_socket
// in case the pid is that of a firejail process, use the pid of the first child process
pid = switch_to_child(pid);
// now check if the pid belongs to a firejail sandbox
if (invalid_sandbox(pid)) {
fprintf(stderr, "Error: no valid sandbox\n");
exit(1);
}
// check privileges for non-root users
uid_t uid = getuid();
if (uid != 0) {
uid_t sandbox_uid = pid_get_uid(pid);
if (uid != sandbox_uid) {
fprintf(stderr, "Error: permission denied.\n");
exit(1);
}
}
// find the seccomp filter
EUID_ROOT();
char *fname;
if (asprintf(&fname, "/proc/%d/root%s", pid, RUN_PROTOCOL_CFG) == -1)
errExit("asprintf");
struct stat s;
if (stat(fname, &s) == -1) {
printf("Cannot access seccomp filter.\n");
exit(1);
}
// read and print the filter
protocol_filter_load(fname);
free(fname);
if (cfg.protocol)
printf("%s\n", cfg.protocol);
exit(0);
#else
fwarning("--protocol not supported on this platform\n");
return;
#endif
}
#endif // HAVE_SECCOMP
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