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/*
* Copyright (C) 2014-2017 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.
*/
#include "fbuilder.h"
void build_seccomp(const char *fname, FILE *fp) {
assert(fname);
assert(fp);
FILE *fp2 = fopen(fname, "r");
if (!fp2) {
fprintf(stderr, "Error: cannot open %s\n", fname);
exit(1);
}
char buf[MAX_BUF];
int line = 1;
int position = 0;
int cnt = 0;
while (fgets(buf, MAX_BUF, fp2)) {
// remove \n
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
// first line:
//% time seconds usecs/call calls errors syscall
if (line == 1) {
// extract syscall position
ptr = strstr(buf, "syscall");
if (*buf != '%' || ptr == NULL) {
// skip this line, it could be garbage from strace
continue;
}
position = (int) (ptr - buf);
}
else if (line == 2) {
if (*buf != '-') {
fprintf(stderr, "Error: invalid strace output\n%s\n", buf);
exit(1);
}
}
else {
// get out on the next "----" line
if (*buf == '-')
break;
if (line == 3)
fprintf(fp, "# seccomp.keep %s", buf + position);
else
fprintf(fp, ",%s", buf + position);
cnt++;
}
line++;
}
fprintf(fp, "\n");
fprintf(fp, "# %d syscalls total\n", cnt);
fprintf(fp, "# Probably you will need to add more syscalls to seccomp.keep. Look for\n");
fprintf(fp, "# seccomp errors in /var/log/syslog or /var/log/audit/audit.log while\n");
fprintf(fp, "# running your sandbox.\n");
fclose(fp2);
}
//***************************************
// protocol
//***************************************
int unix_s = 0;
int inet = 0;
int inet6 = 0;
int netlink = 0;
int packet = 0;
static void process_protocol(const char *fname) {
assert(fname);
// process trace file
FILE *fp = fopen(fname, "r");
if (!fp) {
fprintf(stderr, "Error: cannot open %s\n", fname);
exit(1);
}
char buf[MAX_BUF];
while (fgets(buf, MAX_BUF, fp)) {
// remove \n
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
// parse line: 4:galculator:access /etc/fonts/conf.d:0
// number followed by :
ptr = buf;
if (!isdigit(*ptr))
continue;
while (isdigit(*ptr))
ptr++;
if (*ptr != ':')
continue;
ptr++;
// next :
ptr = strchr(ptr, ':');
if (!ptr)
continue;
ptr++;
if (strncmp(ptr, "socket ", 7) == 0)
ptr += 7;
else
continue;
if (strncmp(ptr, "AF_LOCAL ", 9) == 0)
unix_s = 1;
else if (strncmp(ptr, "AF_INET ", 8) == 0)
inet = 1;
else if (strncmp(ptr, "AF_INET6 ", 9) == 0)
inet6 = 1;
else if (strncmp(ptr, "AF_NETLINK ", 9) == 0)
netlink = 1;
else if (strncmp(ptr, "AF_PACKET ", 9) == 0)
packet = 1;
}
fclose(fp);
}
// process fname, fname.1, fname.2, fname.3, fname.4, fname.5
void build_protocol(const char *fname, FILE *fp) {
assert(fname);
// run fname
process_protocol(fname);
// run all the rest
struct stat s;
int i;
for (i = 1; i <= 5; i++) {
char *newname;
if (asprintf(&newname, "%s.%d", fname, i) == -1)
errExit("asprintf");
if (stat(newname, &s) == 0)
process_protocol(newname);
free(newname);
}
int net = 0;
if (unix_s || inet || inet6 || netlink || packet) {
fprintf(fp, "protocol ");
if (unix_s)
fprintf(fp, "unix,");
if (inet) {
fprintf(fp, "inet,");
net = 1;
}
if (inet6) {
fprintf(fp, "inet6,");
net = 1;
}
if (netlink)
fprintf(fp, "netlink,");
if (packet) {
fprintf(fp, "packet");
net = 1;
}
fprintf(fp, "\n");
}
if (net == 0)
fprintf(fp, "net none\n");
else {
fprintf(fp, "# net eth0\n");
fprintf(fp, "netfilter\n");
}
}
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