added support for numeric parameters, tested with rt_sigaction

This commit is contained in:
Cristian Toader 2013-07-23 10:49:56 +03:00
parent 7cf1dbfd51
commit 8b12170f23
2 changed files with 24 additions and 6 deletions

View File

@ -28,14 +28,25 @@
#include <sys/mman.h>
#include <sys/syscall.h>
#include <bits/signum.h>
#include <seccomp.h>
#include <signal.h>
#include <unistd.h>
static ParFilter param_filter[] = {
// Example entries
{SCMP_SYS(execve), (intptr_t)("/usr/local/bin/tor"), 0},
{SCMP_SYS(execve), (intptr_t)("/usr/local/bin/tor"), 0}
{SCMP_SYS(execve), PARAM_PTR, (intptr_t)("/usr/local/bin/tor"), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGINT), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGTERM), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGPIPE), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGUSR1), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGUSR2), 0},
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGHUP), 0},
#ifdef SIGXFSZ
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGXFSZ), 0},
#endif
{SCMP_SYS(rt_sigaction), PARAM_NUM, (intptr_t)(SIGCHLD), 0},
};
/** Variable used for storing all syscall numbers that will be allowed with the
@ -101,7 +112,6 @@ static int general_filter[] = {
SCMP_SYS(prctl),
SCMP_SYS(read),
SCMP_SYS(rename),
SCMP_SYS(rt_sigaction),
SCMP_SYS(rt_sigprocmask),
SCMP_SYS(rt_sigreturn),
#ifdef __NR_sigreturn
@ -166,7 +176,7 @@ get_prot_param(char *param)
for (i = 0; i < filter_size; i++) {
if (param_filter[i].prot && !strncmp(param, (char*) param_filter[i].param,
MAX_PARAM_LEN)) {
MAX_PARAM_LEN) && param_filter[i].ptype == PARAM_PTR) {
return (char*)(param_filter[i].param);
}
}
@ -188,7 +198,7 @@ add_param_filter(scmp_filter_ctx ctx)
// for each parameter filter
for (i = 0; i < filter_size; i++) {
if (!param_filter[i].prot) {
if (!param_filter[i].prot && param_filter[i].ptype == PARAM_PTR) {
// allocating protected memory region for parameter
param_size = 1 + strnlen((char*) param_filter[i].param, MAX_PARAM_LEN);
if (param_size == MAX_PARAM_LEN) {
@ -213,6 +223,8 @@ add_param_filter(scmp_filter_ctx ctx)
}
} // if not protected
param_filter[i].prot = 1;
rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, param_filter[i].syscall, 1,
SCMP_A0(SCMP_CMP_EQ, param_filter[i].param));
if (rc != 0) {

View File

@ -34,9 +34,15 @@
#define MAX_PARAM_LEN 32
#define PARAM_PTR 0
#define PARAM_NUM 1
typedef struct {
int syscall;
intptr_t param; // TODO: make this intptr_t to support multiple types
char ptype;
intptr_t param;
char prot;
} ParFilter;