/**
* Function responsible for setting up the socket syscall for
* the seccomp filter sandbox.
*/
static int
sb_socket(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
{
int rc = 0;
int i, j;
(void) filter;
#ifdef __i386__
rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket));
if (rc)
return rc;
#endif
rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM));
if (rc)
return rc;
for (i = 0; i < 2; ++i) {
const int pf = i ? PF_INET : PF_INET6;
for (j=0; j < 3; ++j) {
const int type = (j == 0) ? SOCK_STREAM :
SOCK_DGRAM;
const int protocol = (j == 0) ? IPPROTO_TCP :
(j == 1) ? IPPROTO_IP :
IPPROTO_UDP;
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, pf),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, type),
SCMP_CMP(2, SCMP_CMP_EQ, protocol));
if (rc)
return rc;
}
}
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_UNIX),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM),
SCMP_CMP(2, SCMP_CMP_EQ, 0));
if (rc)
return rc;
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_UNIX),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_DGRAM),
SCMP_CMP(2, SCMP_CMP_EQ, 0));
if (rc)
return rc;
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_NETLINK),
SCMP_CMP(1, SCMP_CMP_EQ, SOCK_RAW),
SCMP_CMP(2, SCMP_CMP_EQ, 0));
if (rc)
return rc;
return 0;
}
/**
* Function responsible for setting up the open syscall for
* the seccomp filter sandbox.
*/
static int
sb_open(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
{
int rc;
sandbox_cfg_t *elem = NULL;
// for each dynamic parameter filters
for (elem = filter; elem != NULL; elem = elem->next) {
smp_param_t *param = elem->param;
if (param != NULL && param->prot == 1 && param->syscall
== SCMP_SYS(open)) {
rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open),
SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value));
if (rc != 0) {
log_err(LD_BUG,"(Sandbox) failed to add open syscall, received "
"libseccomp error %d", rc);
return rc;
}
}
}
rc = seccomp_rule_add_1(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open),
SCMP_CMP_MASKED(1, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|O_NOFOLLOW,
O_RDONLY));
if (rc != 0) {
log_err(LD_BUG,"(Sandbox) failed to add open syscall, received libseccomp "
"error %d", rc);
return rc;
}
return 0;
}
/**
* Function responsible for setting up the socket syscall for
* the seccomp filter sandbox.
*/
static int
sb_socket(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
{
int rc = 0;
int i;
(void) filter;
#ifdef __i386__
rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket));
if (rc)
return rc;
#endif
rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM));
if (rc)
return rc;
for (i = 0; i < 2; ++i) {
const int pf = i ? PF_INET : PF_INET6;
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, pf),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM),
SCMP_CMP(2, SCMP_CMP_EQ, IPPROTO_TCP));
if (rc)
return rc;
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, pf),
SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_DGRAM),
SCMP_CMP(2, SCMP_CMP_EQ, IPPROTO_IP));
if (rc)
return rc;
}
rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
SCMP_CMP(0, SCMP_CMP_EQ, PF_NETLINK),
SCMP_CMP(1, SCMP_CMP_EQ, SOCK_RAW),
SCMP_CMP(2, SCMP_CMP_EQ, 0));
if (rc)
return rc;
return 0;
}
/**
* Function responsible for setting up the accept4 syscall for
* the seccomp filter sandbox.
*/
static int
sb_accept4(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
{
int rc = 0;
(void)filter;
#ifdef __i386__
rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketcall),
SCMP_CMP(0, SCMP_CMP_EQ, 18));
if (rc) {
return rc;
}
#endif
rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(accept4),
SCMP_CMP_MASKED(3, SOCK_CLOEXEC|SOCK_NONBLOCK, 0));
if (rc) {
return rc;
}
return 0;
}