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#include "xs.h"
#include "snac.h"
#include <unistd.h>
#if defined (__linux__)
# define __USE_GNU
# include <linux/landlock.h>
# include <linux/prctl.h>
# include <sys/syscall.h>
# include <sys/prctl.h>
# include <fcntl.h>
# include <arpa/inet.h>
#endif
void sbox_enter(const char *basedir)
{
if (xs_is_true(xs_dict_get(srv_config, "disable_openbsd_security"))) {
srv_log(xs_dup("disable_openbsd_security is deprecated. Use disable_sandbox instead."));
return;
}
if (xs_is_true(xs_dict_get(srv_config, "disable_sandbox"))) {
srv_debug(0, xs_dup("Sandbox disabled by admin"));
return;
}
const char *address = xs_dict_get(srv_config, "address");
#if defined (__OpenBSD__)
int smail = !xs_is_true(xs_dict_get(srv_config, "disable_email_notifications"));
srv_debug(1, xs_fmt("Calling unveil()"));
unveil(basedir, "rwc");
unveil("/tmp", "rwc");
unveil("/etc/resolv.conf", "r");
unveil("/etc/hosts", "r");
unveil("/etc/ssl/openssl.cnf", "r");
unveil("/etc/ssl/cert.pem", "r");
unveil("/usr/share/zoneinfo", "r");
if (smail)
unveil("/usr/sbin/sendmail", "x");
if (*address == '/')
unveil(address, "rwc");
unveil(NULL, NULL);
srv_debug(1, xs_fmt("Calling pledge()"));
xs *p = xs_str_new("stdio rpath wpath cpath flock inet proc dns fattr");
if (smail)
p = xs_str_cat(p, " exec");
if (*address == '/')
p = xs_str_cat(p, " unix");
pledge(p, NULL);
xs_free(p);
#elif defined (__linux__)
int error, ruleset_fd, abi;
struct landlock_ruleset_attr rules = {0};
struct landlock_path_beneath_attr path = {0};
struct landlock_net_port_attr net = {0};
rules.handled_access_fs =
LANDLOCK_ACCESS_FS_EXECUTE |
LANDLOCK_ACCESS_FS_WRITE_FILE |
LANDLOCK_ACCESS_FS_READ_FILE |
LANDLOCK_ACCESS_FS_REMOVE_DIR |
LANDLOCK_ACCESS_FS_REMOVE_FILE |
LANDLOCK_ACCESS_FS_MAKE_CHAR |
LANDLOCK_ACCESS_FS_MAKE_DIR |
LANDLOCK_ACCESS_FS_MAKE_REG |
LANDLOCK_ACCESS_FS_MAKE_SOCK |
LANDLOCK_ACCESS_FS_MAKE_FIFO |
LANDLOCK_ACCESS_FS_MAKE_BLOCK |
LANDLOCK_ACCESS_FS_MAKE_SYM |
LANDLOCK_ACCESS_FS_REFER |
LANDLOCK_ACCESS_FS_TRUNCATE |
LANDLOCK_ACCESS_FS_IOCTL_DEV;
rules.handled_access_net =
LANDLOCK_ACCESS_NET_BIND_TCP |
LANDLOCK_ACCESS_NET_CONNECT_TCP;
abi = syscall(SYS_landlock_create_ruleset, NULL, 0, LANDLOCK_CREATE_RULESET_VERSION);
switch (abi) {
case -1:
srv_debug(0, xs_dup("Kernel without landlock support"));
return;
case 1:
rules.handled_access_fs &= ~LANDLOCK_ACCESS_FS_REFER;
__attribute__((fallthrough));
case 2:
rules.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE;
__attribute__((fallthrough));
case 3:
rules.handled_access_net &= ~(LANDLOCK_ACCESS_NET_BIND_TCP | LANDLOCK_ACCESS_NET_CONNECT_TCP);
__attribute__((fallthrough));
case 4:
rules.handled_access_fs &= ~LANDLOCK_ACCESS_FS_IOCTL_DEV;
}
srv_debug(1, xs_fmt("lanlock abi: %d", abi));
ruleset_fd = syscall(SYS_landlock_create_ruleset, &rules, sizeof(struct landlock_ruleset_attr), 0);
if (ruleset_fd == -1) {
srv_debug(0, xs_fmt("landlock_create_ruleset failed: %s", strerror(errno)));
return;
}
#define LL_R LANDLOCK_ACCESS_FS_READ_FILE
#define LL_X LANDLOCK_ACCESS_FS_EXECUTE
#define LL_RWC (LL_R | LANDLOCK_ACCESS_FS_WRITE_FILE | LANDLOCK_ACCESS_FS_MAKE_REG | LANDLOCK_ACCESS_FS_TRUNCATE)
#define LL_UNX (LL_R | LANDLOCK_ACCESS_FS_WRITE_FILE | LANDLOCK_ACCESS_FS_MAKE_SOCK)
#define LL_CON LANDLOCK_ACCESS_NET_CONNECT_TCP
#define LL_BND LANDLOCK_ACCESS_NET_BIND_TCP
#define LANDLOCK_PATH(p, r) do {\
path.allowed_access = r;\
if (abi < 3)\
path.allowed_access &= ~LANDLOCK_ACCESS_FS_TRUNCATE;\
path.parent_fd = open(p, O_PATH | O_CLOEXEC);\
if (path.parent_fd == -1) {\
srv_debug(2, xs_fmt("open %s: %s", p, strerror(errno)));\
goto close;\
}\
error = syscall(SYS_landlock_add_rule, ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, &path, 0); \
if (error) {\
srv_debug(0, xs_fmt("LANDLOCK_PATH(%s): %s", p, strerror(errno)));\
goto close;\
}\
} while (0)
#define LANDLOCK_PORT(p, r) do {\
uint16_t _p = p;\
net.port = _p;\
net.allowed_access = r;\
error = syscall(SYS_landlock_add_rule, ruleset_fd, LANDLOCK_RULE_NET_PORT, &net, 0);\
if (error) {\
srv_debug(0, xs_fmt("LANDLOCK_PORT(%d): %s", _p, strerror(errno)));\
goto close;\
}\
} while (0)
LANDLOCK_PATH(basedir, LL_RWC);
LANDLOCK_PATH("/tmp", LL_RWC);
LANDLOCK_PATH("/dev/shm", LL_RWC);
LANDLOCK_PATH("/etc/resolv.conf", LL_R );
LANDLOCK_PATH("/etc/hosts", LL_R );
LANDLOCK_PATH("/etc/ssl/openssl.cnf", LL_R );
LANDLOCK_PATH("/etc/ssl/cert.pem", LL_R );
LANDLOCK_PATH("/usr/share/zoneinfo", LL_R );
if (*address == '/')
LANDLOCK_PATH(address, LL_UNX);
if (abi > 3) {
if (*address != '/') {
LANDLOCK_PORT(
(uint16_t)xs_number_get(xs_dict_get(srv_config, "port")), LL_BND);
}
LANDLOCK_PORT(80, LL_CON);
LANDLOCK_PORT(443, LL_CON);
}
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
srv_debug(0, xs_fmt("prctl SET_NO_NEW_PRIVS: %s", strerror(errno)));
goto close;
}
if (syscall(SYS_landlock_restrict_self, ruleset_fd, 0))
srv_debug(0, xs_fmt("landlock_restrict_self: %s", strerror(errno)));
srv_log(xs_dup("landlocked"));
close:
close(ruleset_fd);
#endif
}
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