diff options
Diffstat (limited to 'src/core/execute.c')
| -rw-r--r-- | src/core/execute.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/src/core/execute.c b/src/core/execute.c index daba1a3846..7a72aa486c 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -38,6 +38,7 @@ #include <linux/fs.h> #include <linux/oom.h> #include <sys/poll.h> +#include <linux/seccomp-bpf.h> #ifdef HAVE_PAM #include <security/pam_appl.h> @@ -60,6 +61,7 @@ #include "def.h" #include "loopback-setup.h" #include "path-util.h" +#include "syscall-list.h" #define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC) @@ -924,6 +926,59 @@ static void rename_process_from_path(const char *path) { rename_process(process_name); } +static int apply_seccomp(uint32_t *syscall_filter) { + static const struct sock_filter header[] = { + VALIDATE_ARCHITECTURE, + EXAMINE_SYSCALL + }; + static const struct sock_filter footer[] = { + _KILL_PROCESS + }; + + int i; + unsigned n; + struct sock_filter *f; + struct sock_fprog prog; + + assert(syscall_filter); + + /* First: count the syscalls to check for */ + for (i = 0, n = 0; i < syscall_max(); i++) + if (syscall_filter[i >> 4] & (1 << (i & 31))) + n++; + + /* Second: build the filter program from a header the syscall + * matches and the footer */ + f = alloca(sizeof(struct sock_filter) * (ELEMENTSOF(header) + 2*n + ELEMENTSOF(footer))); + memcpy(f, header, sizeof(header)); + + for (i = 0, n = 0; i < syscall_max(); i++) + if (syscall_filter[i >> 4] & (1 << (i & 31))) { + struct sock_filter item[] = { + BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, i, 0, 1), + BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW) + }; + + assert_cc(ELEMENTSOF(item) == 2); + + f[ELEMENTSOF(header) + 2*n] = item[0]; + f[ELEMENTSOF(header) + 2*n+1] = item[1]; + + n++; + } + + memcpy(f + (ELEMENTSOF(header) + 2*n), footer, sizeof(footer)); + + /* Third: install the filter */ + zero(prog); + prog.len = ELEMENTSOF(header) + ELEMENTSOF(footer) + 2*n; + prog.filter = f; + if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog) < 0) + return -errno; + + return 0; +} + int exec_spawn(ExecCommand *command, char **argv, const ExecContext *context, @@ -1355,6 +1410,21 @@ int exec_spawn(ExecCommand *command, r = EXIT_CAPABILITIES; goto fail_child; } + + if (context->no_new_privileges) + if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) { + err = -errno; + r = EXIT_NO_NEW_PRIVILEGES; + goto fail_child; + } + + if (context->syscall_filter) { + err = apply_seccomp(context->syscall_filter); + if (err < 0) { + r = EXIT_SECCOMP; + goto fail_child; + } + } } if (!(our_env = new0(char*, 7))) { |