service hardening: Add CapabilityBoundingSets

Whitelist with exceptions in webindex and onion-chef

modules/nix-bitcoin-services.nix

@@ -19,6 +19,7 @@ with lib;
       RestrictNamespaces = "true";
       LockPersonality = "true";
       IPAddressDeny = "any";
+      CapabilityBoundingSet = "";
       SystemCallFilter= "accept accept4 access adjtimex alarm bind brk capget capset chdir chmod chown chown32 clock_getres clock_gettime clock_nanosleep close connect copy_file_range creat dup dup2 dup3 epoll_create epoll_create1 epoll_ctl epoll_ctl_old epoll_pwait epoll_wait epoll_wait_old eventfd eventfd2 execve execveat exit exit_group faccessat fadvise64 fadvise64_64 fallocate fanotify_mark fchdir fchmod fchmodat fchown fchown32 fchownat fcntl fcntl64 fdatasync fgetxattr flistxattr flock fork fremovexattr fsetxattr fstat fstat64 fstatat64 fstatfs fstatfs64 fsync ftruncate ftruncate64 futex futimesat getcpu getcwd getdents getdents64 getegid getegid32 geteuid geteuid32 getgid getgid32 getgroups getgroups32 getitimer getpeername getpgid getpgrp getpid getppid getpriority getrandom getresgid getresgid32 getresuid getresuid32 getrlimit get_robust_list getrusage getsid getsockname getsockopt get_thread_area gettid gettimeofday getuid getuid32 getxattr inotify_add_watch inotify_init inotify_init1 inotify_rm_watch io_cancel ioctl io_destroy io_getevents io_pgetevents ioprio_get ioprio_set io_setup io_submit ipc kill lchown lchown32 lgetxattr link linkat listen listxattr llistxattr _llseek lremovexattr lseek lsetxattr lstat lstat64 madvise memfd_create mincore mkdir mkdirat mknod mknodat mlock mlock2 mlockall mmap mmap2 mprotect mq_getsetattr mq_notify mq_open mq_timedreceive mq_timedsend mq_unlink mremap msgctl msgget msgrcv msgsnd msync munlock munlockall munmap nanosleep newfstatat _newselect open openat pause pipe pipe2 poll ppoll prctl pread64 preadv preadv2 prlimit64 pselect6 pwrite64 pwritev pwritev2 read readahead readlink readlinkat readv recv recvfrom recvmmsg recvmsg remap_file_pages removexattr rename renameat renameat2 restart_syscall rmdir rt_sigaction rt_sigpending rt_sigprocmask rt_sigqueueinfo rt_sigreturn rt_sigsuspend rt_sigtimedwait rt_tgsigqueueinfo sched_getaffinity sched_getattr sched_getparam sched_get_priority_max sched_get_priority_min sched_getscheduler sched_rr_get_interval sched_setaffinity sched_setattr sched_setparam sched_setscheduler sched_yield seccomp select semctl semget semop semtimedop send sendfile sendfile64 sendmmsg sendmsg sendto setfsgid setfsgid32 setfsuid setfsuid32 setgid setgid32 setgroups setgroups32 setitimer setpgid setpriority setregid setregid32 setresgid setresgid32 setresuid setresuid32 setreuid setreuid32 setrlimit set_robust_list setsid setsockopt set_thread_area set_tid_address setuid setuid32 setxattr shmat shmctl shmdt shmget shutdown sigaltstack signalfd signalfd4 sigreturn socket socketcall socketpair splice stat stat64 statfs statfs64 statx symlink symlinkat sync sync_file_range syncfs sysinfo tee tgkill time timer_create timer_delete timerfd_create timerfd_gettime timerfd_settime timer_getoverrun timer_gettime timer_settime times tkill truncate truncate64 ugetrlimit umask uname unlink unlinkat utime utimensat utimes vfork vmsplice wait4 waitid waitpid write writev arm_fadvise64_64 arm_sync_file_range sync_file_range2 breakpoint cacheflush set_tls arch_prctl modify_ldt clone";
       SystemCallArchitectures= "native";
   };

modules/nix-bitcoin-webindex.nix

@@ -89,6 +89,7 @@ in {
         Restart = "on-failure";
         RestartSec = "10s";
         PrivateNetwork = "true"; # This service needs no network access
+        CapabilityBoundingSet = "CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_SYS_ADMIN CAP_CHOWN CAP_FSETID CAP_SETFCAP CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH CAP_FOWNER CAP_IPC_OWNER";
       } // (if cfg.enforceTor
           then nix-bitcoin-services.allowTor
           else nix-bitcoin-services.allowAnyIP

modules/onion-chef.nix

@@ -78,6 +78,7 @@ in {
         Type = "oneshot";
         RemainAfterExit = true;
         PrivateNetwork = "true"; # This service needs no network access
+        CapabilityBoundingSet = "CAP_CHOWN CAP_FSETID CAP_SETFCAP CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH CAP_FOWNER CAP_IPC_OWNER";
       };
     };
   };