mirror of
https://git.pwmt.org/pwmt/zathura.git
synced 2024-12-28 20:46:01 +01:00
Apply coding standard
Changes include: - use girara_error everywhere - two space indentation
This commit is contained in:
Sebastian Ramacher
parent
3e841103ea
commit
89831253f9
1 changed files with 350 additions and 355 deletions
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@ -1,5 +1,4 @@
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#include "seccomp-filters.h"
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#include <stdio.h>
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#ifdef WITH_SECCOMP
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#include <girara/log.h>
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@ -14,364 +13,360 @@
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#define DENY_RULE(call) { if (seccomp_rule_add (ctx, SCMP_ACT_KILL, SCMP_SYS(call), 0) < 0) goto out; }
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#define ALLOW_RULE(call) { if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(call), 0) < 0) goto out; }
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int seccomp_enable_basic_filter(void){
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scmp_filter_ctx ctx;
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/* prevent child processes from getting more priv e.g. via setuid, capabilities, ... */
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if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
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girara_error("prctl SET_NO_NEW_PRIVS");
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return -1;
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}
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/* prevent escape via ptrace */
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if(prctl (PR_SET_DUMPABLE, 0, 0, 0, 0)){
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girara_error("prctl PR_SET_DUMPABLE");
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return -1;
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}
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/* initialize the filter */
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ctx = seccomp_init(SCMP_ACT_ALLOW);
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if (ctx == NULL){
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girara_error("seccomp_init failed");
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return -1;
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}
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DENY_RULE (_sysctl);
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DENY_RULE (acct);
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DENY_RULE (add_key);
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DENY_RULE (adjtimex);
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DENY_RULE (chroot);
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DENY_RULE (clock_adjtime);
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DENY_RULE (create_module);
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DENY_RULE (delete_module);
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DENY_RULE (fanotify_init);
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DENY_RULE (finit_module);
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DENY_RULE (get_kernel_syms);
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DENY_RULE (get_mempolicy);
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DENY_RULE (init_module);
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DENY_RULE (io_cancel);
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DENY_RULE (io_destroy);
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DENY_RULE (io_getevents);
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DENY_RULE (io_setup);
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DENY_RULE (io_submit);
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DENY_RULE (ioperm);
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DENY_RULE (iopl);
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DENY_RULE (ioprio_set);
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DENY_RULE (kcmp);
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DENY_RULE (kexec_file_load);
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DENY_RULE (kexec_load);
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DENY_RULE (keyctl);
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DENY_RULE (lookup_dcookie);
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DENY_RULE (mbind);
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DENY_RULE (nfsservctl);
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DENY_RULE (migrate_pages);
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DENY_RULE (modify_ldt);
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DENY_RULE (mount);
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DENY_RULE (move_pages);
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DENY_RULE (name_to_handle_at);
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DENY_RULE (open_by_handle_at);
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DENY_RULE (perf_event_open);
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DENY_RULE (pivot_root);
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DENY_RULE (process_vm_readv);
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DENY_RULE (process_vm_writev);
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DENY_RULE (ptrace);
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DENY_RULE (reboot);
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DENY_RULE (remap_file_pages);
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DENY_RULE (request_key);
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DENY_RULE (set_mempolicy);
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DENY_RULE (swapoff);
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DENY_RULE (swapon);
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DENY_RULE (sysfs);
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DENY_RULE (syslog);
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DENY_RULE (tuxcall);
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DENY_RULE (umount2);
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DENY_RULE (uselib);
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DENY_RULE (vmsplice);
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/* TODO: check for additional syscalls to blacklist */
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/* DENY_RULE (execve); */
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/* applying filter... */
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if (seccomp_load (ctx) >= 0){
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/* free ctx after the filter has been loaded into the kernel */
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seccomp_release(ctx);
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return 0;
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}
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out:
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/* something went wrong */
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seccomp_release(ctx);
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int
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seccomp_enable_basic_filter(void)
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{
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/* prevent child processes from getting more priv e.g. via setuid, capabilities, ... */
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if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
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girara_error("prctl SET_NO_NEW_PRIVS");
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return -1;
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}
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/* prevent escape via ptrace */
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if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0)) {
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girara_error("prctl PR_SET_DUMPABLE");
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return -1;
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}
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/* initialize the filter */
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scmp_filter_ctx ctx = seccomp_init(SCMP_ACT_ALLOW);
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if (ctx == NULL) {
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girara_error("seccomp_init failed");
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return -1;
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}
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DENY_RULE(_sysctl);
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DENY_RULE(acct);
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DENY_RULE(add_key);
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DENY_RULE(adjtimex);
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DENY_RULE(chroot);
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DENY_RULE(clock_adjtime);
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DENY_RULE(create_module);
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DENY_RULE(delete_module);
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DENY_RULE(fanotify_init);
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DENY_RULE(finit_module);
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DENY_RULE(get_kernel_syms);
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DENY_RULE(get_mempolicy);
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DENY_RULE(init_module);
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DENY_RULE(io_cancel);
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DENY_RULE(io_destroy);
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DENY_RULE(io_getevents);
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DENY_RULE(io_setup);
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DENY_RULE(io_submit);
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DENY_RULE(ioperm);
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DENY_RULE(iopl);
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DENY_RULE(ioprio_set);
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DENY_RULE(kcmp);
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DENY_RULE(kexec_file_load);
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DENY_RULE(kexec_load);
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DENY_RULE(keyctl);
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DENY_RULE(lookup_dcookie);
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DENY_RULE(mbind);
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DENY_RULE(nfsservctl);
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DENY_RULE(migrate_pages);
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DENY_RULE(modify_ldt);
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DENY_RULE(mount);
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DENY_RULE(move_pages);
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DENY_RULE(name_to_handle_at);
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DENY_RULE(open_by_handle_at);
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DENY_RULE(perf_event_open);
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DENY_RULE(pivot_root);
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DENY_RULE(process_vm_readv);
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DENY_RULE(process_vm_writev);
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DENY_RULE(ptrace);
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DENY_RULE(reboot);
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DENY_RULE(remap_file_pages);
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DENY_RULE(request_key);
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DENY_RULE(set_mempolicy);
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DENY_RULE(swapoff);
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DENY_RULE(swapon);
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DENY_RULE(sysfs);
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DENY_RULE(syslog);
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DENY_RULE(tuxcall);
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DENY_RULE(umount2);
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DENY_RULE(uselib);
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DENY_RULE(vmsplice);
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/* TODO: check for additional syscalls to blacklist */
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/* DENY_RULE (execve); */
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/* applying filter... */
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if (seccomp_load (ctx) >= 0) {
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/* free ctx after the filter has been loaded into the kernel */
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seccomp_release(ctx);
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return 0;
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}
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out:
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/* something went wrong */
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seccomp_release(ctx);
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return -1;
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}
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int seccomp_enable_strict_filter(void){
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scmp_filter_ctx ctx;
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/* prevent child processes from getting more priv e.g. via setuid, capabilities, ... */
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if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
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perror("prctl SET_NO_NEW_PRIVS");
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exit(EXIT_FAILURE);
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}
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/* prevent escape via ptrace */
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if(prctl (PR_SET_DUMPABLE, 0, 0, 0, 0)){
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perror("prctl PR_SET_DUMPABLE");
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exit(EXIT_FAILURE);
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}
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/* initialize the filter */
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ctx = seccomp_init(SCMP_ACT_KILL);
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if (ctx == NULL){
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perror("seccomp_init failed");
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exit(EXIT_FAILURE);
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}
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ALLOW_RULE (access);
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/* ALLOW_RULE (arch_prctl); */
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ALLOW_RULE (bind);
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ALLOW_RULE (brk);
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ALLOW_RULE (clock_getres);
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ALLOW_RULE (clone); /* TODO: investigate */
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ALLOW_RULE (close);
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/* ALLOW_RULE (connect); */
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ALLOW_RULE (eventfd2);
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ALLOW_RULE (exit);
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ALLOW_RULE (exit_group);
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ALLOW_RULE (fadvise64);
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ALLOW_RULE (fallocate);
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ALLOW_RULE (fcntl); /* TODO: build detailed filter */
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ALLOW_RULE (fstat);
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ALLOW_RULE (fstatfs);
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ALLOW_RULE (ftruncate);
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ALLOW_RULE (futex);
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ALLOW_RULE (getdents);
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ALLOW_RULE (getegid);
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ALLOW_RULE (geteuid);
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ALLOW_RULE (getgid);
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ALLOW_RULE (getuid);
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ALLOW_RULE (getpid);
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/* ALLOW_RULE (getpeername); */
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ALLOW_RULE (getresgid);
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ALLOW_RULE (getresuid);
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ALLOW_RULE (getrlimit);
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/* ALLOW_RULE (getsockname); */
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/* ALLOW_RULE (getsockopt); needed for access to x11 socket in network namespace (without abstract sockets) */
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ALLOW_RULE (inotify_add_watch);
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ALLOW_RULE (inotify_init1);
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ALLOW_RULE (inotify_rm_watch);
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/* ALLOW_RULE (ioctl); specified below */
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ALLOW_RULE (lseek);
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ALLOW_RULE (lstat);
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ALLOW_RULE (madvise);
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ALLOW_RULE (memfd_create);
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ALLOW_RULE (mkdir); /* needed for first run only */
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ALLOW_RULE (mmap);
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ALLOW_RULE (mprotect);
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ALLOW_RULE (mremap);
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ALLOW_RULE (munmap);
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//ALLOW_RULE (open); /* (zathura needs to open for writing) TODO: avoid needing this somehow */
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//ALLOW_RULE (openat);
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ALLOW_RULE (pipe);
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ALLOW_RULE (poll);
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ALLOW_RULE (pwrite64); /* TODO: build detailed filter */
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ALLOW_RULE (pread64);
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/* ALLOW_RULE (prlimit64); */
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/* ALLOW_RULE (prctl); specified below */
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ALLOW_RULE (read);
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ALLOW_RULE (readlink);
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ALLOW_RULE (recvfrom);
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ALLOW_RULE (recvmsg);
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ALLOW_RULE (restart_syscall);
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ALLOW_RULE (rt_sigaction);
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ALLOW_RULE (rt_sigprocmask);
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ALLOW_RULE (sendmsg);
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ALLOW_RULE (sendto);
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ALLOW_RULE (select);
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ALLOW_RULE (set_robust_list);
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/* ALLOW_RULE (set_tid_address); */
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/* ALLOW_RULE (setsockopt); */
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ALLOW_RULE (shmat);
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ALLOW_RULE (shmctl);
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ALLOW_RULE (shmdt);
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ALLOW_RULE (shmget);
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ALLOW_RULE (shutdown);
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ALLOW_RULE (stat);
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ALLOW_RULE (statfs);
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/* ALLOW_RULE (socket); */
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ALLOW_RULE (sysinfo);
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ALLOW_RULE (uname);
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ALLOW_RULE (unlink);
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ALLOW_RULE (write); /* specified below (zathura needs to write files)*/
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ALLOW_RULE (writev);
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ALLOW_RULE (wait4); /* trying to open links should not crash the app */
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/* Special requirements for ioctl, allowed on stdout/stderr */
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1,
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SCMP_CMP(0, SCMP_CMP_EQ, 1)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1,
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SCMP_CMP(0, SCMP_CMP_EQ, 2)) < 0)
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goto out;
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/* needed by gtk??? (does not load content without) */
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/* special restrictions for prctl, only allow PR_SET_NAME/PR_SET_PDEATHSIG */
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1,
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SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_NAME)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1,
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SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_PDEATHSIG)) < 0)
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goto out;
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/* special restrictions for open, prevent opening files for writing */
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(open), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(open), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) < 0)
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goto out;
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/* special restrictions for openat, prevent opening files for writing */
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if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(openat), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) < 0)
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goto out;
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if (seccomp_rule_add (ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(openat), 1,
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SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) < 0)
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goto out;
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/* allowed for debugging: */
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/* ALLOW_RULE (prctl); */
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/* ALLOW_RULE (ioctl); */
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/* TODO: test fcntl rules */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, F_GETFL)) < 0) */
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/* goto out; */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETFL)) < 0) */
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/* goto out; */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETFD)) < 0) */
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/* goto out; */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, F_GETFD)) < 0) */
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/* goto out; */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETLK)) < 0) */
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/* goto out; */
|
||||
|
||||
|
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/* TODO: build detailed filter for prctl */
|
||||
/* needed by gtk??? (does not load content without) */
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||||
|
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/* /\* special restrictions for prctl, only allow PR_SET_NAME/PR_SET_PDEATHSIG *\/ */
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_NAME)) < 0) */
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/* goto out; */
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|
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/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_PDEATHSIG)) < 0) */
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/* goto out; */
|
||||
|
||||
|
||||
/* when zathura is run on wayland, with X11 server available but blocked, unset the DISPLAY variable */
|
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/* otherwise it will try to connect to X11 using inet socket protocol */
|
||||
|
||||
|
||||
/* ------------ experimental filters --------------- */
|
||||
|
||||
/* /\* this filter is susceptible to TOCTOU race conditions, providing limited use *\/ */
|
||||
/* /\* allow opening only specified files identified by their file descriptors*\/ */
|
||||
|
||||
/* this requires either a list of all files to open (A LOT!!!) */
|
||||
/* or needs to be applied only after initialisation, right before parsing */
|
||||
/* if(seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(read), 1, */
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/* SCMP_CMP(SCMP_CMP_EQ, fd)) < 0) /\* or < 1 ??? *\/ */
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/* goto out; */
|
||||
|
||||
|
||||
/* /\* restricting write access *\/ */
|
||||
|
||||
/* /\* allow stdin *\/ */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
|
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/* SCMP_CMP(0, SCMP_CMP_EQ, 0)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
/* /\* allow stdout *\/ */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
|
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/* SCMP_CMP(0, SCMP_CMP_EQ, 1)) < 0 ) */
|
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/* goto out; */
|
||||
|
||||
|
||||
/* /\* allow stderr *\/ */
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||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
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/* SCMP_CMP(0, SCMP_CMP_EQ, 2)) < 0 ) */
|
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/* goto out; */
|
||||
|
||||
|
||||
/* /\* restrict writev (write a vector) access *\/ */
|
||||
/* this does not seem reliable but it surprisingly is. investigate more */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(writev), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 3)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
/* test if repeating this after some time or denying it works */
|
||||
|
||||
|
||||
/* first attempt to filter poll requests */
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(poll), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_MASKED_EQ, POLLIN | POLL, 0)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
|
||||
/* /\* restrict fcntl calls *\/ */
|
||||
/* this syscall sets the file descriptor to read write */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 3)) < 0 ) */
|
||||
/* goto out; */
|
||||
/* fcntl(3, F_GETFL) = 0x2 (flags O_RDWR) */
|
||||
/* fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 */
|
||||
/* fcntl(3, F_SETFD, FD_CLOEXEC) = 0 */
|
||||
|
||||
|
||||
/* ------------------ end of experimental filters ------------------ */
|
||||
|
||||
|
||||
/* applying filter... */
|
||||
if (seccomp_load (ctx) >= 0){
|
||||
/* free ctx after the filter has been loaded into the kernel */
|
||||
seccomp_release(ctx);
|
||||
return 0;
|
||||
}
|
||||
|
||||
out:
|
||||
/* something went wrong */
|
||||
seccomp_release(ctx);
|
||||
int
|
||||
seccomp_enable_strict_filter(void)
|
||||
{
|
||||
/* prevent child processes from getting more priv e.g. via setuid, capabilities, ... */
|
||||
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
|
||||
girara_error("prctl SET_NO_NEW_PRIVS");
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* prevent escape via ptrace */
|
||||
if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0)) {
|
||||
girara_error("prctl PR_SET_DUMPABLE");
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* initialize the filter */
|
||||
scmp_filter_ctx ctx = seccomp_init(SCMP_ACT_KILL);
|
||||
if (ctx == NULL){
|
||||
girara_error("seccomp_init failed");
|
||||
return -1;
|
||||
}
|
||||
|
||||
ALLOW_RULE(access);
|
||||
/* ALLOW_RULE (arch_prctl); */
|
||||
ALLOW_RULE(bind);
|
||||
ALLOW_RULE(brk);
|
||||
ALLOW_RULE(clock_getres);
|
||||
ALLOW_RULE(clone); /* TODO: investigate */
|
||||
ALLOW_RULE(close);
|
||||
/* ALLOW_RULE (connect); */
|
||||
ALLOW_RULE(eventfd2);
|
||||
ALLOW_RULE(exit);
|
||||
ALLOW_RULE(exit_group);
|
||||
ALLOW_RULE(fadvise64);
|
||||
ALLOW_RULE(fallocate);
|
||||
ALLOW_RULE(fcntl); /* TODO: build detailed filter */
|
||||
ALLOW_RULE(fstat);
|
||||
ALLOW_RULE(fstatfs);
|
||||
ALLOW_RULE(ftruncate);
|
||||
ALLOW_RULE(futex);
|
||||
ALLOW_RULE(getdents);
|
||||
ALLOW_RULE(getegid);
|
||||
ALLOW_RULE(geteuid);
|
||||
ALLOW_RULE(getgid);
|
||||
ALLOW_RULE(getuid);
|
||||
ALLOW_RULE(getpid);
|
||||
/* ALLOW_RULE (getpeername); */
|
||||
ALLOW_RULE(getresgid);
|
||||
ALLOW_RULE(getresuid);
|
||||
ALLOW_RULE(getrlimit);
|
||||
/* ALLOW_RULE (getsockname); */
|
||||
/* ALLOW_RULE (getsockopt); needed for access to x11 socket in network namespace (without abstract sockets) */
|
||||
ALLOW_RULE(inotify_add_watch);
|
||||
ALLOW_RULE(inotify_init1);
|
||||
ALLOW_RULE(inotify_rm_watch);
|
||||
/* ALLOW_RULE (ioctl); specified below */
|
||||
ALLOW_RULE(lseek);
|
||||
ALLOW_RULE(lstat);
|
||||
ALLOW_RULE(madvise);
|
||||
ALLOW_RULE(memfd_create);
|
||||
ALLOW_RULE(mkdir); /* needed for first run only */
|
||||
ALLOW_RULE(mmap);
|
||||
ALLOW_RULE(mprotect);
|
||||
ALLOW_RULE(mremap);
|
||||
ALLOW_RULE(munmap);
|
||||
//ALLOW_RULE (open); /* (zathura needs to open for writing) TODO: avoid needing this somehow */
|
||||
//ALLOW_RULE (openat);
|
||||
ALLOW_RULE(pipe);
|
||||
ALLOW_RULE(poll);
|
||||
ALLOW_RULE(pwrite64); /* TODO: build detailed filter */
|
||||
ALLOW_RULE(pread64);
|
||||
/* ALLOW_RULE (prlimit64); */
|
||||
/* ALLOW_RULE (prctl); specified below */
|
||||
ALLOW_RULE(read);
|
||||
ALLOW_RULE(readlink);
|
||||
ALLOW_RULE(recvfrom);
|
||||
ALLOW_RULE(recvmsg);
|
||||
ALLOW_RULE(restart_syscall);
|
||||
ALLOW_RULE(rt_sigaction);
|
||||
ALLOW_RULE(rt_sigprocmask);
|
||||
ALLOW_RULE(sendmsg);
|
||||
ALLOW_RULE(sendto);
|
||||
ALLOW_RULE(select);
|
||||
ALLOW_RULE(set_robust_list);
|
||||
/* ALLOW_RULE (set_tid_address); */
|
||||
/* ALLOW_RULE (setsockopt); */
|
||||
ALLOW_RULE(shmat);
|
||||
ALLOW_RULE(shmctl);
|
||||
ALLOW_RULE(shmdt);
|
||||
ALLOW_RULE(shmget);
|
||||
ALLOW_RULE(shutdown);
|
||||
ALLOW_RULE(stat);
|
||||
ALLOW_RULE(statfs);
|
||||
/* ALLOW_RULE (socket); */
|
||||
ALLOW_RULE(sysinfo);
|
||||
ALLOW_RULE(uname);
|
||||
ALLOW_RULE(unlink);
|
||||
ALLOW_RULE(write); /* specified below (zathura needs to write files)*/
|
||||
ALLOW_RULE(writev);
|
||||
ALLOW_RULE(wait4); /* trying to open links should not crash the app */
|
||||
|
||||
/* Special requirements for ioctl, allowed on stdout/stderr */
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1,
|
||||
SCMP_CMP(0, SCMP_CMP_EQ, 1)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1,
|
||||
SCMP_CMP(0, SCMP_CMP_EQ, 2)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* needed by gtk??? (does not load content without) */
|
||||
|
||||
/* special restrictions for prctl, only allow PR_SET_NAME/PR_SET_PDEATHSIG */
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1,
|
||||
SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_NAME)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1,
|
||||
SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_PDEATHSIG)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* special restrictions for open, prevent opening files for writing */
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(open), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(open), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* special restrictions for openat, prevent opening files for writing */
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(openat), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO (EACCES), SCMP_SYS(openat), 1,
|
||||
SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) < 0) {
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* allowed for debugging: */
|
||||
|
||||
/* ALLOW_RULE (prctl); */
|
||||
/* ALLOW_RULE (ioctl); */
|
||||
|
||||
/* TODO: test fcntl rules */
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, F_GETFL)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETFL)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETFD)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, F_GETFD)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, F_SETLK)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
|
||||
/* TODO: build detailed filter for prctl */
|
||||
/* needed by gtk??? (does not load content without) */
|
||||
|
||||
/* /\* special restrictions for prctl, only allow PR_SET_NAME/PR_SET_PDEATHSIG *\/ */
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_NAME)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_PDEATHSIG)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
/* when zathura is run on wayland, with X11 server available but blocked, unset the DISPLAY variable */
|
||||
/* otherwise it will try to connect to X11 using inet socket protocol */
|
||||
|
||||
/* ------------ experimental filters --------------- */
|
||||
|
||||
/* /\* this filter is susceptible to TOCTOU race conditions, providing limited use *\/ */
|
||||
/* /\* allow opening only specified files identified by their file descriptors*\/ */
|
||||
|
||||
/* this requires either a list of all files to open (A LOT!!!) */
|
||||
/* or needs to be applied only after initialisation, right before parsing */
|
||||
/* if(seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(read), 1, */
|
||||
/* SCMP_CMP(SCMP_CMP_EQ, fd)) < 0) /\* or < 1 ??? *\/ */
|
||||
/* goto out; */
|
||||
|
||||
/* /\* restricting write access *\/ */
|
||||
|
||||
/* /\* allow stdin *\/ */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 0)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
/* /\* allow stdout *\/ */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 1)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
|
||||
/* /\* allow stderr *\/ */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 2)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
/* /\* restrict writev (write a vector) access *\/ */
|
||||
/* this does not seem reliable but it surprisingly is. investigate more */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(writev), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 3)) < 0 ) */
|
||||
/* goto out; */
|
||||
|
||||
/* test if repeating this after some time or denying it works */
|
||||
|
||||
|
||||
/* first attempt to filter poll requests */
|
||||
/* if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(poll), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_MASKED_EQ, POLLIN | POLL, 0)) < 0) */
|
||||
/* goto out; */
|
||||
|
||||
|
||||
/* /\* restrict fcntl calls *\/ */
|
||||
/* this syscall sets the file descriptor to read write */
|
||||
/* if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl), 1, */
|
||||
/* SCMP_CMP(0, SCMP_CMP_EQ, 3)) < 0 ) */
|
||||
/* goto out; */
|
||||
/* fcntl(3, F_GETFL) = 0x2 (flags O_RDWR) */
|
||||
/* fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 */
|
||||
/* fcntl(3, F_SETFD, FD_CLOEXEC) = 0 */
|
||||
|
||||
/* ------------------ end of experimental filters ------------------ */
|
||||
|
||||
/* applying filter... */
|
||||
if (seccomp_load(ctx) >= 0) {
|
||||
/* free ctx after the filter has been loaded into the kernel */
|
||||
seccomp_release(ctx);
|
||||
return 0;
|
||||
}
|
||||
|
||||
out:
|
||||
/* something went wrong */
|
||||
seccomp_release(ctx);
|
||||
return -1;
|
||||
}
|
||||
|
||||
#endif /* WITH_SECCOMP */
|
||||
|
|
|
|||
Loading…
Reference in a new issue