Remove libcap/prctl artifacts

They seem like relics of the pasts, from when we were retaining the
ptrace cap.

Some translations still may need updates.

1 files changed, 4 insertions, 59 deletions

diff --git a/sway/main.c b/sway/main.c
index 990f5f3a..80111b8f 100644
--- a/sway/main.c
+++ b/sway/main.c
@@ -12,10 +12,6 @@
 #include <sys/wait.h>
 #include <sys/un.h>
 #include <unistd.h>
-#ifdef __linux__
-#include <sys/capability.h>
-#include <sys/prctl.h>
-#endif
 #include <wlr/util/log.h>
 #include "sway/commands.h"
 #include "sway/config.h"
@@ -181,28 +177,8 @@ static void log_kernel() {
         pclose(f);
 }
 
-static void executable_sanity_check() {
-#ifdef __linux__
-                struct stat sb;
-                char *exe = realpath("/proc/self/exe", NULL);
-                stat(exe, &sb);
-                // We assume that cap_get_file returning NULL implies ENODATA
-                if (sb.st_mode & (S_ISUID|S_ISGID) && cap_get_file(exe)) {
-                        wlr_log(WLR_ERROR,
-                                "sway executable has both the s(g)uid bit AND file caps set.");
-                        wlr_log(WLR_ERROR,
-                                "This is strongly discouraged (and completely broken).");
-                        wlr_log(WLR_ERROR,
-                                "Please clear one of them (either the suid bit, or the file caps).");
-                        wlr_log(WLR_ERROR,
-                                "If unsure, strip the file caps.");
-                        exit(EXIT_FAILURE);
-                }
-                free(exe);
-#endif
-}
 
-static void drop_permissions(bool keep_caps) {
+static void drop_permissions(void) {
         if (getuid() != geteuid() || getgid() != getegid()) {
                 if (setgid(getgid()) != 0) {
                         wlr_log(WLR_ERROR, "Unable to drop root");
@@ -217,20 +193,6 @@ static void drop_permissions(bool keep_caps) {
                 wlr_log(WLR_ERROR, "Root privileges can be restored.");
                 exit(EXIT_FAILURE);
         }
-#ifdef __linux__
-        if (keep_caps) {
-                // Drop every cap except CAP_SYS_PTRACE
-                cap_t caps = cap_init();
-                cap_value_t keep = CAP_SYS_PTRACE;
-                wlr_log(WLR_INFO, "Dropping extra capabilities");
-                if (cap_set_flag(caps, CAP_PERMITTED, 1, &keep, CAP_SET) ||
-                        cap_set_flag(caps, CAP_EFFECTIVE, 1, &keep, CAP_SET) ||
-                        cap_set_proc(caps)) {
-                        wlr_log(WLR_ERROR, "Failed to drop extra capabilities");
-                        exit(EXIT_FAILURE);
-                }
-        }
-#endif
 }
 
 void enable_debug_flag(const char *flag) {
@@ -347,7 +309,7 @@ int main(int argc, char **argv) {
                         wlr_log(WLR_ERROR, "Don't use options with the IPC client");
                         exit(EXIT_FAILURE);
                 }
-                drop_permissions(false);
+                drop_permissions();
                 char *socket_path = getenv("SWAYSOCK");
                 if (!socket_path) {
                         wlr_log(WLR_ERROR, "Unable to retrieve socket path");
@@ -358,34 +320,17 @@ int main(int argc, char **argv) {
                 return 0;
         }
 
-        executable_sanity_check();
-        bool suid = false;
-
         if (!server_privileged_prepare(&server)) {
                 return 1;
         }
 
-#if defined(__linux__) || defined(__FreeBSD__)
-        if (getuid() != geteuid() || getgid() != getegid()) {
-#ifdef __linux__
-                // Retain capabilities after setuid()
-                if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0)) {
-                        wlr_log(WLR_ERROR, "Cannot keep caps after setuid()");
-                        exit(EXIT_FAILURE);
-                }
-#endif
-                suid = true;
-        }
-#endif
-
         log_kernel();
         log_distro();
         detect_proprietary();
         detect_raspi();
 
-#if defined(__linux__) || defined(__FreeBSD__)
-        drop_permissions(suid);
-#endif
+        drop_permissions();
+
         // handle SIGTERM signals
         signal(SIGTERM, sig_handler);