noexec: set comm field for noexecs
authorDenys Vlasenko <vda.linux@googlemail.com>
Mon, 7 Aug 2017 16:45:33 +0000 (18:45 +0200)
committerDenys Vlasenko <vda.linux@googlemail.com>
Mon, 7 Aug 2017 16:45:33 +0000 (18:45 +0200)
function                                             old     new   delta
set_task_comm                                          -      18     +18
tryexec                                              152     159      +7
pseudo_exec_argv                                     321     328      +7
main                                                 106      97      -9
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/2 up/down: 34/-13)             Total: 23 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
include/libbb.h
libbb/appletlib.c
libbb/vfork_daemon_rexec.c
shell/ash.c
shell/hush.c

index 51e8f27a522fa519c045320422bdb87365f66895..e4a19ac045cf54a7bd969762596927ca163deda5 100644 (file)
@@ -1116,6 +1116,11 @@ int run_nofork_applet(int applet_no, char **argv) FAST_FUNC;
 extern int find_applet_by_name(const char *name) FAST_FUNC;
 extern void run_applet_no_and_exit(int a, const char *name, char **argv) NORETURN FAST_FUNC;
 #endif
+#if defined(__linux__)
+void set_task_comm(const char *comm) FAST_FUNC;
+#else
+# define set_task_comm(name) ((void)0)
+#endif
 
 /* Helpers for daemonization.
  *
index fa28d433b2a35c92ad8d13be3ba356958786d297..ce259446b48fe6062cacf731cb8d03b9dce07692 100644 (file)
@@ -911,6 +911,14 @@ int busybox_main(int argc UNUSED_PARAM, char **argv)
 }
 # endif
 
+#if defined(__linux__) && (NUM_APPLETS > 1)
+void FAST_FUNC set_task_comm(const char *comm)
+{
+       /* okay if too long (truncates) */
+       prctl(PR_SET_NAME, (long)comm, 0, 0, 0);
+}
+#endif
+
 # if NUM_APPLETS > 0
 void FAST_FUNC run_applet_no_and_exit(int applet_no, const char *name, char **argv)
 {
@@ -1064,15 +1072,14 @@ int main(int argc UNUSED_PARAM, char **argv)
                applet_name++;
        applet_name = bb_basename(applet_name);
 
-# if defined(__linux__)
        /* If we are a result of execv("/proc/self/exe"), fix ugly comm of "exe" */
        if (ENABLE_FEATURE_SH_STANDALONE
         || ENABLE_FEATURE_PREFER_APPLETS
         || !BB_MMU
        ) {
-               prctl(PR_SET_NAME, (long)applet_name, 0, 0, 0);
+               if (NUM_APPLETS > 1)
+                       set_task_comm(applet_name);
        }
-# endif
 
        parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
        run_applet_and_exit(applet_name, argv);
index 50ecea762ead413e48d4c3d27dacb08ae5982aa9..546cc9e36ce63f0fbdc5cfbd6564931d39c0bac6 100644 (file)
@@ -175,8 +175,6 @@ int FAST_FUNC spawn_and_wait(char **argv)
                                return wait4pid(rc);
 
                        /* child */
-//TODO: prctl(PR_SET_NAME, (long)argv[0], 0, 0, 0);? [think pidof, pgrep, pkill]
-//Rewrite /proc/PID/cmdline? (need to save argv0 and length at init for this to work!)
                        /* reset some state and run without execing */
 
                        /* msg_eol = "\n"; - no caller needs this reinited yet */
@@ -185,6 +183,11 @@ int FAST_FUNC spawn_and_wait(char **argv)
                         * init, or a NOFORK applet. But none of those call us
                         * as of yet (and that should probably always stay true).
                         */
+//TODO: think pidof, pgrep, pkill!
+//set_task_comm() makes our pidof find NOEXECs (e.g. "yes >/dev/null"),
+//but one from procps-ng-3.3.10 needs more!
+//Rewrite /proc/PID/cmdline? (need to save argv0 and length at init for this to work!)
+                       set_task_comm(argv[0]);
                        /* xfunc_error_retval and applet_name are init by: */
                        run_applet_no_and_exit(a, argv[0], argv);
                }
index 0a323e957fa83514500194d528bc9098bbceadb9..507d15c908e66ce3a062c33d810d20a729202c15 100644 (file)
@@ -7803,8 +7803,11 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, c
                        while (*envp)
                                putenv(*envp++);
                        popredir(/*drop:*/ 1);
-//TODO: prctl(PR_SET_NAME, (long)argv[0], 0, 0, 0);? [think pidof, pgrep, pkill]
+//TODO: think pidof, pgrep, pkill!
+//set_task_comm() makes our pidof find NOEXECs (e.g. "yes >/dev/null"),
+//but one from procps-ng-3.3.10 needs more!
 //Rewrite /proc/PID/cmdline? (need to save argv0 and length at init for this to work!)
+                       set_task_comm(argv[0]);
                        run_applet_no_and_exit(applet_no, cmd, argv);
                }
                /* re-exec ourselves with the new arguments */
index b4fe7146b528cfb8fd11a44cb84440db58f2d03e..021c1f0ff968927bae68957b80898170faf86a33 100644 (file)
@@ -7387,8 +7387,11 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
                                /* Without this, "rm -i FILE" can't be ^C'ed: */
                                switch_off_special_sigs(G.special_sig_mask);
                                debug_printf_exec("running applet '%s'\n", argv[0]);
-//TODO: prctl(PR_SET_NAME, (long)argv[0], 0, 0, 0);? [think pidof, pgrep, pkill]
+//TODO: think pidof, pgrep, pkill!
+//set_task_comm() makes our pidof find NOEXECs (e.g. "yes >/dev/null"),
+//but one from procps-ng-3.3.10 needs more!
 //Rewrite /proc/PID/cmdline? (need to save argv0 and length at init for this to work!)
+                               set_task_comm(argv[0]);
                                run_applet_no_and_exit(a, argv[0], argv);
                        }
 # endif