diff options
| -rw-r--r-- | coreutils/rm.c | 5 | ||||
| -rw-r--r-- | coreutils/seq.c | 5 | ||||
| -rw-r--r-- | coreutils/usleep.c | 7 | ||||
| -rw-r--r-- | coreutils/yes.c | 3 | ||||
| -rw-r--r-- | docs/nofork_noexec.txt | 3 | ||||
| -rw-r--r-- | shell/hush.c | 31 |
6 files changed, 48 insertions, 6 deletions
diff --git a/coreutils/rm.c b/coreutils/rm.c index f91c945..5e4acab 100644 --- a/coreutils/rm.c +++ b/coreutils/rm.c @@ -16,7 +16,8 @@ //config: help //config: rm is used to remove files or directories. -//applet:IF_RM(APPLET_NOFORK(rm, rm, BB_DIR_BIN, BB_SUID_DROP, rm)) +//applet:IF_RM(APPLET_NOEXEC(rm, rm, BB_DIR_BIN, BB_SUID_DROP, rm)) +/* was NOFORK, but then "rm -i FILE" can't be ^C'ed if run by hush */ //kbuild:lib-$(CONFIG_RM) += rm.o @@ -36,7 +37,7 @@ #include "libbb.h" -/* This is a NOFORK applet. Be very careful! */ +/* This is a NOEXEC applet. Be very careful! */ int rm_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int rm_main(int argc UNUSED_PARAM, char **argv) diff --git a/coreutils/seq.c b/coreutils/seq.c index f36dbb4..c26ff06 100644 --- a/coreutils/seq.c +++ b/coreutils/seq.c @@ -12,7 +12,8 @@ //config: help //config: print a sequence of numbers -//applet:IF_SEQ(APPLET_NOFORK(seq, seq, BB_DIR_USR_BIN, BB_SUID_DROP, seq)) +//applet:IF_SEQ(APPLET_NOEXEC(seq, seq, BB_DIR_USR_BIN, BB_SUID_DROP, seq)) +/* was NOFORK, but then "seq 1 999999999" can't be ^C'ed if run by hush */ //kbuild:lib-$(CONFIG_SEQ) += seq.o @@ -26,7 +27,7 @@ #include "libbb.h" -/* This is a NOFORK applet. Be very careful! */ +/* This is a NOEXEC applet. Be very careful! */ int seq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int seq_main(int argc, char **argv) diff --git a/coreutils/usleep.c b/coreutils/usleep.c index 7c25aad..684ab78 100644 --- a/coreutils/usleep.c +++ b/coreutils/usleep.c @@ -38,6 +38,13 @@ int usleep_main(int argc UNUSED_PARAM, char **argv) bb_show_usage(); } + /* Safe wrt NOFORK? (noforks are not allowed to run for + * a long time). Try "usleep 99999999" + ^C + "echo $?" + * in hush with FEATURE_SH_NOFORK=y. + * At least on uclibc, usleep() thanslates to nanosleep() + * which returns early on any signal (even caught one), + * and uclibc does not loop back on EINTR. + */ usleep(xatou(argv[1])); return EXIT_SUCCESS; diff --git a/coreutils/yes.c b/coreutils/yes.c index ea35d14..c244bfe 100644 --- a/coreutils/yes.c +++ b/coreutils/yes.c @@ -17,7 +17,8 @@ //config: yes is used to repeatedly output a specific string, or //config: the default string 'y'. -//applet:IF_YES(APPLET_NOFORK(yes, yes, BB_DIR_USR_BIN, BB_SUID_DROP, yes)) +//applet:IF_YES(APPLET_NOEXEC(yes, yes, BB_DIR_USR_BIN, BB_SUID_DROP, yes)) +/* was NOFORK, but then yes can't be ^C'ed if run by hush */ //kbuild:lib-$(CONFIG_YES) += yes.o diff --git a/docs/nofork_noexec.txt b/docs/nofork_noexec.txt index a24dd9c..0ad4e6e 100644 --- a/docs/nofork_noexec.txt +++ b/docs/nofork_noexec.txt @@ -52,6 +52,9 @@ xargs, find, shells do it (grep for "spawn_and_wait" and This poses much more serious limitations on what applet can do: * all NOEXEC limitations apply. +* do not run for a long time or wait for user input: + hush shell only handles signals (like ^C) after you return + from APPLET_main(). * do not ever exit() or exec(). - xfuncs are okay. They are using special trick to return to the caller applet instead of dying when they detect "x" condition. diff --git a/shell/hush.c b/shell/hush.c index 9f946d8..cfefb73 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -7363,6 +7363,8 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save, */ close_saved_fds_and_FILE_fds(); //FIXME: should also close saved redir fds + /* 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]); run_applet_no_and_exit(a, argv[0], argv); } @@ -8045,6 +8047,24 @@ static NOINLINE int run_pipe(struct pipe *pi) add_vars(old_vars); /* clean_up_and_ret0: */ restore_redirects(squirrel); + /* + * Try "usleep 99999999" + ^C + "echo $?" + * with FEATURE_SH_NOFORK=y. + */ + if (!funcp) { + /* It was builtin or nofork. + * if this would be a real fork/execed program, + * it should have died if a fatal sig was received. + * But OTOH, there was no separate process, + * the sig was sent to _shell_, not to non-existing + * child. + * Let's just handle ^C only, this one is obvious: + * we aren't ok with exitcode 0 when ^C was pressed + * during builtin/nofork. + */ + if (sigismember(&G.pending_set, SIGINT)) + rcode = 128 + SIGINT; + } clean_up_and_ret1: free(argv_expanded); IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) @@ -8060,6 +8080,14 @@ static NOINLINE int run_pipe(struct pipe *pi) if (rcode == 0) { debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]); + /* + * Note: signals (^C) can't interrupt here. + * We remember them and they will be acted upon + * after applet returns. + * This makes applets which can run for a long time + * and/or wait for user input ineligible for NOFORK: + * for example, "yes" or "rm" (rm -i waits for input). + */ rcode = run_nofork_applet(n, argv_expanded); } goto clean_up_and_ret; @@ -8491,7 +8519,7 @@ static int run_list(struct pipe *pi) G.last_bg_pid = pi->cmds[pi->num_cmds - 1].pid; G.last_bg_pid_exitcode = 0; debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n"); -/* Check pi->pi_inverted? "! sleep 1 & echo $?": bash says 1. dash and ash says 0 */ +/* Check pi->pi_inverted? "! sleep 1 & echo $?": bash says 1. dash and ash say 0 */ rcode = EXIT_SUCCESS; goto check_traps; } else { @@ -10178,6 +10206,7 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid /* So, did we get a signal? */ sig = check_and_run_traps(); if (sig /*&& sig != SIGCHLD - always true */) { + /* Do this for any (non-ignored) signal, not only for ^C */ ret = 128 + sig; break; } |