This change makes the standalone shell use the BB_EXECVPE utility. BB_EXECVPE calls BB_EXECVP which has NOEXEC and applets only logic.
This allows for better control of the executed processes. Signed-off-by: Nadav Tasher <[email protected]> --- shell/ash.c | 66 ++++++++++++++++++++++------------------------------- 1 file changed, 27 insertions(+), 39 deletions(-) diff --git a/shell/ash.c b/shell/ash.c index 9173b8608..82f7bc226 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -8271,22 +8271,22 @@ static int builtinloc = -1; /* index in path of %builtin, or -1 */ static void -tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, char **envp) +tryexec(const char *cmd, char **argv, char **envp) { #if ENABLE_FEATURE_SH_STANDALONE - if (applet_no >= 0) { - if (APPLET_IS_NOEXEC(applet_no)) { - clearenv(); - while (*envp) - putenv(*envp++); - popredir(/*drop:*/ 1); - run_noexec_applet_and_exit(applet_no, cmd, argv); - } - /* re-exec ourselves with the new arguments */ - execve(bb_busybox_exec_path, argv, envp); - /* If they called chroot or otherwise made the binary no longer - * executable, fall through */ - } + /* because we might not actually exec, redirected fds + * might not close, since they have the CLOEXEC flag. + * this ensures they are closed. */ + popredir(/*drop:*/ 1); + + /* use BB_EXECVP to attempt execution of command */ + BB_EXECVPE(cmd, argv, envp); + + /* if BB_EXECVP returned ENOENT, don't bother falling through + * as BB_EXECVP already uses execvp behind the scenes. + */ + if (errno == ENOENT) + return; #endif repeat: @@ -8338,33 +8338,21 @@ static void shellexec(char *prog, char **argv, const char *path, int idx) int e; char **envp; int exerrno; - int applet_no = -1; /* used only by FEATURE_SH_STANDALONE */ envp = listvars(VEXPORT, VUNSET, /*strlist:*/ NULL, /*end:*/ NULL); - if (strchr(prog, '/') != NULL -#if ENABLE_FEATURE_SH_STANDALONE - || (applet_no = find_applet_by_name(prog)) >= 0 -#endif - ) { - tryexec(IF_FEATURE_SH_STANDALONE(applet_no,) prog, argv, envp); - if (applet_no >= 0) { - /* We tried execing ourself, but it didn't work. - * Maybe /proc/self/exe doesn't exist? - * Try $PATH search. - */ - goto try_PATH; - } - e = errno; - } else { - try_PATH: - e = ENOENT; - while (padvance(&path, argv[0]) >= 0) { - cmdname = stackblock(); - if (--idx < 0 && pathopt == NULL) { - tryexec(IF_FEATURE_SH_STANDALONE(-1,) cmdname, argv, envp); - if (errno != ENOENT && errno != ENOTDIR) - e = errno; - } + /* try executing using tryexec, which might execute applets + * using NOEXEC logic, and might execute a matching binary. + */ + tryexec(prog, argv, envp); + e = errno; + + /* fallback to PATH search and try executing using tryexec */ + while (padvance(&path, argv[0]) >= 0) { + cmdname = stackblock(); + if (--idx < 0 && pathopt == NULL) { + tryexec(cmdname, argv, envp); + if (errno != ENOENT && errno != ENOTDIR) + e = errno; } } -- 2.43.0 _______________________________________________ busybox mailing list [email protected] https://lists.busybox.net/mailman/listinfo/busybox
