ash,hush: ">&10" redirects to script/tty fds should not work
The fact that shell has open fds to tty and/or scripts should be
unobservable, if possible. In particular, if redirect tries to dup
one of them via ">&script_fd", it's better to pretend that script_fd
is closed, and thus redirect fails with EBADF.
Fixes these two testcase failures:
ash-redir/redir_to_bad_fd.tests
hush-redir/redir_to_bad_fd3.tests
function old new delta
redirect 1018 1129 +111
setup_redirects 250 359 +109
readtoken1 2651 2655 +4
cmdloop 185 187 +2
changepath 194 195 +1
save_fd_on_redirect 203 194 -9
evaltree 501 484 -17
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/2 up/down: 227/-26) Total: 201 bytes
text data bss dec hex filename
914553 485 6848 921886 e111e busybox_old
914754 485 6848 922087 e11e7 busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash.c b/shell/ash.c
index ac676c2..5c2e065 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5503,6 +5503,31 @@
return 0; /* "we did not close fd" */
}
+static int
+internally_opened_fd(int fd, struct redirtab *sq)
+{
+ int i;
+#if JOBS
+ if (fd == ttyfd)
+ return 1;
+#endif
+ /* If this one of script's fds? */
+ if (fd != 0) {
+ struct parsefile *pf = g_parsefile;
+ while (pf) {
+ if (fd == pf->pf_fd)
+ return 1;
+ pf = pf->prev;
+ }
+ }
+
+ if (sq) for (i = 0; i < sq->pair_count && sq->two_fd[i].orig_fd != EMPTY; i++) {
+ if (fd == sq->two_fd[i].moved_to)
+ return 1;
+ }
+ return 0;
+}
+
/*
* Process a list of redirection commands. If the REDIR_PUSH flag is set,
* old file descriptors are stashed away so that the redirection can be
@@ -5567,15 +5592,11 @@
close(fd);
}
} else {
-///TODO: if _newfd_ is a script fd or saved fd, then simulate EBADF!
-//if (newfd == ttyfd) {
-// errno = EBADF;
-// ash_msg_and_raise_perror("A %d", newfd);
-//}
-//if (newfd == g_parsefile->pf_fd) {
-// errno = EBADF;
-// ash_msg_and_raise_perror("B %d", newfd);
-//}
+ /* if newfd is a script fd or saved fd, simulate EBADF */
+ if (internally_opened_fd(newfd, sv)) {
+ errno = EBADF;
+ ash_msg_and_raise_perror("%d", newfd);
+ }
dup2_or_raise(newfd, fd);
if (close_fd >= 0) /* "N>FILE" or ">&FILE" or heredoc? */
close(close_fd);