From 32fdf2f9fc9a617918672d71579f4ad42eb9bde9 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 31 Jul 2017 04:32:06 +0200 Subject: 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 --- shell/ash.c | 39 ++++++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 9 deletions(-) (limited to 'shell/ash.c') diff --git a/shell/ash.c b/shell/ash.c index ac676c2dc..5c2e06599 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -5503,6 +5503,31 @@ save_fd_on_redirect(int fd, int avoid_fd, struct redirtab *sq) 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 @@ redirect(union node *redir, int flags) 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); -- cgit v1.2.3