From 41126226e186d92a45ed664e546abb5204588359 Mon Sep 17 00:00:00 2001 From: Miloslav Trmac Date: Fri, 18 Apr 2008 13:30:14 -0700 Subject: [PATCH] [patch 1/2] audit: let userspace fully control TTY input auditing Remove the code that automatically disables TTY input auditing in processes that open TTYs when they have no other TTY open; this heuristic was intended to automatically handle daemons, but it has false positives (e.g. with sshd) that make it impossible to control TTY input auditing from a PAM module. With this patch, TTY input auditing is controlled from user-space only. On the other hand, not even for daemons does it make sense to audit "input" from PTY masters; this data was produced by a program writing to the PTY slave, and does not represent data entered by the user. Signed-off-by: Miloslav Trmac Cc: Al Viro Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- drivers/char/tty_audit.c | 54 ++++-------------------------------------------- drivers/char/tty_io.c | 5 +---- include/linux/tty.h | 5 ----- 3 files changed, 5 insertions(+), 59 deletions(-) diff --git a/drivers/char/tty_audit.c b/drivers/char/tty_audit.c index caeedd12d49..6342b0534f4 100644 --- a/drivers/char/tty_audit.c +++ b/drivers/char/tty_audit.c @@ -233,6 +233,10 @@ void tty_audit_add_data(struct tty_struct *tty, unsigned char *data, if (unlikely(size == 0)) return; + if (tty->driver->type == TTY_DRIVER_TYPE_PTY + && tty->driver->subtype == PTY_TYPE_MASTER) + return; + buf = tty_audit_buf_get(tty); if (!buf) return; @@ -295,53 +299,3 @@ void tty_audit_push(struct tty_struct *tty) tty_audit_buf_put(buf); } } - -/** - * tty_audit_opening - A TTY is being opened. - * - * As a special hack, tasks that close all their TTYs and open new ones - * are assumed to be system daemons (e.g. getty) and auditing is - * automatically disabled for them. - */ -void tty_audit_opening(void) -{ - int disable; - - disable = 1; - spin_lock_irq(¤t->sighand->siglock); - if (current->signal->audit_tty == 0) - disable = 0; - spin_unlock_irq(¤t->sighand->siglock); - if (!disable) - return; - - task_lock(current); - if (current->files) { - struct fdtable *fdt; - unsigned i; - - /* - * We don't take a ref to the file, so we must hold ->file_lock - * instead. - */ - spin_lock(¤t->files->file_lock); - fdt = files_fdtable(current->files); - for (i = 0; i < fdt->max_fds; i++) { - struct file *filp; - - filp = fcheck_files(current->files, i); - if (filp && is_tty(filp)) { - disable = 0; - break; - } - } - spin_unlock(¤t->files->file_lock); - } - task_unlock(current); - if (!disable) - return; - - spin_lock_irq(¤t->sighand->siglock); - current->signal->audit_tty = 0; - spin_unlock_irq(¤t->sighand->siglock); -} diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 4d3c7018f0c..afddccf1bb3 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2755,7 +2755,6 @@ got_driver: __proc_set_tty(current, tty); spin_unlock_irq(¤t->sighand->siglock); mutex_unlock(&tty_mutex); - tty_audit_opening(); return 0; } @@ -2818,10 +2817,8 @@ static int ptmx_open(struct inode *inode, struct file *filp) check_tty_count(tty, "tty_open"); retval = ptm_driver->open(tty, filp); - if (!retval) { - tty_audit_opening(); + if (!retval) return 0; - } out1: release_dev(filp); return retval; diff --git a/include/linux/tty.h b/include/linux/tty.h index 430624504ca..265831ccaa8 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -300,7 +300,6 @@ extern void tty_hangup(struct tty_struct * tty); extern void tty_vhangup(struct tty_struct * tty); extern void tty_unhangup(struct file *filp); extern int tty_hung_up_p(struct file * filp); -extern int is_tty(struct file *filp); extern void do_SAK(struct tty_struct *tty); extern void __do_SAK(struct tty_struct *tty); extern void disassociate_ctty(int priv); @@ -352,7 +351,6 @@ extern void tty_audit_exit(void); extern void tty_audit_fork(struct signal_struct *sig); extern void tty_audit_push(struct tty_struct *tty); extern void tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid); -extern void tty_audit_opening(void); #else static inline void tty_audit_add_data(struct tty_struct *tty, unsigned char *data, size_t size) @@ -370,9 +368,6 @@ static inline void tty_audit_push(struct tty_struct *tty) static inline void tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid) { } -static inline void tty_audit_opening(void) -{ -} #endif /* tty_ioctl.c */ -- 2.11.4.GIT