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tty: audit: Remove icanon mode from call chain

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The tty termios bits cannot change while n_tty_read() is in the
i/o loop; the termios_rwsem ensures mutual exclusion with termios
changes in n_tty_set_termios(). Check L_ICANON() directly and
eliminate icanon parameter.

NB: tty_audit_add_data() => tty_audit_buf_get() => tty_audit_buf_alloc()
is a single path; ie., tty_audit_buf_get() and tty_audit_buf_alloc()
have no other callers.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2016-01-09 22:55:27 -08:00 committed by Greg Kroah-Hartman
parent eab25a5cd1
commit 309426ae69
3 changed files with 14 additions and 18 deletions
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6
drivers/tty/n_tty.c
View file

@ -162,7 +162,7 @@ static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
int uncopied;
if (n > size) {
tty_audit_add_data(tty, from, size, ldata->icanon);
tty_audit_add_data(tty, from, size);
uncopied = copy_to_user(to, from, size);
if (uncopied)
return uncopied;
@ -171,7 +171,7 @@ static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
from = ldata->read_buf;
}
tty_audit_add_data(tty, from, n, ldata->icanon);
tty_audit_add_data(tty, from, n);
return copy_to_user(to, from, n);
}
@ -1978,7 +1978,7 @@ static int copy_from_read_buf(struct tty_struct *tty,
retval = copy_to_user(*b, from, n);
n -= retval;
is_eof = n == 1 && *from == EOF_CHAR(tty);
tty_audit_add_data(tty, from, n, ldata->icanon);
tty_audit_add_data(tty, from, n);
smp_store_release(&ldata->read_tail, ldata->read_tail + n);
/* Turn single EOF into zero-length read */
if (L_EXTPROC(tty) && ldata->icanon && is_eof &&

22
drivers/tty/tty_audit.c
View file

@ -22,8 +22,7 @@ struct tty_audit_buf {
unsigned char *data; /* Allocated size N_TTY_BUF_SIZE */
};
static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor,
unsigned icanon)
static struct tty_audit_buf *tty_audit_buf_alloc(struct tty_struct *tty)
{
struct tty_audit_buf *buf;
@ -35,9 +34,9 @@ static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor,
goto err_buf;
atomic_set(&buf->count, 1);
mutex_init(&buf->mutex);
buf->major = major;
buf->minor = minor;
buf->icanon = icanon;
buf->major = tty->driver->major;
buf->minor = tty->driver->minor_start + tty->index;
buf->icanon = !!L_ICANON(tty);
buf->valid = 0;
return buf;
@ -216,8 +215,7 @@ int tty_audit_push_current(void)
* if TTY auditing is disabled or out of memory. Otherwise, return a new
* reference to the buffer.
*/
static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
unsigned icanon)
static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
{
struct tty_audit_buf *buf, *buf2;
unsigned long flags;
@ -234,9 +232,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
}
spin_unlock_irqrestore(&current->sighand->siglock, flags);
buf2 = tty_audit_buf_alloc(tty->driver->major,
tty->driver->minor_start + tty->index,
icanon);
buf2 = tty_audit_buf_alloc(tty);
if (buf2 == NULL) {
audit_log_lost("out of memory in TTY auditing");
return NULL;
@ -265,13 +261,13 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
*
* Audit @data of @size from @tty, if necessary.
*/
void tty_audit_add_data(struct tty_struct *tty, const void *data,
size_t size, unsigned icanon)
void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
{
struct tty_audit_buf *buf;
int major, minor;
int audit_log_tty_passwd;
unsigned long flags;
unsigned int icanon = !!L_ICANON(tty);
if (unlikely(size == 0))
return;
@ -286,7 +282,7 @@ void tty_audit_add_data(struct tty_struct *tty, const void *data,
if (!audit_log_tty_passwd && icanon && !L_ECHO(tty))
return;
buf = tty_audit_buf_get(tty, icanon);
buf = tty_audit_buf_get(tty);
if (!buf)
return;

4
include/linux/tty.h
View file

@ -593,7 +593,7 @@ extern void __init n_tty_init(void);
/* tty_audit.c */
#ifdef CONFIG_AUDIT
extern void tty_audit_add_data(struct tty_struct *tty, const void *data,
size_t size, unsigned icanon);
size_t size);
extern void tty_audit_exit(void);
extern void tty_audit_fork(struct signal_struct *sig);
extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
@ -601,7 +601,7 @@ extern void tty_audit_push(struct tty_struct *tty);
extern int tty_audit_push_current(void);
#else
static inline void tty_audit_add_data(struct tty_struct *tty, const void *data,
size_t size, unsigned icanon)
size_t size)
{
}
static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)