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authorPeter Hurley <peter@hurleysoftware.com>2016-01-10 09:55:33 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-28 03:41:04 +0300
commit2e28d38ae1d9ced6ac2deb4001aca3f267304cdb (patch)
treec5d29fa6d7f7198d9500a7b78066c13b5cd77705 /drivers/tty/tty_audit.c
parent4d240b6442824df3b5e401459789bab5ee7777ae (diff)
downloadlinux-2e28d38ae1d9ced6ac2deb4001aca3f267304cdb.tar.xz
tty: audit: Handle tty audit enable atomically
The audit_tty and audit_tty_log_passwd fields are actually bool values, so merge into single memory location to access atomically. NB: audit log operations may still occur after tty audit is disabled which is consistent with the existing functionality Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_audit.c')
-rw-r--r--drivers/tty/tty_audit.c53
1 files changed, 22 insertions, 31 deletions
diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
index 50380d87061d..3d90f88c5ff9 100644
--- a/drivers/tty/tty_audit.c
+++ b/drivers/tty/tty_audit.c
@@ -131,7 +131,6 @@ void tty_audit_exit(void)
void tty_audit_fork(struct signal_struct *sig)
{
sig->audit_tty = current->signal->audit_tty;
- sig->audit_tty_log_passwd = current->signal->audit_tty_log_passwd;
}
/**
@@ -141,11 +140,9 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
{
struct tty_audit_buf *buf;
dev_t dev;
- int should_audit;
unsigned long flags;
spin_lock_irqsave(&current->sighand->siglock, flags);
- should_audit = current->signal->audit_tty;
buf = current->signal->tty_audit_buf;
if (buf)
atomic_inc(&buf->count);
@@ -160,7 +157,7 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
tty_audit_buf_put(buf);
}
- if (should_audit && audit_enabled) {
+ if (audit_enabled && (current->signal->audit_tty & AUDIT_TTY_ENABLE)) {
kuid_t auid;
unsigned int sessionid;
@@ -177,29 +174,25 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
*/
int tty_audit_push(void)
{
- struct tty_audit_buf *buf = ERR_PTR(-EPERM);
+ struct tty_audit_buf *buf;
unsigned long flags;
+ if (~current->signal->audit_tty & AUDIT_TTY_ENABLE)
+ return -EPERM;
+
spin_lock_irqsave(&current->sighand->siglock, flags);
- if (current->signal->audit_tty) {
- buf = current->signal->tty_audit_buf;
- if (buf)
- atomic_inc(&buf->count);
- }
+ buf = current->signal->tty_audit_buf;
+ if (buf)
+ atomic_inc(&buf->count);
spin_unlock_irqrestore(&current->sighand->siglock, flags);
- /*
- * Return 0 when signal->audit_tty set
- * but current->signal->tty_audit_buf == NULL.
- */
- if (!buf || IS_ERR(buf))
- return PTR_ERR(buf);
-
- mutex_lock(&buf->mutex);
- tty_audit_buf_push(buf);
- mutex_unlock(&buf->mutex);
+ if (buf) {
+ mutex_lock(&buf->mutex);
+ tty_audit_buf_push(buf);
+ mutex_unlock(&buf->mutex);
- tty_audit_buf_put(buf);
+ tty_audit_buf_put(buf);
+ }
return 0;
}
@@ -218,8 +211,6 @@ static struct tty_audit_buf *tty_audit_buf_get(void)
buf = NULL;
buf2 = NULL;
spin_lock_irqsave(&current->sighand->siglock, flags);
- if (likely(!current->signal->audit_tty))
- goto out;
buf = current->signal->tty_audit_buf;
if (buf) {
atomic_inc(&buf->count);
@@ -233,9 +224,10 @@ static struct tty_audit_buf *tty_audit_buf_get(void)
return NULL;
}
- spin_lock_irqsave(&current->sighand->siglock, flags);
- if (!current->signal->audit_tty)
+ if (~current->signal->audit_tty & AUDIT_TTY_ENABLE)
goto out;
+
+ spin_lock_irqsave(&current->sighand->siglock, flags);
buf = current->signal->tty_audit_buf;
if (!buf) {
current->signal->tty_audit_buf = buf2;
@@ -259,9 +251,8 @@ static struct tty_audit_buf *tty_audit_buf_get(void)
void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
{
struct tty_audit_buf *buf;
- int audit_log_tty_passwd;
- unsigned long flags;
unsigned int icanon = !!L_ICANON(tty);
+ unsigned int audit_tty;
dev_t dev;
if (unlikely(size == 0))
@@ -271,10 +262,10 @@ void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
&& tty->driver->subtype == PTY_TYPE_MASTER)
return;
- spin_lock_irqsave(&current->sighand->siglock, flags);
- audit_log_tty_passwd = current->signal->audit_tty_log_passwd;
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
- if (!audit_log_tty_passwd && icanon && !L_ECHO(tty))
+ audit_tty = READ_ONCE(current->signal->audit_tty);
+ if (~audit_tty & AUDIT_TTY_ENABLE)
+ return;
+ if ((~audit_tty & AUDIT_TTY_LOG_PASSWD) && icanon && !L_ECHO(tty))
return;
buf = tty_audit_buf_get();