#include <linux/tty.h>
struct tty_audit_buf {
- atomic_t count;
struct mutex mutex; /* Protects all data below */
- int major, minor; /* The TTY which the data is from */
+ dev_t dev; /* The TTY which the data is from */
unsigned icanon:1;
size_t valid;
unsigned char *data; /* Allocated size N_TTY_BUF_SIZE */
};
+static struct tty_audit_buf *tty_audit_buf_ref(void)
+{
+ struct tty_audit_buf *buf;
+
+ buf = current->signal->tty_audit_buf;
+ WARN_ON(buf == ERR_PTR(-ESRCH));
+ return buf;
+}
+
static struct tty_audit_buf *tty_audit_buf_alloc(void)
{
struct tty_audit_buf *buf;
buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
if (!buf->data)
goto err_buf;
- atomic_set(&buf->count, 1);
mutex_init(&buf->mutex);
- buf->major = 0;
- buf->minor = 0;
+ buf->dev = MKDEV(0, 0);
buf->icanon = 0;
buf->valid = 0;
return buf;
kfree(buf);
}
-static void tty_audit_buf_put(struct tty_audit_buf *buf)
-{
- if (atomic_dec_and_test(&buf->count))
- tty_audit_buf_free(buf);
-}
-
-static void tty_audit_log(const char *description, int major, int minor,
+static void tty_audit_log(const char *description, dev_t dev,
unsigned char *data, size_t size)
{
struct audit_buffer *ab;
audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u major=%d"
" minor=%d comm=", description, pid, uid,
- loginuid, sessionid, major, minor);
+ loginuid, sessionid, MAJOR(dev), MINOR(dev));
get_task_comm(name, tsk);
audit_log_untrustedstring(ab, name);
audit_log_format(ab, " data=");
buf->valid = 0;
return;
}
- tty_audit_log("tty", buf->major, buf->minor, buf->data, buf->valid);
+ tty_audit_log("tty", buf->dev, buf->data, buf->valid);
buf->valid = 0;
}
*
* Make sure all buffered data is written out and deallocate the buffer.
* Only needs to be called if current->signal->tty_audit_buf != %NULL.
+ *
+ * The process is single-threaded at this point; no other threads share
+ * current->signal.
*/
void tty_audit_exit(void)
{
struct tty_audit_buf *buf;
- buf = current->signal->tty_audit_buf;
- current->signal->tty_audit_buf = NULL;
+ buf = xchg(¤t->signal->tty_audit_buf, ERR_PTR(-ESRCH));
if (!buf)
return;
- mutex_lock(&buf->mutex);
tty_audit_buf_push(buf);
- mutex_unlock(&buf->mutex);
-
- tty_audit_buf_put(buf);
+ tty_audit_buf_free(buf);
}
/**
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;
}
/**
*/
void tty_audit_tiocsti(struct tty_struct *tty, char ch)
{
- struct tty_audit_buf *buf;
- int major, minor, should_audit;
- unsigned long flags;
-
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- should_audit = current->signal->audit_tty;
- buf = current->signal->tty_audit_buf;
- if (buf)
- atomic_inc(&buf->count);
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
-
- major = tty->driver->major;
- minor = tty->driver->minor_start + tty->index;
- if (buf) {
- mutex_lock(&buf->mutex);
- if (buf->major == major && buf->minor == minor)
- tty_audit_buf_push(buf);
- mutex_unlock(&buf->mutex);
- tty_audit_buf_put(buf);
- }
+ dev_t dev;
- if (should_audit && audit_enabled) {
- kuid_t auid;
- unsigned int sessionid;
+ dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
+ if (tty_audit_push())
+ return;
- auid = audit_get_loginuid(current);
- sessionid = audit_get_sessionid(current);
- tty_audit_log("ioctl=TIOCSTI", major, minor, &ch, 1);
- }
+ if (audit_enabled)
+ tty_audit_log("ioctl=TIOCSTI", dev, &ch, 1);
}
/**
*/
int tty_audit_push(void)
{
- struct tty_audit_buf *buf = ERR_PTR(-EPERM);
- unsigned long flags;
-
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- if (current->signal->audit_tty) {
- buf = current->signal->tty_audit_buf;
- if (buf)
- atomic_inc(&buf->count);
- }
- spin_unlock_irqrestore(¤t->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);
+ struct tty_audit_buf *buf;
- mutex_lock(&buf->mutex);
- tty_audit_buf_push(buf);
- mutex_unlock(&buf->mutex);
+ if (~current->signal->audit_tty & AUDIT_TTY_ENABLE)
+ return -EPERM;
- tty_audit_buf_put(buf);
+ buf = tty_audit_buf_ref();
+ if (!IS_ERR_OR_NULL(buf)) {
+ mutex_lock(&buf->mutex);
+ tty_audit_buf_push(buf);
+ mutex_unlock(&buf->mutex);
+ }
return 0;
}
* tty_audit_buf_get - Get an audit buffer.
*
* Get an audit buffer, allocate it if necessary. Return %NULL
- * if TTY auditing is disabled or out of memory. Otherwise, return a new
- * reference to the buffer.
+ * if out of memory or ERR_PTR(-ESRCH) if tty_audit_exit() has already
+ * occurred. Otherwise, return a new reference to the buffer.
*/
static struct tty_audit_buf *tty_audit_buf_get(void)
{
- struct tty_audit_buf *buf, *buf2;
- unsigned long flags;
-
- buf = NULL;
- buf2 = NULL;
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- if (likely(!current->signal->audit_tty))
- goto out;
- buf = current->signal->tty_audit_buf;
- if (buf) {
- atomic_inc(&buf->count);
- goto out;
- }
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ struct tty_audit_buf *buf;
- buf2 = tty_audit_buf_alloc();
- if (buf2 == NULL) {
+ buf = tty_audit_buf_ref();
+ if (buf)
+ return buf;
+
+ buf = tty_audit_buf_alloc();
+ if (buf == NULL) {
audit_log_lost("out of memory in TTY auditing");
return NULL;
}
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- if (!current->signal->audit_tty)
- goto out;
- buf = current->signal->tty_audit_buf;
- if (!buf) {
- current->signal->tty_audit_buf = buf2;
- buf = buf2;
- buf2 = NULL;
- }
- atomic_inc(&buf->count);
- /* Fall through */
- out:
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
- if (buf2)
- tty_audit_buf_free(buf2);
- return buf;
+ /* Race to use this buffer, free it if another wins */
+ if (cmpxchg(¤t->signal->tty_audit_buf, NULL, buf) != NULL)
+ tty_audit_buf_free(buf);
+ return tty_audit_buf_ref();
}
/**
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);
+ unsigned int audit_tty;
+ dev_t dev;
+
+ audit_tty = READ_ONCE(current->signal->audit_tty);
+ if (~audit_tty & AUDIT_TTY_ENABLE)
+ return;
if (unlikely(size == 0))
return;
&& tty->driver->subtype == PTY_TYPE_MASTER)
return;
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- audit_log_tty_passwd = current->signal->audit_tty_log_passwd;
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
- if (!audit_log_tty_passwd && icanon && !L_ECHO(tty))
+ if ((~audit_tty & AUDIT_TTY_LOG_PASSWD) && icanon && !L_ECHO(tty))
return;
buf = tty_audit_buf_get();
- if (!buf)
+ if (IS_ERR_OR_NULL(buf))
return;
mutex_lock(&buf->mutex);
- major = tty->driver->major;
- minor = tty->driver->minor_start + tty->index;
- if (buf->major != major || buf->minor != minor
- || buf->icanon != icanon) {
+ dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
+ if (buf->dev != dev || buf->icanon != icanon) {
tty_audit_buf_push(buf);
- buf->major = major;
- buf->minor = minor;
+ buf->dev = dev;
buf->icanon = icanon;
}
do {
tty_audit_buf_push(buf);
} while (size != 0);
mutex_unlock(&buf->mutex);
- tty_audit_buf_put(buf);
}
projects / mirror_ubuntu-bionic-kernel.git / blobdiff