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The functions tty_audit_add_data() and tty_audit_tiocsti() are local to the tty core code, and do not need to be in a "kernel-wide" header file so move them to drivers/tty/tty.h Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210408125134.3016837-9-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
249 lines
5.6 KiB
C
249 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Creating audit events from TTY input.
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*
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* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
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*
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* Authors: Miloslav Trmac <mitr@redhat.com>
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*/
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#include <linux/audit.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include "tty.h"
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struct tty_audit_buf {
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struct mutex mutex; /* Protects all data below */
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dev_t dev; /* The TTY which the data is from */
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unsigned icanon:1;
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size_t valid;
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unsigned char *data; /* Allocated size N_TTY_BUF_SIZE */
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};
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static struct tty_audit_buf *tty_audit_buf_ref(void)
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{
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struct tty_audit_buf *buf;
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buf = current->signal->tty_audit_buf;
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WARN_ON(buf == ERR_PTR(-ESRCH));
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return buf;
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}
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static struct tty_audit_buf *tty_audit_buf_alloc(void)
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{
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struct tty_audit_buf *buf;
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buf = kmalloc(sizeof(*buf), GFP_KERNEL);
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if (!buf)
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goto err;
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buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
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if (!buf->data)
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goto err_buf;
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mutex_init(&buf->mutex);
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buf->dev = MKDEV(0, 0);
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buf->icanon = 0;
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buf->valid = 0;
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return buf;
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err_buf:
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kfree(buf);
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err:
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return NULL;
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}
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static void tty_audit_buf_free(struct tty_audit_buf *buf)
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{
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WARN_ON(buf->valid != 0);
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kfree(buf->data);
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kfree(buf);
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}
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static void tty_audit_log(const char *description, dev_t dev,
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unsigned char *data, size_t size)
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{
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struct audit_buffer *ab;
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pid_t pid = task_pid_nr(current);
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uid_t uid = from_kuid(&init_user_ns, task_uid(current));
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uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
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unsigned int sessionid = audit_get_sessionid(current);
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ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_TTY);
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if (ab) {
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char name[sizeof(current->comm)];
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audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u major=%d"
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" minor=%d comm=", description, pid, uid,
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loginuid, sessionid, MAJOR(dev), MINOR(dev));
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get_task_comm(name, current);
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audit_log_untrustedstring(ab, name);
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audit_log_format(ab, " data=");
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audit_log_n_hex(ab, data, size);
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audit_log_end(ab);
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}
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}
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/*
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* tty_audit_buf_push - Push buffered data out
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*
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* Generate an audit message from the contents of @buf, which is owned by
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* the current task. @buf->mutex must be locked.
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*/
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static void tty_audit_buf_push(struct tty_audit_buf *buf)
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{
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if (buf->valid == 0)
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return;
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if (audit_enabled == AUDIT_OFF) {
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buf->valid = 0;
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return;
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}
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tty_audit_log("tty", buf->dev, buf->data, buf->valid);
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buf->valid = 0;
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}
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/**
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* tty_audit_exit - Handle a task exit
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*
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* Make sure all buffered data is written out and deallocate the buffer.
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* Only needs to be called if current->signal->tty_audit_buf != %NULL.
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*
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* The process is single-threaded at this point; no other threads share
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* current->signal.
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*/
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void tty_audit_exit(void)
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{
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struct tty_audit_buf *buf;
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buf = xchg(¤t->signal->tty_audit_buf, ERR_PTR(-ESRCH));
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if (!buf)
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return;
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tty_audit_buf_push(buf);
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tty_audit_buf_free(buf);
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}
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/*
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* tty_audit_fork - Copy TTY audit state for a new task
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*
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* Set up TTY audit state in @sig from current. @sig needs no locking.
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*/
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void tty_audit_fork(struct signal_struct *sig)
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{
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sig->audit_tty = current->signal->audit_tty;
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}
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/*
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* tty_audit_tiocsti - Log TIOCSTI
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*/
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void tty_audit_tiocsti(struct tty_struct *tty, char ch)
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{
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dev_t dev;
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dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
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if (tty_audit_push())
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return;
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if (audit_enabled)
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tty_audit_log("ioctl=TIOCSTI", dev, &ch, 1);
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}
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/*
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* tty_audit_push - Flush current's pending audit data
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*
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* Returns 0 if success, -EPERM if tty audit is disabled
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*/
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int tty_audit_push(void)
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{
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struct tty_audit_buf *buf;
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if (~current->signal->audit_tty & AUDIT_TTY_ENABLE)
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return -EPERM;
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buf = tty_audit_buf_ref();
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if (!IS_ERR_OR_NULL(buf)) {
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mutex_lock(&buf->mutex);
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tty_audit_buf_push(buf);
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mutex_unlock(&buf->mutex);
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}
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return 0;
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}
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/*
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* tty_audit_buf_get - Get an audit buffer.
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*
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* Get an audit buffer, allocate it if necessary. Return %NULL
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* if out of memory or ERR_PTR(-ESRCH) if tty_audit_exit() has already
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* occurred. Otherwise, return a new reference to the buffer.
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*/
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static struct tty_audit_buf *tty_audit_buf_get(void)
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{
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struct tty_audit_buf *buf;
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buf = tty_audit_buf_ref();
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if (buf)
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return buf;
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buf = tty_audit_buf_alloc();
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if (buf == NULL) {
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audit_log_lost("out of memory in TTY auditing");
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return NULL;
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}
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/* Race to use this buffer, free it if another wins */
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if (cmpxchg(¤t->signal->tty_audit_buf, NULL, buf) != NULL)
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tty_audit_buf_free(buf);
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return tty_audit_buf_ref();
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}
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/*
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* tty_audit_add_data - Add data for TTY auditing.
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*
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* Audit @data of @size from @tty, if necessary.
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*/
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void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
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{
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struct tty_audit_buf *buf;
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unsigned int icanon = !!L_ICANON(tty);
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unsigned int audit_tty;
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dev_t dev;
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audit_tty = READ_ONCE(current->signal->audit_tty);
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if (~audit_tty & AUDIT_TTY_ENABLE)
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return;
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if (unlikely(size == 0))
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return;
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if (tty->driver->type == TTY_DRIVER_TYPE_PTY
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&& tty->driver->subtype == PTY_TYPE_MASTER)
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return;
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if ((~audit_tty & AUDIT_TTY_LOG_PASSWD) && icanon && !L_ECHO(tty))
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return;
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buf = tty_audit_buf_get();
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if (IS_ERR_OR_NULL(buf))
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return;
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mutex_lock(&buf->mutex);
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dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
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if (buf->dev != dev || buf->icanon != icanon) {
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tty_audit_buf_push(buf);
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buf->dev = dev;
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buf->icanon = icanon;
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}
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do {
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size_t run;
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run = N_TTY_BUF_SIZE - buf->valid;
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if (run > size)
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run = size;
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memcpy(buf->data + buf->valid, data, run);
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buf->valid += run;
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data += run;
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size -= run;
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if (buf->valid == N_TTY_BUF_SIZE)
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tty_audit_buf_push(buf);
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} while (size != 0);
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mutex_unlock(&buf->mutex);
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}
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