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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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cca080d9b6
- Explicitly format uids gids in audit messges in the initial user namespace. This is safe because auditd is restrected to be in the initial user namespace. - Convert audit_sig_uid into a kuid_t. - Enable building the audit code and user namespaces at the same time. The net result is that the audit subsystem now uses kuid_t and kgid_t whenever possible making it almost impossible to confuse a raw uid_t with a kuid_t preventing bugs. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
364 lines
8.6 KiB
C
364 lines
8.6 KiB
C
/*
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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. This copyrighted
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* material is made available to anyone wishing to use, modify, copy, or
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* redistribute it subject to the terms and conditions of the GNU General
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* Public License v.2.
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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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struct tty_audit_buf {
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atomic_t count;
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struct mutex mutex; /* Protects all data below */
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int major, minor; /* 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_alloc(int major, int minor,
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int icanon)
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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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atomic_set(&buf->count, 1);
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mutex_init(&buf->mutex);
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buf->major = major;
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buf->minor = minor;
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buf->icanon = icanon;
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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_buf_put(struct tty_audit_buf *buf)
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{
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if (atomic_dec_and_test(&buf->count))
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tty_audit_buf_free(buf);
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}
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static void tty_audit_log(const char *description, struct task_struct *tsk,
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kuid_t loginuid, unsigned sessionid, int major,
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int minor, unsigned char *data, size_t size)
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{
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struct audit_buffer *ab;
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ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY);
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if (ab) {
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char name[sizeof(tsk->comm)];
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kuid_t uid = task_uid(tsk);
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audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u "
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"major=%d minor=%d comm=", description,
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tsk->pid,
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from_kuid(&init_user_ns, uid),
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from_kuid(&init_user_ns, loginuid),
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sessionid,
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major, minor);
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get_task_comm(name, tsk);
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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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* @tsk with @loginuid. @buf->mutex must be locked.
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*/
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static void tty_audit_buf_push(struct task_struct *tsk, kuid_t loginuid,
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unsigned int sessionid,
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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 == 0) {
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buf->valid = 0;
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return;
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}
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tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor,
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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_buf_push_current - 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_current(struct tty_audit_buf *buf)
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{
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kuid_t auid = audit_get_loginuid(current);
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unsigned int sessionid = audit_get_sessionid(current);
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tty_audit_buf_push(current, auid, sessionid, buf);
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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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void tty_audit_exit(void)
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{
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struct tty_audit_buf *buf;
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spin_lock_irq(¤t->sighand->siglock);
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buf = current->signal->tty_audit_buf;
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current->signal->tty_audit_buf = NULL;
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spin_unlock_irq(¤t->sighand->siglock);
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if (!buf)
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return;
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mutex_lock(&buf->mutex);
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tty_audit_buf_push_current(buf);
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mutex_unlock(&buf->mutex);
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tty_audit_buf_put(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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spin_lock_irq(¤t->sighand->siglock);
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sig->audit_tty = current->signal->audit_tty;
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spin_unlock_irq(¤t->sighand->siglock);
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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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struct tty_audit_buf *buf;
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int major, minor, should_audit;
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spin_lock_irq(¤t->sighand->siglock);
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should_audit = current->signal->audit_tty;
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buf = current->signal->tty_audit_buf;
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if (buf)
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atomic_inc(&buf->count);
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spin_unlock_irq(¤t->sighand->siglock);
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major = tty->driver->major;
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minor = tty->driver->minor_start + tty->index;
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if (buf) {
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mutex_lock(&buf->mutex);
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if (buf->major == major && buf->minor == minor)
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tty_audit_buf_push_current(buf);
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mutex_unlock(&buf->mutex);
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tty_audit_buf_put(buf);
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}
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if (should_audit && audit_enabled) {
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kuid_t auid;
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unsigned int sessionid;
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auid = audit_get_loginuid(current);
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sessionid = audit_get_sessionid(current);
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tty_audit_log("ioctl=TIOCSTI", current, auid, sessionid, major,
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minor, &ch, 1);
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}
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}
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/**
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* tty_audit_push_task - Flush task's pending audit data
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* @tsk: task pointer
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* @loginuid: sender login uid
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* @sessionid: sender session id
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*
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* Called with a ref on @tsk held. Try to lock sighand and get a
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* reference to the tty audit buffer if available.
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* Flush the buffer or return an appropriate error code.
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*/
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int tty_audit_push_task(struct task_struct *tsk, kuid_t loginuid, u32 sessionid)
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{
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struct tty_audit_buf *buf = ERR_PTR(-EPERM);
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unsigned long flags;
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if (!lock_task_sighand(tsk, &flags))
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return -ESRCH;
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if (tsk->signal->audit_tty) {
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buf = tsk->signal->tty_audit_buf;
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if (buf)
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atomic_inc(&buf->count);
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}
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unlock_task_sighand(tsk, &flags);
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/*
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* Return 0 when signal->audit_tty set
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* but tsk->signal->tty_audit_buf == NULL.
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*/
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if (!buf || IS_ERR(buf))
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return PTR_ERR(buf);
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mutex_lock(&buf->mutex);
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tty_audit_buf_push(tsk, loginuid, sessionid, buf);
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mutex_unlock(&buf->mutex);
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tty_audit_buf_put(buf);
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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 for @tty, allocate it if necessary. Return %NULL
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* if TTY auditing is disabled or out of memory. Otherwise, return a new
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* reference to the buffer.
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*/
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static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
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{
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struct tty_audit_buf *buf, *buf2;
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buf = NULL;
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buf2 = NULL;
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spin_lock_irq(¤t->sighand->siglock);
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if (likely(!current->signal->audit_tty))
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goto out;
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buf = current->signal->tty_audit_buf;
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if (buf) {
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atomic_inc(&buf->count);
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goto out;
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}
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spin_unlock_irq(¤t->sighand->siglock);
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buf2 = tty_audit_buf_alloc(tty->driver->major,
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tty->driver->minor_start + tty->index,
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tty->icanon);
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if (buf2 == 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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spin_lock_irq(¤t->sighand->siglock);
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if (!current->signal->audit_tty)
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goto out;
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buf = current->signal->tty_audit_buf;
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if (!buf) {
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current->signal->tty_audit_buf = buf2;
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buf = buf2;
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buf2 = NULL;
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}
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atomic_inc(&buf->count);
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/* Fall through */
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out:
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spin_unlock_irq(¤t->sighand->siglock);
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if (buf2)
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tty_audit_buf_free(buf2);
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return buf;
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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, unsigned char *data,
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size_t size)
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{
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struct tty_audit_buf *buf;
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int major, minor;
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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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buf = tty_audit_buf_get(tty);
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if (!buf)
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return;
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mutex_lock(&buf->mutex);
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major = tty->driver->major;
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minor = tty->driver->minor_start + tty->index;
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if (buf->major != major || buf->minor != minor
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|| buf->icanon != tty->icanon) {
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tty_audit_buf_push_current(buf);
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buf->major = major;
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buf->minor = minor;
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buf->icanon = tty->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_current(buf);
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} while (size != 0);
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mutex_unlock(&buf->mutex);
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tty_audit_buf_put(buf);
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}
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/**
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* tty_audit_push - Push buffered data out
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*
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* Make sure no audit data is pending for @tty on the current process.
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*/
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void tty_audit_push(struct tty_struct *tty)
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{
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struct tty_audit_buf *buf;
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spin_lock_irq(¤t->sighand->siglock);
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if (likely(!current->signal->audit_tty)) {
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spin_unlock_irq(¤t->sighand->siglock);
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return;
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}
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buf = current->signal->tty_audit_buf;
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if (buf)
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atomic_inc(&buf->count);
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spin_unlock_irq(¤t->sighand->siglock);
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if (buf) {
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int major, minor;
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major = tty->driver->major;
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minor = tty->driver->minor_start + tty->index;
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mutex_lock(&buf->mutex);
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if (buf->major == major && buf->minor == minor)
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tty_audit_buf_push_current(buf);
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mutex_unlock(&buf->mutex);
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tty_audit_buf_put(buf);
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}
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}
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