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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/tty/tty_audit.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/tty/tty_audit.c')
-rw-r--r--drivers/tty/tty_audit.c248
1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
new file mode 100644
index 000000000..ca7afd7b2
--- /dev/null
+++ b/drivers/tty/tty_audit.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Creating audit events from TTY input.
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All rights reserved.
+ *
+ * Authors: Miloslav Trmac <mitr@redhat.com>
+ */
+
+#include <linux/audit.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include "tty.h"
+
+struct tty_audit_buf {
+ struct mutex mutex; /* Protects all data below */
+ 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 = kmalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ goto err;
+ buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
+ if (!buf->data)
+ goto err_buf;
+ mutex_init(&buf->mutex);
+ buf->dev = MKDEV(0, 0);
+ buf->icanon = 0;
+ buf->valid = 0;
+ return buf;
+
+err_buf:
+ kfree(buf);
+err:
+ return NULL;
+}
+
+static void tty_audit_buf_free(struct tty_audit_buf *buf)
+{
+ WARN_ON(buf->valid != 0);
+ kfree(buf->data);
+ kfree(buf);
+}
+
+static void tty_audit_log(const char *description, dev_t dev,
+ unsigned char *data, size_t size)
+{
+ struct audit_buffer *ab;
+ pid_t pid = task_pid_nr(current);
+ uid_t uid = from_kuid(&init_user_ns, task_uid(current));
+ uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
+ unsigned int sessionid = audit_get_sessionid(current);
+
+ ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_TTY);
+ if (ab) {
+ char name[sizeof(current->comm)];
+
+ audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u major=%d"
+ " minor=%d comm=", description, pid, uid,
+ loginuid, sessionid, MAJOR(dev), MINOR(dev));
+ get_task_comm(name, current);
+ audit_log_untrustedstring(ab, name);
+ audit_log_format(ab, " data=");
+ audit_log_n_hex(ab, data, size);
+ audit_log_end(ab);
+ }
+}
+
+/*
+ * tty_audit_buf_push - Push buffered data out
+ *
+ * Generate an audit message from the contents of @buf, which is owned by
+ * the current task. @buf->mutex must be locked.
+ */
+static void tty_audit_buf_push(struct tty_audit_buf *buf)
+{
+ if (buf->valid == 0)
+ return;
+ if (audit_enabled == AUDIT_OFF) {
+ buf->valid = 0;
+ return;
+ }
+ tty_audit_log("tty", buf->dev, buf->data, buf->valid);
+ buf->valid = 0;
+}
+
+/**
+ * tty_audit_exit - Handle a task exit
+ *
+ * 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 = xchg(&current->signal->tty_audit_buf, ERR_PTR(-ESRCH));
+ if (!buf)
+ return;
+
+ tty_audit_buf_push(buf);
+ tty_audit_buf_free(buf);
+}
+
+/*
+ * tty_audit_fork - Copy TTY audit state for a new task
+ *
+ * Set up TTY audit state in @sig from current. @sig needs no locking.
+ */
+void tty_audit_fork(struct signal_struct *sig)
+{
+ sig->audit_tty = current->signal->audit_tty;
+}
+
+/*
+ * tty_audit_tiocsti - Log TIOCSTI
+ */
+void tty_audit_tiocsti(struct tty_struct *tty, char ch)
+{
+ dev_t dev;
+
+ dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
+ if (tty_audit_push())
+ return;
+
+ if (audit_enabled)
+ tty_audit_log("ioctl=TIOCSTI", dev, &ch, 1);
+}
+
+/*
+ * tty_audit_push - Flush current's pending audit data
+ *
+ * Returns 0 if success, -EPERM if tty audit is disabled
+ */
+int tty_audit_push(void)
+{
+ struct tty_audit_buf *buf;
+
+ if (~current->signal->audit_tty & AUDIT_TTY_ENABLE)
+ return -EPERM;
+
+ 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 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;
+
+ 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;
+ }
+
+ /* Race to use this buffer, free it if another wins */
+ if (cmpxchg(&current->signal->tty_audit_buf, NULL, buf) != NULL)
+ tty_audit_buf_free(buf);
+ return tty_audit_buf_ref();
+}
+
+/*
+ * tty_audit_add_data - Add data for TTY auditing.
+ *
+ * Audit @data of @size from @tty, if necessary.
+ */
+void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size)
+{
+ struct tty_audit_buf *buf;
+ 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;
+
+ if (tty->driver->type == TTY_DRIVER_TYPE_PTY
+ && tty->driver->subtype == PTY_TYPE_MASTER)
+ return;
+
+ if ((~audit_tty & AUDIT_TTY_LOG_PASSWD) && icanon && !L_ECHO(tty))
+ return;
+
+ buf = tty_audit_buf_get();
+ if (IS_ERR_OR_NULL(buf))
+ return;
+
+ mutex_lock(&buf->mutex);
+ dev = MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
+ if (buf->dev != dev || buf->icanon != icanon) {
+ tty_audit_buf_push(buf);
+ buf->dev = dev;
+ buf->icanon = icanon;
+ }
+ do {
+ size_t run;
+
+ run = N_TTY_BUF_SIZE - buf->valid;
+ if (run > size)
+ run = size;
+ memcpy(buf->data + buf->valid, data, run);
+ buf->valid += run;
+ data += run;
+ size -= run;
+ if (buf->valid == N_TTY_BUF_SIZE)
+ tty_audit_buf_push(buf);
+ } while (size != 0);
+ mutex_unlock(&buf->mutex);
+}