openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 193 insertions, 0 deletions

diff --git a/drivers/bluetooth/btmrvl_debugfs.c b/drivers/bluetooth/btmrvl_debugfs.c
new file mode 100644
index 000000000..9b3e768c0
--- /dev/null
+++ b/drivers/bluetooth/btmrvl_debugfs.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Marvell Bluetooth driver: debugfs related functions
+ *
+ * Copyright (C) 2009, Marvell International Ltd.
+ **/
+
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "btmrvl_drv.h"
+
+struct btmrvl_debugfs_data {
+	struct dentry *config_dir;
+	struct dentry *status_dir;
+};
+
+static ssize_t btmrvl_hscfgcmd_write(struct file *file,
+			const char __user *ubuf, size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	long result, ret;
+
+	ret = kstrtol_from_user(ubuf, count, 10, &result);
+	if (ret)
+		return ret;
+
+	priv->btmrvl_dev.hscfgcmd = result;
+
+	if (priv->btmrvl_dev.hscfgcmd) {
+		btmrvl_prepare_command(priv);
+		wake_up_interruptible(&priv->main_thread.wait_q);
+	}
+
+	return count;
+}
+
+static ssize_t btmrvl_hscfgcmd_read(struct file *file, char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	char buf[16];
+	int ret;
+
+	ret = snprintf(buf, sizeof(buf) - 1, "%d\n",
+						priv->btmrvl_dev.hscfgcmd);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
+}
+
+static const struct file_operations btmrvl_hscfgcmd_fops = {
+	.read	= btmrvl_hscfgcmd_read,
+	.write	= btmrvl_hscfgcmd_write,
+	.open	= simple_open,
+	.llseek = default_llseek,
+};
+
+static ssize_t btmrvl_pscmd_write(struct file *file, const char __user *ubuf,
+						size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	long result, ret;
+
+	ret = kstrtol_from_user(ubuf, count, 10, &result);
+	if (ret)
+		return ret;
+
+	priv->btmrvl_dev.pscmd = result;
+
+	if (priv->btmrvl_dev.pscmd) {
+		btmrvl_prepare_command(priv);
+		wake_up_interruptible(&priv->main_thread.wait_q);
+	}
+
+	return count;
+
+}
+
+static ssize_t btmrvl_pscmd_read(struct file *file, char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	char buf[16];
+	int ret;
+
+	ret = snprintf(buf, sizeof(buf) - 1, "%d\n", priv->btmrvl_dev.pscmd);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
+}
+
+static const struct file_operations btmrvl_pscmd_fops = {
+	.read = btmrvl_pscmd_read,
+	.write = btmrvl_pscmd_write,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
+static ssize_t btmrvl_hscmd_write(struct file *file, const char __user *ubuf,
+						size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	long result, ret;
+
+	ret = kstrtol_from_user(ubuf, count, 10, &result);
+	if (ret)
+		return ret;
+
+	priv->btmrvl_dev.hscmd = result;
+	if (priv->btmrvl_dev.hscmd) {
+		btmrvl_prepare_command(priv);
+		wake_up_interruptible(&priv->main_thread.wait_q);
+	}
+
+	return count;
+}
+
+static ssize_t btmrvl_hscmd_read(struct file *file, char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	struct btmrvl_private *priv = file->private_data;
+	char buf[16];
+	int ret;
+
+	ret = snprintf(buf, sizeof(buf) - 1, "%d\n", priv->btmrvl_dev.hscmd);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
+}
+
+static const struct file_operations btmrvl_hscmd_fops = {
+	.read	= btmrvl_hscmd_read,
+	.write	= btmrvl_hscmd_write,
+	.open	= simple_open,
+	.llseek = default_llseek,
+};
+
+void btmrvl_debugfs_init(struct hci_dev *hdev)
+{
+	struct btmrvl_private *priv = hci_get_drvdata(hdev);
+	struct btmrvl_debugfs_data *dbg;
+
+	if (!hdev->debugfs)
+		return;
+
+	dbg = kzalloc_obj(*dbg);
+	priv->debugfs_data = dbg;
+
+	if (!dbg) {
+		BT_ERR("Can not allocate memory for btmrvl_debugfs_data.");
+		return;
+	}
+
+	dbg->config_dir = debugfs_create_dir("config", hdev->debugfs);
+
+	debugfs_create_u8("psmode", 0644, dbg->config_dir,
+			  &priv->btmrvl_dev.psmode);
+	debugfs_create_file("pscmd", 0644, dbg->config_dir,
+			    priv, &btmrvl_pscmd_fops);
+	debugfs_create_x16("gpiogap", 0644, dbg->config_dir,
+			   &priv->btmrvl_dev.gpio_gap);
+	debugfs_create_u8("hsmode", 0644, dbg->config_dir,
+			  &priv->btmrvl_dev.hsmode);
+	debugfs_create_file("hscmd", 0644, dbg->config_dir,
+			    priv, &btmrvl_hscmd_fops);
+	debugfs_create_file("hscfgcmd", 0644, dbg->config_dir,
+			    priv, &btmrvl_hscfgcmd_fops);
+
+	dbg->status_dir = debugfs_create_dir("status", hdev->debugfs);
+	debugfs_create_u8("curpsmode", 0444, dbg->status_dir,
+			  &priv->adapter->psmode);
+	debugfs_create_u8("psstate", 0444, dbg->status_dir,
+			  &priv->adapter->ps_state);
+	debugfs_create_u8("hsstate", 0444, dbg->status_dir,
+			  &priv->adapter->hs_state);
+	debugfs_create_u8("txdnldready", 0444, dbg->status_dir,
+			  &priv->btmrvl_dev.tx_dnld_rdy);
+}
+
+void btmrvl_debugfs_remove(struct hci_dev *hdev)
+{
+	struct btmrvl_private *priv = hci_get_drvdata(hdev);
+	struct btmrvl_debugfs_data *dbg = priv->debugfs_data;
+
+	if (!dbg)
+		return;
+
+	debugfs_remove_recursive(dbg->config_dir);
+	debugfs_remove_recursive(dbg->status_dir);
+
+	kfree(dbg);
+}