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, 29 insertions, 0 deletions

diff --git a/net/wireless/ethtool.c b/net/wireless/ethtool.c
new file mode 100644
index 000000000..46e4317cb
--- /dev/null
+++ b/net/wireless/ethtool.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/utsname.h>
+#include <net/cfg80211.h>
+#include "core.h"
+#include "rdev-ops.h"
+
+void cfg80211_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct device *pdev = wiphy_dev(wdev->wiphy);
+
+	if (pdev->driver)
+		strscpy(info->driver, pdev->driver->name,
+			sizeof(info->driver));
+	else
+		strscpy(info->driver, "N/A", sizeof(info->driver));
+
+	strscpy(info->version, init_utsname()->release, sizeof(info->version));
+
+	if (wdev->wiphy->fw_version[0])
+		strscpy(info->fw_version, wdev->wiphy->fw_version,
+			sizeof(info->fw_version));
+	else
+		strscpy(info->fw_version, "N/A", sizeof(info->fw_version));
+
+	strscpy(info->bus_info, dev_name(pdev),
+		sizeof(info->bus_info));
+}
+EXPORT_SYMBOL(cfg80211_get_drvinfo);