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, 70 insertions, 0 deletions

diff --git a/drivers/net/phy/phy-caps.h b/drivers/net/phy/phy-caps.h
new file mode 100644
index 000000000..421088e6f
--- /dev/null
+++ b/drivers/net/phy/phy-caps.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * link caps internal header, for link modes <-> capabilities <-> interfaces
+ * conversions.
+ */
+
+#ifndef __PHY_CAPS_H
+#define __PHY_CAPS_H
+
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+
+enum {
+	LINK_CAPA_10HD = 0,
+	LINK_CAPA_10FD,
+	LINK_CAPA_100HD,
+	LINK_CAPA_100FD,
+	LINK_CAPA_1000HD,
+	LINK_CAPA_1000FD,
+	LINK_CAPA_2500FD,
+	LINK_CAPA_5000FD,
+	LINK_CAPA_10000FD,
+	LINK_CAPA_20000FD,
+	LINK_CAPA_25000FD,
+	LINK_CAPA_40000FD,
+	LINK_CAPA_50000FD,
+	LINK_CAPA_56000FD,
+	LINK_CAPA_80000FD,
+	LINK_CAPA_100000FD,
+	LINK_CAPA_200000FD,
+	LINK_CAPA_400000FD,
+	LINK_CAPA_800000FD,
+	LINK_CAPA_1600000FD,
+
+	__LINK_CAPA_MAX,
+};
+
+#define LINK_CAPA_ALL	GENMASK((__LINK_CAPA_MAX - 1), 0)
+
+struct link_capabilities {
+	int speed;
+	unsigned int duplex;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(linkmodes);
+};
+
+int __init phy_caps_init(void);
+
+size_t phy_caps_speeds(unsigned int *speeds, size_t size,
+		       unsigned long *linkmodes);
+void phy_caps_linkmode_max_speed(u32 max_speed, unsigned long *linkmodes);
+bool phy_caps_valid(int speed, int duplex, const unsigned long *linkmodes);
+void phy_caps_linkmodes(unsigned long caps, unsigned long *linkmodes);
+unsigned long phy_caps_from_interface(phy_interface_t interface);
+
+const struct link_capabilities *
+phy_caps_lookup_by_linkmode(const unsigned long *linkmodes);
+
+const struct link_capabilities *
+phy_caps_lookup_by_linkmode_rev(const unsigned long *linkmodes, bool fdx_only);
+
+const struct link_capabilities *
+phy_caps_lookup(int speed, unsigned int duplex, const unsigned long *supported,
+		bool exact);
+
+void phy_caps_medium_get_supported(unsigned long *supported,
+				   enum ethtool_link_medium medium,
+				   int lanes);
+u32 phy_caps_mediums_from_linkmodes(unsigned long *linkmodes);
+
+#endif /* __PHY_CAPS_H */