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, 39 insertions, 0 deletions

diff --git a/drivers/net/phy/phylib.h b/drivers/net/phy/phylib.h
new file mode 100644
index 000000000..0fba245f9
--- /dev/null
+++ b/drivers/net/phy/phylib.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phylib header
+ */
+
+#ifndef __PHYLIB_H
+#define __PHYLIB_H
+
+struct device_node;
+struct phy_device;
+struct mii_bus;
+
+struct device_node *phy_package_get_node(struct phy_device *phydev);
+void *phy_package_get_priv(struct phy_device *phydev);
+int __phy_package_read(struct phy_device *phydev, unsigned int addr_offset,
+		       u32 regnum);
+int __phy_package_write(struct phy_device *phydev, unsigned int addr_offset,
+			u32 regnum, u16 val);
+int __phy_package_read_mmd(struct phy_device *phydev,
+			   unsigned int addr_offset, int devad,
+			   u32 regnum);
+int __phy_package_write_mmd(struct phy_device *phydev,
+			    unsigned int addr_offset, int devad,
+			    u32 regnum, u16 val);
+bool phy_package_init_once(struct phy_device *phydev);
+bool phy_package_probe_once(struct phy_device *phydev);
+int phy_package_join(struct phy_device *phydev, int base_addr, size_t priv_size);
+int of_phy_package_join(struct phy_device *phydev, size_t priv_size);
+void phy_package_leave(struct phy_device *phydev);
+int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
+			  int base_addr, size_t priv_size);
+int devm_of_phy_package_join(struct device *dev, struct phy_device *phydev,
+			     size_t priv_size);
+int mmd_phy_read(struct mii_bus *bus, int phy_addr, bool is_c45,
+		 int devad, u32 regnum);
+int mmd_phy_write(struct mii_bus *bus, int phy_addr, bool is_c45,
+		  int devad, u32 regnum, u16 val);
+
+#endif /* __PHYLIB_H */