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, 168 insertions, 0 deletions

diff --git a/drivers/net/phy/dp83848.c b/drivers/net/phy/dp83848.c
new file mode 100644
index 000000000..d88b1999d
--- /dev/null
+++ b/drivers/net/phy/dp83848.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the Texas Instruments DP83848 PHY
+ *
+ * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define TI_DP83848C_PHY_ID		0x20005ca0
+#define TI_DP83620_PHY_ID		0x20005ce0
+#define NS_DP83848C_PHY_ID		0x20005c90
+#define TLK10X_PHY_ID			0x2000a210
+
+/* Registers */
+#define DP83848_MICR			0x11 /* MII Interrupt Control Register */
+#define DP83848_MISR			0x12 /* MII Interrupt Status Register */
+
+/* MICR Register Fields */
+#define DP83848_MICR_INT_OE		BIT(0) /* Interrupt Output Enable */
+#define DP83848_MICR_INTEN		BIT(1) /* Interrupt Enable */
+
+/* MISR Register Fields */
+#define DP83848_MISR_RHF_INT_EN		BIT(0) /* Receive Error Counter */
+#define DP83848_MISR_FHF_INT_EN		BIT(1) /* False Carrier Counter */
+#define DP83848_MISR_ANC_INT_EN		BIT(2) /* Auto-negotiation complete */
+#define DP83848_MISR_DUP_INT_EN		BIT(3) /* Duplex Status */
+#define DP83848_MISR_SPD_INT_EN		BIT(4) /* Speed status */
+#define DP83848_MISR_LINK_INT_EN	BIT(5) /* Link status */
+#define DP83848_MISR_ED_INT_EN		BIT(6) /* Energy detect */
+#define DP83848_MISR_LQM_INT_EN		BIT(7) /* Link Quality Monitor */
+
+#define DP83848_INT_EN_MASK		\
+	(DP83848_MISR_ANC_INT_EN |	\
+	 DP83848_MISR_DUP_INT_EN |	\
+	 DP83848_MISR_SPD_INT_EN |	\
+	 DP83848_MISR_LINK_INT_EN)
+
+#define DP83848_MISR_RHF_INT		BIT(8)
+#define DP83848_MISR_FHF_INT		BIT(9)
+#define DP83848_MISR_ANC_INT		BIT(10)
+#define DP83848_MISR_DUP_INT		BIT(11)
+#define DP83848_MISR_SPD_INT		BIT(12)
+#define DP83848_MISR_LINK_INT		BIT(13)
+#define DP83848_MISR_ED_INT		BIT(14)
+
+#define DP83848_INT_MASK		\
+	(DP83848_MISR_ANC_INT |	\
+	 DP83848_MISR_DUP_INT |	\
+	 DP83848_MISR_SPD_INT |	\
+	 DP83848_MISR_LINK_INT)
+
+static int dp83848_ack_interrupt(struct phy_device *phydev)
+{
+	int err = phy_read(phydev, DP83848_MISR);
+
+	return err < 0 ? err : 0;
+}
+
+static int dp83848_config_intr(struct phy_device *phydev)
+{
+	int control, ret;
+
+	control = phy_read(phydev, DP83848_MICR);
+	if (control < 0)
+		return control;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		ret = dp83848_ack_interrupt(phydev);
+		if (ret)
+			return ret;
+
+		control |= DP83848_MICR_INT_OE;
+		control |= DP83848_MICR_INTEN;
+
+		ret = phy_write(phydev, DP83848_MISR, DP83848_INT_EN_MASK);
+		if (ret < 0)
+			return ret;
+
+		ret = phy_write(phydev, DP83848_MICR, control);
+	} else {
+		control &= ~DP83848_MICR_INTEN;
+		ret = phy_write(phydev, DP83848_MICR, control);
+		if (ret)
+			return ret;
+
+		ret = dp83848_ack_interrupt(phydev);
+	}
+
+	return ret;
+}
+
+static irqreturn_t dp83848_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	irq_status = phy_read(phydev, DP83848_MISR);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_status & DP83848_INT_MASK))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+static int dp83848_config_init(struct phy_device *phydev)
+{
+	int val;
+
+	/* DP83620 always reports Auto Negotiation Ability on BMSR. Instead,
+	 * we check initial value of BMCR Auto negotiation enable bit
+	 */
+	val = phy_read(phydev, MII_BMCR);
+	if (!(val & BMCR_ANENABLE))
+		phydev->autoneg = AUTONEG_DISABLE;
+
+	return 0;
+}
+
+static const struct mdio_device_id __maybe_unused dp83848_tbl[] = {
+	{ TI_DP83848C_PHY_ID, 0xfffffff0 },
+	{ NS_DP83848C_PHY_ID, 0xfffffff0 },
+	{ TI_DP83620_PHY_ID, 0xfffffff0 },
+	{ TLK10X_PHY_ID, 0xfffffff0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(mdio, dp83848_tbl);
+
+#define DP83848_PHY_DRIVER(_id, _name, _config_init)		\
+	{							\
+		.phy_id		= _id,				\
+		.phy_id_mask	= 0xfffffff0,			\
+		.name		= _name,			\
+		/* PHY_BASIC_FEATURES */			\
+								\
+		.soft_reset	= genphy_soft_reset,		\
+		.config_init	= _config_init,			\
+		.suspend	= genphy_suspend,		\
+		.resume		= genphy_resume,		\
+								\
+		/* IRQ related */				\
+		.config_intr	= dp83848_config_intr,		\
+		.handle_interrupt = dp83848_handle_interrupt,	\
+								\
+		.flags		= PHY_RST_AFTER_CLK_EN,		\
+	}
+
+static struct phy_driver dp83848_driver[] = {
+	DP83848_PHY_DRIVER(TI_DP83848C_PHY_ID, "TI DP83848C 10/100 Mbps PHY",
+			   NULL),
+	DP83848_PHY_DRIVER(NS_DP83848C_PHY_ID, "NS DP83848C 10/100 Mbps PHY",
+			   NULL),
+	DP83848_PHY_DRIVER(TI_DP83620_PHY_ID, "TI DP83620 10/100 Mbps PHY",
+			   dp83848_config_init),
+	DP83848_PHY_DRIVER(TLK10X_PHY_ID, "TI TLK10X 10/100 Mbps PHY",
+			   NULL),
+};
+module_phy_driver(dp83848_driver);
+
+MODULE_DESCRIPTION("Texas Instruments DP83848 PHY driver");
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_LICENSE("GPL v2");