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, 358 insertions, 0 deletions

diff --git a/drivers/net/phy/lxt.c b/drivers/net/phy/lxt.c
new file mode 100644
index 000000000..5251a61c8
--- /dev/null
+++ b/drivers/net/phy/lxt.c
@@ -0,0 +1,358 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * drivers/net/phy/lxt.c
+ *
+ * Driver for Intel LXT PHYs
+ *
+ * Author: Andy Fleming
+ *
+ * Copyright (c) 2004 Freescale Semiconductor, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mii.h>
+#include <linux/ethtool.h>
+#include <linux/phy.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <linux/uaccess.h>
+
+/* The Level one LXT970 is used by many boards				     */
+
+#define MII_LXT970_IER       17  /* Interrupt Enable Register */
+
+#define MII_LXT970_IER_IEN	0x0002
+
+#define MII_LXT970_ISR       18  /* Interrupt Status Register */
+
+#define MII_LXT970_IRS_MINT  BIT(15)
+
+#define MII_LXT970_CONFIG    19  /* Configuration Register    */
+
+/* ------------------------------------------------------------------------- */
+/* The Level one LXT971 is used on some of my custom boards                  */
+
+/* register definitions for the 971 */
+#define MII_LXT971_IER		18  /* Interrupt Enable Register */
+#define MII_LXT971_IER_IEN	0x00f2
+
+#define MII_LXT971_ISR		19  /* Interrupt Status Register */
+#define MII_LXT971_ISR_MASK	0x00f0
+
+/* register definitions for the 973 */
+#define MII_LXT973_PCR 16 /* Port Configuration Register */
+#define PCR_FIBER_SELECT 1
+
+MODULE_DESCRIPTION("Intel LXT PHY driver");
+MODULE_AUTHOR("Andy Fleming");
+MODULE_LICENSE("GPL");
+
+static int lxt970_ack_interrupt(struct phy_device *phydev)
+{
+	int err;
+
+	err = phy_read(phydev, MII_BMSR);
+
+	if (err < 0)
+		return err;
+
+	err = phy_read(phydev, MII_LXT970_ISR);
+
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int lxt970_config_intr(struct phy_device *phydev)
+{
+	int err;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		err = lxt970_ack_interrupt(phydev);
+		if (err)
+			return err;
+
+		err = phy_write(phydev, MII_LXT970_IER, MII_LXT970_IER_IEN);
+	} else {
+		err = phy_write(phydev, MII_LXT970_IER, 0);
+		if (err)
+			return err;
+
+		err = lxt970_ack_interrupt(phydev);
+	}
+
+	return err;
+}
+
+static irqreturn_t lxt970_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	/* The interrupt status register is cleared by reading BMSR
+	 * followed by MII_LXT970_ISR
+	 */
+	irq_status = phy_read(phydev, MII_BMSR);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	irq_status = phy_read(phydev, MII_LXT970_ISR);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_status & MII_LXT970_IRS_MINT))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+static int lxt970_config_init(struct phy_device *phydev)
+{
+	return phy_write(phydev, MII_LXT970_CONFIG, 0);
+}
+
+
+static int lxt971_ack_interrupt(struct phy_device *phydev)
+{
+	int err = phy_read(phydev, MII_LXT971_ISR);
+
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int lxt971_config_intr(struct phy_device *phydev)
+{
+	int err;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		err = lxt971_ack_interrupt(phydev);
+		if (err)
+			return err;
+
+		err = phy_write(phydev, MII_LXT971_IER, MII_LXT971_IER_IEN);
+	} else {
+		err = phy_write(phydev, MII_LXT971_IER, 0);
+		if (err)
+			return err;
+
+		err = lxt971_ack_interrupt(phydev);
+	}
+
+	return err;
+}
+
+static irqreturn_t lxt971_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	irq_status = phy_read(phydev, MII_LXT971_ISR);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_status & MII_LXT971_ISR_MASK))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * A2 version of LXT973 chip has an ERRATA: it randomly return the contents
+ * of the previous even register when you read a odd register regularly
+ */
+
+static int lxt973a2_update_link(struct phy_device *phydev)
+{
+	int status;
+	int control;
+	int retry = 8; /* we try 8 times */
+
+	/* Do a fake read */
+	status = phy_read(phydev, MII_BMSR);
+
+	if (status < 0)
+		return status;
+
+	control = phy_read(phydev, MII_BMCR);
+	if (control < 0)
+		return control;
+
+	do {
+		/* Read link and autonegotiation status */
+		status = phy_read(phydev, MII_BMSR);
+	} while (status >= 0 && retry-- && status == control);
+
+	if (status < 0)
+		return status;
+
+	if ((status & BMSR_LSTATUS) == 0)
+		phydev->link = 0;
+	else
+		phydev->link = 1;
+
+	return 0;
+}
+
+static int lxt973a2_read_status(struct phy_device *phydev)
+{
+	int adv;
+	int err;
+	int lpa;
+
+	/* Update the link, but return if there was an error */
+	err = lxt973a2_update_link(phydev);
+	if (err)
+		return err;
+
+	if (AUTONEG_ENABLE == phydev->autoneg) {
+		int retry = 1;
+
+		adv = phy_read(phydev, MII_ADVERTISE);
+
+		if (adv < 0)
+			return adv;
+
+		do {
+			lpa = phy_read(phydev, MII_LPA);
+
+			if (lpa < 0)
+				return lpa;
+
+			/* If both registers are equal, it is suspect but not
+			 * impossible, hence a new try
+			 */
+		} while (lpa == adv && retry--);
+
+		mii_lpa_to_linkmode_lpa_t(phydev->lp_advertising, lpa);
+
+		lpa &= adv;
+
+		phydev->speed = SPEED_10;
+		phydev->duplex = DUPLEX_HALF;
+		phydev->pause = phydev->asym_pause = 0;
+
+		if (lpa & (LPA_100FULL | LPA_100HALF)) {
+			phydev->speed = SPEED_100;
+
+			if (lpa & LPA_100FULL)
+				phydev->duplex = DUPLEX_FULL;
+		} else {
+			if (lpa & LPA_10FULL)
+				phydev->duplex = DUPLEX_FULL;
+		}
+
+		phy_resolve_aneg_pause(phydev);
+	} else {
+		err = genphy_read_status_fixed(phydev);
+		if (err < 0)
+			return err;
+
+		phydev->pause = phydev->asym_pause = 0;
+		linkmode_zero(phydev->lp_advertising);
+	}
+
+	return 0;
+}
+
+static int lxt973_probe(struct phy_device *phydev)
+{
+	int val = phy_read(phydev, MII_LXT973_PCR);
+
+	if (val & PCR_FIBER_SELECT) {
+		/*
+		 * If fiber is selected, then the only correct setting
+		 * is 100Mbps, full duplex, and auto negotiation off.
+		 */
+		val = phy_read(phydev, MII_BMCR);
+		val |= (BMCR_SPEED100 | BMCR_FULLDPLX);
+		val &= ~BMCR_ANENABLE;
+		phy_write(phydev, MII_BMCR, val);
+		/* Remember that the port is in fiber mode. */
+		phydev->priv = lxt973_probe;
+		phydev->port = PORT_FIBRE;
+	} else {
+		phydev->priv = NULL;
+	}
+	return 0;
+}
+
+static int lxt973_config_aneg(struct phy_device *phydev)
+{
+	/* Do nothing if port is in fiber mode. */
+	return phydev->priv ? 0 : genphy_config_aneg(phydev);
+}
+
+static struct phy_driver lxt97x_driver[] = {
+{
+	.phy_id		= 0x78100000,
+	.name		= "LXT970",
+	.phy_id_mask	= 0xfffffff0,
+	/* PHY_BASIC_FEATURES */
+	.config_init	= lxt970_config_init,
+	.config_intr	= lxt970_config_intr,
+	.handle_interrupt = lxt970_handle_interrupt,
+}, {
+	.phy_id		= 0x001378e0,
+	.name		= "LXT971",
+	.phy_id_mask	= 0xfffffff0,
+	/* PHY_BASIC_FEATURES */
+	.config_intr	= lxt971_config_intr,
+	.handle_interrupt = lxt971_handle_interrupt,
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+}, {
+	.phy_id		= 0x00137a10,
+	.name		= "LXT973-A2",
+	.phy_id_mask	= 0xffffffff,
+	/* PHY_BASIC_FEATURES */
+	.flags		= 0,
+	.probe		= lxt973_probe,
+	.config_aneg	= lxt973_config_aneg,
+	.read_status	= lxt973a2_read_status,
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+}, {
+	.phy_id		= 0x00137a10,
+	.name		= "LXT973",
+	.phy_id_mask	= 0xfffffff0,
+	/* PHY_BASIC_FEATURES */
+	.flags		= 0,
+	.probe		= lxt973_probe,
+	.config_aneg	= lxt973_config_aneg,
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+} };
+
+module_phy_driver(lxt97x_driver);
+
+static const struct mdio_device_id __maybe_unused lxt_tbl[] = {
+	{ 0x78100000, 0xfffffff0 },
+	{ 0x001378e0, 0xfffffff0 },
+	{ 0x00137a10, 0xfffffff0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(mdio, lxt_tbl);