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, 359 insertions, 0 deletions

diff --git a/drivers/misc/keba/lan9252.c b/drivers/misc/keba/lan9252.c
new file mode 100644
index 000000000..fc54afd1d
--- /dev/null
+++ b/drivers/misc/keba/lan9252.c
@@ -0,0 +1,359 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) KEBA Industrial Automation Gmbh 2024
+ *
+ * Driver for LAN9252 on KEBA CP500 devices
+ *
+ * This driver is used for updating the configuration of the LAN9252 controller
+ * on KEBA CP500 devices. The LAN9252 is connected over SPI, which is also named
+ * PDI.
+ */
+
+#include <linux/spi/spi.h>
+#include <linux/mii.h>
+
+/* SPI commands */
+#define LAN9252_SPI_READ	0x3
+#define LAN9252_SPI_WRITE	0x2
+
+struct lan9252_read_cmd {
+	u8 cmd;
+	u8 addr_0;
+	u8 addr_1;
+} __packed;
+
+struct lan9252_write_cmd {
+	u8 cmd;
+	u8 addr_0;
+	u8 addr_1;
+	u32 data;
+} __packed;
+
+/* byte test register */
+#define LAN9252_BYTE_TEST		0x64
+#define   LAN9252_BYTE_TEST_VALUE	0x87654321
+
+/* hardware configuration register */
+#define LAN9252_HW_CFG		0x74
+#define   LAN9252_HW_CFG_READY	0x08000000
+
+/* EtherCAT CSR interface data register */
+#define LAN9252_ECAT_CSR_DATA	0x300
+
+/* EtherCAT CSR interface command register */
+#define LAN9252_ECAT_CSR_CMD	0x304
+#define   LAN9252_ECAT_CSR_BUSY	0x80000000
+#define   LAN9252_ECAT_CSR_READ	0x40000000
+
+/* EtherCAT slave controller MII register */
+#define LAN9252_ESC_MII			0x510
+#define   LAN9252_ESC_MII_BUSY		0x8000
+#define   LAN9252_ESC_MII_CMD_ERR	0x4000
+#define   LAN9252_ESC_MII_READ_ERR	0x2000
+#define   LAN9252_ESC_MII_ERR_MASK	(LAN9252_ESC_MII_CMD_ERR | \
+					 LAN9252_ESC_MII_READ_ERR)
+#define   LAN9252_ESC_MII_WRITE		0x0200
+#define   LAN9252_ESC_MII_READ		0x0100
+
+/* EtherCAT slave controller PHY address register */
+#define LAN9252_ESC_PHY_ADDR		0x512
+
+/* EtherCAT slave controller PHY register address register */
+#define LAN9252_ESC_PHY_REG_ADDR	0x513
+
+/* EtherCAT slave controller PHY data register */
+#define LAN9252_ESC_PHY_DATA		0x514
+
+/* EtherCAT slave controller PDI access state register */
+#define LAN9252_ESC_MII_PDI		0x517
+#define   LAN9252_ESC_MII_ACCESS_PDI	0x01
+#define   LAN9252_ESC_MII_ACCESS_ECAT	0x00
+
+/* PHY address */
+#define PHY_ADDRESS	2
+
+#define SPI_RETRY_COUNT		10
+#define SPI_WAIT_US		100
+#define SPI_CSR_WAIT_US		500
+
+static int lan9252_spi_read(struct spi_device *spi, u16 addr, u32 *data)
+{
+	struct lan9252_read_cmd cmd;
+
+	cmd.cmd = LAN9252_SPI_READ;
+	cmd.addr_0 = (addr >> 8) & 0xFF;
+	cmd.addr_1 = addr & 0xFF;
+
+	return spi_write_then_read(spi, (u8 *)&cmd,
+				   sizeof(struct lan9252_read_cmd),
+				   (u8 *)data, sizeof(u32));
+}
+
+static int lan9252_spi_write(struct spi_device *spi, u16 addr, u32 data)
+{
+	struct lan9252_write_cmd cmd;
+
+	cmd.cmd = LAN9252_SPI_WRITE;
+	cmd.addr_0 = (addr >> 8) & 0xFF;
+	cmd.addr_1 = addr & 0xFF;
+	cmd.data = data;
+
+	return spi_write(spi, (u8 *)&cmd, sizeof(struct lan9252_write_cmd));
+}
+
+static bool lan9252_init(struct spi_device *spi)
+{
+	u32 data;
+	int ret;
+
+	ret = lan9252_spi_read(spi, LAN9252_BYTE_TEST, &data);
+	if (ret || data != LAN9252_BYTE_TEST_VALUE)
+		return false;
+
+	ret = lan9252_spi_read(spi, LAN9252_HW_CFG, &data);
+	if (ret || !(data & LAN9252_HW_CFG_READY))
+		return false;
+
+	return true;
+}
+
+static u8 lan9252_esc_get_size(u16 addr)
+{
+	if (addr == LAN9252_ESC_MII || addr == LAN9252_ESC_PHY_DATA)
+		return 2;
+
+	return 1;
+}
+
+static int lan9252_esc_wait(struct spi_device *spi)
+{
+	ktime_t timeout = ktime_add_us(ktime_get(), SPI_WAIT_US);
+	u32 data;
+	int ret;
+
+	/* wait while CSR command is busy */
+	for (;;) {
+		ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_CMD, &data);
+		if (ret)
+			return ret;
+		if (!(data & LAN9252_ECAT_CSR_BUSY))
+			return 0;
+
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_CMD, &data);
+			if (ret)
+				return ret;
+			break;
+		}
+	}
+
+	return (!(data & LAN9252_ECAT_CSR_BUSY)) ? 0 : -ETIMEDOUT;
+}
+
+static int lan9252_esc_read(struct spi_device *spi, u16 addr, u32 *data)
+{
+	u32 csr_cmd;
+	u8 size;
+	int ret;
+
+	size = lan9252_esc_get_size(addr);
+	csr_cmd = LAN9252_ECAT_CSR_BUSY | LAN9252_ECAT_CSR_READ;
+	csr_cmd |= (size << 16) | addr;
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_CMD, csr_cmd);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_wait(spi);
+	if (ret)
+		return ret;
+
+	ret = lan9252_spi_read(spi, LAN9252_ECAT_CSR_DATA, data);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int lan9252_esc_write(struct spi_device *spi, u16 addr, u32 data)
+{
+	u32 csr_cmd;
+	u8 size;
+	int ret;
+
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_DATA, data);
+	if (ret)
+		return ret;
+
+	size = lan9252_esc_get_size(addr);
+	csr_cmd = LAN9252_ECAT_CSR_BUSY;
+	csr_cmd |= (size << 16) | addr;
+	ret = lan9252_spi_write(spi, LAN9252_ECAT_CSR_CMD, csr_cmd);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_wait(spi);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int lan9252_access_mii(struct spi_device *spi, bool access)
+{
+	u32 data;
+
+	if (access)
+		data = LAN9252_ESC_MII_ACCESS_PDI;
+	else
+		data = LAN9252_ESC_MII_ACCESS_ECAT;
+
+	return lan9252_esc_write(spi, LAN9252_ESC_MII_PDI, data);
+}
+
+static int lan9252_mii_wait(struct spi_device *spi)
+{
+	ktime_t timeout = ktime_add_us(ktime_get(), SPI_CSR_WAIT_US);
+	u32 data;
+	int ret;
+
+	/* wait while MII control state machine is busy */
+	for (;;) {
+		ret = lan9252_esc_read(spi, LAN9252_ESC_MII, &data);
+		if (ret)
+			return ret;
+		if (data & LAN9252_ESC_MII_ERR_MASK)
+			return -EIO;
+		if (!(data & LAN9252_ESC_MII_BUSY))
+			return 0;
+
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			ret = lan9252_esc_read(spi, LAN9252_ESC_MII, &data);
+			if (ret)
+				return ret;
+			if (data & LAN9252_ESC_MII_ERR_MASK)
+				return -EIO;
+			break;
+		}
+	}
+
+	return (!(data & LAN9252_ESC_MII_BUSY)) ? 0 : -ETIMEDOUT;
+}
+
+static int lan9252_mii_read(struct spi_device *spi, u8 phy_addr, u8 reg_addr,
+			    u32 *data)
+{
+	int ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_ADDR, phy_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_REG_ADDR, reg_addr);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_MII, LAN9252_ESC_MII_READ);
+	if (ret)
+		return ret;
+
+	ret = lan9252_mii_wait(spi);
+	if (ret)
+		return ret;
+
+	return lan9252_esc_read(spi, LAN9252_ESC_PHY_DATA, data);
+}
+
+static int lan9252_mii_write(struct spi_device *spi, u8 phy_addr, u8 reg_addr,
+			     u32 data)
+{
+	int ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_ADDR, phy_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_REG_ADDR, reg_addr);
+	if (ret)
+		return ret;
+	ret = lan9252_esc_write(spi, LAN9252_ESC_PHY_DATA, data);
+	if (ret)
+		return ret;
+
+	ret = lan9252_esc_write(spi, LAN9252_ESC_MII, LAN9252_ESC_MII_WRITE);
+	if (ret)
+		return ret;
+
+	return lan9252_mii_wait(spi);
+}
+
+static int lan9252_probe(struct spi_device *spi)
+{
+	u32 data;
+	int retry = SPI_RETRY_COUNT;
+	int ret;
+
+	/* execute specified initialization sequence */
+	while (retry && !lan9252_init(spi))
+		retry--;
+	if (retry == 0) {
+		dev_err(&spi->dev,
+			"Can't initialize LAN9252 SPI communication!");
+		return -EIO;
+	}
+
+	/* enable access to MII management for PDI */
+	ret = lan9252_access_mii(spi, true);
+	if (ret) {
+		dev_err(&spi->dev, "Can't enable access to MII management!");
+		return ret;
+	}
+
+	/*
+	 * check PHY configuration and configure if necessary
+	 *	- full duplex
+	 *	- auto negotiation disabled
+	 *	- 100 Mbps
+	 */
+	ret = lan9252_mii_read(spi, PHY_ADDRESS, MII_BMCR, &data);
+	if (ret) {
+		dev_err(&spi->dev, "Can't read LAN9252 configuration!");
+		goto out;
+	}
+	if (!(data & BMCR_FULLDPLX) || (data & BMCR_ANENABLE) ||
+	    !(data & BMCR_SPEED100)) {
+		/*
+		 */
+		data &= ~(BMCR_ANENABLE);
+		data |= (BMCR_FULLDPLX | BMCR_SPEED100);
+		ret = lan9252_mii_write(spi, PHY_ADDRESS, MII_BMCR, data);
+		if (ret)
+			dev_err(&spi->dev,
+				"Can't write LAN9252 configuration!");
+	}
+
+	dev_info(&spi->dev, "LAN9252 PHY configuration");
+
+out:
+	/* disable access to MII management for PDI */
+	lan9252_access_mii(spi, false);
+
+	return ret;
+}
+
+static const struct spi_device_id lan9252_id[] = {
+	{"lan9252"},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, lan9252_id);
+
+static struct spi_driver lan9252_driver = {
+	.driver = {
+		.name	= "lan9252",
+	},
+	.probe		= lan9252_probe,
+	.id_table	= lan9252_id,
+};
+module_spi_driver(lan9252_driver);
+
+MODULE_AUTHOR("Petar Bojanic <boja@keba.com>");
+MODULE_AUTHOR("Gerhard Engleder <eg@keba.com>");
+MODULE_DESCRIPTION("KEBA LAN9252 driver");
+MODULE_LICENSE("GPL");