Merge: at24: fix memory corruption race condition

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4469

JIRA: https://issues.redhat.com/browse/RHEL-37020
CVE: CVE-2024-35848

If the eeprom is not accessible, an nvmem device will be registered, the
read will fail, and the device will be torn down. If another driver
accesses the nvmem device after the teardown, it will reference
invalid memory.

Signed-off-by: Mark Salter <msalter@redhat.com>

Approved-by: Eric Chanudet <echanude@redhat.com>
Approved-by: Andrew Halaney <ahalaney@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Scott Weaver <scweaver@redhat.com>

Author: swvrrh

drivers/misc/eeprom/at24.c

@@ -68,11 +68,6 @@
  * which won't work on pure SMBus systems.
  */
 
-struct at24_client {
-	struct i2c_client *client;
-	struct regmap *regmap;
-};
-
 struct at24_data {
 	/*
 	 * Lock protects against activities from other Linux tasks,
@@ -94,9 +89,10 @@ struct at24_data {
 
 	/*
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
-	 * them for us, and we'll use them with SMBus calls.
+	 * them for us.
 	 */
-	struct at24_client client[];
+	u8 bank_addr_shift;
+	struct regmap *client_regmaps[];
 };
 
 /*
@@ -123,6 +119,7 @@ MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
 struct at24_chip_data {
 	u32 byte_len;
 	u8 flags;
+	u8 bank_addr_shift;
 	void (*read_post)(unsigned int off, char *buf, size_t count);
 };
 
@@ -137,6 +134,12 @@ struct at24_chip_data {
 		.read_post = _read_post,				\
 	}
 
+#define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift)	\
+	static const struct at24_chip_data _name = {			\
+		.byte_len = _len, .flags = _flags,			\
+		.bank_addr_shift = _bank_addr_shift			\
+	}
+
 static void at24_read_post_vaio(unsigned int off, char *buf, size_t count)
 {
 	int i;
@@ -197,6 +200,7 @@ AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA_BS(at24_data_24c1025, 1048576 / 8, AT24_FLAG_ADDR16, 2);
 AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16);
 /* identical to 24c08 ? */
 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
@@ -225,6 +229,7 @@ static const struct i2c_device_id at24_ids[] = {
 	{ "24c256",	(kernel_ulong_t)&at24_data_24c256 },
 	{ "24c512",	(kernel_ulong_t)&at24_data_24c512 },
 	{ "24c1024",	(kernel_ulong_t)&at24_data_24c1024 },
+	{ "24c1025",	(kernel_ulong_t)&at24_data_24c1025 },
 	{ "24c2048",    (kernel_ulong_t)&at24_data_24c2048 },
 	{ "at24",	0 },
 	{ /* END OF LIST */ }
@@ -254,6 +259,7 @@ static const struct of_device_id at24_of_match[] = {
 	{ .compatible = "atmel,24c256",		.data = &at24_data_24c256 },
 	{ .compatible = "atmel,24c512",		.data = &at24_data_24c512 },
 	{ .compatible = "atmel,24c1024",	.data = &at24_data_24c1024 },
+	{ .compatible = "atmel,24c1025",	.data = &at24_data_24c1025 },
 	{ .compatible = "atmel,24c2048",	.data = &at24_data_24c2048 },
 	{ /* END OF LIST */ },
 };
@@ -275,8 +281,8 @@ MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
  * set the byte address; on a multi-master board, another master
  * may have changed the chip's "current" address pointer.
  */
-static struct at24_client *at24_translate_offset(struct at24_data *at24,
-						 unsigned int *offset)
+static struct regmap *at24_translate_offset(struct at24_data *at24,
+					    unsigned int *offset)
 {
 	unsigned int i;
 
@@ -288,12 +294,12 @@ static struct at24_client *at24_translate_offset(struct at24_data *at24,
 		*offset &= 0xff;
 	}
 
-	return &at24->client[i];
+	return at24->client_regmaps[i];
 }
 
 static struct device *at24_base_client_dev(struct at24_data *at24)
 {
-	return &at24->client[0].client->dev;
+	return regmap_get_device(at24->client_regmaps[0]);
 }
 
 static size_t at24_adjust_read_count(struct at24_data *at24,
@@ -324,14 +330,10 @@ static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
 				unsigned int offset, size_t count)
 {
 	unsigned long timeout, read_time;
-	struct at24_client *at24_client;
-	struct i2c_client *client;
 	struct regmap *regmap;
 	int ret;
 
-	at24_client = at24_translate_offset(at24, &offset);
-	regmap = at24_client->regmap;
-	client = at24_client->client;
+	regmap = at24_translate_offset(at24, &offset);
 	count = at24_adjust_read_count(at24, offset, count);
 
 	/* adjust offset for mac and serial read ops */
@@ -346,7 +348,7 @@ static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
 		read_time = jiffies;
 
 		ret = regmap_bulk_read(regmap, offset, buf, count);
-		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
+		dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n",
 			count, offset, ret, jiffies);
 		if (!ret)
 			return count;
@@ -387,14 +389,10 @@ static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
 				 unsigned int offset, size_t count)
 {
 	unsigned long timeout, write_time;
-	struct at24_client *at24_client;
-	struct i2c_client *client;
 	struct regmap *regmap;
 	int ret;
 
-	at24_client = at24_translate_offset(at24, &offset);
-	regmap = at24_client->regmap;
-	client = at24_client->client;
+	regmap = at24_translate_offset(at24, &offset);
 	count = at24_adjust_write_count(at24, offset, count);
 	timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
 
@@ -406,7 +404,7 @@ static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
 		write_time = jiffies;
 
 		ret = regmap_bulk_write(regmap, offset, buf, count);
-		dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n",
+		dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n",
 			count, offset, ret, jiffies);
 		if (!ret)
 			return count;
@@ -538,26 +536,24 @@ static const struct at24_chip_data *at24_get_chip_data(struct device *dev)
 }
 
 static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
+				  struct i2c_client *base_client,
 				  struct regmap_config *regmap_config)
 {
-	struct i2c_client *base_client, *dummy_client;
+	struct i2c_client *dummy_client;
 	struct regmap *regmap;
-	struct device *dev;
-
-	base_client = at24->client[0].client;
-	dev = &base_client->dev;
 
-	dummy_client = devm_i2c_new_dummy_device(dev, base_client->adapter,
-						 base_client->addr + index);
+	dummy_client = devm_i2c_new_dummy_device(&base_client->dev,
+						 base_client->adapter,
+						 base_client->addr +
+						 (index << at24->bank_addr_shift));
 	if (IS_ERR(dummy_client))
 		return PTR_ERR(dummy_client);
 
 	regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
-	at24->client[index].client = dummy_client;
-	at24->client[index].regmap = regmap;
+	at24->client_regmaps[index] = regmap;
 
 	return 0;
 }
@@ -585,6 +581,31 @@ static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
 	}
 }
 
+static void at24_probe_temp_sensor(struct i2c_client *client)
+{
+	struct at24_data *at24 = i2c_get_clientdata(client);
+	struct i2c_board_info info = { .type = "jc42" };
+	int ret;
+	u8 val;
+
+	/*
+	 * Byte 2 has value 11 for DDR3, earlier versions don't
+	 * support the thermal sensor present flag
+	 */
+	ret = at24_read(at24, 2, &val, 1);
+	if (ret || val != 11)
+		return;
+
+	/* Byte 32, bit 7 is set if temp sensor is present */
+	ret = at24_read(at24, 32, &val, 1);
+	if (ret || !(val & BIT(7)))
+		return;
+
+	info.addr = 0x18 | (client->addr & 7);
+
+	i2c_new_client_device(client->adapter, &info);
+}
+
 static int at24_probe(struct i2c_client *client)
 {
 	struct regmap_config regmap_config = { };
@@ -595,6 +616,7 @@ static int at24_probe(struct i2c_client *client)
 	bool i2c_fn_i2c, i2c_fn_block;
 	unsigned int i, num_addresses;
 	struct at24_data *at24;
+	bool full_power;
 	struct regmap *regmap;
 	bool writable;
 	u8 test_byte;
@@ -679,7 +701,7 @@ static int at24_probe(struct i2c_client *client)
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
-	at24 = devm_kzalloc(dev, struct_size(at24, client, num_addresses),
+	at24 = devm_kzalloc(dev, struct_size(at24, client_regmaps, num_addresses),
 			    GFP_KERNEL);
 	if (!at24)
 		return -ENOMEM;
@@ -689,10 +711,10 @@ static int at24_probe(struct i2c_client *client)
 	at24->page_size = page_size;
 	at24->flags = flags;
 	at24->read_post = cdata->read_post;
+	at24->bank_addr_shift = cdata->bank_addr_shift;
 	at24->num_addresses = num_addresses;
 	at24->offset_adj = at24_get_offset_adj(flags, byte_len);
-	at24->client[0].client = client;
-	at24->client[0].regmap = regmap;
+	at24->client_regmaps[0] = regmap;
 
 	at24->vcc_reg = devm_regulator_get(dev, "vcc");
 	if (IS_ERR(at24->vcc_reg))
@@ -708,7 +730,7 @@ static int at24_probe(struct i2c_client *client)
 
 	/* use dummy devices for multiple-address chips */
 	for (i = 1; i < num_addresses; i++) {
-		err = at24_make_dummy_client(at24, i, &regmap_config);
+		err = at24_make_dummy_client(at24, i, client, &regmap_config);
 		if (err)
 			return err;
 	}
@@ -747,35 +769,45 @@ static int at24_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, at24);
 
-	err = regulator_enable(at24->vcc_reg);
-	if (err) {
-		dev_err(dev, "Failed to enable vcc regulator\n");
-		return err;
-	}
+	full_power = acpi_dev_state_d0(&client->dev);
+	if (full_power) {
+		err = regulator_enable(at24->vcc_reg);
+		if (err) {
+			dev_err(dev, "Failed to enable vcc regulator\n");
+			return err;
+		}
 
-	/* enable runtime pm */
-	pm_runtime_set_active(dev);
+		pm_runtime_set_active(dev);
+	}
 	pm_runtime_enable(dev);
 
+	/*
+	 * Perform a one-byte test read to verify that the chip is functional,
+	 * unless powering on the device is to be avoided during probe (i.e.
+	 * it's powered off right now).
+	 */
+	if (full_power) {
+		err = at24_read(at24, 0, &test_byte, 1);
+		if (err) {
+			pm_runtime_disable(dev);
+			if (!pm_runtime_status_suspended(dev))
+				regulator_disable(at24->vcc_reg);
+			return -ENODEV;
+		}
+	}
+
 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
 	if (IS_ERR(at24->nvmem)) {
 		pm_runtime_disable(dev);
 		if (!pm_runtime_status_suspended(dev))
 			regulator_disable(at24->vcc_reg);
-		return PTR_ERR(at24->nvmem);
+		return dev_err_probe(dev, PTR_ERR(at24->nvmem),
+				     "failed to register nvmem\n");
 	}
 
-	/*
-	 * Perform a one-byte test read to verify that the
-	 * chip is functional.
-	 */
-	err = at24_read(at24, 0, &test_byte, 1);
-	if (err) {
-		pm_runtime_disable(dev);
-		if (!pm_runtime_status_suspended(dev))
-			regulator_disable(at24->vcc_reg);
-		return -ENODEV;
-	}
+	/* If this a SPD EEPROM, probe for DDR3 thermal sensor */
+	if (cdata == &at24_data_spd)
+		at24_probe_temp_sensor(client);
 
 	pm_runtime_idle(dev);
 
@@ -794,9 +826,11 @@ static int at24_remove(struct i2c_client *client)
 	struct at24_data *at24 = i2c_get_clientdata(client);
 
 	pm_runtime_disable(&client->dev);
-	if (!pm_runtime_status_suspended(&client->dev))
-		regulator_disable(at24->vcc_reg);
-	pm_runtime_set_suspended(&client->dev);
+	if (acpi_dev_state_d0(&client->dev)) {
+		if (!pm_runtime_status_suspended(&client->dev))
+			regulator_disable(at24->vcc_reg);
+		pm_runtime_set_suspended(&client->dev);
+	}
 
 	return 0;
 }
@@ -833,6 +867,7 @@ static struct i2c_driver at24_driver = {
 	.probe_new = at24_probe,
 	.remove = at24_remove,
 	.id_table = at24_ids,
+	.flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 
 static int __init at24_init(void)