From eee213daa1e1b402eb631bcd1b8c5aa340a6b081 Mon Sep 17 00:00:00 2001 From: Abdurrahman Hussain Date: Fri, 15 May 2026 15:11:48 -0700 Subject: [PATCH] hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX adm1266_nvmem_read_blackbox() declares a 5-byte stack buffer and passes it to i2c_smbus_read_block_data() to retrieve the 4-byte BLACKBOX_INFO response. i2c_smbus_read_block_data() does not honour caller buffer sizes -- it memcpy()s data.block[0] bytes from the SMBus transaction (where data.block[0] is the length byte returned by the slave device, up to I2C_SMBUS_BLOCK_MAX = 32): memcpy(values, &data.block[1], data.block[0]); If the device returns any block length above 5, the call overflows the caller's 5-byte stack buffer before the post-call if (ret != 4) return -EIO; check has a chance to reject the response. Widen the local buffer to I2C_SMBUS_BLOCK_MAX so the helper has room for any well-formed SMBus block response, matching the convention used by the other i2c_smbus_read_block_data() callers in this driver. Fixes: 15609d189302 ("hwmon: (pmbus/adm1266) read blackbox") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Link: https://lore.kernel.org/r/20260515-adm1266-fixes-v1-2-1c1ea1349cfe@nexthop.ai Signed-off-by: Guenter Roeck --- drivers/hwmon/pmbus/adm1266.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c index a86666c73a5e..94691dec1359 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -349,7 +349,7 @@ static int adm1266_nvmem_read_blackbox(struct adm1266_data *data, u8 *read_buff) { int record_count; char index; - u8 buf[5]; + u8 buf[I2C_SMBUS_BLOCK_MAX]; int ret; ret = i2c_smbus_read_block_data(data->client, ADM1266_BLACKBOX_INFO, buf);