From 4afca954622d672ea65ed961bed01cf91caa034e Mon Sep 17 00:00:00 2001 From: Abdurrahman Hussain Date: Fri, 15 May 2026 15:11:49 -0700 Subject: [PATCH] hwmon: (pmbus/adm1266) reject implausible blackbox record_count adm1266_nvmem_read_blackbox() loops over a record_count that comes straight from byte 3 of the BLACKBOX_INFO response. The destination buffer is data->dev_mem, sized for the nvmem cell's declared 2048 bytes (ADM1266_BLACKBOX_MAX_RECORDS * ADM1266_BLACKBOX_SIZE = 32 * 64). A device that reports a record_count greater than 32 -- whether due to firmware bugs, bus corruption, or a non-responsive slave returning 0xff -- would walk read_buff past the end of the dev_mem allocation on the trailing iterations. Cap record_count at ADM1266_BLACKBOX_MAX_RECORDS (introduced here) before entering the loop and return -EIO on any larger value, so a malformed BLACKBOX_INFO response cannot drive the loop out of bounds. 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-v1-3-1c1ea1349cfe@nexthop.ai Signed-off-by: Guenter Roeck --- drivers/hwmon/pmbus/adm1266.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c index 94691dec1359..43d9e7407795 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -46,6 +46,7 @@ #define ADM1266_BLACKBOX_OFFSET 0 #define ADM1266_BLACKBOX_SIZE 64 +#define ADM1266_BLACKBOX_MAX_RECORDS 32 #define ADM1266_PMBUS_BLOCK_MAX 255 @@ -360,6 +361,8 @@ static int adm1266_nvmem_read_blackbox(struct adm1266_data *data, u8 *read_buff) return -EIO; record_count = buf[3]; + if (record_count > ADM1266_BLACKBOX_MAX_RECORDS) + return -EIO; for (index = 0; index < record_count; index++) { ret = adm1266_pmbus_block_xfer(data, ADM1266_READ_BLACKBOX, 1, &index, read_buff);