From 3c586354aae65bdbecfab8f8263f48a2c4200c92 Mon Sep 17 00:00:00 2001 From: tuhaowen Date: Wed, 31 Dec 2025 10:46:30 +0800 Subject: [PATCH] udev/scsi_id: increase MAX_SERIAL_LEN from 256 to 512 The current MAX_SERIAL_LEN value of 256 is insufficient for some SCSI devices with non-standard serial number lengths. In do_scsi_page80_inquiry(), the required buffer length is calculated as: len = 1 + VENDOR_LENGTH + MODEL_LENGTH + buf[3] = 1 + 8 + 16 + buf[3] = 25 + buf[3] where buf[3] contains the serial number length reported by the device. According to the SCSI specification, this field is an unsigned 8-bit value, meaning it can theoretically be up to 255 bytes. This results in a maximum required length of 280 bytes, exceeding the current limit of 256 bytes. When this occurs, scsi_id fails with an error message like: "length 256 too short - need 280" This has been observed with certain vendor devices that report unusually long serial numbers in VPD page 0x80. Increase MAX_SERIAL_LEN to 512 to accommodate the maximum possible serial number length plus all required prefixes (vendor, model, and type identifiers), providing sufficient headroom for non-compliant devices while maintaining reasonable memory usage. Signed-off-by: tuhaowen --- src/udev/scsi_id/scsi_id.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/udev/scsi_id/scsi_id.h b/src/udev/scsi_id/scsi_id.h index 9ab3341855..db49c7f3d9 100644 --- a/src/udev/scsi_id/scsi_id.h +++ b/src/udev/scsi_id/scsi_id.h @@ -17,7 +17,7 @@ * MAX_SERIAL_LEN: the maximum length of the serial number, including * added prefixes such as vendor and product (model) strings. */ -#define MAX_SERIAL_LEN 256 +#define MAX_SERIAL_LEN 512 /* * MAX_BUFFER_LEN: maximum buffer size and line length used while reading