Commit e17d6340 authored by Martin K. Petersen's avatar Martin K. Petersen
Browse files

scsi: core: Pick suitable allocation length in scsi_report_opcode() 

Some devices hang when a buffer size larger than expected is passed in the
ALLOCATION LENGTH field. For REPORT SUPPORTED OPERATION CODES we currently
only request a single command descriptor at a time and therefore the actual
size of the command is known ahead of time. Limit the ALLOCATION LENGTH to
the header size plus the command length of the opcode we are asking about.

Link: https://lore.kernel.org/r/20220302053559.32147-5-martin.petersen@oracle.com


Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent c92a6b5d

drivers/scsi/scsi.c

+13 −4
Original line number Diff line number Diff line
@@ -503,21 +503,30 @@ int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 
{

	unsigned char cmd[16];

	struct scsi_sense_hdr sshdr;

	int result;

	int result, request_len;



	if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)

		return -EINVAL;



	/* RSOC header + size of command we are asking about */

	request_len = 4 + COMMAND_SIZE(opcode);

	if (request_len > len) {

		dev_warn_once(&sdev->sdev_gendev,

			      "%s: len %u bytes, opcode 0x%02x needs %u\n",

			      __func__, len, opcode, request_len);

		return -EINVAL;

	}



	memset(cmd, 0, 16);

	cmd[0] = MAINTENANCE_IN;

	cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;

	cmd[2] = 1;		/* One command format */

	cmd[3] = opcode;

	put_unaligned_be32(len, &cmd[6]);

	put_unaligned_be32(request_len, &cmd[6]);

	memset(buffer, 0, len);



	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,

				  &sshdr, 30 * HZ, 3, NULL);

	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,

				  request_len, &sshdr, 30 * HZ, 3, NULL);



	if (result < 0)

		return result;