scsi: stex: Properly zero out the passthrough command structure

stable inclusion
from stable-v5.10.148
commit 36b33c63515a93246487691046d18dd37a9f589b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I601VT
CVE: CVE-2022-40768

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=36b33c63515a93246487691046d18dd37a9f589b

-------------------------------

commit 6022f210 upstream.

The passthrough structure is declared off of the stack, so it needs to be
set to zero before copied back to userspace to prevent any unintentional
data leakage.  Switch things to be statically allocated which will fill the
unused fields with 0 automatically.

Link: https://lore.kernel.org/r/YxrjN3OOw2HHl9tx@kroah.com
Cc: stable@kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Nhdthky <hdthky0@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLu Jialin <lujialin4@huawei.com>
Reviewed-by: NGUO Zihua <guozihua@huawei.com>
Reviewed-by: NGONG Ruiqi <gongruiqi1@huawei.com>
Reviewed-by: NWang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/scsi/stex.c

@@ -668,16 +668,17 @@ stex_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 		return 0;
 	case PASSTHRU_CMD:
 		if (cmd->cmnd[1] == PASSTHRU_GET_DRVVER) {
-			struct st_drvver ver;
+			const struct st_drvver ver = {
+				.major = ST_VER_MAJOR,
+				.minor = ST_VER_MINOR,
+				.oem = ST_OEM,
+				.build = ST_BUILD_VER,
+				.signature[0] = PASSTHRU_SIGNATURE,
+				.console_id = host->max_id - 1,
+				.host_no = hba->host->host_no,
+			};
 			size_t cp_len = sizeof(ver);
 
-			ver.major = ST_VER_MAJOR;
-			ver.minor = ST_VER_MINOR;
-			ver.oem = ST_OEM;
-			ver.build = ST_BUILD_VER;
-			ver.signature[0] = PASSTHRU_SIGNATURE;
-			ver.console_id = host->max_id - 1;
-			ver.host_no = hba->host->host_no;
 			cp_len = scsi_sg_copy_from_buffer(cmd, &ver, cp_len);
 			cmd->result = sizeof(ver) == cp_len ?
 				DID_OK << 16 | COMMAND_COMPLETE << 8 :

include/scsi/scsi_cmnd.h

@@ -211,7 +211,7 @@ static inline unsigned int scsi_get_resid(struct scsi_cmnd *cmd)
 	for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 
 static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
-					   void *buf, int buflen)
+					   const void *buf, int buflen)
 {
 	return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 				   buf, buflen);