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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, stable@kernel.org,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        hdthky <hdthky0@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 5.4 25/38] scsi: stex: Properly zero out the passthrough command structure
Date:   Thu, 13 Oct 2022 19:52:26 +0200
Message-Id: <20221013175145.100366344@linuxfoundation.org>
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From: Linus Torvalds <torvalds@linux-foundation.org>

commit 6022f210461fef67e6e676fd8544ca02d1bcfa7a 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: hdthky <hdthky0@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/scsi/stex.c      |   17 +++++++++--------
 include/scsi/scsi_cmnd.h |    2 +-
 2 files changed, 10 insertions(+), 9 deletions(-)

--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -668,16 +668,17 @@ stex_queuecommand_lck(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 :
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -204,7 +204,7 @@ static inline int scsi_get_resid(struct
 	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);