[PATCH] ch: Do not read past the end of vendor_labels[]

[Bart Van Assche <bvanassche@acm.org>]

This patch fixes the following gcc 10 compiler error:

In function 'memcpy',
    inlined from 'ch_ioctl' at drivers/scsi/ch.c:666:4:
./include/linux/string.h:377:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
  377 |    __read_overflow2();
      |    ^~~~~~~~~~~~~~~~~~

Cc: Hannes Reinecke <hare@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/ch.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index b81b397366db..b675a01380eb 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -651,19 +651,23 @@ static long ch_ioctl(struct file *file,
 		memset(&vparams,0,sizeof(vparams));
 		if (ch->counts[CHET_V1]) {
 			vparams.cvp_n1  = ch->counts[CHET_V1];
-			memcpy(vparams.cvp_label1,vendor_labels[0],16);
+			strncpy(vparams.cvp_label1, vendor_labels[0],
+				ARRAY_SIZE(vparams.cvp_label1));
 		}
 		if (ch->counts[CHET_V2]) {
 			vparams.cvp_n2  = ch->counts[CHET_V2];
-			memcpy(vparams.cvp_label2,vendor_labels[1],16);
+			strncpy(vparams.cvp_label2, vendor_labels[1],
+				ARRAY_SIZE(vparams.cvp_label2));
 		}
 		if (ch->counts[CHET_V3]) {
 			vparams.cvp_n3  = ch->counts[CHET_V3];
-			memcpy(vparams.cvp_label3,vendor_labels[2],16);
+			strncpy(vparams.cvp_label3, vendor_labels[2],
+				ARRAY_SIZE(vparams.cvp_label3));
 		}
 		if (ch->counts[CHET_V4]) {
 			vparams.cvp_n4  = ch->counts[CHET_V4];
-			memcpy(vparams.cvp_label4,vendor_labels[3],16);
+			strncpy(vparams.cvp_label4, vendor_labels[3],
+				ARRAY_SIZE(vparams.cvp_label4));
 		}
 		if (copy_to_user(argp, &vparams, sizeof(vparams)))
 			return -EFAULT;