From: Jiri Bohac <jbohac@suse.cz>
Patch-mainline: Never, problem no longer present in v5.14
References: bsc#1192802
Subject: gigaset: fix spectre issue in do_data_b3_req

Found by Smatch:
  drivers/isdn/gigaset/capi.c:2088 do_data_b3_req() warn: potential spectre issue 'cs->bcs' [r]

diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index ccec7778cad2..92dfff65fa35 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -19,6 +19,7 @@
 #include <linux/isdn/capicmd.h>
 #include <linux/isdn/capiutil.h>
 #include <linux/export.h>
+#include <linux/nospec.h>
 
 /* missing from kernelcapi.h */
 #define CapiNcpiNotSupportedByProtocol	0x0001
@@ -2085,6 +2086,7 @@ static void do_data_b3_req(struct gigaset_capi_ctr *iif,
 		send_conf(iif, ap, skb, CapiIllContrPlciNcci);
 		return;
 	}
+	channel = array_index_nospec(channel, cs->channels + 1);
 	bcs = &cs->bcs[channel - 1];
 	if (msglen != CAPI_DATA_B3_REQ_LEN && msglen != CAPI_DATA_B3_REQ_LEN64)
 		dev_notice(cs->dev, "%s: unexpected length %d\n",
-- 
2.33.0