From: Arnd Bergmann <arnd@arndb.de>
Date: Fri, 2 Feb 2018 16:18:37 +0100
Subject: net: cxgb4: avoid memcpy beyond end of source buffer
Patch-mainline: v4.16-rc1
Git-commit: 1a91649fd35ff53a646981e212496f1ae92a8487
References: bsc#1104279 FATE#325938

Building with link-time-optimizations revealed that the cxgb4 driver does
a fixed-size memcpy() from a variable-length constant string into the
network interface name:

In function 'memcpy',
    inlined from 'cfg_queues_uld.constprop' at drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:335:2,
    inlined from 'cxgb4_register_uld.constprop' at drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:719:9:
include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
   __read_overflow2();
   ^

I can see two equally workable solutions: either we use a strncpy() instead
of the memcpy() to stop at the end of the input, or we make the source buffer
fixed length as well. This implements the latter.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.h
@@ -355,7 +355,7 @@ struct cxgb4_lld_info {
 };
 
 struct cxgb4_uld_info {
-	const char *name;
+	char name[IFNAMSIZ];
 	void *handle;
 	unsigned int nrxq;
 	unsigned int rxq_size;