diff mbox series

[5.11,088/329] ethtool: ioctl: Fix out-of-bounds warning in store_link_ksettings_for_user()

Message ID 20210517140305.091775922@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg KH May 17, 2021, 1:59 p.m. UTC 
From: Gustavo A. R. Silva <gustavoars@kernel.org>

[ Upstream commit c1d9e34e11281a8ba1a1c54e4db554232a461488 ]

Fix the following out-of-bounds warning:

net/ethtool/ioctl.c:492:2: warning: 'memcpy' offset [49, 84] from the object at 'link_usettings' is out of the bounds of referenced subobject 'base' with type 'struct ethtool_link_settings' at offset 0 [-Warray-bounds]

The problem is that the original code is trying to copy data into a
some struct members adjacent to each other in a single call to
memcpy(). This causes a legitimate compiler warning because memcpy()
overruns the length of &link_usettings.base. Fix this by directly
using &link_usettings and _from_ as destination and source addresses,
instead.

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

Link: https://github.com/KSPP/linux/issues/109
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ethtool/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 771688e1b0da..2603966da904 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -489,7 +489,7 @@  store_link_ksettings_for_user(void __user *to,
 {
 	struct ethtool_link_usettings link_usettings;
 
-	memcpy(&link_usettings.base, &from->base, sizeof(link_usettings));
+	memcpy(&link_usettings, from, sizeof(link_usettings));
 	bitmap_to_arr32(link_usettings.link_modes.supported,
 			from->link_modes.supported,
 			__ETHTOOL_LINK_MODE_MASK_NBITS);