diff mbox series

[next] ethtool: ioctl: Fix out-of-bounds warning in store_link_ksettings_for_user()

Message ID 20210416201540.GA593906@embeddedor (mailing list archive)
State Accepted
Commit c1d9e34e11281a8ba1a1c54e4db554232a461488
Delegated to: Netdev Maintainers
Headers show
Series [next] ethtool: ioctl: Fix out-of-bounds warning in store_link_ksettings_for_user() | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Guessed tree name to be net-next
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cc_maintainers warning 8 maintainers not CCed: ecree@solarflare.com andrew@lunn.ch magnus.karlsson@intel.com mkubecek@suse.cz danieller@nvidia.com f.fainelli@gmail.com irusskikh@marvell.com alexanderduyck@fb.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/header_inline success Link

Commit Message

Gustavo A. R. Silva April 16, 2021, 8:15 p.m. UTC
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>
---
 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 27f1c5224acb..3fa7a394eabf 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);