[PATCH AUTOSEL 6.6 14/22] enic: Avoid false positive under FORTIFY_SOURCE

Sasha Levin
2024-02-29T20:40:05Z

From: Kees Cook <keescook@chromium.org>

[ Upstream commit 40b9385dd8e6a0515e1c9cd06a277483556b7286 ]

FORTIFY_SOURCE has been ignoring 0-sized destinations while the kernel
code base has been converted to flexible arrays. In order to enforce
the 0-sized destinations (e.g. with __counted_by), the remaining 0-sized
destinations need to be handled. Unfortunately, struct vic_provinfo
resists full conversion, as it contains a flexible array of flexible
arrays, which is only possible with the 0-sized fake flexible array.

Use unsafe_memcpy() to avoid future false positives under
CONFIG_FORTIFY_SOURCE.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/cisco/enic/vnic_vic.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cisco/enic/vnic_vic.c b/drivers/net/ethernet/cisco/enic/vnic_vic.c
index 20fcb20b42ede..66b5778353389 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_vic.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_vic.c
@@ -49,7 +49,8 @@ int vic_provinfo_add_tlv(struct vic_provinfo *vp, u16 type, u16 length,

tlv->type = htons(type);
tlv->length = htons(length);
- memcpy(tlv->value, value, length);
+ unsafe_memcpy(tlv->value, value, length,
+ /* Flexible array of flexible arrays */);

vp->num_tlvs = htonl(ntohl(vp->num_tlvs) + 1);
vp->length = htonl(ntohl(vp->length) +
--
2.43.0