[PATCH 4.14 83/88] net: qed: Fix memcpy() overflow of qed_dcbx_params()

Sasha Levin
2021-06-28T15:14:26Z

From: Kees Cook <keescook@chromium.org>

[ Upstream commit 1c200f832e14420fa770193f9871f4ce2df00d07 ]

The source (&dcbx_info->operational.params) and dest
(&p_hwfn->p_dcbx_info->set.config.params) are both struct qed_dcbx_params
(560 bytes), not struct qed_dcbx_admin_params (564 bytes), which is used
as the memcpy() size.

However it seems that struct qed_dcbx_operational_params
(dcbx_info->operational)'s layout matches struct qed_dcbx_admin_params
(p_hwfn->p_dcbx_info->set.config)'s 4 byte difference (3 padding, 1 byte
for "valid").

On the assumption that the size is wrong (rather than the source structure
type), adjust the memcpy() size argument to be 4 bytes smaller and add
a BUILD_BUG_ON() to validate any changes to the structure sizes.

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/qlogic/qed/qed_dcbx.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_dcbx.c b/drivers/net/ethernet/qlogic/qed/qed_dcbx.c
index d62dccb85539..1ee58a24afe3 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_dcbx.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dcbx.c
@@ -1259,9 +1259,11 @@ int qed_dcbx_get_config_params(struct qed_hwfn *p_hwfn,
p_hwfn->p_dcbx_info->set.ver_num |= DCBX_CONFIG_VERSION_STATIC;

p_hwfn->p_dcbx_info->set.enabled = dcbx_info->operational.enabled;
+ BUILD_BUG_ON(sizeof(dcbx_info->operational.params) !=
+ sizeof(p_hwfn->p_dcbx_info->set.config.params));
memcpy(&p_hwfn->p_dcbx_info->set.config.params,
&dcbx_info->operational.params,
- sizeof(struct qed_dcbx_admin_params));
+ sizeof(p_hwfn->p_dcbx_info->set.config.params));
p_hwfn->p_dcbx_info->set.config.valid = true;

memcpy(params, &p_hwfn->p_dcbx_info->set, sizeof(struct qed_dcbx_set));
--
2.30.2