[PATCH 5.18 55/88] macsec: always read MACSEC_SA_ATTR_PN as a u64

Greg Kroah-Hartman
2022-08-01T12:15:24Z

From: Sabrina Dubroca <sd@queasysnail.net>

[ Upstream commit c630d1fe6219769049c87d1a6a0e9a6de55328a1 ]

Currently, MACSEC_SA_ATTR_PN is handled inconsistently, sometimes as a
u32, sometimes forced into a u64 without checking the actual length of
the attribute. Instead, we can use nla_get_u64 everywhere, which will
read up to 64 bits into a u64, capped by the actual length of the
attribute coming from userspace.

This fixes several issues:
- the check in validate_add_rxsa doesn't work with 32-bit attributes
- the checks in validate_add_txsa and validate_upd_sa incorrectly
reject X << 32 (with X != 0)

Fixes: 48ef50fa866a ("macsec: Netlink support of XPN cipher suites (IEEE 802.1AEbw)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/macsec.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index b3834e353c22..95578f04f212 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -1698,7 +1698,7 @@ static bool validate_add_rxsa(struct nlattr **attrs)
return false;

if (attrs[MACSEC_SA_ATTR_PN] &&
- *(u64 *)nla_data(attrs[MACSEC_SA_ATTR_PN]) == 0)
+ nla_get_u64(attrs[MACSEC_SA_ATTR_PN]) == 0)
return false;

if (attrs[MACSEC_SA_ATTR_ACTIVE]) {
@@ -1941,7 +1941,7 @@ static bool validate_add_txsa(struct nlattr **attrs)
if (nla_get_u8(attrs[MACSEC_SA_ATTR_AN]) >= MACSEC_NUM_AN)
return false;

- if (nla_get_u32(attrs[MACSEC_SA_ATTR_PN]) == 0)
+ if (nla_get_u64(attrs[MACSEC_SA_ATTR_PN]) == 0)
return false;

if (attrs[MACSEC_SA_ATTR_ACTIVE]) {
@@ -2295,7 +2295,7 @@ static bool validate_upd_sa(struct nlattr **attrs)
if (nla_get_u8(attrs[MACSEC_SA_ATTR_AN]) >= MACSEC_NUM_AN)
return false;

- if (attrs[MACSEC_SA_ATTR_PN] && nla_get_u32(attrs[MACSEC_SA_ATTR_PN]) == 0)
+ if (attrs[MACSEC_SA_ATTR_PN] && nla_get_u64(attrs[MACSEC_SA_ATTR_PN]) == 0)
return false;

if (attrs[MACSEC_SA_ATTR_ACTIVE]) {
--
2.35.1