From: Pedro Tammela <pctammela@xxxxxxxxxxxx>
[ Upstream commit f4e4534850a9d18c250a93f8d7fbb51310828110 ]
The current code for the length calculation wrongly truncates the reported
length of the groups array, causing an under report of the subscribed
groups. To fix this, use 'BITS_TO_BYTES()' which rounds up the
division by 8.
Fixes: b42be38b2778 ("netlink: add API to retrieve all group memberships")
Signed-off-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230529153335.389815-1-pctammela@xxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netlink/af_netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 45d47b39de225..717e27a4b66a0 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1779,7 +1779,7 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname,
break;
}
}
- if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
+ if (put_user(ALIGN(BITS_TO_BYTES(nlk->ngroups), sizeof(u32)), optlen))
err = -EFAULT;
netlink_unlock_table();
return err;
--
2.39.2
