From: Pedro Tammela pctammela@mojatatu.com
[ 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@mojatatu.com Reviewed-by: Simon Horman simon.horman@corigine.com Link: https://lore.kernel.org/r/20230529153335.389815-1-pctammela@mojatatu.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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;