From: Petr Machata petrm@nvidia.com
[ Upstream commit df85bc140a4d6cbaa78d8e9c35154e1a2f0622c7 ]
In commit 826f328e2b7e ("net: dcb: Validate netlink message in DCB handler"), Linux started rejecting RTM_GETDCB netlink messages if they contained a set-like DCB_CMD_ command.
The reason was that privileges were only verified for RTM_SETDCB messages, but the value that determined the action to be taken is the command, not the message type. And validation of message type against the DCB command was the obvious missing piece.
Unfortunately it turns out that mlnx_qos, a somewhat widely deployed tool for configuration of DCB, accesses the DCB set-like APIs through RTM_GETDCB.
Therefore do not bounce the discrepancy between message type and command. Instead, in addition to validating privileges based on the actual message type, validate them also based on the expected message type. This closes the loophole of allowing DCB configuration on non-admin accounts, while maintaining backward compatibility.
Fixes: 2f90b8657ec9 ("ixgbe: this patch adds support for DCB to the kernel and ixgbe driver") Fixes: 826f328e2b7e ("net: dcb: Validate netlink message in DCB handler") Signed-off-by: Petr Machata petrm@nvidia.com Link: https://lore.kernel.org/r/a3edcfda0825f2aa2591801c5232f2bbf2d8a554.161038480... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/dcb/dcbnl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -1725,7 +1725,7 @@ static int dcb_doit(struct sk_buff *skb, fn = &reply_funcs[dcb->cmd]; if (!fn->cb) return -EOPNOTSUPP; - if (fn->type != nlh->nlmsg_type) + if (fn->type == RTM_SETDCB && !netlink_capable(skb, CAP_NET_ADMIN)) return -EPERM;
if (!tb[DCB_ATTR_IFNAME])