From: Petr Machata Date: Mon, 11 Jan 2021 17:07:07 +0000 (+0100) Subject: net: dcb: Accept RTM_GETDCB messages carrying set-like DCB commands X-Git-Tag: microblaze-v5.13~391^2~25 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=df85bc140a4d6cbaa78d8e9c35154e1a2f0622c7;p=linux-2.6-microblaze.git net: dcb: Accept RTM_GETDCB messages carrying set-like DCB commands 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 Link: https://lore.kernel.org/r/a3edcfda0825f2aa2591801c5232f2bbf2d8a554.1610384801.git.me@pmachata.org Signed-off-by: Jakub Kicinski --- diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c index 7d49b6fd6cef..653e3bc9c87b 100644 --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -1765,7 +1765,7 @@ static int dcb_doit(struct sk_buff *skb, struct nlmsghdr *nlh, 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])