From: Petr Machata <me@pmachata.org> [ Upstream commit 826f328e2b7e8854dd42ea44e6519cd75018e7b1 ] DCB uses the same handler function for both RTM_GETDCB and RTM_SETDCB messages. dcb_doit() bounces RTM_SETDCB mesasges if the user does not have the CAP_NET_ADMIN capability. However, the operation to be performed is not decided from the DCB message type, but from the DCB command. Thus DCB_CMD_*_GET commands are used for reading DCB objects, the corresponding SET and DEL commands are used for manipulation. The assumption is that set-like commands will be sent via an RTM_SETDCB message, and get-like ones via RTM_GETDCB. However, this assumption is not enforced. It is therefore possible to manipulate DCB objects without CAP_NET_ADMIN capability by sending the corresponding command in an RTM_GETDCB message. That is a bug. Fix it by validating the type of the request message against the type used for the response. Fixes: 2f90b8657ec9 ("ixgbe: this patch adds support for DCB to the kernel and ixgbe driver") Signed-off-by: Petr Machata <me@pmachata.org> Link: https://lore.kernel.org/r/a2a9b88418f3a58ef211b718f2970128ef9e3793.160867364... 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, 2 insertions(+) diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c index 5ee6b94131b23..e2cad3dfb4847 100644 --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -1756,6 +1756,8 @@ 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) + return -EPERM; if (!tb[DCB_ATTR_IFNAME]) return -EINVAL; -- 2.25.1