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authorPetr Machata <me@pmachata.org>2020-12-23 00:49:44 +0300
committerJakub Kicinski <kuba@kernel.org>2020-12-23 23:19:48 +0300
commit826f328e2b7e8854dd42ea44e6519cd75018e7b1 (patch)
treef0b822b652a6db49ed1f3ea675364771f1b722c1
parent6313138619f398666212577f8b4f0ddf215a2bed (diff)
downloadlinux-826f328e2b7e8854dd42ea44e6519cd75018e7b1.tar.xz
net: dcb: Validate netlink message in DCB handler
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/a2a9b88418f3a58ef211b718f2970128ef9e3793.1608673640.git.me@pmachata.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--net/dcb/dcbnl.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 084e159a12ba..7d49b6fd6cef 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -1765,6 +1765,8 @@ 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;