From fd3f8e52b673bbf695ded218d3f566826fa1ce3f Mon Sep 17 00:00:00 2001 From: Donald Sharp Date: Wed, 15 Apr 2020 08:56:03 -0400 Subject: [PATCH] zebra: Modify netlink_request to statisfy coverity The netlink_request function takes a `struct nlmsghdr *` pointer from a common pattern that we use: struct { struct nlmsghdr n; struct fib_rule_hdr frh; char buf[NL_PKT_BUF_SIZE]; } req; We were calling it `netlink_request(Socket, &req.n)` The problem here is that coverity, rightly so, sees that we access the data after the nlmsghdr in netlink_request and tells us we have an read beyond end of the structure. While we know we haven't mangled anything up here because of manual inspection coverity doesn't have this knowledge implicitly. So let's modify the code call to netlink_request to pass in the void pointer of the req structure itself, cast to the appropriate data structure in the function and do the right thing. Hopefully the coverity SA will be happy and we can move on with our life. Signed-off-by: Donald Sharp --- zebra/if_netlink.c | 2 +- zebra/kernel_netlink.c | 5 +++-- zebra/kernel_netlink.h | 2 +- zebra/rt_netlink.c | 12 ++++++------ zebra/rule_netlink.c | 2 +- 5 files changed, 12 insertions(+), 11 deletions(-) diff --git a/zebra/if_netlink.c b/zebra/if_netlink.c index 65a0add57e..78155b1455 100644 --- a/zebra/if_netlink.c +++ b/zebra/if_netlink.c @@ -764,7 +764,7 @@ static int netlink_request_intf_addr(struct nlsock *netlink_cmd, int family, if (filter_mask) addattr32(&req.n, sizeof(req), IFLA_EXT_MASK, filter_mask); - return netlink_request(netlink_cmd, &req.n); + return netlink_request(netlink_cmd, &req); } /* Interface lookup by netlink socket. */ diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c index 97b0238362..a1f7014ce9 100644 --- a/zebra/kernel_netlink.c +++ b/zebra/kernel_netlink.c @@ -1061,10 +1061,11 @@ int netlink_talk(int (*filter)(struct nlmsghdr *, ns_id_t, int startup), /* Issue request message to kernel via netlink socket. GET messages * are issued through this interface. */ -int netlink_request(struct nlsock *nl, struct nlmsghdr *n) +int netlink_request(struct nlsock *nl, void *req) { int ret; struct sockaddr_nl snl; + struct nlmsghdr *n = (struct nlmsghdr *)req; /* Check netlink socket. */ if (nl->sock < 0) { @@ -1082,7 +1083,7 @@ int netlink_request(struct nlsock *nl, struct nlmsghdr *n) /* Raise capabilities and send message, then lower capabilities. */ frr_with_privs(&zserv_privs) { - ret = sendto(nl->sock, (void *)n, n->nlmsg_len, 0, + ret = sendto(nl->sock, req, n->nlmsg_len, 0, (struct sockaddr *)&snl, sizeof(snl)); } diff --git a/zebra/kernel_netlink.h b/zebra/kernel_netlink.h index 076ca5c5c7..6a4077abf6 100644 --- a/zebra/kernel_netlink.h +++ b/zebra/kernel_netlink.h @@ -68,7 +68,7 @@ int netlink_talk_info(int (*filter)(struct nlmsghdr *, ns_id_t, int startup), struct nlmsghdr *n, const struct zebra_dplane_info *dp_info, int startup); -extern int netlink_request(struct nlsock *nl, struct nlmsghdr *n); +extern int netlink_request(struct nlsock *nl, void *req); #endif /* HAVE_NETLINK */ diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c index c4af082e72..5c9d2f69a6 100644 --- a/zebra/rt_netlink.c +++ b/zebra/rt_netlink.c @@ -983,7 +983,7 @@ static int netlink_request_route(struct zebra_ns *zns, int family, int type) req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)); req.rtm.rtm_family = family; - return netlink_request(&zns->netlink_cmd, &req.n); + return netlink_request(&zns->netlink_cmd, &req); } /* Routing table read function using netlink interface. Only called @@ -2492,7 +2492,7 @@ static int netlink_request_nexthop(struct zebra_ns *zns, int family, int type) req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct nhmsg)); req.nhm.nh_family = family; - return netlink_request(&zns->netlink_cmd, &req.n); + return netlink_request(&zns->netlink_cmd, &req); } @@ -2822,7 +2822,7 @@ static int netlink_request_macs(struct nlsock *netlink_cmd, int family, if (master_ifindex) addattr32(&req.n, sizeof(req), IFLA_MASTER, master_ifindex); - return netlink_request(netlink_cmd, &req.n); + return netlink_request(netlink_cmd, &req); } /* @@ -2925,7 +2925,7 @@ static int netlink_request_specific_mac_in_bridge(struct zebra_ns *zns, vrf_id_to_name(br_if->vrf_id), br_if->vrf_id, prefix_mac2str(mac, buf, sizeof(buf)), vid); - return netlink_request(&zns->netlink_cmd, &req.n); + return netlink_request(&zns->netlink_cmd, &req); } int netlink_macfdb_read_specific_mac(struct zebra_ns *zns, @@ -3225,7 +3225,7 @@ static int netlink_request_neigh(struct nlsock *netlink_cmd, int family, if (ifindex) addattr32(&req.n, sizeof(req), NDA_IFINDEX, ifindex); - return netlink_request(netlink_cmd, &req.n); + return netlink_request(netlink_cmd, &req); } /* @@ -3313,7 +3313,7 @@ static int netlink_request_specific_neigh_in_vlan(struct zebra_ns *zns, ipaddr2str(ip, buf, sizeof(buf)), req.n.nlmsg_flags); } - return netlink_request(&zns->netlink_cmd, &req.n); + return netlink_request(&zns->netlink_cmd, &req); } int netlink_neigh_read_specific_ip(struct ipaddr *ip, diff --git a/zebra/rule_netlink.c b/zebra/rule_netlink.c index 07e1902f65..a5a605f27e 100644 --- a/zebra/rule_netlink.c +++ b/zebra/rule_netlink.c @@ -355,7 +355,7 @@ static int netlink_request_rules(struct zebra_ns *zns, int family, int type) req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct fib_rule_hdr)); req.frh.family = family; - return netlink_request(&zns->netlink_cmd, &req.n); + return netlink_request(&zns->netlink_cmd, &req); } /*