rtnetlink: fix rtnl_calcit() and rtnl_dump_ifinfo()

commit a4b64fbe482c7766f7925f03067fc637716bfa3f upstream.

nlmsg_parse() might return an error, so test its return value before
potential random memory accesses.

Errors introduced in commit 115c9b81928 (rtnetlink: Fix problem with
buffer allocation)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e41ce2a0264a9620473f0b582b6ba13d1e49d13e..49f281e60643300c0c989e9c3fde0bda1f5c29c4 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1044,11 +1044,12 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 
        rcu_read_lock();
 
-       nlmsg_parse(cb->nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX,
-                   ifla_policy);
+       if (nlmsg_parse(cb->nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX,
+                       ifla_policy) >= 0) {
 
-       if (tb[IFLA_EXT_MASK])
-               ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
+               if (tb[IFLA_EXT_MASK])
+                       ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
+       }
 
        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                idx = 0;
@@ -1874,10 +1875,11 @@ static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh)
        u32 ext_filter_mask = 0;
        u16 min_ifinfo_dump_size = 0;
 
-       nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX, ifla_policy);
-
-       if (tb[IFLA_EXT_MASK])
-               ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
+       if (nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX,
+                       ifla_policy) >= 0) {
+               if (tb[IFLA_EXT_MASK])
+                       ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
+       }
 
        if (!ext_filter_mask)
                return NLMSG_GOODSIZE;