netlink: rate-limit leftover bytes warning and print process name

[ Upstream commit bfc5184b69cf9eeb286137640351c650c27f118a ]

Any process is able to send netlink messages with leftover bytes.
Make the warning rate-limited to prevent too much log spam.

The warning is supposed to help find userspace bugs, so print the
triggering command name to implicate the buggy program.

[v2: Use pr_warn_ratelimited instead of printk_ratelimited.]

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Add #include of <linux/sched.h> for definition of struct task_struct,
 as in 3.2 it doesn't get included indirectly on all architectures.  Thanks
 to Guenter Roeck for debugging this.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/lib/nlattr.c b/lib/nlattr.c
index 190ae10..be25e35 100644 (file)
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -12,6 +12,8 @@
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
 #include <linux/string.h>
+#include <linux/ratelimit.h>
+#include <linux/sched.h>
 #include <linux/types.h>
 #include <net/netlink.h>
 
@@ -197,8 +199,8 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
        }
 
        if (unlikely(rem > 0))
-               printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
-                      "attributes.\n", rem);
+               pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
+                                   rem, current->comm);
 
        err = 0;
 errout: