[PATCH 3.4 09/26] netlink: rate-limit leftover bytes warning and print process name

[Greg Kroah-Hartman]

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Schmidt <mschmidt@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 lib/nlattr.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -13,6 +13,7 @@
 #include <linux/skbuff.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <linux/ratelimit.h>
 #include <net/netlink.h>
 
 static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
@@ -197,8 +198,8 @@ int nla_parse(struct nlattr **tb, int ma
 	}
 
 	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:


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