[PATCH] audit: fix size of netlink messages
Netlink messages must be aligned on NLMSG_ALIGNTO (4 bytes), thus we need to
update the skb length before sending it to userspace.
This patch adds the needed padding to be compliant with this requirement.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel(a)6wind.com>
---
kernel/audit.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/kernel/audit.c b/kernel/audit.c
index 21c7fa6..31d213a 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1669,6 +1669,17 @@ void audit_log_end(struct audit_buffer *ab)
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
+ if (NLMSG_ALIGN(ab->skb->len) != ab->skb->len) {
+ unsigned int pad = NLMSG_ALIGN(ab->skb->len) -
+ ab->skb->len;
+
+ if (skb_tailroom(ab->skb) >= pad)
+ skb_put(ab->skb, pad);
+ else if (pskb_expand_head(ab->skb, 0, pad,
+ GFP_KERNEL) < 0)
+ audit_log_lost("out of memory in audit_log_end");
+ }
+
if (audit_pid) {
skb_queue_tail(&audit_skb_queue, ab->skb);
wake_up_interruptible(&kauditd_wait);
--
1.8.2.1