Commit fc910a27 authored by David S. Miller's avatar David S. Miller Committed by David S. Miller
Browse files

[NETLINK]: Limit NLMSG_GOODSIZE to 8K.


Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ca043569
......@@ -171,9 +171,16 @@ int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
/*
* skb should fit one page. This choice is good for headerless malloc.
* But we should limit to 8K so that userspace does not have to
* use enormous buffer sizes on recvmsg() calls just to avoid
* MSG_TRUNC when PAGE_SIZE is very large.
*/
#define NLMSG_GOODORDER 0
#define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
#if PAGE_SIZE < 8192UL
#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
#else
#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
#endif
#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
......
......@@ -39,9 +39,11 @@
#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
~(SMP_CACHE_BYTES - 1))
#define SKB_MAX_ORDER(X, ORDER) (((PAGE_SIZE << (ORDER)) - (X) - \
sizeof(struct skb_shared_info)) & \
~(SMP_CACHE_BYTES - 1))
#define SKB_WITH_OVERHEAD(X) \
(((X) - sizeof(struct skb_shared_info)) & \
~(SMP_CACHE_BYTES - 1))
#define SKB_MAX_ORDER(X, ORDER) \
SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
......
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