rose: limit sk_filter trim to payload

[android-x86/kernel.git] / net / core / filter.c

diff --git a/net/core/filter.c b/net/core/filter.c
index c4b330c..e759d90 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -53,9 +53,10 @@
 #include <net/sock_reuseport.h>
 
 /**
- *     sk_filter - run a packet through a socket filter
+ *     sk_filter_trim_cap - run a packet through a socket filter
  *     @sk: sock associated with &sk_buff
  *     @skb: buffer to filter
+ *     @cap: limit on how short the eBPF program may trim the packet
  *
  * Run the eBPF program and then cut skb->data to correct size returned by
  * the program. If pkt_len is 0 we toss packet. If skb->len is smaller
@@ -64,7 +65,7 @@
  * be accepted or -EPERM if the packet should be tossed.
  *
  */
-int sk_filter(struct sock *sk, struct sk_buff *skb)
+int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap)
 {
        int err;
        struct sk_filter *filter;
@@ -85,14 +86,13 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
        filter = rcu_dereference(sk->sk_filter);
        if (filter) {
                unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb);
-
-               err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
+               err = pkt_len ? pskb_trim(skb, max(cap, pkt_len)) : -EPERM;
        }
        rcu_read_unlock();
 
        return err;
 }
-EXPORT_SYMBOL(sk_filter);
+EXPORT_SYMBOL(sk_filter_trim_cap);
 
 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
 {