Initial import

1 files changed, 1553 insertions, 0 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
new file mode 100644
index 000000000..bf831a85c
--- /dev/null
+++ b/net/core/filter.c
@@ -0,0 +1,1553 @@
+/*
+ * Linux Socket Filter - Kernel level socket filtering
+ *
+ * Based on the design of the Berkeley Packet Filter. The new
+ * internal format has been designed by PLUMgrid:
+ *
+ *	Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
+ *
+ * Authors:
+ *
+ *	Jay Schulist <jschlst@samba.org>
+ *	Alexei Starovoitov <ast@plumgrid.com>
+ *	Daniel Borkmann <dborkman@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Andi Kleen - Fix a few bad bugs and races.
+ * Kris Katterjohn - Added many additional checks in bpf_check_classic()
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/fcntl.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_packet.h>
+#include <linux/gfp.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/netlink.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <asm/uaccess.h>
+#include <asm/unaligned.h>
+#include <linux/filter.h>
+#include <linux/ratelimit.h>
+#include <linux/seccomp.h>
+#include <linux/if_vlan.h>
+#include <linux/bpf.h>
+
+/**
+ *	sk_filter - run a packet through a socket filter
+ *	@sk: sock associated with &sk_buff
+ *	@skb: buffer to filter
+ *
+ * Run the filter code and then cut skb->data to correct size returned by
+ * SK_RUN_FILTER. If pkt_len is 0 we toss packet. If skb->len is smaller
+ * than pkt_len we keep whole skb->data. This is the socket level
+ * wrapper to SK_RUN_FILTER. It returns 0 if the packet should
+ * be accepted or -EPERM if the packet should be tossed.
+ *
+ */
+int sk_filter(struct sock *sk, struct sk_buff *skb)
+{
+	int err;
+	struct sk_filter *filter;
+
+	/*
+	 * If the skb was allocated from pfmemalloc reserves, only
+	 * allow SOCK_MEMALLOC sockets to use it as this socket is
+	 * helping free memory
+	 */
+	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
+		return -ENOMEM;
+
+	err = security_sock_rcv_skb(sk, skb);
+	if (err)
+		return err;
+
+	rcu_read_lock();
+	filter = rcu_dereference(sk->sk_filter);
+	if (filter) {
+		unsigned int pkt_len = SK_RUN_FILTER(filter, skb);
+
+		err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
+	}
+	rcu_read_unlock();
+
+	return err;
+}
+EXPORT_SYMBOL(sk_filter);
+
+static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
+{
+	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
+}
+
+static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
+{
+	struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
+	struct nlattr *nla;
+
+	if (skb_is_nonlinear(skb))
+		return 0;
+
+	if (skb->len < sizeof(struct nlattr))
+		return 0;
+
+	if (a > skb->len - sizeof(struct nlattr))
+		return 0;
+
+	nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
+	if (nla)
+		return (void *) nla - (void *) skb->data;
+
+	return 0;
+}
+
+static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
+{
+	struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx;
+	struct nlattr *nla;
+
+	if (skb_is_nonlinear(skb))
+		return 0;
+
+	if (skb->len < sizeof(struct nlattr))
+		return 0;
+
+	if (a > skb->len - sizeof(struct nlattr))
+		return 0;
+
+	nla = (struct nlattr *) &skb->data[a];
+	if (nla->nla_len > skb->len - a)
+		return 0;
+
+	nla = nla_find_nested(nla, x);
+	if (nla)
+		return (void *) nla - (void *) skb->data;
+
+	return 0;
+}
+
+static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
+{
+	return raw_smp_processor_id();
+}
+
+/* note that this only generates 32-bit random numbers */
+static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
+{
+	return prandom_u32();
+}
+
+static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,
+			      struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (skb_field) {
+	case SKF_AD_MARK:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
+
+		*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
+				      offsetof(struct sk_buff, mark));
+		break;
+
+	case SKF_AD_PKTTYPE:
+		*insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET());
+		*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX);
+#ifdef __BIG_ENDIAN_BITFIELD
+		*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5);
+#endif
+		break;
+
+	case SKF_AD_QUEUE:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
+
+		*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
+				      offsetof(struct sk_buff, queue_mapping));
+		break;
+
+	case SKF_AD_VLAN_TAG:
+	case SKF_AD_VLAN_TAG_PRESENT:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
+		BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
+
+		/* dst_reg = *(u16 *) (src_reg + offsetof(vlan_tci)) */
+		*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
+				      offsetof(struct sk_buff, vlan_tci));
+		if (skb_field == SKF_AD_VLAN_TAG) {
+			*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg,
+						~VLAN_TAG_PRESENT);
+		} else {
+			/* dst_reg >>= 12 */
+			*insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 12);
+			/* dst_reg &= 1 */
+			*insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, 1);
+		}
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+static bool convert_bpf_extensions(struct sock_filter *fp,
+				   struct bpf_insn **insnp)
+{
+	struct bpf_insn *insn = *insnp;
+	u32 cnt;
+
+	switch (fp->k) {
+	case SKF_AD_OFF + SKF_AD_PROTOCOL:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
+
+		/* A = *(u16 *) (CTX + offsetof(protocol)) */
+		*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+				      offsetof(struct sk_buff, protocol));
+		/* A = ntohs(A) [emitting a nop or swap16] */
+		*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
+		break;
+
+	case SKF_AD_OFF + SKF_AD_PKTTYPE:
+		cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn);
+		insn += cnt - 1;
+		break;
+
+	case SKF_AD_OFF + SKF_AD_IFINDEX:
+	case SKF_AD_OFF + SKF_AD_HATYPE:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
+		BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
+		BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
+
+		*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
+				      BPF_REG_TMP, BPF_REG_CTX,
+				      offsetof(struct sk_buff, dev));
+		/* if (tmp != 0) goto pc + 1 */
+		*insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
+		*insn++ = BPF_EXIT_INSN();
+		if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
+			*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
+					    offsetof(struct net_device, ifindex));
+		else
+			*insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
+					    offsetof(struct net_device, type));
+		break;
+
+	case SKF_AD_OFF + SKF_AD_MARK:
+		cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn);
+		insn += cnt - 1;
+		break;
+
+	case SKF_AD_OFF + SKF_AD_RXHASH:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
+
+		*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX,
+				    offsetof(struct sk_buff, hash));
+		break;
+
+	case SKF_AD_OFF + SKF_AD_QUEUE:
+		cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn);
+		insn += cnt - 1;
+		break;
+
+	case SKF_AD_OFF + SKF_AD_VLAN_TAG:
+		cnt = convert_skb_access(SKF_AD_VLAN_TAG,
+					 BPF_REG_A, BPF_REG_CTX, insn);
+		insn += cnt - 1;
+		break;
+
+	case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
+		cnt = convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
+					 BPF_REG_A, BPF_REG_CTX, insn);
+		insn += cnt - 1;
+		break;
+
+	case SKF_AD_OFF + SKF_AD_VLAN_TPID:
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+
+		/* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
+		*insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+				      offsetof(struct sk_buff, vlan_proto));
+		/* A = ntohs(A) [emitting a nop or swap16] */
+		*insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
+		break;
+
+	case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
+	case SKF_AD_OFF + SKF_AD_NLATTR:
+	case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
+	case SKF_AD_OFF + SKF_AD_CPU:
+	case SKF_AD_OFF + SKF_AD_RANDOM:
+		/* arg1 = CTX */
+		*insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
+		/* arg2 = A */
+		*insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
+		/* arg3 = X */
+		*insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
+		/* Emit call(arg1=CTX, arg2=A, arg3=X) */
+		switch (fp->k) {
+		case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
+			*insn = BPF_EMIT_CALL(__skb_get_pay_offset);
+			break;
+		case SKF_AD_OFF + SKF_AD_NLATTR:
+			*insn = BPF_EMIT_CALL(__skb_get_nlattr);
+			break;
+		case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
+			*insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
+			break;
+		case SKF_AD_OFF + SKF_AD_CPU:
+			*insn = BPF_EMIT_CALL(__get_raw_cpu_id);
+			break;
+		case SKF_AD_OFF + SKF_AD_RANDOM:
+			*insn = BPF_EMIT_CALL(__get_random_u32);
+			break;
+		}
+		break;
+
+	case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
+		/* A ^= X */
+		*insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X);
+		break;
+
+	default:
+		/* This is just a dummy call to avoid letting the compiler
+		 * evict __bpf_call_base() as an optimization. Placed here
+		 * where no-one bothers.
+		 */
+		BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0);
+		return false;
+	}
+
+	*insnp = insn;
+	return true;
+}
+
+/**
+ *	bpf_convert_filter - convert filter program
+ *	@prog: the user passed filter program
+ *	@len: the length of the user passed filter program
+ *	@new_prog: buffer where converted program will be stored
+ *	@new_len: pointer to store length of converted program
+ *
+ * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
+ * Conversion workflow:
+ *
+ * 1) First pass for calculating the new program length:
+ *   bpf_convert_filter(old_prog, old_len, NULL, &new_len)
+ *
+ * 2) 2nd pass to remap in two passes: 1st pass finds new
+ *    jump offsets, 2nd pass remapping:
+ *   new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
+ *   bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
+ *
+ * User BPF's register A is mapped to our BPF register 6, user BPF
+ * register X is mapped to BPF register 7; frame pointer is always
+ * register 10; Context 'void *ctx' is stored in register 1, that is,
+ * for socket filters: ctx == 'struct sk_buff *', for seccomp:
+ * ctx == 'struct seccomp_data *'.
+ */
+int bpf_convert_filter(struct sock_filter *prog, int len,
+		       struct bpf_insn *new_prog, int *new_len)
+{
+	int new_flen = 0, pass = 0, target, i;
+	struct bpf_insn *new_insn;
+	struct sock_filter *fp;
+	int *addrs = NULL;
+	u8 bpf_src;
+
+	BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
+	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
+
+	if (len <= 0 || len > BPF_MAXINSNS)
+		return -EINVAL;
+
+	if (new_prog) {
+		addrs = kcalloc(len, sizeof(*addrs), GFP_KERNEL);
+		if (!addrs)
+			return -ENOMEM;
+	}
+
+do_pass:
+	new_insn = new_prog;
+	fp = prog;
+
+	if (new_insn)
+		*new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
+	new_insn++;
+
+	for (i = 0; i < len; fp++, i++) {
+		struct bpf_insn tmp_insns[6] = { };
+		struct bpf_insn *insn = tmp_insns;
+
+		if (addrs)
+			addrs[i] = new_insn - new_prog;
+
+		switch (fp->code) {
+		/* All arithmetic insns and skb loads map as-is. */
+		case BPF_ALU | BPF_ADD | BPF_X:
+		case BPF_ALU | BPF_ADD | BPF_K:
+		case BPF_ALU | BPF_SUB | BPF_X:
+		case BPF_ALU | BPF_SUB | BPF_K:
+		case BPF_ALU | BPF_AND | BPF_X:
+		case BPF_ALU | BPF_AND | BPF_K:
+		case BPF_ALU | BPF_OR | BPF_X:
+		case BPF_ALU | BPF_OR | BPF_K:
+		case BPF_ALU | BPF_LSH | BPF_X:
+		case BPF_ALU | BPF_LSH | BPF_K:
+		case BPF_ALU | BPF_RSH | BPF_X:
+		case BPF_ALU | BPF_RSH | BPF_K:
+		case BPF_ALU | BPF_XOR | BPF_X:
+		case BPF_ALU | BPF_XOR | BPF_K:
+		case BPF_ALU | BPF_MUL | BPF_X:
+		case BPF_ALU | BPF_MUL | BPF_K:
+		case BPF_ALU | BPF_DIV | BPF_X:
+		case BPF_ALU | BPF_DIV | BPF_K:
+		case BPF_ALU | BPF_MOD | BPF_X:
+		case BPF_ALU | BPF_MOD | BPF_K:
+		case BPF_ALU | BPF_NEG:
+		case BPF_LD | BPF_ABS | BPF_W:
+		case BPF_LD | BPF_ABS | BPF_H:
+		case BPF_LD | BPF_ABS | BPF_B:
+		case BPF_LD | BPF_IND | BPF_W:
+		case BPF_LD | BPF_IND | BPF_H:
+		case BPF_LD | BPF_IND | BPF_B:
+			/* Check for overloaded BPF extension and
+			 * directly convert it if found, otherwise
+			 * just move on with mapping.
+			 */
+			if (BPF_CLASS(fp->code) == BPF_LD &&
+			    BPF_MODE(fp->code) == BPF_ABS &&
+			    convert_bpf_extensions(fp, &insn))
+				break;
+
+			*insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
+			break;
+
+		/* Jump transformation cannot use BPF block macros
+		 * everywhere as offset calculation and target updates
+		 * require a bit more work than the rest, i.e. jump
+		 * opcodes map as-is, but offsets need adjustment.
+		 */
+
+#define BPF_EMIT_JMP							\
+	do {								\
+		if (target >= len || target < 0)			\
+			goto err;					\
+		insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0;	\
+		/* Adjust pc relative offset for 2nd or 3rd insn. */	\
+		insn->off -= insn - tmp_insns;				\
+	} while (0)
+
+		case BPF_JMP | BPF_JA:
+			target = i + fp->k + 1;
+			insn->code = fp->code;
+			BPF_EMIT_JMP;
+			break;
+
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JEQ | BPF_X:
+		case BPF_JMP | BPF_JSET | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_X:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_X:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_X:
+			if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) {
+				/* BPF immediates are signed, zero extend
+				 * immediate into tmp register and use it
+				 * in compare insn.
+				 */
+				*insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
+
+				insn->dst_reg = BPF_REG_A;
+				insn->src_reg = BPF_REG_TMP;
+				bpf_src = BPF_X;
+			} else {
+				insn->dst_reg = BPF_REG_A;
+				insn->src_reg = BPF_REG_X;
+				insn->imm = fp->k;
+				bpf_src = BPF_SRC(fp->code);
+			}
+
+			/* Common case where 'jump_false' is next insn. */
+			if (fp->jf == 0) {
+				insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
+				target = i + fp->jt + 1;
+				BPF_EMIT_JMP;
+				break;
+			}
+
+			/* Convert JEQ into JNE when 'jump_true' is next insn. */
+			if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
+				insn->code = BPF_JMP | BPF_JNE | bpf_src;
+				target = i + fp->jf + 1;
+				BPF_EMIT_JMP;
+				break;
+			}
+
+			/* Other jumps are mapped into two insns: Jxx and JA. */
+			target = i + fp->jt + 1;
+			insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
+			BPF_EMIT_JMP;
+			insn++;
+
+			insn->code = BPF_JMP | BPF_JA;
+			target = i + fp->jf + 1;
+			BPF_EMIT_JMP;
+			break;
+
+		/* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
+		case BPF_LDX | BPF_MSH | BPF_B:
+			/* tmp = A */
+			*insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
+			/* A = BPF_R0 = *(u8 *) (skb->data + K) */
+			*insn++ = BPF_LD_ABS(BPF_B, fp->k);
+			/* A &= 0xf */
+			*insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
+			/* A <<= 2 */
+			*insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
+			/* X = A */
+			*insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
+			/* A = tmp */
+			*insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
+			break;
+
+		/* RET_K, RET_A are remaped into 2 insns. */
+		case BPF_RET | BPF_A:
+		case BPF_RET | BPF_K:
+			*insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ?
+						BPF_K : BPF_X, BPF_REG_0,
+						BPF_REG_A, fp->k);
+			*insn = BPF_EXIT_INSN();
+			break;
+
+		/* Store to stack. */
+		case BPF_ST:
+		case BPF_STX:
+			*insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
+					    BPF_ST ? BPF_REG_A : BPF_REG_X,
+					    -(BPF_MEMWORDS - fp->k) * 4);
+			break;
+
+		/* Load from stack. */
+		case BPF_LD | BPF_MEM:
+		case BPF_LDX | BPF_MEM:
+			*insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD  ?
+					    BPF_REG_A : BPF_REG_X, BPF_REG_FP,
+					    -(BPF_MEMWORDS - fp->k) * 4);
+			break;
+
+		/* A = K or X = K */
+		case BPF_LD | BPF_IMM:
+		case BPF_LDX | BPF_IMM:
+			*insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
+					      BPF_REG_A : BPF_REG_X, fp->k);
+			break;
+
+		/* X = A */
+		case BPF_MISC | BPF_TAX:
+			*insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
+			break;
+
+		/* A = X */
+		case BPF_MISC | BPF_TXA:
+			*insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
+			break;
+
+		/* A = skb->len or X = skb->len */
+		case BPF_LD | BPF_W | BPF_LEN:
+		case BPF_LDX | BPF_W | BPF_LEN:
+			*insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
+					    BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
+					    offsetof(struct sk_buff, len));
+			break;
+
+		/* Access seccomp_data fields. */
+		case BPF_LDX | BPF_ABS | BPF_W:
+			/* A = *(u32 *) (ctx + K) */
+			*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
+			break;
+
+		/* Unknown instruction. */
+		default:
+			goto err;
+		}
+
+		insn++;
+		if (new_prog)
+			memcpy(new_insn, tmp_insns,
+			       sizeof(*insn) * (insn - tmp_insns));
+		new_insn += insn - tmp_insns;
+	}
+
+	if (!new_prog) {
+		/* Only calculating new length. */
+		*new_len = new_insn - new_prog;
+		return 0;
+	}
+
+	pass++;
+	if (new_flen != new_insn - new_prog) {
+		new_flen = new_insn - new_prog;
+		if (pass > 2)
+			goto err;
+		goto do_pass;
+	}
+
+	kfree(addrs);
+	BUG_ON(*new_len != new_flen);
+	return 0;
+err:
+	kfree(addrs);
+	return -EINVAL;
+}
+
+/* Security:
+ *
+ * As we dont want to clear mem[] array for each packet going through
+ * __bpf_prog_run(), we check that filter loaded by user never try to read
+ * a cell if not previously written, and we check all branches to be sure
+ * a malicious user doesn't try to abuse us.
+ */
+static int check_load_and_stores(const struct sock_filter *filter, int flen)
+{
+	u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */
+	int pc, ret = 0;
+
+	BUILD_BUG_ON(BPF_MEMWORDS > 16);
+
+	masks = kmalloc_array(flen, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		return -ENOMEM;
+
+	memset(masks, 0xff, flen * sizeof(*masks));
+
+	for (pc = 0; pc < flen; pc++) {
+		memvalid &= masks[pc];
+
+		switch (filter[pc].code) {
+		case BPF_ST:
+		case BPF_STX:
+			memvalid |= (1 << filter[pc].k);
+			break;
+		case BPF_LD | BPF_MEM:
+		case BPF_LDX | BPF_MEM:
+			if (!(memvalid & (1 << filter[pc].k))) {
+				ret = -EINVAL;
+				goto error;
+			}
+			break;
+		case BPF_JMP | BPF_JA:
+			/* A jump must set masks on target */
+			masks[pc + 1 + filter[pc].k] &= memvalid;
+			memvalid = ~0;
+			break;
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JEQ | BPF_X:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_X:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_X:
+		case BPF_JMP | BPF_JSET | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_X:
+			/* A jump must set masks on targets */
+			masks[pc + 1 + filter[pc].jt] &= memvalid;
+			masks[pc + 1 + filter[pc].jf] &= memvalid;
+			memvalid = ~0;
+			break;
+		}
+	}
+error:
+	kfree(masks);
+	return ret;
+}
+
+static bool chk_code_allowed(u16 code_to_probe)
+{
+	static const bool codes[] = {
+		/* 32 bit ALU operations */
+		[BPF_ALU | BPF_ADD | BPF_K] = true,
+		[BPF_ALU | BPF_ADD | BPF_X] = true,
+		[BPF_ALU | BPF_SUB | BPF_K] = true,
+		[BPF_ALU | BPF_SUB | BPF_X] = true,
+		[BPF_ALU | BPF_MUL | BPF_K] = true,
+		[BPF_ALU | BPF_MUL | BPF_X] = true,
+		[BPF_ALU | BPF_DIV | BPF_K] = true,
+		[BPF_ALU | BPF_DIV | BPF_X] = true,
+		[BPF_ALU | BPF_MOD | BPF_K] = true,
+		[BPF_ALU | BPF_MOD | BPF_X] = true,
+		[BPF_ALU | BPF_AND | BPF_K] = true,
+		[BPF_ALU | BPF_AND | BPF_X] = true,
+		[BPF_ALU | BPF_OR | BPF_K] = true,
+		[BPF_ALU | BPF_OR | BPF_X] = true,
+		[BPF_ALU | BPF_XOR | BPF_K] = true,
+		[BPF_ALU | BPF_XOR | BPF_X] = true,
+		[BPF_ALU | BPF_LSH | BPF_K] = true,
+		[BPF_ALU | BPF_LSH | BPF_X] = true,
+		[BPF_ALU | BPF_RSH | BPF_K] = true,
+		[BPF_ALU | BPF_RSH | BPF_X] = true,
+		[BPF_ALU | BPF_NEG] = true,
+		/* Load instructions */
+		[BPF_LD | BPF_W | BPF_ABS] = true,
+		[BPF_LD | BPF_H | BPF_ABS] = true,
+		[BPF_LD | BPF_B | BPF_ABS] = true,
+		[BPF_LD | BPF_W | BPF_LEN] = true,
+		[BPF_LD | BPF_W | BPF_IND] = true,
+		[BPF_LD | BPF_H | BPF_IND] = true,
+		[BPF_LD | BPF_B | BPF_IND] = true,
+		[BPF_LD | BPF_IMM] = true,
+		[BPF_LD | BPF_MEM] = true,
+		[BPF_LDX | BPF_W | BPF_LEN] = true,
+		[BPF_LDX | BPF_B | BPF_MSH] = true,
+		[BPF_LDX | BPF_IMM] = true,
+		[BPF_LDX | BPF_MEM] = true,
+		/* Store instructions */
+		[BPF_ST] = true,
+		[BPF_STX] = true,
+		/* Misc instructions */
+		[BPF_MISC | BPF_TAX] = true,
+		[BPF_MISC | BPF_TXA] = true,
+		/* Return instructions */
+		[BPF_RET | BPF_K] = true,
+		[BPF_RET | BPF_A] = true,
+		/* Jump instructions */
+		[BPF_JMP | BPF_JA] = true,
+		[BPF_JMP | BPF_JEQ | BPF_K] = true,
+		[BPF_JMP | BPF_JEQ | BPF_X] = true,
+		[BPF_JMP | BPF_JGE | BPF_K] = true,
+		[BPF_JMP | BPF_JGE | BPF_X] = true,
+		[BPF_JMP | BPF_JGT | BPF_K] = true,
+		[BPF_JMP | BPF_JGT | BPF_X] = true,
+		[BPF_JMP | BPF_JSET | BPF_K] = true,
+		[BPF_JMP | BPF_JSET | BPF_X] = true,
+	};
+
+	if (code_to_probe >= ARRAY_SIZE(codes))
+		return false;
+
+	return codes[code_to_probe];
+}
+
+/**
+ *	bpf_check_classic - verify socket filter code
+ *	@filter: filter to verify
+ *	@flen: length of filter
+ *
+ * Check the user's filter code. If we let some ugly
+ * filter code slip through kaboom! The filter must contain
+ * no references or jumps that are out of range, no illegal
+ * instructions, and must end with a RET instruction.
+ *
+ * All jumps are forward as they are not signed.
+ *
+ * Returns 0 if the rule set is legal or -EINVAL if not.
+ */
+int bpf_check_classic(const struct sock_filter *filter, unsigned int flen)
+{
+	bool anc_found;
+	int pc;
+
+	if (flen == 0 || flen > BPF_MAXINSNS)
+		return -EINVAL;
+
+	/* Check the filter code now */
+	for (pc = 0; pc < flen; pc++) {
+		const struct sock_filter *ftest = &filter[pc];
+
+		/* May we actually operate on this code? */
+		if (!chk_code_allowed(ftest->code))
+			return -EINVAL;
+
+		/* Some instructions need special checks */
+		switch (ftest->code) {
+		case BPF_ALU | BPF_DIV | BPF_K:
+		case BPF_ALU | BPF_MOD | BPF_K:
+			/* Check for division by zero */
+			if (ftest->k == 0)
+				return -EINVAL;
+			break;
+		case BPF_LD | BPF_MEM:
+		case BPF_LDX | BPF_MEM:
+		case BPF_ST:
+		case BPF_STX:
+			/* Check for invalid memory addresses */
+			if (ftest->k >= BPF_MEMWORDS)
+				return -EINVAL;
+			break;
+		case BPF_JMP | BPF_JA:
+			/* Note, the large ftest->k might cause loops.
+			 * Compare this with conditional jumps below,
+			 * where offsets are limited. --ANK (981016)
+			 */
+			if (ftest->k >= (unsigned int)(flen - pc - 1))
+				return -EINVAL;
+			break;
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JEQ | BPF_X:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_X:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_X:
+		case BPF_JMP | BPF_JSET | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_X:
+			/* Both conditionals must be safe */
+			if (pc + ftest->jt + 1 >= flen ||
+			    pc + ftest->jf + 1 >= flen)
+				return -EINVAL;
+			break;
+		case BPF_LD | BPF_W | BPF_ABS:
+		case BPF_LD | BPF_H | BPF_ABS:
+		case BPF_LD | BPF_B | BPF_ABS:
+			anc_found = false;
+			if (bpf_anc_helper(ftest) & BPF_ANC)
+				anc_found = true;
+			/* Ancillary operation unknown or unsupported */
+			if (anc_found == false && ftest->k >= SKF_AD_OFF)
+				return -EINVAL;
+		}
+	}
+
+	/* Last instruction must be a RET code */
+	switch (filter[flen - 1].code) {
+	case BPF_RET | BPF_K:
+	case BPF_RET | BPF_A:
+		return check_load_and_stores(filter, flen);
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(bpf_check_classic);
+
+static int bpf_prog_store_orig_filter(struct bpf_prog *fp,
+				      const struct sock_fprog *fprog)
+{
+	unsigned int fsize = bpf_classic_proglen(fprog);
+	struct sock_fprog_kern *fkprog;
+
+	fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL);
+	if (!fp->orig_prog)
+		return -ENOMEM;
+
+	fkprog = fp->orig_prog;
+	fkprog->len = fprog->len;
+	fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL);
+	if (!fkprog->filter) {
+		kfree(fp->orig_prog);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void bpf_release_orig_filter(struct bpf_prog *fp)
+{
+	struct sock_fprog_kern *fprog = fp->orig_prog;
+
+	if (fprog) {
+		kfree(fprog->filter);
+		kfree(fprog);
+	}
+}
+
+static void __bpf_prog_release(struct bpf_prog *prog)
+{
+	if (prog->type == BPF_PROG_TYPE_SOCKET_FILTER) {
+		bpf_prog_put(prog);
+	} else {
+		bpf_release_orig_filter(prog);
+		bpf_prog_free(prog);
+	}
+}
+
+static void __sk_filter_release(struct sk_filter *fp)
+{
+	__bpf_prog_release(fp->prog);
+	kfree(fp);
+}
+
+/**
+ * 	sk_filter_release_rcu - Release a socket filter by rcu_head
+ *	@rcu: rcu_head that contains the sk_filter to free
+ */
+static void sk_filter_release_rcu(struct rcu_head *rcu)
+{
+	struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
+
+	__sk_filter_release(fp);
+}
+
+/**
+ *	sk_filter_release - release a socket filter
+ *	@fp: filter to remove
+ *
+ *	Remove a filter from a socket and release its resources.
+ */
+static void sk_filter_release(struct sk_filter *fp)
+{
+	if (atomic_dec_and_test(&fp->refcnt))
+		call_rcu(&fp->rcu, sk_filter_release_rcu);
+}
+
+void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
+{
+	u32 filter_size = bpf_prog_size(fp->prog->len);
+
+	atomic_sub(filter_size, &sk->sk_omem_alloc);
+	sk_filter_release(fp);
+}
+
+/* try to charge the socket memory if there is space available
+ * return true on success
+ */
+bool sk_filter_charge(struct sock *sk, struct sk_filter *fp)
+{
+	u32 filter_size = bpf_prog_size(fp->prog->len);
+
+	/* same check as in sock_kmalloc() */
+	if (filter_size <= sysctl_optmem_max &&
+	    atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) {
+		atomic_inc(&fp->refcnt);
+		atomic_add(filter_size, &sk->sk_omem_alloc);
+		return true;
+	}
+	return false;
+}
+
+static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
+{
+	struct sock_filter *old_prog;
+	struct bpf_prog *old_fp;
+	int err, new_len, old_len = fp->len;
+
+	/* We are free to overwrite insns et al right here as it
+	 * won't be used at this point in time anymore internally
+	 * after the migration to the internal BPF instruction
+	 * representation.
+	 */
+	BUILD_BUG_ON(sizeof(struct sock_filter) !=
+		     sizeof(struct bpf_insn));
+
+	/* Conversion cannot happen on overlapping memory areas,
+	 * so we need to keep the user BPF around until the 2nd
+	 * pass. At this time, the user BPF is stored in fp->insns.
+	 */
+	old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
+			   GFP_KERNEL);
+	if (!old_prog) {
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	/* 1st pass: calculate the new program length. */
+	err = bpf_convert_filter(old_prog, old_len, NULL, &new_len);
+	if (err)
+		goto out_err_free;
+
+	/* Expand fp for appending the new filter representation. */
+	old_fp = fp;
+	fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0);
+	if (!fp) {
+		/* The old_fp is still around in case we couldn't
+		 * allocate new memory, so uncharge on that one.
+		 */
+		fp = old_fp;
+		err = -ENOMEM;
+		goto out_err_free;
+	}
+
+	fp->len = new_len;
+
+	/* 2nd pass: remap sock_filter insns into bpf_insn insns. */
+	err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
+	if (err)
+		/* 2nd bpf_convert_filter() can fail only if it fails
+		 * to allocate memory, remapping must succeed. Note,
+		 * that at this time old_fp has already been released
+		 * by krealloc().
+		 */
+		goto out_err_free;
+
+	bpf_prog_select_runtime(fp);
+
+	kfree(old_prog);
+	return fp;
+
+out_err_free:
+	kfree(old_prog);
+out_err:
+	__bpf_prog_release(fp);
+	return ERR_PTR(err);
+}
+
+static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp)
+{
+	int err;
+
+	fp->bpf_func = NULL;
+	fp->jited = false;
+
+	err = bpf_check_classic(fp->insns, fp->len);
+	if (err) {
+		__bpf_prog_release(fp);
+		return ERR_PTR(err);
+	}
+
+	/* Probe if we can JIT compile the filter and if so, do
+	 * the compilation of the filter.
+	 */
+	bpf_jit_compile(fp);
+
+	/* JIT compiler couldn't process this filter, so do the
+	 * internal BPF translation for the optimized interpreter.
+	 */
+	if (!fp->jited)
+		fp = bpf_migrate_filter(fp);
+
+	return fp;
+}
+
+/**
+ *	bpf_prog_create - create an unattached filter
+ *	@pfp: the unattached filter that is created
+ *	@fprog: the filter program
+ *
+ * Create a filter independent of any socket. We first run some
+ * sanity checks on it to make sure it does not explode on us later.
+ * If an error occurs or there is insufficient memory for the filter
+ * a negative errno code is returned. On success the return is zero.
+ */
+int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog)
+{
+	unsigned int fsize = bpf_classic_proglen(fprog);
+	struct bpf_prog *fp;
+
+	/* Make sure new filter is there and in the right amounts. */
+	if (fprog->filter == NULL)
+		return -EINVAL;
+
+	fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0);
+	if (!fp)
+		return -ENOMEM;
+
+	memcpy(fp->insns, fprog->filter, fsize);
+
+	fp->len = fprog->len;
+	/* Since unattached filters are not copied back to user
+	 * space through sk_get_filter(), we do not need to hold
+	 * a copy here, and can spare us the work.
+	 */
+	fp->orig_prog = NULL;
+
+	/* bpf_prepare_filter() already takes care of freeing
+	 * memory in case something goes wrong.
+	 */
+	fp = bpf_prepare_filter(fp);
+	if (IS_ERR(fp))
+		return PTR_ERR(fp);
+
+	*pfp = fp;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_create);
+
+void bpf_prog_destroy(struct bpf_prog *fp)
+{
+	__bpf_prog_release(fp);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_destroy);
+
+static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk)
+{
+	struct sk_filter *fp, *old_fp;
+
+	fp = kmalloc(sizeof(*fp), GFP_KERNEL);
+	if (!fp)
+		return -ENOMEM;
+
+	fp->prog = prog;
+	atomic_set(&fp->refcnt, 0);
+
+	if (!sk_filter_charge(sk, fp)) {
+		kfree(fp);
+		return -ENOMEM;
+	}
+
+	old_fp = rcu_dereference_protected(sk->sk_filter,
+					   sock_owned_by_user(sk));
+	rcu_assign_pointer(sk->sk_filter, fp);
+
+	if (old_fp)
+		sk_filter_uncharge(sk, old_fp);
+
+	return 0;
+}
+
+/**
+ *	sk_attach_filter - attach a socket filter
+ *	@fprog: the filter program
+ *	@sk: the socket to use
+ *
+ * Attach the user's filter code. We first run some sanity checks on
+ * it to make sure it does not explode on us later. If an error
+ * occurs or there is insufficient memory for the filter a negative
+ * errno code is returned. On success the return is zero.
+ */
+int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
+{
+	unsigned int fsize = bpf_classic_proglen(fprog);
+	unsigned int bpf_fsize = bpf_prog_size(fprog->len);
+	struct bpf_prog *prog;
+	int err;
+
+	if (sock_flag(sk, SOCK_FILTER_LOCKED))
+		return -EPERM;
+
+	/* Make sure new filter is there and in the right amounts. */
+	if (fprog->filter == NULL)
+		return -EINVAL;
+
+	prog = bpf_prog_alloc(bpf_fsize, 0);
+	if (!prog)
+		return -ENOMEM;
+
+	if (copy_from_user(prog->insns, fprog->filter, fsize)) {
+		__bpf_prog_free(prog);
+		return -EFAULT;
+	}
+
+	prog->len = fprog->len;
+
+	err = bpf_prog_store_orig_filter(prog, fprog);
+	if (err) {
+		__bpf_prog_free(prog);
+		return -ENOMEM;
+	}
+
+	/* bpf_prepare_filter() already takes care of freeing
+	 * memory in case something goes wrong.
+	 */
+	prog = bpf_prepare_filter(prog);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	err = __sk_attach_prog(prog, sk);
+	if (err < 0) {
+		__bpf_prog_release(prog);
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sk_attach_filter);
+
+int sk_attach_bpf(u32 ufd, struct sock *sk)
+{
+	struct bpf_prog *prog;
+	int err;
+
+	if (sock_flag(sk, SOCK_FILTER_LOCKED))
+		return -EPERM;
+
+	prog = bpf_prog_get(ufd);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) {
+		bpf_prog_put(prog);
+		return -EINVAL;
+	}
+
+	err = __sk_attach_prog(prog, sk);
+	if (err < 0) {
+		bpf_prog_put(prog);
+		return err;
+	}
+
+	return 0;
+}
+
+/**
+ *	bpf_skb_clone_not_writable - is the header of a clone not writable
+ *	@skb: buffer to check
+ *	@len: length up to which to write, can be negative
+ *
+ *	Returns true if modifying the header part of the cloned buffer
+ *	does require the data to be copied. I.e. this version works with
+ *	negative lengths needed for eBPF case!
+ */
+static bool bpf_skb_clone_unwritable(const struct sk_buff *skb, int len)
+{
+	return skb_header_cloned(skb) ||
+	       (int) skb_headroom(skb) + len > skb->hdr_len;
+}
+
+#define BPF_RECOMPUTE_CSUM(flags)	((flags) & 1)
+
+static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
+{
+	struct sk_buff *skb = (struct sk_buff *) (long) r1;
+	int offset = (int) r2;
+	void *from = (void *) (long) r3;
+	unsigned int len = (unsigned int) r4;
+	char buf[16];
+	void *ptr;
+
+	/* bpf verifier guarantees that:
+	 * 'from' pointer points to bpf program stack
+	 * 'len' bytes of it were initialized
+	 * 'len' > 0
+	 * 'skb' is a valid pointer to 'struct sk_buff'
+	 *
+	 * so check for invalid 'offset' and too large 'len'
+	 */
+	if (unlikely((u32) offset > 0xffff || len > sizeof(buf)))
+		return -EFAULT;
+
+	offset -= skb->data - skb_mac_header(skb);
+	if (unlikely(skb_cloned(skb) &&
+		     bpf_skb_clone_unwritable(skb, offset + len)))
+		return -EFAULT;
+
+	ptr = skb_header_pointer(skb, offset, len, buf);
+	if (unlikely(!ptr))
+		return -EFAULT;
+
+	if (BPF_RECOMPUTE_CSUM(flags))
+		skb_postpull_rcsum(skb, ptr, len);
+
+	memcpy(ptr, from, len);
+
+	if (ptr == buf)
+		/* skb_store_bits cannot return -EFAULT here */
+		skb_store_bits(skb, offset, ptr, len);
+
+	if (BPF_RECOMPUTE_CSUM(flags) && skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->csum = csum_add(skb->csum, csum_partial(ptr, len, 0));
+	return 0;
+}
+
+const struct bpf_func_proto bpf_skb_store_bytes_proto = {
+	.func		= bpf_skb_store_bytes,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_PTR_TO_STACK,
+	.arg4_type	= ARG_CONST_STACK_SIZE,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+#define BPF_HEADER_FIELD_SIZE(flags)	((flags) & 0x0f)
+#define BPF_IS_PSEUDO_HEADER(flags)	((flags) & 0x10)
+
+static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
+{
+	struct sk_buff *skb = (struct sk_buff *) (long) r1;
+	int offset = (int) r2;
+	__sum16 sum, *ptr;
+
+	if (unlikely((u32) offset > 0xffff))
+		return -EFAULT;
+
+	offset -= skb->data - skb_mac_header(skb);
+	if (unlikely(skb_cloned(skb) &&
+		     bpf_skb_clone_unwritable(skb, offset + sizeof(sum))))
+		return -EFAULT;
+
+	ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
+	if (unlikely(!ptr))
+		return -EFAULT;
+
+	switch (BPF_HEADER_FIELD_SIZE(flags)) {
+	case 2:
+		csum_replace2(ptr, from, to);
+		break;
+	case 4:
+		csum_replace4(ptr, from, to);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (ptr == &sum)
+		/* skb_store_bits guaranteed to not return -EFAULT here */
+		skb_store_bits(skb, offset, ptr, sizeof(sum));
+
+	return 0;
+}
+
+const struct bpf_func_proto bpf_l3_csum_replace_proto = {
+	.func		= bpf_l3_csum_replace,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags)
+{
+	struct sk_buff *skb = (struct sk_buff *) (long) r1;
+	u32 is_pseudo = BPF_IS_PSEUDO_HEADER(flags);
+	int offset = (int) r2;
+	__sum16 sum, *ptr;
+
+	if (unlikely((u32) offset > 0xffff))
+		return -EFAULT;
+
+	offset -= skb->data - skb_mac_header(skb);
+	if (unlikely(skb_cloned(skb) &&
+		     bpf_skb_clone_unwritable(skb, offset + sizeof(sum))))
+		return -EFAULT;
+
+	ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum);
+	if (unlikely(!ptr))
+		return -EFAULT;
+
+	switch (BPF_HEADER_FIELD_SIZE(flags)) {
+	case 2:
+		inet_proto_csum_replace2(ptr, skb, from, to, is_pseudo);
+		break;
+	case 4:
+		inet_proto_csum_replace4(ptr, skb, from, to, is_pseudo);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (ptr == &sum)
+		/* skb_store_bits guaranteed to not return -EFAULT here */
+		skb_store_bits(skb, offset, ptr, sizeof(sum));
+
+	return 0;
+}
+
+const struct bpf_func_proto bpf_l4_csum_replace_proto = {
+	.func		= bpf_l4_csum_replace,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+sk_filter_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	case BPF_FUNC_map_lookup_elem:
+		return &bpf_map_lookup_elem_proto;
+	case BPF_FUNC_map_update_elem:
+		return &bpf_map_update_elem_proto;
+	case BPF_FUNC_map_delete_elem:
+		return &bpf_map_delete_elem_proto;
+	case BPF_FUNC_get_prandom_u32:
+		return &bpf_get_prandom_u32_proto;
+	case BPF_FUNC_get_smp_processor_id:
+		return &bpf_get_smp_processor_id_proto;
+	default:
+		return NULL;
+	}
+}
+
+static const struct bpf_func_proto *
+tc_cls_act_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	case BPF_FUNC_skb_store_bytes:
+		return &bpf_skb_store_bytes_proto;
+	case BPF_FUNC_l3_csum_replace:
+		return &bpf_l3_csum_replace_proto;
+	case BPF_FUNC_l4_csum_replace:
+		return &bpf_l4_csum_replace_proto;
+	default:
+		return sk_filter_func_proto(func_id);
+	}
+}
+
+static bool sk_filter_is_valid_access(int off, int size,
+				      enum bpf_access_type type)
+{
+	/* only read is allowed */
+	if (type != BPF_READ)
+		return false;
+
+	/* check bounds */
+	if (off < 0 || off >= sizeof(struct __sk_buff))
+		return false;
+
+	/* disallow misaligned access */
+	if (off % size != 0)
+		return false;
+
+	/* all __sk_buff fields are __u32 */
+	if (size != 4)
+		return false;
+
+	return true;
+}
+
+static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off,
+					struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (ctx_off) {
+	case offsetof(struct __sk_buff, len):
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
+
+		*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
+				      offsetof(struct sk_buff, len));
+		break;
+
+	case offsetof(struct __sk_buff, protocol):
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
+
+		*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
+				      offsetof(struct sk_buff, protocol));
+		break;
+
+	case offsetof(struct __sk_buff, vlan_proto):
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+
+		*insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
+				      offsetof(struct sk_buff, vlan_proto));
+		break;
+
+	case offsetof(struct __sk_buff, priority):
+		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, priority) != 4);
+
+		*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
+				      offsetof(struct sk_buff, priority));
+		break;
+
+	case offsetof(struct __sk_buff, mark):
+		return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn);
+
+	case offsetof(struct __sk_buff, pkt_type):
+		return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn);
+
+	case offsetof(struct __sk_buff, queue_mapping):
+		return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn);
+
+	case offsetof(struct __sk_buff, vlan_present):
+		return convert_skb_access(SKF_AD_VLAN_TAG_PRESENT,
+					  dst_reg, src_reg, insn);
+
+	case offsetof(struct __sk_buff, vlan_tci):
+		return convert_skb_access(SKF_AD_VLAN_TAG,
+					  dst_reg, src_reg, insn);
+	}
+
+	return insn - insn_buf;
+}
+
+static const struct bpf_verifier_ops sk_filter_ops = {
+	.get_func_proto = sk_filter_func_proto,
+	.is_valid_access = sk_filter_is_valid_access,
+	.convert_ctx_access = sk_filter_convert_ctx_access,
+};
+
+static const struct bpf_verifier_ops tc_cls_act_ops = {
+	.get_func_proto = tc_cls_act_func_proto,
+	.is_valid_access = sk_filter_is_valid_access,
+	.convert_ctx_access = sk_filter_convert_ctx_access,
+};
+
+static struct bpf_prog_type_list sk_filter_type __read_mostly = {
+	.ops = &sk_filter_ops,
+	.type = BPF_PROG_TYPE_SOCKET_FILTER,
+};
+
+static struct bpf_prog_type_list sched_cls_type __read_mostly = {
+	.ops = &tc_cls_act_ops,
+	.type = BPF_PROG_TYPE_SCHED_CLS,
+};
+
+static struct bpf_prog_type_list sched_act_type __read_mostly = {
+	.ops = &tc_cls_act_ops,
+	.type = BPF_PROG_TYPE_SCHED_ACT,
+};
+
+static int __init register_sk_filter_ops(void)
+{
+	bpf_register_prog_type(&sk_filter_type);
+	bpf_register_prog_type(&sched_cls_type);
+	bpf_register_prog_type(&sched_act_type);
+
+	return 0;
+}
+late_initcall(register_sk_filter_ops);
+
+int sk_detach_filter(struct sock *sk)
+{
+	int ret = -ENOENT;
+	struct sk_filter *filter;
+
+	if (sock_flag(sk, SOCK_FILTER_LOCKED))
+		return -EPERM;
+
+	filter = rcu_dereference_protected(sk->sk_filter,
+					   sock_owned_by_user(sk));
+	if (filter) {
+		RCU_INIT_POINTER(sk->sk_filter, NULL);
+		sk_filter_uncharge(sk, filter);
+		ret = 0;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sk_detach_filter);
+
+int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
+		  unsigned int len)
+{
+	struct sock_fprog_kern *fprog;
+	struct sk_filter *filter;
+	int ret = 0;
+
+	lock_sock(sk);
+	filter = rcu_dereference_protected(sk->sk_filter,
+					   sock_owned_by_user(sk));
+	if (!filter)
+		goto out;
+
+	/* We're copying the filter that has been originally attached,
+	 * so no conversion/decode needed anymore.
+	 */
+	fprog = filter->prog->orig_prog;
+
+	ret = fprog->len;
+	if (!len)
+		/* User space only enquires number of filter blocks. */
+		goto out;
+
+	ret = -EINVAL;
+	if (len < fprog->len)
+		goto out;
+
+	ret = -EFAULT;
+	if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog)))
+		goto out;
+
+	/* Instead of bytes, the API requests to return the number
+	 * of filter blocks.
+	 */
+	ret = fprog->len;
+out:
+	release_sock(sk);
+	return ret;
+}