diff options
Diffstat (limited to 'net/core/filter.c')
-rw-r--r-- | net/core/filter.c | 1553 |
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; +} |