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92b31a9af7
linux/kernel/bpf/core.c
Daniel Borkmann 92b31a9af7 bpf: add BPF_J{LT,LE,SLT,SLE} instructions 
Currently, eBPF only understands BPF_JGT (>), BPF_JGE (>=),
BPF_JSGT (s>), BPF_JSGE (s>=) instructions, this means that
particularly *JLT/*JLE counterparts involving immediates need
to be rewritten from e.g. X < [IMM] by swapping arguments into
[IMM] > X, meaning the immediate first is required to be loaded
into a register Y := [IMM], such that then we can compare with
Y > X. Note that the destination operand is always required to
be a register.

This has the downside of having unnecessarily increased register
pressure, meaning complex program would need to spill other
registers temporarily to stack in order to obtain an unused
register for the [IMM]. Loading to registers will thus also
affect state pruning since we need to account for that register
use and potentially those registers that had to be spilled/filled
again. As a consequence slightly more stack space might have
been used due to spilling, and BPF programs are a bit longer
due to extra code involving the register load and potentially
required spill/fills.

Thus, add BPF_JLT (<), BPF_JLE (<=), BPF_JSLT (s<), BPF_JSLE (s<=)
counterparts to the eBPF instruction set. Modifying LLVM to
remove the NegateCC() workaround in a PoC patch at [1] and
allowing it to also emit the new instructions resulted in
cilium's BPF programs that are injected into the fast-path to
have a reduced program length in the range of 2-3% (e.g.
accumulated main and tail call sections from one of the object
file reduced from 4864 to 4729 insns), reduced complexity in
the range of 10-30% (e.g. accumulated sections reduced in one
of the cases from 116432 to 88428 insns), and reduced stack
usage in the range of 1-5% (e.g. accumulated sections from one
of the object files reduced from 824 to 784b).

The modification for LLVM will be incorporated in a backwards
compatible way. Plan is for LLVM to have i) a target specific
option to offer a possibility to explicitly enable the extension
by the user (as we have with -m target specific extensions today
for various CPU insns), and ii) have the kernel checked for
presence of the extensions and enable them transparently when
the user is selecting more aggressive options such as -march=native
in a bpf target context. (Other frontends generating BPF byte
code, e.g. ply can probe the kernel directly for its code
generation.)

  [1] https://github.com/borkmann/llvm/tree/bpf-insns

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-09 16:53:56 -07:00

1502 lines
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/*
* 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/filter.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/random.h>
#include <linux/moduleloader.h>
#include <linux/bpf.h>
#include <linux/frame.h>
#include <linux/rbtree_latch.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>
#include <asm/unaligned.h>
/* Registers */
#define BPF_R0 regs[BPF_REG_0]
#define BPF_R1 regs[BPF_REG_1]
#define BPF_R2 regs[BPF_REG_2]
#define BPF_R3 regs[BPF_REG_3]
#define BPF_R4 regs[BPF_REG_4]
#define BPF_R5 regs[BPF_REG_5]
#define BPF_R6 regs[BPF_REG_6]
#define BPF_R7 regs[BPF_REG_7]
#define BPF_R8 regs[BPF_REG_8]
#define BPF_R9 regs[BPF_REG_9]
#define BPF_R10 regs[BPF_REG_10]
/* Named registers */
#define DST regs[insn->dst_reg]
#define SRC regs[insn->src_reg]
#define FP regs[BPF_REG_FP]
#define ARG1 regs[BPF_REG_ARG1]
#define CTX regs[BPF_REG_CTX]
#define IMM insn->imm
/* No hurry in this branch
*
* Exported for the bpf jit load helper.
*/
void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
{
u8 *ptr = NULL;
if (k >= SKF_NET_OFF)
ptr = skb_network_header(skb) + k - SKF_NET_OFF;
else if (k >= SKF_LL_OFF)
ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
return ptr;
return NULL;
}
struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
{
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
struct bpf_prog_aux *aux;
struct bpf_prog *fp;
size = round_up(size, PAGE_SIZE);
fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
if (fp == NULL)
return NULL;
kmemcheck_annotate_bitfield(fp, meta);
aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
if (aux == NULL) {
vfree(fp);
return NULL;
}
fp->pages = size / PAGE_SIZE;
fp->aux = aux;
fp->aux->prog = fp;
INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);
return fp;
}
EXPORT_SYMBOL_GPL(bpf_prog_alloc);
struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
gfp_t gfp_extra_flags)
{
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
struct bpf_prog *fp;
u32 pages, delta;
int ret;
BUG_ON(fp_old == NULL);
size = round_up(size, PAGE_SIZE);
pages = size / PAGE_SIZE;
if (pages <= fp_old->pages)
return fp_old;
delta = pages - fp_old->pages;
ret = __bpf_prog_charge(fp_old->aux->user, delta);
if (ret)
return NULL;
fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
if (fp == NULL) {
__bpf_prog_uncharge(fp_old->aux->user, delta);
} else {
kmemcheck_annotate_bitfield(fp, meta);
memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
fp->pages = pages;
fp->aux->prog = fp;
/* We keep fp->aux from fp_old around in the new
* reallocated structure.
*/
fp_old->aux = NULL;
__bpf_prog_free(fp_old);
}
return fp;
}
void __bpf_prog_free(struct bpf_prog *fp)
{
kfree(fp->aux);
vfree(fp);
}
int bpf_prog_calc_tag(struct bpf_prog *fp)
{
const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
u32 raw_size = bpf_prog_tag_scratch_size(fp);
u32 digest[SHA_DIGEST_WORDS];
u32 ws[SHA_WORKSPACE_WORDS];
u32 i, bsize, psize, blocks;
struct bpf_insn *dst;
bool was_ld_map;
u8 *raw, *todo;
__be32 *result;
__be64 *bits;
raw = vmalloc(raw_size);
if (!raw)
return -ENOMEM;
sha_init(digest);
memset(ws, 0, sizeof(ws));
/* We need to take out the map fd for the digest calculation
* since they are unstable from user space side.
*/
dst = (void *)raw;
for (i = 0, was_ld_map = false; i < fp->len; i++) {
dst[i] = fp->insnsi[i];
if (!was_ld_map &&
dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
was_ld_map = true;
dst[i].imm = 0;
} else if (was_ld_map &&
dst[i].code == 0 &&
dst[i].dst_reg == 0 &&
dst[i].src_reg == 0 &&
dst[i].off == 0) {
was_ld_map = false;
dst[i].imm = 0;
} else {
was_ld_map = false;
}
}
psize = bpf_prog_insn_size(fp);
memset(&raw[psize], 0, raw_size - psize);
raw[psize++] = 0x80;
bsize = round_up(psize, SHA_MESSAGE_BYTES);
blocks = bsize / SHA_MESSAGE_BYTES;
todo = raw;
if (bsize - psize >= sizeof(__be64)) {
bits = (__be64 *)(todo + bsize - sizeof(__be64));
} else {
bits = (__be64 *)(todo + bsize + bits_offset);
blocks++;
}
*bits = cpu_to_be64((psize - 1) << 3);
while (blocks--) {
sha_transform(digest, todo, ws);
todo += SHA_MESSAGE_BYTES;
}
result = (__force __be32 *)digest;
for (i = 0; i < SHA_DIGEST_WORDS; i++)
result[i] = cpu_to_be32(digest[i]);
memcpy(fp->tag, result, sizeof(fp->tag));
vfree(raw);
return 0;
}
static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
{
return BPF_CLASS(insn->code) == BPF_JMP &&
/* Call and Exit are both special jumps with no
* target inside the BPF instruction image.
*/
BPF_OP(insn->code) != BPF_CALL &&
BPF_OP(insn->code) != BPF_EXIT;
}
static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
{
struct bpf_insn *insn = prog->insnsi;
u32 i, insn_cnt = prog->len;
for (i = 0; i < insn_cnt; i++, insn++) {
if (!bpf_is_jmp_and_has_target(insn))
continue;
/* Adjust offset of jmps if we cross boundaries. */
if (i < pos && i + insn->off + 1 > pos)
insn->off += delta;
else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
insn->off -= delta;
}
}
struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
const struct bpf_insn *patch, u32 len)
{
u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
struct bpf_prog *prog_adj;
/* Since our patchlet doesn't expand the image, we're done. */
if (insn_delta == 0) {
memcpy(prog->insnsi + off, patch, sizeof(*patch));
return prog;
}
insn_adj_cnt = prog->len + insn_delta;
/* Several new instructions need to be inserted. Make room
* for them. Likely, there's no need for a new allocation as
* last page could have large enough tailroom.
*/
prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
GFP_USER);
if (!prog_adj)
return NULL;
prog_adj->len = insn_adj_cnt;
/* Patching happens in 3 steps:
*
* 1) Move over tail of insnsi from next instruction onwards,
* so we can patch the single target insn with one or more
* new ones (patching is always from 1 to n insns, n > 0).
* 2) Inject new instructions at the target location.
* 3) Adjust branch offsets if necessary.
*/
insn_rest = insn_adj_cnt - off - len;
memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
sizeof(*patch) * insn_rest);
memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
bpf_adj_branches(prog_adj, off, insn_delta);
return prog_adj;
}
#ifdef CONFIG_BPF_JIT
static __always_inline void
bpf_get_prog_addr_region(const struct bpf_prog *prog,
unsigned long *symbol_start,
unsigned long *symbol_end)
{
const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
unsigned long addr = (unsigned long)hdr;
WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
*symbol_start = addr;
*symbol_end = addr + hdr->pages * PAGE_SIZE;
}
static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
{
BUILD_BUG_ON(sizeof("bpf_prog_") +
sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
*sym = 0;
}
static __always_inline unsigned long
bpf_get_prog_addr_start(struct latch_tree_node *n)
{
unsigned long symbol_start, symbol_end;
const struct bpf_prog_aux *aux;
aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
return symbol_start;
}
static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
struct latch_tree_node *b)
{
return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
}
static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
{
unsigned long val = (unsigned long)key;
unsigned long symbol_start, symbol_end;
const struct bpf_prog_aux *aux;
aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
if (val < symbol_start)
return -1;
if (val >= symbol_end)
return 1;
return 0;
}
static const struct latch_tree_ops bpf_tree_ops = {
.less = bpf_tree_less,
.comp = bpf_tree_comp,
};
static DEFINE_SPINLOCK(bpf_lock);
static LIST_HEAD(bpf_kallsyms);
static struct latch_tree_root bpf_tree __cacheline_aligned;
int bpf_jit_kallsyms __read_mostly;
static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
{
WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
}
static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
{
if (list_empty(&aux->ksym_lnode))
return;
latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
list_del_rcu(&aux->ksym_lnode);
}
static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
{
return fp->jited && !bpf_prog_was_classic(fp);
}
static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
{
return list_empty(&fp->aux->ksym_lnode) ||
fp->aux->ksym_lnode.prev == LIST_POISON2;
}
void bpf_prog_kallsyms_add(struct bpf_prog *fp)
{
if (!bpf_prog_kallsyms_candidate(fp) ||
!capable(CAP_SYS_ADMIN))
return;
spin_lock_bh(&bpf_lock);
bpf_prog_ksym_node_add(fp->aux);
spin_unlock_bh(&bpf_lock);
}
void bpf_prog_kallsyms_del(struct bpf_prog *fp)
{
if (!bpf_prog_kallsyms_candidate(fp))
return;
spin_lock_bh(&bpf_lock);
bpf_prog_ksym_node_del(fp->aux);
spin_unlock_bh(&bpf_lock);
}
static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
{
struct latch_tree_node *n;
if (!bpf_jit_kallsyms_enabled())
return NULL;
n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
return n ?
container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
NULL;
}
const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
unsigned long *off, char *sym)
{
unsigned long symbol_start, symbol_end;
struct bpf_prog *prog;
char *ret = NULL;
rcu_read_lock();
prog = bpf_prog_kallsyms_find(addr);
if (prog) {
bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
bpf_get_prog_name(prog, sym);
ret = sym;
if (size)
*size = symbol_end - symbol_start;
if (off)
*off = addr - symbol_start;
}
rcu_read_unlock();
return ret;
}
bool is_bpf_text_address(unsigned long addr)
{
bool ret;
rcu_read_lock();
ret = bpf_prog_kallsyms_find(addr) != NULL;
rcu_read_unlock();
return ret;
}
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *sym)
{
unsigned long symbol_start, symbol_end;
struct bpf_prog_aux *aux;
unsigned int it = 0;
int ret = -ERANGE;
if (!bpf_jit_kallsyms_enabled())
return ret;
rcu_read_lock();
list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
if (it++ != symnum)
continue;
bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
bpf_get_prog_name(aux->prog, sym);
*value = symbol_start;
*type = BPF_SYM_ELF_TYPE;
ret = 0;
break;
}
rcu_read_unlock();
return ret;
}
struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
unsigned int alignment,
bpf_jit_fill_hole_t bpf_fill_ill_insns)
{
struct bpf_binary_header *hdr;
unsigned int size, hole, start;
/* Most of BPF filters are really small, but if some of them
* fill a page, allow at least 128 extra bytes to insert a
* random section of illegal instructions.
*/
size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
hdr = module_alloc(size);
if (hdr == NULL)
return NULL;
/* Fill space with illegal/arch-dep instructions. */
bpf_fill_ill_insns(hdr, size);
hdr->pages = size / PAGE_SIZE;
hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
PAGE_SIZE - sizeof(*hdr));
start = (get_random_int() % hole) & ~(alignment - 1);
/* Leave a random number of instructions before BPF code. */
*image_ptr = &hdr->image[start];
return hdr;
}
void bpf_jit_binary_free(struct bpf_binary_header *hdr)
{
module_memfree(hdr);
}
/* This symbol is only overridden by archs that have different
* requirements than the usual eBPF JITs, f.e. when they only
* implement cBPF JIT, do not set images read-only, etc.
*/
void __weak bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited) {
struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
bpf_jit_binary_unlock_ro(hdr);
bpf_jit_binary_free(hdr);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
}
bpf_prog_unlock_free(fp);
}
int bpf_jit_harden __read_mostly;
static int bpf_jit_blind_insn(const struct bpf_insn *from,
const struct bpf_insn *aux,
struct bpf_insn *to_buff)
{
struct bpf_insn *to = to_buff;
u32 imm_rnd = get_random_int();
s16 off;
BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
if (from->imm == 0 &&
(from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
goto out;
}
switch (from->code) {
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_MOV | BPF_K:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_MOD | BPF_K:
*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
break;
case BPF_ALU64 | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_MOV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
break;
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JLE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_K:
case BPF_JMP | BPF_JSET | BPF_K:
/* Accommodate for extra offset in case of a backjump. */
off = from->off;
if (off < 0)
off -= 2;
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
break;
case BPF_LD | BPF_ABS | BPF_W:
case BPF_LD | BPF_ABS | BPF_H:
case BPF_LD | BPF_ABS | BPF_B:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
break;
case BPF_LD | BPF_IND | BPF_W:
case BPF_LD | BPF_IND | BPF_H:
case BPF_LD | BPF_IND | BPF_B:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
*to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
break;
case BPF_LD | BPF_IMM | BPF_DW:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
break;
case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
break;
case BPF_ST | BPF_MEM | BPF_DW:
case BPF_ST | BPF_MEM | BPF_W:
case BPF_ST | BPF_MEM | BPF_H:
case BPF_ST | BPF_MEM | BPF_B:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
break;
}
out:
return to - to_buff;
}
static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
gfp_t gfp_extra_flags)
{
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
struct bpf_prog *fp;
fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
if (fp != NULL) {
kmemcheck_annotate_bitfield(fp, meta);
/* aux->prog still points to the fp_other one, so
* when promoting the clone to the real program,
* this still needs to be adapted.
*/
memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
}
return fp;
}
static void bpf_prog_clone_free(struct bpf_prog *fp)
{
/* aux was stolen by the other clone, so we cannot free
* it from this path! It will be freed eventually by the
* other program on release.
*
* At this point, we don't need a deferred release since
* clone is guaranteed to not be locked.
*/
fp->aux = NULL;
__bpf_prog_free(fp);
}
void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
{
/* We have to repoint aux->prog to self, as we don't
* know whether fp here is the clone or the original.
*/
fp->aux->prog = fp;
bpf_prog_clone_free(fp_other);
}
struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
{
struct bpf_insn insn_buff[16], aux[2];
struct bpf_prog *clone, *tmp;
int insn_delta, insn_cnt;
struct bpf_insn *insn;
int i, rewritten;
if (!bpf_jit_blinding_enabled())
return prog;
clone = bpf_prog_clone_create(prog, GFP_USER);
if (!clone)
return ERR_PTR(-ENOMEM);
insn_cnt = clone->len;
insn = clone->insnsi;
for (i = 0; i < insn_cnt; i++, insn++) {
/* We temporarily need to hold the original ld64 insn
* so that we can still access the first part in the
* second blinding run.
*/
if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
insn[1].code == 0)
memcpy(aux, insn, sizeof(aux));
rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
if (!rewritten)
continue;
tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
if (!tmp) {
/* Patching may have repointed aux->prog during
* realloc from the original one, so we need to
* fix it up here on error.
*/
bpf_jit_prog_release_other(prog, clone);
return ERR_PTR(-ENOMEM);
}
clone = tmp;
insn_delta = rewritten - 1;
/* Walk new program and skip insns we just inserted. */
insn = clone->insnsi + i + insn_delta;
insn_cnt += insn_delta;
i += insn_delta;
}
return clone;
}
#endif /* CONFIG_BPF_JIT */
/* Base function for offset calculation. Needs to go into .text section,
* therefore keeping it non-static as well; will also be used by JITs
* anyway later on, so do not let the compiler omit it.
*/
noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
return 0;
}
EXPORT_SYMBOL_GPL(__bpf_call_base);
/**
* __bpf_prog_run - run eBPF program on a given context
* @ctx: is the data we are operating on
* @insn: is the array of eBPF instructions
*
* Decode and execute eBPF instructions.
*/
static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn,
u64 *stack)
{
u64 tmp;
static const void *jumptable[256] = {
[0 ... 255] = &&default_label,
/* Now overwrite non-defaults ... */
/* 32 bit ALU operations */
[BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
[BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
[BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
[BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
[BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
[BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
[BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
[BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
[BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
[BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
[BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
[BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
[BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
[BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
[BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
[BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
[BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
[BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
[BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
[BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
[BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
[BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
[BPF_ALU | BPF_NEG] = &&ALU_NEG,
[BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
[BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
/* 64 bit ALU operations */
[BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
[BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
[BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
[BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
[BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
[BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
[BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
[BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
[BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
[BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
[BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
[BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
[BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
[BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
[BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
[BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
[BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
[BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
[BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
[BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
[BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
[BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
[BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
[BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
[BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
/* Call instruction */
[BPF_JMP | BPF_CALL] = &&JMP_CALL,
[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
/* Jumps */
[BPF_JMP | BPF_JA] = &&JMP_JA,
[BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
[BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
[BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
[BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
[BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
[BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
[BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X,
[BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K,
[BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
[BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
[BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X,
[BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K,
[BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
[BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
[BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X,
[BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K,
[BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
[BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
[BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X,
[BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K,
[BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
[BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
/* Program return */
[BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
/* Store instructions */
[BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
[BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
[BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
[BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
[BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
[BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
[BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
[BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
[BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
[BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
/* Load instructions */
[BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
[BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
[BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
[BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
[BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
[BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
[BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
[BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
[BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
[BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
[BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
};
u32 tail_call_cnt = 0;
void *ptr;
int off;
#define CONT ({ insn++; goto select_insn; })
#define CONT_JMP ({ insn++; goto select_insn; })
select_insn:
goto *jumptable[insn->code];
/* ALU */
#define ALU(OPCODE, OP) \
ALU64_##OPCODE##_X: \
DST = DST OP SRC; \
CONT; \
ALU_##OPCODE##_X: \
DST = (u32) DST OP (u32) SRC; \
CONT; \
ALU64_##OPCODE##_K: \
DST = DST OP IMM; \
CONT; \
ALU_##OPCODE##_K: \
DST = (u32) DST OP (u32) IMM; \
CONT;
ALU(ADD, +)
ALU(SUB, -)
ALU(AND, &)
ALU(OR, |)
ALU(LSH, <<)
ALU(RSH, >>)
ALU(XOR, ^)
ALU(MUL, *)
#undef ALU
ALU_NEG:
DST = (u32) -DST;
CONT;
ALU64_NEG:
DST = -DST;
CONT;
ALU_MOV_X:
DST = (u32) SRC;
CONT;
ALU_MOV_K:
DST = (u32) IMM;
CONT;
ALU64_MOV_X:
DST = SRC;
CONT;
ALU64_MOV_K:
DST = IMM;
CONT;
LD_IMM_DW:
DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
insn++;
CONT;
ALU64_ARSH_X:
(*(s64 *) &DST) >>= SRC;
CONT;
ALU64_ARSH_K:
(*(s64 *) &DST) >>= IMM;
CONT;
ALU64_MOD_X:
if (unlikely(SRC == 0))
return 0;
div64_u64_rem(DST, SRC, &tmp);
DST = tmp;
CONT;
ALU_MOD_X:
if (unlikely(SRC == 0))
return 0;
tmp = (u32) DST;
DST = do_div(tmp, (u32) SRC);
CONT;
ALU64_MOD_K:
div64_u64_rem(DST, IMM, &tmp);
DST = tmp;
CONT;
ALU_MOD_K:
tmp = (u32) DST;
DST = do_div(tmp, (u32) IMM);
CONT;
ALU64_DIV_X:
if (unlikely(SRC == 0))
return 0;
DST = div64_u64(DST, SRC);
CONT;
ALU_DIV_X:
if (unlikely(SRC == 0))
return 0;
tmp = (u32) DST;
do_div(tmp, (u32) SRC);
DST = (u32) tmp;
CONT;
ALU64_DIV_K:
DST = div64_u64(DST, IMM);
CONT;
ALU_DIV_K:
tmp = (u32) DST;
do_div(tmp, (u32) IMM);
DST = (u32) tmp;
CONT;
ALU_END_TO_BE:
switch (IMM) {
case 16:
DST = (__force u16) cpu_to_be16(DST);
break;
case 32:
DST = (__force u32) cpu_to_be32(DST);
break;
case 64:
DST = (__force u64) cpu_to_be64(DST);
break;
}
CONT;
ALU_END_TO_LE:
switch (IMM) {
case 16:
DST = (__force u16) cpu_to_le16(DST);
break;
case 32:
DST = (__force u32) cpu_to_le32(DST);
break;
case 64:
DST = (__force u64) cpu_to_le64(DST);
break;
}
CONT;
/* CALL */
JMP_CALL:
/* Function call scratches BPF_R1-BPF_R5 registers,
* preserves BPF_R6-BPF_R9, and stores return value
* into BPF_R0.
*/
BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
BPF_R4, BPF_R5);
CONT;
JMP_TAIL_CALL: {
struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_prog *prog;
u64 index = BPF_R3;
if (unlikely(index >= array->map.max_entries))
goto out;
if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
goto out;
tail_call_cnt++;
prog = READ_ONCE(array->ptrs[index]);
if (!prog)
goto out;
/* ARG1 at this point is guaranteed to point to CTX from
* the verifier side due to the fact that the tail call is
* handeled like a helper, that is, bpf_tail_call_proto,
* where arg1_type is ARG_PTR_TO_CTX.
*/
insn = prog->insnsi;
goto select_insn;
out:
CONT;
}
/* JMP */
JMP_JA:
insn += insn->off;
CONT;
JMP_JEQ_X:
if (DST == SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JEQ_K:
if (DST == IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JNE_X:
if (DST != SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JNE_K:
if (DST != IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JGT_X:
if (DST > SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JGT_K:
if (DST > IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JLT_X:
if (DST < SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JLT_K:
if (DST < IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JGE_X:
if (DST >= SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JGE_K:
if (DST >= IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JLE_X:
if (DST <= SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JLE_K:
if (DST <= IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSGT_X:
if (((s64) DST) > ((s64) SRC)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSGT_K:
if (((s64) DST) > ((s64) IMM)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSLT_X:
if (((s64) DST) < ((s64) SRC)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSLT_K:
if (((s64) DST) < ((s64) IMM)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSGE_X:
if (((s64) DST) >= ((s64) SRC)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSGE_K:
if (((s64) DST) >= ((s64) IMM)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSLE_X:
if (((s64) DST) <= ((s64) SRC)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSLE_K:
if (((s64) DST) <= ((s64) IMM)) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSET_X:
if (DST & SRC) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_JSET_K:
if (DST & IMM) {
insn += insn->off;
CONT_JMP;
}
CONT;
JMP_EXIT:
return BPF_R0;
/* STX and ST and LDX*/
#define LDST(SIZEOP, SIZE) \
STX_MEM_##SIZEOP: \
*(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
CONT; \
ST_MEM_##SIZEOP: \
*(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
CONT; \
LDX_MEM_##SIZEOP: \
DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
CONT;
LDST(B, u8)
LDST(H, u16)
LDST(W, u32)
LDST(DW, u64)
#undef LDST
STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
atomic_add((u32) SRC, (atomic_t *)(unsigned long)
(DST + insn->off));
CONT;
STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
(DST + insn->off));
CONT;
LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
off = IMM;
load_word:
/* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
* appearing in the programs where ctx == skb
* (see may_access_skb() in the verifier). All programs
* keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
* bpf_convert_filter() saves it in BPF_R6, internal BPF
* verifier will check that BPF_R6 == ctx.
*
* BPF_ABS and BPF_IND are wrappers of function calls,
* so they scratch BPF_R1-BPF_R5 registers, preserve
* BPF_R6-BPF_R9, and store return value into BPF_R0.
*
* Implicit input:
* ctx == skb == BPF_R6 == CTX
*
* Explicit input:
* SRC == any register
* IMM == 32-bit immediate
*
* Output:
* BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
*/
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = get_unaligned_be32(ptr);
CONT;
}
return 0;
LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
off = IMM;
load_half:
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = get_unaligned_be16(ptr);
CONT;
}
return 0;
LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
off = IMM;
load_byte:
ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = *(u8 *)ptr;
CONT;
}
return 0;
LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
off = IMM + SRC;
goto load_word;
LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
off = IMM + SRC;
goto load_half;
LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
off = IMM + SRC;
goto load_byte;
default_label:
/* If we ever reach this, we have a bug somewhere. */
WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
return 0;
}
STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
#define PROG_NAME(stack_size) __bpf_prog_run##stack_size
#define DEFINE_BPF_PROG_RUN(stack_size) \
static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
{ \
u64 stack[stack_size / sizeof(u64)]; \
u64 regs[MAX_BPF_REG]; \
\
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
ARG1 = (u64) (unsigned long) ctx; \
return ___bpf_prog_run(regs, insn, stack); \
}
#define EVAL1(FN, X) FN(X)
#define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
#define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
#define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
#define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
static unsigned int (*interpreters[])(const void *ctx,
const struct bpf_insn *insn) = {
EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
};
bool bpf_prog_array_compatible(struct bpf_array *array,
const struct bpf_prog *fp)
{
if (!array->owner_prog_type) {
/* There's no owner yet where we could check for
* compatibility.
*/
array->owner_prog_type = fp->type;
array->owner_jited = fp->jited;
return true;
}
return array->owner_prog_type == fp->type &&
array->owner_jited == fp->jited;
}
static int bpf_check_tail_call(const struct bpf_prog *fp)
{
struct bpf_prog_aux *aux = fp->aux;
int i;
for (i = 0; i < aux->used_map_cnt; i++) {
struct bpf_map *map = aux->used_maps[i];
struct bpf_array *array;
if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
continue;
array = container_of(map, struct bpf_array, map);
if (!bpf_prog_array_compatible(array, fp))
return -EINVAL;
}
return 0;
}
/**
* bpf_prog_select_runtime - select exec runtime for BPF program
* @fp: bpf_prog populated with internal BPF program
* @err: pointer to error variable
*
* Try to JIT eBPF program, if JIT is not available, use interpreter.
* The BPF program will be executed via BPF_PROG_RUN() macro.
*/
struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
{
u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
/* eBPF JITs can rewrite the program in case constant
* blinding is active. However, in case of error during
* blinding, bpf_int_jit_compile() must always return a
* valid program, which in this case would simply not
* be JITed, but falls back to the interpreter.
*/
fp = bpf_int_jit_compile(fp);
bpf_prog_lock_ro(fp);
/* The tail call compatibility check can only be done at
* this late stage as we need to determine, if we deal
* with JITed or non JITed program concatenations and not
* all eBPF JITs might immediately support all features.
*/
*err = bpf_check_tail_call(fp);
return fp;
}
EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
static void bpf_prog_free_deferred(struct work_struct *work)
{
struct bpf_prog_aux *aux;
aux = container_of(work, struct bpf_prog_aux, work);
bpf_jit_free(aux->prog);
}
/* Free internal BPF program */
void bpf_prog_free(struct bpf_prog *fp)
{
struct bpf_prog_aux *aux = fp->aux;
INIT_WORK(&aux->work, bpf_prog_free_deferred);
schedule_work(&aux->work);
}
EXPORT_SYMBOL_GPL(bpf_prog_free);
/* RNG for unpriviledged user space with separated state from prandom_u32(). */
static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
void bpf_user_rnd_init_once(void)
{
prandom_init_once(&bpf_user_rnd_state);
}
BPF_CALL_0(bpf_user_rnd_u32)
{
/* Should someone ever have the rather unwise idea to use some
* of the registers passed into this function, then note that
* this function is called from native eBPF and classic-to-eBPF
* transformations. Register assignments from both sides are
* different, f.e. classic always sets fn(ctx, A, X) here.
*/
struct rnd_state *state;
u32 res;
state = &get_cpu_var(bpf_user_rnd_state);
res = prandom_u32_state(state);
put_cpu_var(bpf_user_rnd_state);
return res;
}
/* Weak definitions of helper functions in case we don't have bpf syscall. */
const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
const struct bpf_func_proto bpf_map_update_elem_proto __weak;
const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
const struct bpf_func_proto bpf_get_current_comm_proto __weak;
const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
return NULL;
}
u64 __weak
bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
{
return -ENOTSUPP;
}
/* Always built-in helper functions. */
const struct bpf_func_proto bpf_tail_call_proto = {
.func = NULL,
.gpl_only = false,
.ret_type = RET_VOID,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
};
/* Stub for JITs that only support cBPF. eBPF programs are interpreted.
* It is encouraged to implement bpf_int_jit_compile() instead, so that
* eBPF and implicitly also cBPF can get JITed!
*/
struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
{
return prog;
}
/* Stub for JITs that support eBPF. All cBPF code gets transformed into
* eBPF by the kernel and is later compiled by bpf_int_jit_compile().
*/
void __weak bpf_jit_compile(struct bpf_prog *prog)
{
}
bool __weak bpf_helper_changes_pkt_data(void *func)
{
return false;
}
/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
* skb_copy_bits(), so provide a weak definition of it for NET-less config.
*/
int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
int len)
{
return -EFAULT;
}
/* All definitions of tracepoints related to BPF. */
#define CREATE_TRACE_POINTS
#include <linux/bpf_trace.h>
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);
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