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android-kvm / linux / ec8f7f4821d5e70d71601519bc2325b311324a96 / . / kernel / bpf / core.c
blob: 5f6f3f829b368aca466b07772a2938629ecb600f [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*
* Andi Kleen - Fix a few bad bugs and races.
* Kris Katterjohn - Added many additional checks in bpf_check_classic()
*/
#include <uapi/linux/btf.h>
#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/btf.h>
#include <linux/objtool.h>
#include <linux/rbtree_latch.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>
#include <linux/perf_event.h>
#include <linux/extable.h>
#include <linux/log2.h>
#include <linux/bpf_verifier.h>
#include <linux/nodemask.h>
#include <asm/barrier.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 AX regs[BPF_REG_AX]
#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_no_stats(unsigned int size, gfp_t gfp_extra_flags)
{
gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __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);
if (fp == NULL)
return NULL;
aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags);
if (aux == NULL) {
vfree(fp);
return NULL;
}
fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags);
if (!fp->active) {
vfree(fp);
kfree(aux);
return NULL;
}
fp->pages = size / PAGE_SIZE;
fp->aux = aux;
fp->aux->prog = fp;
fp->jit_requested = ebpf_jit_enabled();
fp->blinding_requested = bpf_jit_blinding_enabled(fp);
INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
mutex_init(&fp->aux->used_maps_mutex);
mutex_init(&fp->aux->dst_mutex);
return fp;
}
struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
{
gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
struct bpf_prog *prog;
int cpu;
prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
if (!prog)
return NULL;
prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
if (!prog->stats) {
free_percpu(prog->active);
kfree(prog->aux);
vfree(prog);
return NULL;
}
for_each_possible_cpu(cpu) {
struct bpf_prog_stats *pstats;
pstats = per_cpu_ptr(prog->stats, cpu);
u64_stats_init(&pstats->syncp);
}
return prog;
}
EXPORT_SYMBOL_GPL(bpf_prog_alloc);
int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
{
if (!prog->aux->nr_linfo || !prog->jit_requested)
return 0;
prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
sizeof(*prog->aux->jited_linfo),
GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
if (!prog->aux->jited_linfo)
return -ENOMEM;
return 0;
}
void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
{
if (prog->aux->jited_linfo &&
(!prog->jited || !prog->aux->jited_linfo[0])) {
kvfree(prog->aux->jited_linfo);
prog->aux->jited_linfo = NULL;
}
kfree(prog->aux->kfunc_tab);
prog->aux->kfunc_tab = NULL;
}
/* The jit engine is responsible to provide an array
* for insn_off to the jited_off mapping (insn_to_jit_off).
*
* The idx to this array is the insn_off. Hence, the insn_off
* here is relative to the prog itself instead of the main prog.
* This array has one entry for each xlated bpf insn.
*
* jited_off is the byte off to the last byte of the jited insn.
*
* Hence, with
* insn_start:
* The first bpf insn off of the prog. The insn off
* here is relative to the main prog.
* e.g. if prog is a subprog, insn_start > 0
* linfo_idx:
* The prog's idx to prog->aux->linfo and jited_linfo
*
* jited_linfo[linfo_idx] = prog->bpf_func
*
* For i > linfo_idx,
*
* jited_linfo[i] = prog->bpf_func +
* insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
*/
void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
const u32 *insn_to_jit_off)
{
u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
const struct bpf_line_info *linfo;
void **jited_linfo;
if (!prog->aux->jited_linfo)
/* Userspace did not provide linfo */
return;
linfo_idx = prog->aux->linfo_idx;
linfo = &prog->aux->linfo[linfo_idx];
insn_start = linfo[0].insn_off;
insn_end = insn_start + prog->len;
jited_linfo = &prog->aux->jited_linfo[linfo_idx];
jited_linfo[0] = prog->bpf_func;
nr_linfo = prog->aux->nr_linfo - linfo_idx;
for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
/* The verifier ensures that linfo[i].insn_off is
* strictly increasing
*/
jited_linfo[i] = prog->bpf_func +
insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
}
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_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
struct bpf_prog *fp;
u32 pages;
size = round_up(size, PAGE_SIZE);
pages = size / PAGE_SIZE;
if (pages <= fp_old->pages)
return fp_old;
fp = __vmalloc(size, gfp_flags);
if (fp) {
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;
fp_old->stats = NULL;
fp_old->active = NULL;
__bpf_prog_free(fp_old);
}
return fp;
}
void __bpf_prog_free(struct bpf_prog *fp)
{
if (fp->aux) {
mutex_destroy(&fp->aux->used_maps_mutex);
mutex_destroy(&fp->aux->dst_mutex);
kfree(fp->aux->poke_tab);
kfree(fp->aux);
}
free_percpu(fp->stats);
free_percpu(fp->active);
vfree(fp);
}
int bpf_prog_calc_tag(struct bpf_prog *fp)
{
const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
u32 raw_size = bpf_prog_tag_scratch_size(fp);
u32 digest[SHA1_DIGEST_WORDS];
u32 ws[SHA1_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;
sha1_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 ||
dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
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, SHA1_BLOCK_SIZE);
blocks = bsize / SHA1_BLOCK_SIZE;
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--) {
sha1_transform(digest, todo, ws);
todo += SHA1_BLOCK_SIZE;
}
result = (__force __be32 *)digest;
for (i = 0; i < SHA1_DIGEST_WORDS; i++)
result[i] = cpu_to_be32(digest[i]);
memcpy(fp->tag, result, sizeof(fp->tag));
vfree(raw);
return 0;
}
static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
s32 end_new, s32 curr, const bool probe_pass)
{
const s64 imm_min = S32_MIN, imm_max = S32_MAX;
s32 delta = end_new - end_old;
s64 imm = insn->imm;
if (curr < pos && curr + imm + 1 >= end_old)
imm += delta;
else if (curr >= end_new && curr + imm + 1 < end_new)
imm -= delta;
if (imm < imm_min || imm > imm_max)
return -ERANGE;
if (!probe_pass)
insn->imm = imm;
return 0;
}
static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
s32 end_new, s32 curr, const bool probe_pass)
{
const s32 off_min = S16_MIN, off_max = S16_MAX;
s32 delta = end_new - end_old;
s32 off = insn->off;
if (curr < pos && curr + off + 1 >= end_old)
off += delta;
else if (curr >= end_new && curr + off + 1 < end_new)
off -= delta;
if (off < off_min || off > off_max)
return -ERANGE;
if (!probe_pass)
insn->off = off;
return 0;
}
static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
s32 end_new, const bool probe_pass)
{
u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
struct bpf_insn *insn = prog->insnsi;
int ret = 0;
for (i = 0; i < insn_cnt; i++, insn++) {
u8 code;
/* In the probing pass we still operate on the original,
* unpatched image in order to check overflows before we
* do any other adjustments. Therefore skip the patchlet.
*/
if (probe_pass && i == pos) {
i = end_new;
insn = prog->insnsi + end_old;
}
if (bpf_pseudo_func(insn)) {
ret = bpf_adj_delta_to_imm(insn, pos, end_old,
end_new, i, probe_pass);
if (ret)
return ret;
continue;
}
code = insn->code;
if ((BPF_CLASS(code) != BPF_JMP &&
BPF_CLASS(code) != BPF_JMP32) ||
BPF_OP(code) == BPF_EXIT)
continue;
/* Adjust offset of jmps if we cross patch boundaries. */
if (BPF_OP(code) == BPF_CALL) {
if (insn->src_reg != BPF_PSEUDO_CALL)
continue;
ret = bpf_adj_delta_to_imm(insn, pos, end_old,
end_new, i, probe_pass);
} else {
ret = bpf_adj_delta_to_off(insn, pos, end_old,
end_new, i, probe_pass);
}
if (ret)
break;
}
return ret;
}
static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
{
struct bpf_line_info *linfo;
u32 i, nr_linfo;
nr_linfo = prog->aux->nr_linfo;
if (!nr_linfo || !delta)
return;
linfo = prog->aux->linfo;
for (i = 0; i < nr_linfo; i++)
if (off < linfo[i].insn_off)
break;
/* Push all off < linfo[i].insn_off by delta */
for (; i < nr_linfo; i++)
linfo[i].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;
const u32 cnt_max = S16_MAX;
struct bpf_prog *prog_adj;
int err;
/* 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;
/* Reject anything that would potentially let the insn->off
* target overflow when we have excessive program expansions.
* We need to probe here before we do any reallocation where
* we afterwards may not fail anymore.
*/
if (insn_adj_cnt > cnt_max &&
(err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
return ERR_PTR(err);
/* 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 ERR_PTR(-ENOMEM);
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);
/* We are guaranteed to not fail at this point, otherwise
* the ship has sailed to reverse to the original state. An
* overflow cannot happen at this point.
*/
BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
bpf_adj_linfo(prog_adj, off, insn_delta);
return prog_adj;
}
int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
{
/* Branch offsets can't overflow when program is shrinking, no need
* to call bpf_adj_branches(..., true) here
*/
memmove(prog->insnsi + off, prog->insnsi + off + cnt,
sizeof(struct bpf_insn) * (prog->len - off - cnt));
prog->len -= cnt;
return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
}
static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
{
int i;
for (i = 0; i < fp->aux->func_cnt; i++)
bpf_prog_kallsyms_del(fp->aux->func[i]);
}
void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
{
bpf_prog_kallsyms_del_subprogs(fp);
bpf_prog_kallsyms_del(fp);
}
#ifdef CONFIG_BPF_JIT
/* All BPF JIT sysctl knobs here. */
int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_harden __read_mostly;
long bpf_jit_limit __read_mostly;
long bpf_jit_limit_max __read_mostly;
static void
bpf_prog_ksym_set_addr(struct bpf_prog *prog)
{
WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
prog->aux->ksym.start = (unsigned long) prog->bpf_func;
prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len;
}
static void
bpf_prog_ksym_set_name(struct bpf_prog *prog)
{
char *sym = prog->aux->ksym.name;
const char *end = sym + KSYM_NAME_LEN;
const struct btf_type *type;
const char *func_name;
BUILD_BUG_ON(sizeof("bpf_prog_") +
sizeof(prog->tag) * 2 +
/* name has been null terminated.
* We should need +1 for the '_' preceding
* the name. However, the null character
* is double counted between the name and the
* sizeof("bpf_prog_") above, so we omit
* the +1 here.
*/
sizeof(prog->aux->name) > KSYM_NAME_LEN);
sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
/* prog->aux->name will be ignored if full btf name is available */
if (prog->aux->func_info_cnt) {
type = btf_type_by_id(prog->aux->btf,
prog->aux->func_info[prog->aux->func_idx].type_id);
func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
snprintf(sym, (size_t)(end - sym), "_%s", func_name);
return;
}
if (prog->aux->name[0])
snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
else
*sym = 0;
}
static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
{
return container_of(n, struct bpf_ksym, tnode)->start;
}
static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
struct latch_tree_node *b)
{
return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
}
static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
{
unsigned long val = (unsigned long)key;
const struct bpf_ksym *ksym;
ksym = container_of(n, struct bpf_ksym, tnode);
if (val < ksym->start)
return -1;
if (val >= ksym->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;
void bpf_ksym_add(struct bpf_ksym *ksym)
{
spin_lock_bh(&bpf_lock);
WARN_ON_ONCE(!list_empty(&ksym->lnode));
list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
spin_unlock_bh(&bpf_lock);
}
static void __bpf_ksym_del(struct bpf_ksym *ksym)
{
if (list_empty(&ksym->lnode))
return;
latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
list_del_rcu(&ksym->lnode);
}
void bpf_ksym_del(struct bpf_ksym *ksym)
{
spin_lock_bh(&bpf_lock);
__bpf_ksym_del(ksym);
spin_unlock_bh(&bpf_lock);
}
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) ||
!bpf_capable())
return;
bpf_prog_ksym_set_addr(fp);
bpf_prog_ksym_set_name(fp);
fp->aux->ksym.prog = true;
bpf_ksym_add(&fp->aux->ksym);
}
void bpf_prog_kallsyms_del(struct bpf_prog *fp)
{
if (!bpf_prog_kallsyms_candidate(fp))
return;
bpf_ksym_del(&fp->aux->ksym);
}
static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
{
struct latch_tree_node *n;
n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
}
const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
unsigned long *off, char *sym)
{
struct bpf_ksym *ksym;
char *ret = NULL;
rcu_read_lock();
ksym = bpf_ksym_find(addr);
if (ksym) {
unsigned long symbol_start = ksym->start;
unsigned long symbol_end = ksym->end;
strncpy(sym, ksym->name, KSYM_NAME_LEN);
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_ksym_find(addr) != NULL;
rcu_read_unlock();
return ret;
}
static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
{
struct bpf_ksym *ksym = bpf_ksym_find(addr);
return ksym && ksym->prog ?
container_of(ksym, struct bpf_prog_aux, ksym)->prog :
NULL;
}
const struct exception_table_entry *search_bpf_extables(unsigned long addr)
{
const struct exception_table_entry *e = NULL;
struct bpf_prog *prog;
rcu_read_lock();
prog = bpf_prog_ksym_find(addr);
if (!prog)
goto out;
if (!prog->aux->num_exentries)
goto out;
e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
out:
rcu_read_unlock();
return e;
}
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *sym)
{
struct bpf_ksym *ksym;
unsigned int it = 0;
int ret = -ERANGE;
if (!bpf_jit_kallsyms_enabled())
return ret;
rcu_read_lock();
list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
if (it++ != symnum)
continue;
strncpy(sym, ksym->name, KSYM_NAME_LEN);
*value = ksym->start;
*type = BPF_SYM_ELF_TYPE;
ret = 0;
break;
}
rcu_read_unlock();
return ret;
}
int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
struct bpf_jit_poke_descriptor *poke)
{
struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
static const u32 poke_tab_max = 1024;
u32 slot = prog->aux->size_poke_tab;
u32 size = slot + 1;
if (size > poke_tab_max)
return -ENOSPC;
if (poke->tailcall_target || poke->tailcall_target_stable ||
poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
return -EINVAL;
switch (poke->reason) {
case BPF_POKE_REASON_TAIL_CALL:
if (!poke->tail_call.map)
return -EINVAL;
break;
default:
return -EINVAL;
}
tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
if (!tab)
return -ENOMEM;
memcpy(&tab[slot], poke, sizeof(*poke));
prog->aux->size_poke_tab = size;
prog->aux->poke_tab = tab;
return slot;
}
/*
* BPF program pack allocator.
*
* Most BPF programs are pretty small. Allocating a hole page for each
* program is sometime a waste. Many small bpf program also adds pressure
* to instruction TLB. To solve this issue, we introduce a BPF program pack
* allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
* to host BPF programs.
*/
#define BPF_PROG_CHUNK_SHIFT 6
#define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT)
#define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1))
struct bpf_prog_pack {
struct list_head list;
void *ptr;
unsigned long bitmap[];
};
#define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
static size_t bpf_prog_pack_size = -1;
static size_t bpf_prog_pack_mask = -1;
static int bpf_prog_chunk_count(void)
{
WARN_ON_ONCE(bpf_prog_pack_size == -1);
return bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE;
}
static DEFINE_MUTEX(pack_mutex);
static LIST_HEAD(pack_list);
/* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
* CONFIG_MMU=n. Use PAGE_SIZE in these cases.
*/
#ifdef PMD_SIZE
#define BPF_HPAGE_SIZE PMD_SIZE
#define BPF_HPAGE_MASK PMD_MASK
#else
#define BPF_HPAGE_SIZE PAGE_SIZE
#define BPF_HPAGE_MASK PAGE_MASK
#endif
static size_t select_bpf_prog_pack_size(void)
{
size_t size;
void *ptr;
size = BPF_HPAGE_SIZE * num_online_nodes();
ptr = module_alloc(size);
/* Test whether we can get huge pages. If not just use PAGE_SIZE
* packs.
*/
if (!ptr || !is_vm_area_hugepages(ptr)) {
size = PAGE_SIZE;
bpf_prog_pack_mask = PAGE_MASK;
} else {
bpf_prog_pack_mask = BPF_HPAGE_MASK;
}
vfree(ptr);
return size;
}
static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
{
struct bpf_prog_pack *pack;
pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(bpf_prog_chunk_count())),
GFP_KERNEL);
if (!pack)
return NULL;
pack->ptr = module_alloc(bpf_prog_pack_size);
if (!pack->ptr) {
kfree(pack);
return NULL;
}
bpf_fill_ill_insns(pack->ptr, bpf_prog_pack_size);
bitmap_zero(pack->bitmap, bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE);
list_add_tail(&pack->list, &pack_list);
set_vm_flush_reset_perms(pack->ptr);
set_memory_ro((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
set_memory_x((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
return pack;
}
static void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
{
unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
struct bpf_prog_pack *pack;
unsigned long pos;
void *ptr = NULL;
mutex_lock(&pack_mutex);
if (bpf_prog_pack_size == -1)
bpf_prog_pack_size = select_bpf_prog_pack_size();
if (size > bpf_prog_pack_size) {
size = round_up(size, PAGE_SIZE);
ptr = module_alloc(size);
if (ptr) {
bpf_fill_ill_insns(ptr, size);
set_vm_flush_reset_perms(ptr);
set_memory_ro((unsigned long)ptr, size / PAGE_SIZE);
set_memory_x((unsigned long)ptr, size / PAGE_SIZE);
}
goto out;
}
list_for_each_entry(pack, &pack_list, list) {
pos = bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
nbits, 0);
if (pos < bpf_prog_chunk_count())
goto found_free_area;
}
pack = alloc_new_pack(bpf_fill_ill_insns);
if (!pack)
goto out;
pos = 0;
found_free_area:
bitmap_set(pack->bitmap, pos, nbits);
ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
out:
mutex_unlock(&pack_mutex);
return ptr;
}
static void bpf_prog_pack_free(struct bpf_binary_header *hdr)
{
struct bpf_prog_pack *pack = NULL, *tmp;
unsigned int nbits;
unsigned long pos;
void *pack_ptr;
mutex_lock(&pack_mutex);
if (hdr->size > bpf_prog_pack_size) {
module_memfree(hdr);
goto out;
}
pack_ptr = (void *)((unsigned long)hdr & bpf_prog_pack_mask);
list_for_each_entry(tmp, &pack_list, list) {
if (tmp->ptr == pack_ptr) {
pack = tmp;
break;
}
}
if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
goto out;
nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size);
pos = ((unsigned long)hdr - (unsigned long)pack_ptr) >> BPF_PROG_CHUNK_SHIFT;
WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size),
"bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
bitmap_clear(pack->bitmap, pos, nbits);
if (bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
bpf_prog_chunk_count(), 0) == 0) {
list_del(&pack->list);
module_memfree(pack->ptr);
kfree(pack);
}
out:
mutex_unlock(&pack_mutex);
}
static atomic_long_t bpf_jit_current;
/* Can be overridden by an arch's JIT compiler if it has a custom,
* dedicated BPF backend memory area, or if neither of the two
* below apply.
*/
u64 __weak bpf_jit_alloc_exec_limit(void)
{
#if defined(MODULES_VADDR)
return MODULES_END - MODULES_VADDR;
#else
return VMALLOC_END - VMALLOC_START;
#endif
}
static int __init bpf_jit_charge_init(void)
{
/* Only used as heuristic here to derive limit. */
bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2,
PAGE_SIZE), LONG_MAX);
return 0;
}
pure_initcall(bpf_jit_charge_init);
int bpf_jit_charge_modmem(u32 size)
{
if (atomic_long_add_return(size, &bpf_jit_current) > bpf_jit_limit) {
if (!bpf_capable()) {
atomic_long_sub(size, &bpf_jit_current);
return -EPERM;
}
}
return 0;
}
void bpf_jit_uncharge_modmem(u32 size)
{
atomic_long_sub(size, &bpf_jit_current);
}
void *__weak bpf_jit_alloc_exec(unsigned long size)
{
return module_alloc(size);
}
void __weak bpf_jit_free_exec(void *addr)
{
module_memfree(addr);
}
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;
u32 size, hole, start;
WARN_ON_ONCE(!is_power_of_2(alignment) ||
alignment > BPF_IMAGE_ALIGNMENT);
/* 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);
if (bpf_jit_charge_modmem(size))
return NULL;
hdr = bpf_jit_alloc_exec(size);
if (!hdr) {
bpf_jit_uncharge_modmem(size);
return NULL;
}
/* Fill space with illegal/arch-dep instructions. */
bpf_fill_ill_insns(hdr, size);
hdr->size = 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)
{
u32 size = hdr->size;
bpf_jit_free_exec(hdr);
bpf_jit_uncharge_modmem(size);
}
/* Allocate jit binary from bpf_prog_pack allocator.
* Since the allocated memory is RO+X, the JIT engine cannot write directly
* to the memory. To solve this problem, a RW buffer is also allocated at
* as the same time. The JIT engine should calculate offsets based on the
* RO memory address, but write JITed program to the RW buffer. Once the
* JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
* the JITed program to the RO memory.
*/
struct bpf_binary_header *
bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
unsigned int alignment,
struct bpf_binary_header **rw_header,
u8 **rw_image,
bpf_jit_fill_hole_t bpf_fill_ill_insns)
{
struct bpf_binary_header *ro_header;
u32 size, hole, start;
WARN_ON_ONCE(!is_power_of_2(alignment) ||
alignment > BPF_IMAGE_ALIGNMENT);
/* add 16 bytes for a random section of illegal instructions */
size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
if (bpf_jit_charge_modmem(size))
return NULL;
ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
if (!ro_header) {
bpf_jit_uncharge_modmem(size);
return NULL;
}
*rw_header = kvmalloc(size, GFP_KERNEL);
if (!*rw_header) {
bpf_arch_text_copy(&ro_header->size, &size, sizeof(size));
bpf_prog_pack_free(ro_header);
bpf_jit_uncharge_modmem(size);
return NULL;
}
/* Fill space with illegal/arch-dep instructions. */
bpf_fill_ill_insns(*rw_header, size);
(*rw_header)->size = size;
hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
start = (get_random_int() % hole) & ~(alignment - 1);
*image_ptr = &ro_header->image[start];
*rw_image = &(*rw_header)->image[start];
return ro_header;
}
/* Copy JITed text from rw_header to its final location, the ro_header. */
int bpf_jit_binary_pack_finalize(struct bpf_prog *prog,
struct bpf_binary_header *ro_header,
struct bpf_binary_header *rw_header)
{
void *ptr;
ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
kvfree(rw_header);
if (IS_ERR(ptr)) {
bpf_prog_pack_free(ro_header);
return PTR_ERR(ptr);
}
prog->aux->use_bpf_prog_pack = true;
return 0;
}
/* bpf_jit_binary_pack_free is called in two different scenarios:
* 1) when the program is freed after;
* 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
* For case 2), we need to free both the RO memory and the RW buffer.
*
* bpf_jit_binary_pack_free requires proper ro_header->size. However,
* bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
* must be set with either bpf_jit_binary_pack_finalize (normal path) or
* bpf_arch_text_copy (when jit fails).
*/
void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
struct bpf_binary_header *rw_header)
{
u32 size = ro_header->size;
bpf_prog_pack_free(ro_header);
kvfree(rw_header);
bpf_jit_uncharge_modmem(size);
}
static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog *fp)
{
unsigned long real_start = (unsigned long)fp->bpf_func;
unsigned long addr;
if (fp->aux->use_bpf_prog_pack)
addr = real_start & BPF_PROG_CHUNK_MASK;
else
addr = real_start & PAGE_MASK;
return (void *)addr;
}
/* 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);
if (fp->aux->use_bpf_prog_pack)
bpf_jit_binary_pack_free(hdr, NULL /* rw_buffer */);
else
bpf_jit_binary_free(hdr);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
}
bpf_prog_unlock_free(fp);
}
int bpf_jit_get_func_addr(const struct bpf_prog *prog,
const struct bpf_insn *insn, bool extra_pass,
u64 *func_addr, bool *func_addr_fixed)
{
s16 off = insn->off;
s32 imm = insn->imm;
u8 *addr;
*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
if (!*func_addr_fixed) {
/* Place-holder address till the last pass has collected
* all addresses for JITed subprograms in which case we
* can pick them up from prog->aux.
*/
if (!extra_pass)
addr = NULL;
else if (prog->aux->func &&
off >= 0 && off < prog->aux->func_cnt)
addr = (u8 *)prog->aux->func[off]->bpf_func;
else
return -EINVAL;
} else {
/* Address of a BPF helper call. Since part of the core
* kernel, it's always at a fixed location. __bpf_call_base
* and the helper with imm relative to it are both in core
* kernel.
*/
addr = (u8 *)__bpf_call_base + imm;
}
*func_addr = (unsigned long)addr;
return 0;
}
static int bpf_jit_blind_insn(const struct bpf_insn *from,
const struct bpf_insn *aux,
struct bpf_insn *to_buff,
bool emit_zext)
{
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);
/* Constraints on AX register:
*
* AX register is inaccessible from user space. It is mapped in
* all JITs, and used here for constant blinding rewrites. It is
* typically "stateless" meaning its contents are only valid within
* the executed instruction, but not across several instructions.
* There are a few exceptions however which are further detailed
* below.
*
* Constant blinding is only used by JITs, not in the interpreter.
* The interpreter uses AX in some occasions as a local temporary
* register e.g. in DIV or MOD instructions.
*
* In restricted circumstances, the verifier can also use the AX
* register for rewrites as long as they do not interfere with
* the above cases!
*/
if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
goto out;
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_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
/* Accommodate for extra offset in case of a backjump. */
off = from->off;
if (off < 0)
off -= 2;
*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_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
off);
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);
if (emit_zext)
*to++ = BPF_ZEXT_REG(BPF_REG_AX);
*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);
if (fp != NULL) {
/* 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;
fp->stats = NULL;
fp->active = 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 (!prog->blinding_requested || prog->blinded)
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++) {
if (bpf_pseudo_func(insn)) {
/* ld_imm64 with an address of bpf subprog is not
* a user controlled constant. Don't randomize it,
* since it will conflict with jit_subprogs() logic.
*/
insn++;
i++;
continue;
}
/* 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,
clone->aux->verifier_zext);
if (!rewritten)
continue;
tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
if (IS_ERR(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 tmp;
}
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;
}
clone->blinded = 1;
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. This also needs
* to go into kallsyms for correlation from e.g. bpftool, so naming
* must not change.
*/
noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
return 0;
}
EXPORT_SYMBOL_GPL(__bpf_call_base);
/* All UAPI available opcodes. */
#define BPF_INSN_MAP(INSN_2, INSN_3) \
/* 32 bit ALU operations. */ \
/* Register based. */ \
INSN_3(ALU, ADD, X), \
INSN_3(ALU, SUB, X), \
INSN_3(ALU, AND, X), \
INSN_3(ALU, OR, X), \
INSN_3(ALU, LSH, X), \
INSN_3(ALU, RSH, X), \
INSN_3(ALU, XOR, X), \
INSN_3(ALU, MUL, X), \
INSN_3(ALU, MOV, X), \
INSN_3(ALU, ARSH, X), \
INSN_3(ALU, DIV, X), \
INSN_3(ALU, MOD, X), \
INSN_2(ALU, NEG), \
INSN_3(ALU, END, TO_BE), \
INSN_3(ALU, END, TO_LE), \
/* Immediate based. */ \
INSN_3(ALU, ADD, K), \
INSN_3(ALU, SUB, K), \
INSN_3(ALU, AND, K), \
INSN_3(ALU, OR, K), \
INSN_3(ALU, LSH, K), \
INSN_3(ALU, RSH, K), \
INSN_3(ALU, XOR, K), \
INSN_3(ALU, MUL, K), \
INSN_3(ALU, MOV, K), \
INSN_3(ALU, ARSH, K), \
INSN_3(ALU, DIV, K), \
INSN_3(ALU, MOD, K), \
/* 64 bit ALU operations. */ \
/* Register based. */ \
INSN_3(ALU64, ADD, X), \
INSN_3(ALU64, SUB, X), \
INSN_3(ALU64, AND, X), \
INSN_3(ALU64, OR, X), \
INSN_3(ALU64, LSH, X), \
INSN_3(ALU64, RSH, X), \
INSN_3(ALU64, XOR, X), \
INSN_3(ALU64, MUL, X), \
INSN_3(ALU64, MOV, X), \
INSN_3(ALU64, ARSH, X), \
INSN_3(ALU64, DIV, X), \
INSN_3(ALU64, MOD, X), \
INSN_2(ALU64, NEG), \
/* Immediate based. */ \
INSN_3(ALU64, ADD, K), \
INSN_3(ALU64, SUB, K), \
INSN_3(ALU64, AND, K), \
INSN_3(ALU64, OR, K), \
INSN_3(ALU64, LSH, K), \
INSN_3(ALU64, RSH, K), \
INSN_3(ALU64, XOR, K), \
INSN_3(ALU64, MUL, K), \
INSN_3(ALU64, MOV, K), \
INSN_3(ALU64, ARSH, K), \
INSN_3(ALU64, DIV, K), \
INSN_3(ALU64, MOD, K), \
/* Call instruction. */ \
INSN_2(JMP, CALL), \
/* Exit instruction. */ \
INSN_2(JMP, EXIT), \
/* 32-bit Jump instructions. */ \
/* Register based. */ \
INSN_3(JMP32, JEQ, X), \
INSN_3(JMP32, JNE, X), \
INSN_3(JMP32, JGT, X), \
INSN_3(JMP32, JLT, X), \
INSN_3(JMP32, JGE, X), \
INSN_3(JMP32, JLE, X), \
INSN_3(JMP32, JSGT, X), \
INSN_3(JMP32, JSLT, X), \
INSN_3(JMP32, JSGE, X), \
INSN_3(JMP32, JSLE, X), \
INSN_3(JMP32, JSET, X), \
/* Immediate based. */ \
INSN_3(JMP32, JEQ, K), \
INSN_3(JMP32, JNE, K), \
INSN_3(JMP32, JGT, K), \
INSN_3(JMP32, JLT, K), \
INSN_3(JMP32, JGE, K), \
INSN_3(JMP32, JLE, K), \
INSN_3(JMP32, JSGT, K), \
INSN_3(JMP32, JSLT, K), \
INSN_3(JMP32, JSGE, K), \
INSN_3(JMP32, JSLE, K), \
INSN_3(JMP32, JSET, K), \
/* Jump instructions. */ \
/* Register based. */ \
INSN_3(JMP, JEQ, X), \
INSN_3(JMP, JNE, X), \
INSN_3(JMP, JGT, X), \
INSN_3(JMP, JLT, X), \
INSN_3(JMP, JGE, X), \
INSN_3(JMP, JLE, X), \
INSN_3(JMP, JSGT, X), \
INSN_3(JMP, JSLT, X), \
INSN_3(JMP, JSGE, X), \
INSN_3(JMP, JSLE, X), \
INSN_3(JMP, JSET, X), \
/* Immediate based. */ \
INSN_3(JMP, JEQ, K), \
INSN_3(JMP, JNE, K), \
INSN_3(JMP, JGT, K), \
INSN_3(JMP, JLT, K), \
INSN_3(JMP, JGE, K), \
INSN_3(JMP, JLE, K), \
INSN_3(JMP, JSGT, K), \
INSN_3(JMP, JSLT, K), \
INSN_3(JMP, JSGE, K), \
INSN_3(JMP, JSLE, K), \
INSN_3(JMP, JSET, K), \
INSN_2(JMP, JA), \
/* Store instructions. */ \
/* Register based. */ \
INSN_3(STX, MEM, B), \
INSN_3(STX, MEM, H), \
INSN_3(STX, MEM, W), \
INSN_3(STX, MEM, DW), \
INSN_3(STX, ATOMIC, W), \
INSN_3(STX, ATOMIC, DW), \
/* Immediate based. */ \
INSN_3(ST, MEM, B), \
INSN_3(ST, MEM, H), \
INSN_3(ST, MEM, W), \
INSN_3(ST, MEM, DW), \
/* Load instructions. */ \
/* Register based. */ \
INSN_3(LDX, MEM, B), \
INSN_3(LDX, MEM, H), \
INSN_3(LDX, MEM, W), \
INSN_3(LDX, MEM, DW), \
/* Immediate based. */ \
INSN_3(LD, IMM, DW)
bool bpf_opcode_in_insntable(u8 code)
{
#define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
#define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
static const bool public_insntable[256] = {
[0 ... 255] = false,
/* Now overwrite non-defaults ... */
BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
[BPF_LD | BPF_ABS | BPF_B] = true,
[BPF_LD | BPF_ABS | BPF_H] = true,
[BPF_LD | BPF_ABS | BPF_W] = true,
[BPF_LD | BPF_IND | BPF_B] = true,
[BPF_LD | BPF_IND | BPF_H] = true,
[BPF_LD | BPF_IND | BPF_W] = true,
};
#undef BPF_INSN_3_TBL
#undef BPF_INSN_2_TBL
return public_insntable[code];
}
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
{
memset(dst, 0, size);
return -EFAULT;
}
/**
* ___bpf_prog_run - run eBPF program on a given context
* @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
* @insn: is the array of eBPF instructions
*
* Decode and execute eBPF instructions.
*
* Return: whatever value is in %BPF_R0 at program exit
*/
static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
{
#define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
static const void * const jumptable[256] __annotate_jump_table = {
[0 ... 255] = &&default_label,
/* Now overwrite non-defaults ... */
BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
/* Non-UAPI available opcodes. */
[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
[BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC,
[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
};
#undef BPF_INSN_3_LBL
#undef BPF_INSN_2_LBL
u32 tail_call_cnt = 0;
#define CONT ({ insn++; goto select_insn; })
#define CONT_JMP ({ insn++; goto select_insn; })
select_insn:
goto *jumptable[insn->code];
/* Explicitly mask the register-based shift amounts with 63 or 31
* to avoid undefined behavior. Normally this won't affect the
* generated code, for example, in case of native 64 bit archs such
* as x86-64 or arm64, the compiler is optimizing the AND away for
* the interpreter. In case of JITs, each of the JIT backends compiles
* the BPF shift operations to machine instructions which produce
* implementation-defined results in such a case; the resulting
* contents of the register may be arbitrary, but program behaviour
* as a whole remains defined. In other words, in case of JIT backends,
* the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
*/
/* ALU (shifts) */
#define SHT(OPCODE, OP) \
ALU64_##OPCODE##_X: \
DST = DST OP (SRC & 63); \
CONT; \
ALU_##OPCODE##_X: \
DST = (u32) DST OP ((u32) SRC & 31); \
CONT; \
ALU64_##OPCODE##_K: \
DST = DST OP IMM; \
CONT; \
ALU_##OPCODE##_K: \
DST = (u32) DST OP (u32) IMM; \
CONT;
/* ALU (rest) */
#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(XOR, ^)
ALU(MUL, *)
SHT(LSH, <<)
SHT(RSH, >>)
#undef SHT
#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;
ALU_ARSH_X:
DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
CONT;
ALU_ARSH_K:
DST = (u64) (u32) (((s32) DST) >> IMM);
CONT;
ALU64_ARSH_X:
(*(s64 *) &DST) >>= (SRC & 63);
CONT;
ALU64_ARSH_K:
(*(s64 *) &DST) >>= IMM;
CONT;
ALU64_MOD_X:
div64_u64_rem(DST, SRC, &AX);
DST = AX;
CONT;
ALU_MOD_X:
AX = (u32) DST;
DST = do_div(AX, (u32) SRC);
CONT;
ALU64_MOD_K:
div64_u64_rem(DST, IMM, &AX);
DST = AX;
CONT;
ALU_MOD_K:
AX = (u32) DST;
DST = do_div(AX, (u32) IMM);
CONT;
ALU64_DIV_X:
DST = div64_u64(DST, SRC);
CONT;
ALU_DIV_X:
AX = (u32) DST;
do_div(AX, (u32) SRC);
DST = (u32) AX;
CONT;
ALU64_DIV_K:
DST = div64_u64(DST, IMM);
CONT;
ALU_DIV_K:
AX = (u32) DST;
do_div(AX, (u32) IMM);
DST = (u32) AX;
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_CALL_ARGS:
BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
BPF_R3, BPF_R4,
BPF_R5,
insn + insn->off + 1);
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;
u32 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
* handled 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_JA:
insn += insn->off;
CONT;
JMP_EXIT:
return BPF_R0;
/* JMP */
#define COND_JMP(SIGN, OPCODE, CMP_OP) \
JMP_##OPCODE##_X: \
if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
insn += insn->off; \
CONT_JMP; \
} \
CONT; \
JMP32_##OPCODE##_X: \
if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
insn += insn->off; \
CONT_JMP; \
} \
CONT; \
JMP_##OPCODE##_K: \
if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
insn += insn->off; \
CONT_JMP; \
} \
CONT; \
JMP32_##OPCODE##_K: \
if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
insn += insn->off; \
CONT_JMP; \
} \
CONT;
COND_JMP(u, JEQ, ==)
COND_JMP(u, JNE, !=)
COND_JMP(u, JGT, >)
COND_JMP(u, JLT, <)
COND_JMP(u, JGE, >=)
COND_JMP(u, JLE, <=)
COND_JMP(u, JSET, &)
COND_JMP(s, JSGT, >)
COND_JMP(s, JSLT, <)
COND_JMP(s, JSGE, >=)
COND_JMP(s, JSLE, <=)
#undef COND_JMP
/* ST, STX and LDX*/
ST_NOSPEC:
/* Speculation barrier for mitigating Speculative Store Bypass.
* In case of arm64, we rely on the firmware mitigation as
* controlled via the ssbd kernel parameter. Whenever the
* mitigation is enabled, it works for all of the kernel code
* with no need to provide any additional instructions here.
* In case of x86, we use 'lfence' insn for mitigation. We
* reuse preexisting logic from Spectre v1 mitigation that
* happens to produce the required code on x86 for v4 as well.
*/
#ifdef CONFIG_X86
barrier_nospec();
#endif
CONT;
#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; \
LDX_PROBE_MEM_##SIZEOP: \
bpf_probe_read_kernel(&DST, sizeof(SIZE), \
(const void *)(long) (SRC + insn->off)); \
DST = *((SIZE *)&DST); \
CONT;
LDST(B, u8)
LDST(H, u16)
LDST(W, u32)
LDST(DW, u64)
#undef LDST
#define ATOMIC_ALU_OP(BOP, KOP) \
case BOP: \
if (BPF_SIZE(insn->code) == BPF_W) \
atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
(DST + insn->off)); \
else \
atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
(DST + insn->off)); \
break; \
case BOP | BPF_FETCH: \
if (BPF_SIZE(insn->code) == BPF_W) \
SRC = (u32) atomic_fetch_##KOP( \
(u32) SRC, \
(atomic_t *)(unsigned long) (DST + insn->off)); \
else \
SRC = (u64) atomic64_fetch_##KOP( \
(u64) SRC, \
(atomic64_t *)(unsigned long) (DST + insn->off)); \
break;
STX_ATOMIC_DW:
STX_ATOMIC_W:
switch (IMM) {
ATOMIC_ALU_OP(BPF_ADD, add)
ATOMIC_ALU_OP(BPF_AND, and)
ATOMIC_ALU_OP(BPF_OR, or)
ATOMIC_ALU_OP(BPF_XOR, xor)
#undef ATOMIC_ALU_OP
case BPF_XCHG:
if (BPF_SIZE(insn->code) == BPF_W)
SRC = (u32) atomic_xchg(
(atomic_t *)(unsigned long) (DST + insn->off),
(u32) SRC);
else
SRC = (u64) atomic64_xchg(
(atomic64_t *)(unsigned long) (DST + insn->off),
(u64) SRC);
break;
case BPF_CMPXCHG:
if (BPF_SIZE(insn->code) == BPF_W)
BPF_R0 = (u32) atomic_cmpxchg(
(atomic_t *)(unsigned long) (DST + insn->off),
(u32) BPF_R0, (u32) SRC);
else
BPF_R0 = (u64) atomic64_cmpxchg(
(atomic64_t *)(unsigned long) (DST + insn->off),
(u64) BPF_R0, (u64) SRC);
break;
default:
goto default_label;
}
CONT;
default_label:
/* If we ever reach this, we have a bug somewhere. Die hard here
* instead of just returning 0; we could be somewhere in a subprog,
* so execution could continue otherwise which we do /not/ want.
*
* Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
*/
pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
insn->code, insn->imm);
BUG_ON(1);
return 0;
}
#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_EXT_REG]; \
\
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
ARG1 = (u64) (unsigned long) ctx; \
return ___bpf_prog_run(regs, insn); \
}
#define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
#define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
const struct bpf_insn *insn) \
{ \
u64 stack[stack_size / sizeof(u64)]; \
u64 regs[MAX_BPF_EXT_REG]; \
\
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
BPF_R1 = r1; \
BPF_R2 = r2; \
BPF_R3 = r3; \
BPF_R4 = r4; \
BPF_R5 = r5; \
return ___bpf_prog_run(regs, insn); \
}
#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);
EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 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)
};
#undef PROG_NAME_LIST
#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
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)
};
#undef PROG_NAME_LIST
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
{
stack_depth = max_t(u32, stack_depth, 1);
insn->off = (s16) insn->imm;
insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
__bpf_call_base_args;
insn->code = BPF_JMP | BPF_CALL_ARGS;
}
#else
static unsigned int __bpf_prog_ret0_warn(const void *ctx,
const struct bpf_insn *insn)
{
/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
* is not working properly, so warn about it!
*/
WARN_ON_ONCE(1);
return 0;
}
#endif
bool bpf_prog_map_compatible(struct bpf_map *map,
const struct bpf_prog *fp)
{
bool ret;
if (fp->kprobe_override)
return false;
spin_lock(&map->owner.lock);
if (!map->owner.type) {
/* There's no owner yet where we could check for
* compatibility.
*/
map->owner.type = fp->type;
map->owner.jited = fp->jited;
map->owner.xdp_has_frags = fp->aux->xdp_has_frags;
ret = true;
} else {
ret = map->owner.type == fp->type &&
map->owner.jited == fp->jited &&
map->owner.xdp_has_frags == fp->aux->xdp_has_frags;
}
spin_unlock(&map->owner.lock);
return ret;
}
static int bpf_check_tail_call(const struct bpf_prog *fp)
{
struct bpf_prog_aux *aux = fp->aux;
int i, ret = 0;
mutex_lock(&aux->used_maps_mutex);
for (i = 0; i < aux->used_map_cnt; i++) {
struct bpf_map *map = aux->used_maps[i];
if (!map_type_contains_progs(map))
continue;
if (!bpf_prog_map_compatible(map, fp)) {
ret = -EINVAL;
goto out;
}
}
out:
mutex_unlock(&aux->used_maps_mutex);
return ret;
}
static void bpf_prog_select_func(struct bpf_prog *fp)
{
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
#else
fp->bpf_func = __bpf_prog_ret0_warn;
#endif
}
/**
* bpf_prog_select_runtime - select exec runtime for BPF program
* @fp: bpf_prog populated with 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() function.
*
* Return: the &fp argument along with &err set to 0 for success or
* a negative errno code on failure
*/
struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
{
/* In case of BPF to BPF calls, verifier did all the prep
* work with regards to JITing, etc.
*/
bool jit_needed = false;
if (fp->bpf_func)
goto finalize;
if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
bpf_prog_has_kfunc_call(fp))
jit_needed = true;
bpf_prog_select_func(fp);
/* 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.
*/
if (!bpf_prog_is_dev_bound(fp->aux)) {
*err = bpf_prog_alloc_jited_linfo(fp);
if (*err)
return fp;
fp = bpf_int_jit_compile(fp);
bpf_prog_jit_attempt_done(fp);
if (!fp->jited && jit_needed) {
*err = -ENOTSUPP;
return fp;
}
} else {
*err = bpf_prog_offload_compile(fp);
if (*err)
return fp;
}
finalize:
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 unsigned int __bpf_prog_ret1(const void *ctx,
const struct bpf_insn *insn)
{
return 1;
}
static struct bpf_prog_dummy {
struct bpf_prog prog;
} dummy_bpf_prog = {
.prog = {
.bpf_func = __bpf_prog_ret1,
},
};
struct bpf_empty_prog_array bpf_empty_prog_array = {
.null_prog = NULL,
};
EXPORT_SYMBOL(bpf_empty_prog_array);
struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
{
if (prog_cnt)
return kzalloc(sizeof(struct bpf_prog_array) +
sizeof(struct bpf_prog_array_item) *
(prog_cnt + 1),
flags);
return &bpf_empty_prog_array.hdr;
}
void bpf_prog_array_free(struct bpf_prog_array *progs)
{
if (!progs || progs == &bpf_empty_prog_array.hdr)
return;
kfree_rcu(progs, rcu);
}
int bpf_prog_array_length(struct bpf_prog_array *array)
{
struct bpf_prog_array_item *item;
u32 cnt = 0;
for (item = array->items; item->prog; item++)
if (item->prog != &dummy_bpf_prog.prog)
cnt++;
return cnt;
}
bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
{
struct bpf_prog_array_item *item;
for (item = array->items; item->prog; item++)
if (item->prog != &dummy_bpf_prog.prog)
return false;
return true;
}
static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
u32 *prog_ids,
u32 request_cnt)
{
struct bpf_prog_array_item *item;
int i = 0;
for (item = array->items; item->prog; item++) {
if (item->prog == &dummy_bpf_prog.prog)
continue;
prog_ids[i] = item->prog->aux->id;
if (++i == request_cnt) {
item++;
break;
}
}
return !!(item->prog);
}
int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
__u32 __user *prog_ids, u32 cnt)
{
unsigned long err = 0;
bool nospc;
u32 *ids;
/* users of this function are doing:
* cnt = bpf_prog_array_length();
* if (cnt > 0)
* bpf_prog_array_copy_to_user(..., cnt);
* so below kcalloc doesn't need extra cnt > 0 check.
*/
ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
if (!ids)
return -ENOMEM;
nospc = bpf_prog_array_copy_core(array, ids, cnt);
err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
kfree(ids);
if (err)
return -EFAULT;
if (nospc)
return -ENOSPC;
return 0;
}
void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
struct bpf_prog *old_prog)
{
struct bpf_prog_array_item *item;
for (item = array->items; item->prog; item++)
if (item->prog == old_prog) {
WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
break;
}
}
/**
* bpf_prog_array_delete_safe_at() - Replaces the program at the given
* index into the program array with
* a dummy no-op program.
* @array: a bpf_prog_array
* @index: the index of the program to replace
*
* Skips over dummy programs, by not counting them, when calculating
* the position of the program to replace.
*
* Return:
* * 0 - Success
* * -EINVAL - Invalid index value. Must be a non-negative integer.
* * -ENOENT - Index out of range
*/
int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
{
return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
}
/**
* bpf_prog_array_update_at() - Updates the program at the given index
* into the program array.
* @array: a bpf_prog_array
* @index: the index of the program to update
* @prog: the program to insert into the array
*
* Skips over dummy programs, by not counting them, when calculating
* the position of the program to update.
*
* Return:
* * 0 - Success
* * -EINVAL - Invalid index value. Must be a non-negative integer.
* * -ENOENT - Index out of range
*/
int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
struct bpf_prog *prog)
{
struct bpf_prog_array_item *item;
if (unlikely(index < 0))
return -EINVAL;
for (item = array->items; item->prog; item++) {
if (item->prog == &dummy_bpf_prog.prog)
continue;
if (!index) {
WRITE_ONCE(item->prog, prog);
return 0;
}
index--;
}
return -ENOENT;
}
int bpf_prog_array_copy(struct bpf_prog_array *old_array,
struct bpf_prog *exclude_prog,
struct bpf_prog *include_prog,
u64 bpf_cookie,
struct bpf_prog_array **new_array)
{
int new_prog_cnt, carry_prog_cnt = 0;
struct bpf_prog_array_item *existing, *new;
struct bpf_prog_array *array;
bool found_exclude = false;
/* Figure out how many existing progs we need to carry over to
* the new array.
*/
if (old_array) {
existing = old_array->items;
for (; existing->prog; existing++) {
if (existing->prog == exclude_prog) {
found_exclude = true;
continue;
}
if (existing->prog != &dummy_bpf_prog.prog)
carry_prog_cnt++;
if (existing->prog == include_prog)
return -EEXIST;
}
}
if (exclude_prog && !found_exclude)
return -ENOENT;
/* How many progs (not NULL) will be in the new array? */
new_prog_cnt = carry_prog_cnt;
if (include_prog)
new_prog_cnt += 1;
/* Do we have any prog (not NULL) in the new array? */
if (!new_prog_cnt) {
*new_array = NULL;
return 0;
}
/* +1 as the end of prog_array is marked with NULL */
array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
if (!array)
return -ENOMEM;
new = array->items;
/* Fill in the new prog array */
if (carry_prog_cnt) {
existing = old_array->items;
for (; existing->prog; existing++) {
if (existing->prog == exclude_prog ||
existing->prog == &dummy_bpf_prog.prog)
continue;
new->prog = existing->prog;
new->bpf_cookie = existing->bpf_cookie;
new++;
}
}
if (include_prog) {
new->prog = include_prog;
new->bpf_cookie = bpf_cookie;
new++;
}
new->prog = NULL;
*new_array = array;
return 0;
}
int bpf_prog_array_copy_info(struct bpf_prog_array *array,
u32 *prog_ids, u32 request_cnt,
u32 *prog_cnt)
{
u32 cnt = 0;
if (array)
cnt = bpf_prog_array_length(array);
*prog_cnt = cnt;
/* return early if user requested only program count or nothing to copy */
if (!request_cnt || !cnt)
return 0;
/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
: 0;
}
void __bpf_free_used_maps(struct bpf_prog_aux *aux,
struct bpf_map **used_maps, u32 len)
{
struct bpf_map *map;
u32 i;
for (i = 0; i < len; i++) {
map = used_maps[i];
if (map->ops->map_poke_untrack)
map->ops->map_poke_untrack(map, aux);
bpf_map_put(map);
}
}
static void bpf_free_used_maps(struct bpf_prog_aux *aux)
{
__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
kfree(aux->used_maps);
}
void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
struct btf_mod_pair *used_btfs, u32 len)
{
#ifdef CONFIG_BPF_SYSCALL
struct btf_mod_pair *btf_mod;
u32 i;
for (i = 0; i < len; i++) {
btf_mod = &used_btfs[i];
if (btf_mod->module)
module_put(btf_mod->module);
btf_put(btf_mod->btf);
}
#endif
}
static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
{
__bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
kfree(aux->used_btfs);
}
static void bpf_prog_free_deferred(struct work_struct *work)
{
struct bpf_prog_aux *aux;
int i;
aux = container_of(work, struct bpf_prog_aux, work);
#ifdef CONFIG_BPF_SYSCALL
bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
#endif
bpf_free_used_maps(aux);
bpf_free_used_btfs(aux);
if (bpf_prog_is_dev_bound(aux))
bpf_prog_offload_destroy(aux->prog);
#ifdef CONFIG_PERF_EVENTS
if (aux->prog->has_callchain_buf)
put_callchain_buffers();
#endif
if (aux->dst_trampoline)
bpf_trampoline_put(aux->dst_trampoline);
for (i = 0; i < aux->func_cnt; i++) {
/* We can just unlink the subprog poke descriptor table as
* it was originally linked to the main program and is also
* released along with it.
*/
aux->func[i]->aux->poke_tab = NULL;
bpf_jit_free(aux->func[i]);
}
if (aux->func_cnt) {
kfree(aux->func);
bpf_prog_unlock_free(aux->prog);
} else {
bpf_jit_free(aux->prog);
}
}
void bpf_prog_free(struct bpf_prog *fp)
{
struct bpf_prog_aux *aux = fp->aux;
if (aux->dst_prog)
bpf_prog_put(aux->dst_prog);
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;
}
BPF_CALL_0(bpf_get_raw_cpu_id)
{
return raw_smp_processor_id();
}
/* 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_map_push_elem_proto __weak;
const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
const struct bpf_func_proto bpf_spin_lock_proto __weak;
const struct bpf_func_proto bpf_spin_unlock_proto __weak;
const struct bpf_func_proto bpf_jiffies64_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_ktime_get_boot_ns_proto __weak;
const struct bpf_func_proto bpf_ktime_get_coarse_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 bpf_get_current_cgroup_id_proto __weak;
const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
const struct bpf_func_proto bpf_get_local_storage_proto __weak;
const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
return NULL;
}
const struct bpf_func_proto * __weak bpf_get_trace_vprintk_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;
}
EXPORT_SYMBOL_GPL(bpf_event_output);
/* 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;
}
/* Return TRUE if the JIT backend wants verifier to enable sub-register usage
* analysis code and wants explicit zero extension inserted by verifier.
* Otherwise, return FALSE.
*
* The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
* you don't override this. JITs that don't want these extra insns can detect
* them using insn_is_zext.
*/
bool __weak bpf_jit_needs_zext(void)
{
return false;
}
bool __weak bpf_jit_supports_kfunc_call(void)
{
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;
}
int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *addr1, void *addr2)
{
return -ENOTSUPP;
}
void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
{
return ERR_PTR(-ENOTSUPP);
}
int __weak bpf_arch_text_invalidate(void *dst, size_t len)
{
return -ENOTSUPP;
}
DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
EXPORT_SYMBOL(bpf_stats_enabled_key);
/* 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(xdp_bulk_tx);