// 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/prandom.h>

#include <linux/bpf.h>

#include <linux/btf.h>

#include <linux/objtool.h>

#include <linux/overflow.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 <linux/nospec.h>

#include <linux/bpf_mem_alloc.h>

#include <linux/memcontrol.h>

#include <linux/execmem.h>

#include <asm/barrier.h>

#include <linux/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 OFF insn->off

#define IMM insn->imm

struct bpf_mem_alloc bpf_global_ma;

bool bpf_global_ma_set;

/* 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) {

if (unlikely(!skb_mac_header_was_set(skb)))

return NULL;

ptr = skb_mac_header(skb) + k - SKF_LL_OFF;

}

if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))

return ptr;

return NULL;

}

/* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */

enum page_size_enum {

__PAGE_SIZE = PAGE_SIZE

};

struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)

{

gfp_t gfp_flags = bpf_memcg_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);

if (fp == NULL)

return NULL;

aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));

if (aux == NULL) {

vfree(fp);

return NULL;

}

fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | 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);

#ifdef CONFIG_CGROUP_BPF

aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID;

#endif

INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);

#ifdef CONFIG_FINEIBT

INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode);

#endif

mutex_init(&fp->aux->used_maps_mutex);

mutex_init(&fp->aux->ext_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 = bpf_memcg_flags(GFP_KERNEL | __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),

bpf_memcg_flags(GFP_KERNEL | __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 end 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 || prog->aux->func_idx > prog->aux->func_cnt)

/* 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 = bpf_memcg_flags(GFP_KERNEL | __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)

{

s64 off_min, off_max, off;

s32 delta = end_new - end_old;

if (insn->code == (BPF_JMP32 | BPF_JA)) {

off = insn->imm;

off_min = S32_MIN;

off_max = S32_MAX;

} else {

off = insn->off;

off_min = S16_MIN;

off_max = S16_MAX;

}

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) {

if (insn->code == (BPF_JMP32 | BPF_JA))

insn->imm = off;

else

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)

{

int err;

/* 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;

err = bpf_adj_branches(prog, off, off + cnt, off, false);

WARN_ON_ONCE(err);

return err;

}

static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)

{

int i;

for (i = 0; i < fp->aux->real_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 && prog->aux->func_idx < 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;

/* Ensure that we detect return addresses as part of the program, when

* the final instruction is a call for a program part of the stack

* trace. Therefore, do val > ksym->end instead of val >= ksym->end.

*/

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);

}

void bpf_prog_kallsyms_add(struct bpf_prog *fp)

{

if (!bpf_prog_kallsyms_candidate(fp) ||

!bpf_token_capable(fp->aux->token, CAP_BPF))

return;

bpf_prog_ksym_set_addr(fp);

bpf_prog_ksym_set_name(fp);

fp->aux->ksym.prog = true;

bpf_ksym_add(&fp->aux->ksym);

#ifdef CONFIG_FINEIBT

/*

* When FineIBT, code in the __cfi_foo() symbols can get executed

* and hence unwinder needs help.

*/

if (cfi_mode != CFI_FINEIBT)

return;

snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN,

"__cfi_%s", fp->aux->ksym.name);

fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16;

fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func;

bpf_ksym_add(&fp->aux->ksym_prefix);

#endif

}

void bpf_prog_kallsyms_del(struct bpf_prog *fp)

{

if (!bpf_prog_kallsyms_candidate(fp))

return;

bpf_ksym_del(&fp->aux->ksym);

#ifdef CONFIG_FINEIBT

if (cfi_mode != CFI_FINEIBT)

return;

bpf_ksym_del(&fp->aux->ksym_prefix);

#endif

}

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;

}

int __bpf_address_lookup(unsigned long addr, unsigned long *size,

unsigned long *off, char *sym)

{

struct bpf_ksym *ksym;

int ret = 0;

rcu_read_lock();

ksym = bpf_ksym_find(addr);

if (ksym) {

unsigned long symbol_start = ksym->start;

unsigned long symbol_end = ksym->end;

ret = strscpy(sym, ksym->name, KSYM_NAME_LEN);

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;

}

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;

strscpy(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_array(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[];

};

void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)

{

memset(area, 0, size);

}

#define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_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

/* PMD_SIZE is really big for some archs. It doesn't make sense to

* reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to

* 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be

* greater than or equal to 2MB.

*/

#define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes())

#else

#define BPF_PROG_PACK_SIZE PAGE_SIZE

#endif

#define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)

static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)

{

struct bpf_prog_pack *pack;

int err;

pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),

GFP_KERNEL);

if (!pack)

return NULL;

pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);

if (!pack->ptr)

goto out;

bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);

bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);

set_vm_flush_reset_perms(pack->ptr);

err = set_memory_rox((unsigned long)pack->ptr,

BPF_PROG_PACK_SIZE / PAGE_SIZE);

if (err)

goto out;

list_add_tail(&pack->list, &pack_list);

return pack;

out:

bpf_jit_free_exec(pack->ptr);

kfree(pack);

return NULL;

}

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 (size > BPF_PROG_PACK_SIZE) {

size = round_up(size, PAGE_SIZE);

ptr = bpf_jit_alloc_exec(size);

if (ptr) {

int err;

bpf_fill_ill_insns(ptr, size);

set_vm_flush_reset_perms(ptr);

err = set_memory_rox((unsigned long)ptr,

size / PAGE_SIZE);

if (err) {

bpf_jit_free_exec(ptr);

ptr = NULL;

}

}

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;

}

void bpf_prog_pack_free(void *ptr, u32 size)

{

struct bpf_prog_pack *pack = NULL, *tmp;

unsigned int nbits;

unsigned long pos;

mutex_lock(&pack_mutex);

if (size > BPF_PROG_PACK_SIZE) {

bpf_jit_free_exec(ptr);

goto out;

}