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1/* SPDX-License-Identifier: GPL-2.0-only */2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com3 */4#ifndef _LINUX_BPF_VERIFIER_H5#define _LINUX_BPF_VERIFIER_H 16 7#include <linux/bpf.h> /* for enum bpf_reg_type */8#include <linux/btf.h> /* for struct btf and btf_id() */9#include <linux/filter.h> /* for MAX_BPF_STACK */10#include <linux/tnum.h>11 12/* Maximum variable offset umax_value permitted when resolving memory accesses.13 * In practice this is far bigger than any realistic pointer offset; this limit14 * ensures that umax_value + (int)off + (int)size cannot overflow a u64.15 */16#define BPF_MAX_VAR_OFF (1 << 29)17/* Maximum variable size permitted for ARG_CONST_SIZE[_OR_ZERO]. This ensures18 * that converting umax_value to int cannot overflow.19 */20#define BPF_MAX_VAR_SIZ (1 << 29)21/* size of tmp_str_buf in bpf_verifier.22 * we need at least 306 bytes to fit full stack mask representation23 * (in the "-8,-16,...,-512" form)24 */25#define TMP_STR_BUF_LEN 32026/* Patch buffer size */27#define INSN_BUF_SIZE 3228 29/* Liveness marks, used for registers and spilled-regs (in stack slots).30 * Read marks propagate upwards until they find a write mark; they record that31 * "one of this state's descendants read this reg" (and therefore the reg is32 * relevant for states_equal() checks).33 * Write marks collect downwards and do not propagate; they record that "the34 * straight-line code that reached this state (from its parent) wrote this reg"35 * (and therefore that reads propagated from this state or its descendants36 * should not propagate to its parent).37 * A state with a write mark can receive read marks; it just won't propagate38 * them to its parent, since the write mark is a property, not of the state,39 * but of the link between it and its parent. See mark_reg_read() and40 * mark_stack_slot_read() in kernel/bpf/verifier.c.41 */42enum bpf_reg_liveness {43 REG_LIVE_NONE = 0, /* reg hasn't been read or written this branch */44 REG_LIVE_READ32 = 0x1, /* reg was read, so we're sensitive to initial value */45 REG_LIVE_READ64 = 0x2, /* likewise, but full 64-bit content matters */46 REG_LIVE_READ = REG_LIVE_READ32 | REG_LIVE_READ64,47 REG_LIVE_WRITTEN = 0x4, /* reg was written first, screening off later reads */48 REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */49};50 51/* For every reg representing a map value or allocated object pointer,52 * we consider the tuple of (ptr, id) for them to be unique in verifier53 * context and conside them to not alias each other for the purposes of54 * tracking lock state.55 */56struct bpf_active_lock {57 /* This can either be reg->map_ptr or reg->btf. If ptr is NULL,58 * there's no active lock held, and other fields have no59 * meaning. If non-NULL, it indicates that a lock is held and60 * id member has the reg->id of the register which can be >= 0.61 */62 void *ptr;63 /* This will be reg->id */64 u32 id;65};66 67#define ITER_PREFIX "bpf_iter_"68 69enum bpf_iter_state {70 BPF_ITER_STATE_INVALID, /* for non-first slot */71 BPF_ITER_STATE_ACTIVE,72 BPF_ITER_STATE_DRAINED,73};74 75struct bpf_reg_state {76 /* Ordering of fields matters. See states_equal() */77 enum bpf_reg_type type;78 /*79 * Fixed part of pointer offset, pointer types only.80 * Or constant delta between "linked" scalars with the same ID.81 */82 s32 off;83 union {84 /* valid when type == PTR_TO_PACKET */85 int range;86 87 /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |88 * PTR_TO_MAP_VALUE_OR_NULL89 */90 struct {91 struct bpf_map *map_ptr;92 /* To distinguish map lookups from outer map93 * the map_uid is non-zero for registers94 * pointing to inner maps.95 */96 u32 map_uid;97 };98 99 /* for PTR_TO_BTF_ID */100 struct {101 struct btf *btf;102 u32 btf_id;103 };104 105 struct { /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */106 u32 mem_size;107 u32 dynptr_id; /* for dynptr slices */108 };109 110 /* For dynptr stack slots */111 struct {112 enum bpf_dynptr_type type;113 /* A dynptr is 16 bytes so it takes up 2 stack slots.114 * We need to track which slot is the first slot115 * to protect against cases where the user may try to116 * pass in an address starting at the second slot of the117 * dynptr.118 */119 bool first_slot;120 } dynptr;121 122 /* For bpf_iter stack slots */123 struct {124 /* BTF container and BTF type ID describing125 * struct bpf_iter_<type> of an iterator state126 */127 struct btf *btf;128 u32 btf_id;129 /* packing following two fields to fit iter state into 16 bytes */130 enum bpf_iter_state state:2;131 int depth:30;132 } iter;133 134 /* Max size from any of the above. */135 struct {136 unsigned long raw1;137 unsigned long raw2;138 } raw;139 140 u32 subprogno; /* for PTR_TO_FUNC */141 };142 /* For scalar types (SCALAR_VALUE), this represents our knowledge of143 * the actual value.144 * For pointer types, this represents the variable part of the offset145 * from the pointed-to object, and is shared with all bpf_reg_states146 * with the same id as us.147 */148 struct tnum var_off;149 /* Used to determine if any memory access using this register will150 * result in a bad access.151 * These refer to the same value as var_off, not necessarily the actual152 * contents of the register.153 */154 s64 smin_value; /* minimum possible (s64)value */155 s64 smax_value; /* maximum possible (s64)value */156 u64 umin_value; /* minimum possible (u64)value */157 u64 umax_value; /* maximum possible (u64)value */158 s32 s32_min_value; /* minimum possible (s32)value */159 s32 s32_max_value; /* maximum possible (s32)value */160 u32 u32_min_value; /* minimum possible (u32)value */161 u32 u32_max_value; /* maximum possible (u32)value */162 /* For PTR_TO_PACKET, used to find other pointers with the same variable163 * offset, so they can share range knowledge.164 * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we165 * came from, when one is tested for != NULL.166 * For PTR_TO_MEM_OR_NULL this is used to identify memory allocation167 * for the purpose of tracking that it's freed.168 * For PTR_TO_SOCKET this is used to share which pointers retain the169 * same reference to the socket, to determine proper reference freeing.170 * For stack slots that are dynptrs, this is used to track references to171 * the dynptr to determine proper reference freeing.172 * Similarly to dynptrs, we use ID to track "belonging" of a reference173 * to a specific instance of bpf_iter.174 */175 /*176 * Upper bit of ID is used to remember relationship between "linked"177 * registers. Example:178 * r1 = r2; both will have r1->id == r2->id == N179 * r1 += 10; r1->id == N | BPF_ADD_CONST and r1->off == 10180 */181#define BPF_ADD_CONST (1U << 31)182 u32 id;183 /* PTR_TO_SOCKET and PTR_TO_TCP_SOCK could be a ptr returned184 * from a pointer-cast helper, bpf_sk_fullsock() and185 * bpf_tcp_sock().186 *187 * Consider the following where "sk" is a reference counted188 * pointer returned from "sk = bpf_sk_lookup_tcp();":189 *190 * 1: sk = bpf_sk_lookup_tcp();191 * 2: if (!sk) { return 0; }192 * 3: fullsock = bpf_sk_fullsock(sk);193 * 4: if (!fullsock) { bpf_sk_release(sk); return 0; }194 * 5: tp = bpf_tcp_sock(fullsock);195 * 6: if (!tp) { bpf_sk_release(sk); return 0; }196 * 7: bpf_sk_release(sk);197 * 8: snd_cwnd = tp->snd_cwnd; // verifier will complain198 *199 * After bpf_sk_release(sk) at line 7, both "fullsock" ptr and200 * "tp" ptr should be invalidated also. In order to do that,201 * the reg holding "fullsock" and "sk" need to remember202 * the original refcounted ptr id (i.e. sk_reg->id) in ref_obj_id203 * such that the verifier can reset all regs which have204 * ref_obj_id matching the sk_reg->id.205 *206 * sk_reg->ref_obj_id is set to sk_reg->id at line 1.207 * sk_reg->id will stay as NULL-marking purpose only.208 * After NULL-marking is done, sk_reg->id can be reset to 0.209 *210 * After "fullsock = bpf_sk_fullsock(sk);" at line 3,211 * fullsock_reg->ref_obj_id is set to sk_reg->ref_obj_id.212 *213 * After "tp = bpf_tcp_sock(fullsock);" at line 5,214 * tp_reg->ref_obj_id is set to fullsock_reg->ref_obj_id215 * which is the same as sk_reg->ref_obj_id.216 *217 * From the verifier perspective, if sk, fullsock and tp218 * are not NULL, they are the same ptr with different219 * reg->type. In particular, bpf_sk_release(tp) is also220 * allowed and has the same effect as bpf_sk_release(sk).221 */222 u32 ref_obj_id;223 /* parentage chain for liveness checking */224 struct bpf_reg_state *parent;225 /* Inside the callee two registers can be both PTR_TO_STACK like226 * R1=fp-8 and R2=fp-8, but one of them points to this function stack227 * while another to the caller's stack. To differentiate them 'frameno'228 * is used which is an index in bpf_verifier_state->frame[] array229 * pointing to bpf_func_state.230 */231 u32 frameno;232 /* Tracks subreg definition. The stored value is the insn_idx of the233 * writing insn. This is safe because subreg_def is used before any insn234 * patching which only happens after main verification finished.235 */236 s32 subreg_def;237 enum bpf_reg_liveness live;238 /* if (!precise && SCALAR_VALUE) min/max/tnum don't affect safety */239 bool precise;240};241 242enum bpf_stack_slot_type {243 STACK_INVALID, /* nothing was stored in this stack slot */244 STACK_SPILL, /* register spilled into stack */245 STACK_MISC, /* BPF program wrote some data into this slot */246 STACK_ZERO, /* BPF program wrote constant zero */247 /* A dynptr is stored in this stack slot. The type of dynptr248 * is stored in bpf_stack_state->spilled_ptr.dynptr.type249 */250 STACK_DYNPTR,251 STACK_ITER,252};253 254#define BPF_REG_SIZE 8 /* size of eBPF register in bytes */255 256#define BPF_REGMASK_ARGS ((1 << BPF_REG_1) | (1 << BPF_REG_2) | \257 (1 << BPF_REG_3) | (1 << BPF_REG_4) | \258 (1 << BPF_REG_5))259 260#define BPF_DYNPTR_SIZE sizeof(struct bpf_dynptr_kern)261#define BPF_DYNPTR_NR_SLOTS (BPF_DYNPTR_SIZE / BPF_REG_SIZE)262 263struct bpf_stack_state {264 struct bpf_reg_state spilled_ptr;265 u8 slot_type[BPF_REG_SIZE];266};267 268struct bpf_reference_state {269 /* Track each reference created with a unique id, even if the same270 * instruction creates the reference multiple times (eg, via CALL).271 */272 int id;273 /* Instruction where the allocation of this reference occurred. This274 * is used purely to inform the user of a reference leak.275 */276 int insn_idx;277 /* There can be a case like:278 * main (frame 0)279 * cb (frame 1)280 * func (frame 3)281 * cb (frame 4)282 * Hence for frame 4, if callback_ref just stored boolean, it would be283 * impossible to distinguish nested callback refs. Hence store the284 * frameno and compare that to callback_ref in check_reference_leak when285 * exiting a callback function.286 */287 int callback_ref;288};289 290struct bpf_retval_range {291 s32 minval;292 s32 maxval;293};294 295/* state of the program:296 * type of all registers and stack info297 */298struct bpf_func_state {299 struct bpf_reg_state regs[MAX_BPF_REG];300 /* index of call instruction that called into this func */301 int callsite;302 /* stack frame number of this function state from pov of303 * enclosing bpf_verifier_state.304 * 0 = main function, 1 = first callee.305 */306 u32 frameno;307 /* subprog number == index within subprog_info308 * zero == main subprog309 */310 u32 subprogno;311 /* Every bpf_timer_start will increment async_entry_cnt.312 * It's used to distinguish:313 * void foo(void) { for(;;); }314 * void foo(void) { bpf_timer_set_callback(,foo); }315 */316 u32 async_entry_cnt;317 struct bpf_retval_range callback_ret_range;318 bool in_callback_fn;319 bool in_async_callback_fn;320 bool in_exception_callback_fn;321 /* For callback calling functions that limit number of possible322 * callback executions (e.g. bpf_loop) keeps track of current323 * simulated iteration number.324 * Value in frame N refers to number of times callback with frame325 * N+1 was simulated, e.g. for the following call:326 *327 * bpf_loop(..., fn, ...); | suppose current frame is N328 * | fn would be simulated in frame N+1329 * | number of simulations is tracked in frame N330 */331 u32 callback_depth;332 333 /* The following fields should be last. See copy_func_state() */334 int acquired_refs;335 struct bpf_reference_state *refs;336 /* The state of the stack. Each element of the array describes BPF_REG_SIZE337 * (i.e. 8) bytes worth of stack memory.338 * stack[0] represents bytes [*(r10-8)..*(r10-1)]339 * stack[1] represents bytes [*(r10-16)..*(r10-9)]340 * ...341 * stack[allocated_stack/8 - 1] represents [*(r10-allocated_stack)..*(r10-allocated_stack+7)]342 */343 struct bpf_stack_state *stack;344 /* Size of the current stack, in bytes. The stack state is tracked below, in345 * `stack`. allocated_stack is always a multiple of BPF_REG_SIZE.346 */347 int allocated_stack;348};349 350#define MAX_CALL_FRAMES 8351 352/* instruction history flags, used in bpf_jmp_history_entry.flags field */353enum {354 /* instruction references stack slot through PTR_TO_STACK register;355 * we also store stack's frame number in lower 3 bits (MAX_CALL_FRAMES is 8)356 * and accessed stack slot's index in next 6 bits (MAX_BPF_STACK is 512,357 * 8 bytes per slot, so slot index (spi) is [0, 63])358 */359 INSN_F_FRAMENO_MASK = 0x7, /* 3 bits */360 361 INSN_F_SPI_MASK = 0x3f, /* 6 bits */362 INSN_F_SPI_SHIFT = 3, /* shifted 3 bits to the left */363 364 INSN_F_STACK_ACCESS = BIT(9), /* we need 10 bits total */365};366 367static_assert(INSN_F_FRAMENO_MASK + 1 >= MAX_CALL_FRAMES);368static_assert(INSN_F_SPI_MASK + 1 >= MAX_BPF_STACK / 8);369 370struct bpf_jmp_history_entry {371 u32 idx;372 /* insn idx can't be bigger than 1 million */373 u32 prev_idx : 22;374 /* special flags, e.g., whether insn is doing register stack spill/load */375 u32 flags : 10;376 /* additional registers that need precision tracking when this377 * jump is backtracked, vector of six 10-bit records378 */379 u64 linked_regs;380};381 382/* Maximum number of register states that can exist at once */383#define BPF_ID_MAP_SIZE ((MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) * MAX_CALL_FRAMES)384struct bpf_verifier_state {385 /* call stack tracking */386 struct bpf_func_state *frame[MAX_CALL_FRAMES];387 struct bpf_verifier_state *parent;388 /*389 * 'branches' field is the number of branches left to explore:390 * 0 - all possible paths from this state reached bpf_exit or391 * were safely pruned392 * 1 - at least one path is being explored.393 * This state hasn't reached bpf_exit394 * 2 - at least two paths are being explored.395 * This state is an immediate parent of two children.396 * One is fallthrough branch with branches==1 and another397 * state is pushed into stack (to be explored later) also with398 * branches==1. The parent of this state has branches==1.399 * The verifier state tree connected via 'parent' pointer looks like:400 * 1401 * 1402 * 2 -> 1 (first 'if' pushed into stack)403 * 1404 * 2 -> 1 (second 'if' pushed into stack)405 * 1406 * 1407 * 1 bpf_exit.408 *409 * Once do_check() reaches bpf_exit, it calls update_branch_counts()410 * and the verifier state tree will look:411 * 1412 * 1413 * 2 -> 1 (first 'if' pushed into stack)414 * 1415 * 1 -> 1 (second 'if' pushed into stack)416 * 0417 * 0418 * 0 bpf_exit.419 * After pop_stack() the do_check() will resume at second 'if'.420 *421 * If is_state_visited() sees a state with branches > 0 it means422 * there is a loop. If such state is exactly equal to the current state423 * it's an infinite loop. Note states_equal() checks for states424 * equivalency, so two states being 'states_equal' does not mean425 * infinite loop. The exact comparison is provided by426 * states_maybe_looping() function. It's a stronger pre-check and427 * much faster than states_equal().428 *429 * This algorithm may not find all possible infinite loops or430 * loop iteration count may be too high.431 * In such cases BPF_COMPLEXITY_LIMIT_INSNS limit kicks in.432 */433 u32 branches;434 u32 insn_idx;435 u32 curframe;436 437 struct bpf_active_lock active_lock;438 bool speculative;439 bool active_rcu_lock;440 u32 active_preempt_lock;441 /* If this state was ever pointed-to by other state's loop_entry field442 * this flag would be set to true. Used to avoid freeing such states443 * while they are still in use.444 */445 bool used_as_loop_entry;446 bool in_sleepable;447 448 /* first and last insn idx of this verifier state */449 u32 first_insn_idx;450 u32 last_insn_idx;451 /* If this state is a part of states loop this field points to some452 * parent of this state such that:453 * - it is also a member of the same states loop;454 * - DFS states traversal starting from initial state visits loop_entry455 * state before this state.456 * Used to compute topmost loop entry for state loops.457 * State loops might appear because of open coded iterators logic.458 * See get_loop_entry() for more information.459 */460 struct bpf_verifier_state *loop_entry;461 /* jmp history recorded from first to last.462 * backtracking is using it to go from last to first.463 * For most states jmp_history_cnt is [0-3].464 * For loops can go up to ~40.465 */466 struct bpf_jmp_history_entry *jmp_history;467 u32 jmp_history_cnt;468 u32 dfs_depth;469 u32 callback_unroll_depth;470 u32 may_goto_depth;471};472 473#define bpf_get_spilled_reg(slot, frame, mask) \474 (((slot < frame->allocated_stack / BPF_REG_SIZE) && \475 ((1 << frame->stack[slot].slot_type[BPF_REG_SIZE - 1]) & (mask))) \476 ? &frame->stack[slot].spilled_ptr : NULL)477 478/* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */479#define bpf_for_each_spilled_reg(iter, frame, reg, mask) \480 for (iter = 0, reg = bpf_get_spilled_reg(iter, frame, mask); \481 iter < frame->allocated_stack / BPF_REG_SIZE; \482 iter++, reg = bpf_get_spilled_reg(iter, frame, mask))483 484#define bpf_for_each_reg_in_vstate_mask(__vst, __state, __reg, __mask, __expr) \485 ({ \486 struct bpf_verifier_state *___vstate = __vst; \487 int ___i, ___j; \488 for (___i = 0; ___i <= ___vstate->curframe; ___i++) { \489 struct bpf_reg_state *___regs; \490 __state = ___vstate->frame[___i]; \491 ___regs = __state->regs; \492 for (___j = 0; ___j < MAX_BPF_REG; ___j++) { \493 __reg = &___regs[___j]; \494 (void)(__expr); \495 } \496 bpf_for_each_spilled_reg(___j, __state, __reg, __mask) { \497 if (!__reg) \498 continue; \499 (void)(__expr); \500 } \501 } \502 })503 504/* Invoke __expr over regsiters in __vst, setting __state and __reg */505#define bpf_for_each_reg_in_vstate(__vst, __state, __reg, __expr) \506 bpf_for_each_reg_in_vstate_mask(__vst, __state, __reg, 1 << STACK_SPILL, __expr)507 508/* linked list of verifier states used to prune search */509struct bpf_verifier_state_list {510 struct bpf_verifier_state state;511 struct bpf_verifier_state_list *next;512 int miss_cnt, hit_cnt;513};514 515struct bpf_loop_inline_state {516 unsigned int initialized:1; /* set to true upon first entry */517 unsigned int fit_for_inline:1; /* true if callback function is the same518 * at each call and flags are always zero519 */520 u32 callback_subprogno; /* valid when fit_for_inline is true */521};522 523/* pointer and state for maps */524struct bpf_map_ptr_state {525 struct bpf_map *map_ptr;526 bool poison;527 bool unpriv;528};529 530/* Possible states for alu_state member. */531#define BPF_ALU_SANITIZE_SRC (1U << 0)532#define BPF_ALU_SANITIZE_DST (1U << 1)533#define BPF_ALU_NEG_VALUE (1U << 2)534#define BPF_ALU_NON_POINTER (1U << 3)535#define BPF_ALU_IMMEDIATE (1U << 4)536#define BPF_ALU_SANITIZE (BPF_ALU_SANITIZE_SRC | \537 BPF_ALU_SANITIZE_DST)538 539struct bpf_insn_aux_data {540 union {541 enum bpf_reg_type ptr_type; /* pointer type for load/store insns */542 struct bpf_map_ptr_state map_ptr_state;543 s32 call_imm; /* saved imm field of call insn */544 u32 alu_limit; /* limit for add/sub register with pointer */545 struct {546 u32 map_index; /* index into used_maps[] */547 u32 map_off; /* offset from value base address */548 };549 struct {550 enum bpf_reg_type reg_type; /* type of pseudo_btf_id */551 union {552 struct {553 struct btf *btf;554 u32 btf_id; /* btf_id for struct typed var */555 };556 u32 mem_size; /* mem_size for non-struct typed var */557 };558 } btf_var;559 /* if instruction is a call to bpf_loop this field tracks560 * the state of the relevant registers to make decision about inlining561 */562 struct bpf_loop_inline_state loop_inline_state;563 };564 union {565 /* remember the size of type passed to bpf_obj_new to rewrite R1 */566 u64 obj_new_size;567 /* remember the offset of node field within type to rewrite */568 u64 insert_off;569 };570 struct btf_struct_meta *kptr_struct_meta;571 u64 map_key_state; /* constant (32 bit) key tracking for maps */572 int ctx_field_size; /* the ctx field size for load insn, maybe 0 */573 u32 seen; /* this insn was processed by the verifier at env->pass_cnt */574 bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */575 bool zext_dst; /* this insn zero extends dst reg */576 bool needs_zext; /* alu op needs to clear upper bits */577 bool storage_get_func_atomic; /* bpf_*_storage_get() with atomic memory alloc */578 bool is_iter_next; /* bpf_iter_<type>_next() kfunc call */579 bool call_with_percpu_alloc_ptr; /* {this,per}_cpu_ptr() with prog percpu alloc */580 u8 alu_state; /* used in combination with alu_limit */581 /* true if STX or LDX instruction is a part of a spill/fill582 * pattern for a bpf_fastcall call.583 */584 u8 fastcall_pattern:1;585 /* for CALL instructions, a number of spill/fill pairs in the586 * bpf_fastcall pattern.587 */588 u8 fastcall_spills_num:3;589 590 /* below fields are initialized once */591 unsigned int orig_idx; /* original instruction index */592 bool jmp_point;593 bool prune_point;594 /* ensure we check state equivalence and save state checkpoint and595 * this instruction, regardless of any heuristics596 */597 bool force_checkpoint;598 /* true if instruction is a call to a helper function that599 * accepts callback function as a parameter.600 */601 bool calls_callback;602};603 604#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */605#define MAX_USED_BTFS 64 /* max number of BTFs accessed by one BPF program */606 607#define BPF_VERIFIER_TMP_LOG_SIZE 1024608 609struct bpf_verifier_log {610 /* Logical start and end positions of a "log window" of the verifier log.611 * start_pos == 0 means we haven't truncated anything.612 * Once truncation starts to happen, start_pos + len_total == end_pos,613 * except during log reset situations, in which (end_pos - start_pos)614 * might get smaller than len_total (see bpf_vlog_reset()).615 * Generally, (end_pos - start_pos) gives number of useful data in616 * user log buffer.617 */618 u64 start_pos;619 u64 end_pos;620 char __user *ubuf;621 u32 level;622 u32 len_total;623 u32 len_max;624 char kbuf[BPF_VERIFIER_TMP_LOG_SIZE];625};626 627#define BPF_LOG_LEVEL1 1628#define BPF_LOG_LEVEL2 2629#define BPF_LOG_STATS 4630#define BPF_LOG_FIXED 8631#define BPF_LOG_LEVEL (BPF_LOG_LEVEL1 | BPF_LOG_LEVEL2)632#define BPF_LOG_MASK (BPF_LOG_LEVEL | BPF_LOG_STATS | BPF_LOG_FIXED)633#define BPF_LOG_KERNEL (BPF_LOG_MASK + 1) /* kernel internal flag */634#define BPF_LOG_MIN_ALIGNMENT 8U635#define BPF_LOG_ALIGNMENT 40U636 637static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)638{639 return log && log->level;640}641 642#define BPF_MAX_SUBPROGS 256643 644struct bpf_subprog_arg_info {645 enum bpf_arg_type arg_type;646 union {647 u32 mem_size;648 u32 btf_id;649 };650};651 652struct bpf_subprog_info {653 /* 'start' has to be the first field otherwise find_subprog() won't work */654 u32 start; /* insn idx of function entry point */655 u32 linfo_idx; /* The idx to the main_prog->aux->linfo */656 u16 stack_depth; /* max. stack depth used by this function */657 u16 stack_extra;658 /* offsets in range [stack_depth .. fastcall_stack_off)659 * are used for bpf_fastcall spills and fills.660 */661 s16 fastcall_stack_off;662 bool has_tail_call: 1;663 bool tail_call_reachable: 1;664 bool has_ld_abs: 1;665 bool is_cb: 1;666 bool is_async_cb: 1;667 bool is_exception_cb: 1;668 bool args_cached: 1;669 /* true if bpf_fastcall stack region is used by functions that can't be inlined */670 bool keep_fastcall_stack: 1;671 672 u8 arg_cnt;673 struct bpf_subprog_arg_info args[MAX_BPF_FUNC_REG_ARGS];674};675 676struct bpf_verifier_env;677 678struct backtrack_state {679 struct bpf_verifier_env *env;680 u32 frame;681 u32 reg_masks[MAX_CALL_FRAMES];682 u64 stack_masks[MAX_CALL_FRAMES];683};684 685struct bpf_id_pair {686 u32 old;687 u32 cur;688};689 690struct bpf_idmap {691 u32 tmp_id_gen;692 struct bpf_id_pair map[BPF_ID_MAP_SIZE];693};694 695struct bpf_idset {696 u32 count;697 u32 ids[BPF_ID_MAP_SIZE];698};699 700/* single container for all structs701 * one verifier_env per bpf_check() call702 */703struct bpf_verifier_env {704 u32 insn_idx;705 u32 prev_insn_idx;706 struct bpf_prog *prog; /* eBPF program being verified */707 const struct bpf_verifier_ops *ops;708 struct module *attach_btf_mod; /* The owner module of prog->aux->attach_btf */709 struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */710 int stack_size; /* number of states to be processed */711 bool strict_alignment; /* perform strict pointer alignment checks */712 bool test_state_freq; /* test verifier with different pruning frequency */713 bool test_reg_invariants; /* fail verification on register invariants violations */714 struct bpf_verifier_state *cur_state; /* current verifier state */715 struct bpf_verifier_state_list **explored_states; /* search pruning optimization */716 struct bpf_verifier_state_list *free_list;717 struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */718 struct btf_mod_pair used_btfs[MAX_USED_BTFS]; /* array of BTF's used by BPF program */719 u32 used_map_cnt; /* number of used maps */720 u32 used_btf_cnt; /* number of used BTF objects */721 u32 id_gen; /* used to generate unique reg IDs */722 u32 hidden_subprog_cnt; /* number of hidden subprogs */723 int exception_callback_subprog;724 bool explore_alu_limits;725 bool allow_ptr_leaks;726 /* Allow access to uninitialized stack memory. Writes with fixed offset are727 * always allowed, so this refers to reads (with fixed or variable offset),728 * to writes with variable offset and to indirect (helper) accesses.729 */730 bool allow_uninit_stack;731 bool bpf_capable;732 bool bypass_spec_v1;733 bool bypass_spec_v4;734 bool seen_direct_write;735 bool seen_exception;736 struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */737 const struct bpf_line_info *prev_linfo;738 struct bpf_verifier_log log;739 struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 2]; /* max + 2 for the fake and exception subprogs */740 union {741 struct bpf_idmap idmap_scratch;742 struct bpf_idset idset_scratch;743 };744 struct {745 int *insn_state;746 int *insn_stack;747 int cur_stack;748 } cfg;749 struct backtrack_state bt;750 struct bpf_jmp_history_entry *cur_hist_ent;751 u32 pass_cnt; /* number of times do_check() was called */752 u32 subprog_cnt;753 /* number of instructions analyzed by the verifier */754 u32 prev_insn_processed, insn_processed;755 /* number of jmps, calls, exits analyzed so far */756 u32 prev_jmps_processed, jmps_processed;757 /* total verification time */758 u64 verification_time;759 /* maximum number of verifier states kept in 'branching' instructions */760 u32 max_states_per_insn;761 /* total number of allocated verifier states */762 u32 total_states;763 /* some states are freed during program analysis.764 * this is peak number of states. this number dominates kernel765 * memory consumption during verification766 */767 u32 peak_states;768 /* longest register parentage chain walked for liveness marking */769 u32 longest_mark_read_walk;770 bpfptr_t fd_array;771 772 /* bit mask to keep track of whether a register has been accessed773 * since the last time the function state was printed774 */775 u32 scratched_regs;776 /* Same as scratched_regs but for stack slots */777 u64 scratched_stack_slots;778 u64 prev_log_pos, prev_insn_print_pos;779 /* buffer used to temporary hold constants as scalar registers */780 struct bpf_reg_state fake_reg[2];781 /* buffer used to generate temporary string representations,782 * e.g., in reg_type_str() to generate reg_type string783 */784 char tmp_str_buf[TMP_STR_BUF_LEN];785 struct bpf_insn insn_buf[INSN_BUF_SIZE];786 struct bpf_insn epilogue_buf[INSN_BUF_SIZE];787};788 789static inline struct bpf_func_info_aux *subprog_aux(struct bpf_verifier_env *env, int subprog)790{791 return &env->prog->aux->func_info_aux[subprog];792}793 794static inline struct bpf_subprog_info *subprog_info(struct bpf_verifier_env *env, int subprog)795{796 return &env->subprog_info[subprog];797}798 799__printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,800 const char *fmt, va_list args);801__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,802 const char *fmt, ...);803__printf(2, 3) void bpf_log(struct bpf_verifier_log *log,804 const char *fmt, ...);805int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level,806 char __user *log_buf, u32 log_size);807void bpf_vlog_reset(struct bpf_verifier_log *log, u64 new_pos);808int bpf_vlog_finalize(struct bpf_verifier_log *log, u32 *log_size_actual);809 810__printf(3, 4) void verbose_linfo(struct bpf_verifier_env *env,811 u32 insn_off,812 const char *prefix_fmt, ...);813 814static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env)815{816 struct bpf_verifier_state *cur = env->cur_state;817 818 return cur->frame[cur->curframe];819}820 821static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env)822{823 return cur_func(env)->regs;824}825 826int bpf_prog_offload_verifier_prep(struct bpf_prog *prog);827int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,828 int insn_idx, int prev_insn_idx);829int bpf_prog_offload_finalize(struct bpf_verifier_env *env);830void831bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,832 struct bpf_insn *insn);833void834bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt);835 836/* this lives here instead of in bpf.h because it needs to dereference tgt_prog */837static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,838 struct btf *btf, u32 btf_id)839{840 if (tgt_prog)841 return ((u64)tgt_prog->aux->id << 32) | btf_id;842 else843 return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id;844}845 846/* unpack the IDs from the key as constructed above */847static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id)848{849 if (obj_id)850 *obj_id = key >> 32;851 if (btf_id)852 *btf_id = key & 0x7FFFFFFF;853}854 855int bpf_check_attach_target(struct bpf_verifier_log *log,856 const struct bpf_prog *prog,857 const struct bpf_prog *tgt_prog,858 u32 btf_id,859 struct bpf_attach_target_info *tgt_info);860void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab);861 862int mark_chain_precision(struct bpf_verifier_env *env, int regno);863 864#define BPF_BASE_TYPE_MASK GENMASK(BPF_BASE_TYPE_BITS - 1, 0)865 866/* extract base type from bpf_{arg, return, reg}_type. */867static inline u32 base_type(u32 type)868{869 return type & BPF_BASE_TYPE_MASK;870}871 872/* extract flags from an extended type. See bpf_type_flag in bpf.h. */873static inline u32 type_flag(u32 type)874{875 return type & ~BPF_BASE_TYPE_MASK;876}877 878/* only use after check_attach_btf_id() */879static inline enum bpf_prog_type resolve_prog_type(const struct bpf_prog *prog)880{881 return (prog->type == BPF_PROG_TYPE_EXT && prog->aux->saved_dst_prog_type) ?882 prog->aux->saved_dst_prog_type : prog->type;883}884 885static inline bool bpf_prog_check_recur(const struct bpf_prog *prog)886{887 switch (resolve_prog_type(prog)) {888 case BPF_PROG_TYPE_TRACING:889 return prog->expected_attach_type != BPF_TRACE_ITER;890 case BPF_PROG_TYPE_STRUCT_OPS:891 case BPF_PROG_TYPE_LSM:892 return false;893 default:894 return true;895 }896}897 898#define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | PTR_TRUSTED | NON_OWN_REF)899 900static inline bool bpf_type_has_unsafe_modifiers(u32 type)901{902 return type_flag(type) & ~BPF_REG_TRUSTED_MODIFIERS;903}904 905static inline bool type_is_ptr_alloc_obj(u32 type)906{907 return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC;908}909 910static inline bool type_is_non_owning_ref(u32 type)911{912 return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF;913}914 915static inline bool type_is_pkt_pointer(enum bpf_reg_type type)916{917 type = base_type(type);918 return type == PTR_TO_PACKET ||919 type == PTR_TO_PACKET_META;920}921 922static inline bool type_is_sk_pointer(enum bpf_reg_type type)923{924 return type == PTR_TO_SOCKET ||925 type == PTR_TO_SOCK_COMMON ||926 type == PTR_TO_TCP_SOCK ||927 type == PTR_TO_XDP_SOCK;928}929 930static inline bool type_may_be_null(u32 type)931{932 return type & PTR_MAYBE_NULL;933}934 935static inline void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)936{937 env->scratched_regs |= 1U << regno;938}939 940static inline void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)941{942 env->scratched_stack_slots |= 1ULL << spi;943}944 945static inline bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)946{947 return (env->scratched_regs >> regno) & 1;948}949 950static inline bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)951{952 return (env->scratched_stack_slots >> regno) & 1;953}954 955static inline bool verifier_state_scratched(const struct bpf_verifier_env *env)956{957 return env->scratched_regs || env->scratched_stack_slots;958}959 960static inline void mark_verifier_state_clean(struct bpf_verifier_env *env)961{962 env->scratched_regs = 0U;963 env->scratched_stack_slots = 0ULL;964}965 966/* Used for printing the entire verifier state. */967static inline void mark_verifier_state_scratched(struct bpf_verifier_env *env)968{969 env->scratched_regs = ~0U;970 env->scratched_stack_slots = ~0ULL;971}972 973static inline bool bpf_stack_narrow_access_ok(int off, int fill_size, int spill_size)974{975#ifdef __BIG_ENDIAN976 off -= spill_size - fill_size;977#endif978 979 return !(off % BPF_REG_SIZE);980}981 982const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type);983const char *dynptr_type_str(enum bpf_dynptr_type type);984const char *iter_type_str(const struct btf *btf, u32 btf_id);985const char *iter_state_str(enum bpf_iter_state state);986 987void print_verifier_state(struct bpf_verifier_env *env,988 const struct bpf_func_state *state, bool print_all);989void print_insn_state(struct bpf_verifier_env *env, const struct bpf_func_state *state);990 991#endif /* _LINUX_BPF_VERIFIER_H */992