/* SPDX-License-Identifier: GPL-2.0-only */ /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com */ #ifndef _LINUX_BPF_VERIFIER_H #define _LINUX_BPF_VERIFIER_H 1 #include /* for enum bpf_reg_type */ #include /* for struct btf and btf_id() */ #include /* for MAX_BPF_STACK */ #include /* Maximum variable offset umax_value permitted when resolving memory accesses. * In practice this is far bigger than any realistic pointer offset; this limit * ensures that umax_value + (int)off + (int)size cannot overflow a u64. */ #define BPF_MAX_VAR_OFF (1 << 29) /* Maximum variable size permitted for ARG_CONST_SIZE[_OR_ZERO]. This ensures * that converting umax_value to int cannot overflow. */ #define BPF_MAX_VAR_SIZ (1 << 29) /* size of tmp_str_buf in bpf_verifier. * we need at least 306 bytes to fit full stack mask representation * (in the "-8,-16,...,-512" form) */ #define TMP_STR_BUF_LEN 320 /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that * "one of this state's descendants read this reg" (and therefore the reg is * relevant for states_equal() checks). * Write marks collect downwards and do not propagate; they record that "the * straight-line code that reached this state (from its parent) wrote this reg" * (and therefore that reads propagated from this state or its descendants * should not propagate to its parent). * A state with a write mark can receive read marks; it just won't propagate * them to its parent, since the write mark is a property, not of the state, * but of the link between it and its parent. See mark_reg_read() and * mark_stack_slot_read() in kernel/bpf/verifier.c. */ enum bpf_reg_liveness { REG_LIVE_NONE = 0, /* reg hasn't been read or written this branch */ REG_LIVE_READ32 = 0x1, /* reg was read, so we're sensitive to initial value */ REG_LIVE_READ64 = 0x2, /* likewise, but full 64-bit content matters */ REG_LIVE_READ = REG_LIVE_READ32 | REG_LIVE_READ64, REG_LIVE_WRITTEN = 0x4, /* reg was written first, screening off later reads */ REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */ }; /* For every reg representing a map value or allocated object pointer, * we consider the tuple of (ptr, id) for them to be unique in verifier * context and conside them to not alias each other for the purposes of * tracking lock state. */ struct bpf_active_lock { /* This can either be reg->map_ptr or reg->btf. If ptr is NULL, * there's no active lock held, and other fields have no * meaning. If non-NULL, it indicates that a lock is held and * id member has the reg->id of the register which can be >= 0. */ void *ptr; /* This will be reg->id */ u32 id; }; #define ITER_PREFIX "bpf_iter_" enum bpf_iter_state { BPF_ITER_STATE_INVALID, /* for non-first slot */ BPF_ITER_STATE_ACTIVE, BPF_ITER_STATE_DRAINED, }; struct bpf_reg_state { /* Ordering of fields matters. See states_equal() */ enum bpf_reg_type type; /* Fixed part of pointer offset, pointer types only */ s32 off; union { /* valid when type == PTR_TO_PACKET */ int range; /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | * PTR_TO_MAP_VALUE_OR_NULL */ struct { struct bpf_map *map_ptr; /* To distinguish map lookups from outer map * the map_uid is non-zero for registers * pointing to inner maps. */ u32 map_uid; }; /* for PTR_TO_BTF_ID */ struct { struct btf *btf; u32 btf_id; }; struct { /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */ u32 mem_size; u32 dynptr_id; /* for dynptr slices */ }; /* For dynptr stack slots */ struct { enum bpf_dynptr_type type; /* A dynptr is 16 bytes so it takes up 2 stack slots. * We need to track which slot is the first slot * to protect against cases where the user may try to * pass in an address starting at the second slot of the * dynptr. */ bool first_slot; } dynptr; /* For bpf_iter stack slots */ struct { /* BTF container and BTF type ID describing * struct bpf_iter_ of an iterator state */ struct btf *btf; u32 btf_id; /* packing following two fields to fit iter state into 16 bytes */ enum bpf_iter_state state:2; int depth:30; } iter; /* Max size from any of the above. */ struct { unsigned long raw1; unsigned long raw2; } raw; u32 subprogno; /* for PTR_TO_FUNC */ }; /* For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us. */ struct tnum var_off; /* Used to determine if any memory access using this register will * result in a bad access. * These refer to the same value as var_off, not necessarily the actual * contents of the register. */ s64 smin_value; /* minimum possible (s64)value */ s64 smax_value; /* maximum possible (s64)value */ u64 umin_value; /* minimum possible (u64)value */ u64 umax_value; /* maximum possible (u64)value */ s32 s32_min_value; /* minimum possible (s32)value */ s32 s32_max_value; /* maximum possible (s32)value */ u32 u32_min_value; /* minimum possible (u32)value */ u32 u32_max_value; /* maximum possible (u32)value */ /* For PTR_TO_PACKET, used to find other pointers with the same variable * offset, so they can share range knowledge. * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we * came from, when one is tested for != NULL. * For PTR_TO_MEM_OR_NULL this is used to identify memory allocation * for the purpose of tracking that it's freed. * For PTR_TO_SOCKET this is used to share which pointers retain the * same reference to the socket, to determine proper reference freeing. * For stack slots that are dynptrs, this is used to track references to * the dynptr to determine proper reference freeing. * Similarly to dynptrs, we use ID to track "belonging" of a reference * to a specific instance of bpf_iter. */ u32 id; /* PTR_TO_SOCKET and PTR_TO_TCP_SOCK could be a ptr returned * from a pointer-cast helper, bpf_sk_fullsock() and * bpf_tcp_sock(). * * Consider the following where "sk" is a reference counted * pointer returned from "sk = bpf_sk_lookup_tcp();": * * 1: sk = bpf_sk_lookup_tcp(); * 2: if (!sk) { return 0; } * 3: fullsock = bpf_sk_fullsock(sk); * 4: if (!fullsock) { bpf_sk_release(sk); return 0; } * 5: tp = bpf_tcp_sock(fullsock); * 6: if (!tp) { bpf_sk_release(sk); return 0; } * 7: bpf_sk_release(sk); * 8: snd_cwnd = tp->snd_cwnd; // verifier will complain * * After bpf_sk_release(sk) at line 7, both "fullsock" ptr and * "tp" ptr should be invalidated also. In order to do that, * the reg holding "fullsock" and "sk" need to remember * the original refcounted ptr id (i.e. sk_reg->id) in ref_obj_id * such that the verifier can reset all regs which have * ref_obj_id matching the sk_reg->id. * * sk_reg->ref_obj_id is set to sk_reg->id at line 1. * sk_reg->id will stay as NULL-marking purpose only. * After NULL-marking is done, sk_reg->id can be reset to 0. * * After "fullsock = bpf_sk_fullsock(sk);" at line 3, * fullsock_reg->ref_obj_id is set to sk_reg->ref_obj_id. * * After "tp = bpf_tcp_sock(fullsock);" at line 5, * tp_reg->ref_obj_id is set to fullsock_reg->ref_obj_id * which is the same as sk_reg->ref_obj_id. * * From the verifier perspective, if sk, fullsock and tp * are not NULL, they are the same ptr with different * reg->type. In particular, bpf_sk_release(tp) is also * allowed and has the same effect as bpf_sk_release(sk). */ u32 ref_obj_id; /* parentage chain for liveness checking */ struct bpf_reg_state *parent; /* Inside the callee two registers can be both PTR_TO_STACK like * R1=fp-8 and R2=fp-8, but one of them points to this function stack * while another to the caller's stack. To differentiate them 'frameno' * is used which is an index in bpf_verifier_state->frame[] array * pointing to bpf_func_state. */ u32 frameno; /* Tracks subreg definition. The stored value is the insn_idx of the * writing insn. This is safe because subreg_def is used before any insn * patching which only happens after main verification finished. */ s32 subreg_def; enum bpf_reg_liveness live; /* if (!precise && SCALAR_VALUE) min/max/tnum don't affect safety */ bool precise; }; enum bpf_stack_slot_type { STACK_INVALID, /* nothing was stored in this stack slot */ STACK_SPILL, /* register spilled into stack */ STACK_MISC, /* BPF program wrote some data into this slot */ STACK_ZERO, /* BPF program wrote constant zero */ /* A dynptr is stored in this stack slot. The type of dynptr * is stored in bpf_stack_state->spilled_ptr.dynptr.type */ STACK_DYNPTR, STACK_ITER, }; #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */ #define BPF_REGMASK_ARGS ((1 << BPF_REG_1) | (1 << BPF_REG_2) | \ (1 << BPF_REG_3) | (1 << BPF_REG_4) | \ (1 << BPF_REG_5)) #define BPF_DYNPTR_SIZE sizeof(struct bpf_dynptr_kern) #define BPF_DYNPTR_NR_SLOTS (BPF_DYNPTR_SIZE / BPF_REG_SIZE) struct bpf_stack_state { struct bpf_reg_state spilled_ptr; u8 slot_type[BPF_REG_SIZE]; }; struct bpf_reference_state { /* Track each reference created with a unique id, even if the same * instruction creates the reference multiple times (eg, via CALL). */ int id; /* Instruction where the allocation of this reference occurred. This * is used purely to inform the user of a reference leak. */ int insn_idx; /* There can be a case like: * main (frame 0) * cb (frame 1) * func (frame 3) * cb (frame 4) * Hence for frame 4, if callback_ref just stored boolean, it would be * impossible to distinguish nested callback refs. Hence store the * frameno and compare that to callback_ref in check_reference_leak when * exiting a callback function. */ int callback_ref; }; struct bpf_retval_range { s32 minval; s32 maxval; }; /* state of the program: * type of all registers and stack info */ struct bpf_func_state { struct bpf_reg_state regs[MAX_BPF_REG]; /* index of call instruction that called into this func */ int callsite; /* stack frame number of this function state from pov of * enclosing bpf_verifier_state. * 0 = main function, 1 = first callee. */ u32 frameno; /* subprog number == index within subprog_info * zero == main subprog */ u32 subprogno; /* Every bpf_timer_start will increment async_entry_cnt. * It's used to distinguish: * void foo(void) { for(;;); } * void foo(void) { bpf_timer_set_callback(,foo); } */ u32 async_entry_cnt; struct bpf_retval_range callback_ret_range; bool in_callback_fn; bool in_async_callback_fn; bool in_exception_callback_fn; /* For callback calling functions that limit number of possible * callback executions (e.g. bpf_loop) keeps track of current * simulated iteration number. * Value in frame N refers to number of times callback with frame * N+1 was simulated, e.g. for the following call: * * bpf_loop(..., fn, ...); | suppose current frame is N * | fn would be simulated in frame N+1 * | number of simulations is tracked in frame N */ u32 callback_depth; /* The following fields should be last. See copy_func_state() */ int acquired_refs; struct bpf_reference_state *refs; /* The state of the stack. Each element of the array describes BPF_REG_SIZE * (i.e. 8) bytes worth of stack memory. * stack[0] represents bytes [*(r10-8)..*(r10-1)] * stack[1] represents bytes [*(r10-16)..*(r10-9)] * ... * stack[allocated_stack/8 - 1] represents [*(r10-allocated_stack)..*(r10-allocated_stack+7)] */ struct bpf_stack_state *stack; /* Size of the current stack, in bytes. The stack state is tracked below, in * `stack`. allocated_stack is always a multiple of BPF_REG_SIZE. */ int allocated_stack; }; #define MAX_CALL_FRAMES 8 /* instruction history flags, used in bpf_jmp_history_entry.flags field */ enum { /* instruction references stack slot through PTR_TO_STACK register; * we also store stack's frame number in lower 3 bits (MAX_CALL_FRAMES is 8) * and accessed stack slot's index in next 6 bits (MAX_BPF_STACK is 512, * 8 bytes per slot, so slot index (spi) is [0, 63]) */ INSN_F_FRAMENO_MASK = 0x7, /* 3 bits */ INSN_F_SPI_MASK = 0x3f, /* 6 bits */ INSN_F_SPI_SHIFT = 3, /* shifted 3 bits to the left */ INSN_F_STACK_ACCESS = BIT(9), /* we need 10 bits total */ }; static_assert(INSN_F_FRAMENO_MASK + 1 >= MAX_CALL_FRAMES); static_assert(INSN_F_SPI_MASK + 1 >= MAX_BPF_STACK / 8); struct bpf_jmp_history_entry { u32 idx; /* insn idx can't be bigger than 1 million */ u32 prev_idx : 22; /* special flags, e.g., whether insn is doing register stack spill/load */ u32 flags : 10; }; /* Maximum number of register states that can exist at once */ #define BPF_ID_MAP_SIZE ((MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) * MAX_CALL_FRAMES) struct bpf_verifier_state { /* call stack tracking */ struct bpf_func_state *frame[MAX_CALL_FRAMES]; struct bpf_verifier_state *parent; /* * 'branches' field is the number of branches left to explore: * 0 - all possible paths from this state reached bpf_exit or * were safely pruned * 1 - at least one path is being explored. * This state hasn't reached bpf_exit * 2 - at least two paths are being explored. * This state is an immediate parent of two children. * One is fallthrough branch with branches==1 and another * state is pushed into stack (to be explored later) also with * branches==1. The parent of this state has branches==1. * The verifier state tree connected via 'parent' pointer looks like: * 1 * 1 * 2 -> 1 (first 'if' pushed into stack) * 1 * 2 -> 1 (second 'if' pushed into stack) * 1 * 1 * 1 bpf_exit. * * Once do_check() reaches bpf_exit, it calls update_branch_counts() * and the verifier state tree will look: * 1 * 1 * 2 -> 1 (first 'if' pushed into stack) * 1 * 1 -> 1 (second 'if' pushed into stack) * 0 * 0 * 0 bpf_exit. * After pop_stack() the do_check() will resume at second 'if'. * * If is_state_visited() sees a state with branches > 0 it means * there is a loop. If such state is exactly equal to the current state * it's an infinite loop. Note states_equal() checks for states * equivalency, so two states being 'states_equal' does not mean * infinite loop. The exact comparison is provided by * states_maybe_looping() function. It's a stronger pre-check and * much faster than states_equal(). * * This algorithm may not find all possible infinite loops or * loop iteration count may be too high. * In such cases BPF_COMPLEXITY_LIMIT_INSNS limit kicks in. */ u32 branches; u32 insn_idx; u32 curframe; struct bpf_active_lock active_lock; bool speculative; bool active_rcu_lock; /* If this state was ever pointed-to by other state's loop_entry field * this flag would be set to true. Used to avoid freeing such states * while they are still in use. */ bool used_as_loop_entry; /* first and last insn idx of this verifier state */ u32 first_insn_idx; u32 last_insn_idx; /* If this state is a part of states loop this field points to some * parent of this state such that: * - it is also a member of the same states loop; * - DFS states traversal starting from initial state visits loop_entry * state before this state. * Used to compute topmost loop entry for state loops. * State loops might appear because of open coded iterators logic. * See get_loop_entry() for more information. */ struct bpf_verifier_state *loop_entry; /* jmp history recorded from first to last. * backtracking is using it to go from last to first. * For most states jmp_history_cnt is [0-3]. * For loops can go up to ~40. */ struct bpf_jmp_history_entry *jmp_history; u32 jmp_history_cnt; u32 dfs_depth; u32 callback_unroll_depth; u32 may_goto_depth; }; #define bpf_get_spilled_reg(slot, frame, mask) \ (((slot < frame->allocated_stack / BPF_REG_SIZE) && \ ((1 << frame->stack[slot].slot_type[BPF_REG_SIZE - 1]) & (mask))) \ ? &frame->stack[slot].spilled_ptr : NULL) /* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */ #define bpf_for_each_spilled_reg(iter, frame, reg, mask) \ for (iter = 0, reg = bpf_get_spilled_reg(iter, frame, mask); \ iter < frame->allocated_stack / BPF_REG_SIZE; \ iter++, reg = bpf_get_spilled_reg(iter, frame, mask)) #define bpf_for_each_reg_in_vstate_mask(__vst, __state, __reg, __mask, __expr) \ ({ \ struct bpf_verifier_state *___vstate = __vst; \ int ___i, ___j; \ for (___i = 0; ___i <= ___vstate->curframe; ___i++) { \ struct bpf_reg_state *___regs; \ __state = ___vstate->frame[___i]; \ ___regs = __state->regs; \ for (___j = 0; ___j < MAX_BPF_REG; ___j++) { \ __reg = &___regs[___j]; \ (void)(__expr); \ } \ bpf_for_each_spilled_reg(___j, __state, __reg, __mask) { \ if (!__reg) \ continue; \ (void)(__expr); \ } \ } \ }) /* Invoke __expr over regsiters in __vst, setting __state and __reg */ #define bpf_for_each_reg_in_vstate(__vst, __state, __reg, __expr) \ bpf_for_each_reg_in_vstate_mask(__vst, __state, __reg, 1 << STACK_SPILL, __expr) /* linked list of verifier states used to prune search */ struct bpf_verifier_state_list { struct bpf_verifier_state state; struct bpf_verifier_state_list *next; int miss_cnt, hit_cnt; }; struct bpf_loop_inline_state { unsigned int initialized:1; /* set to true upon first entry */ unsigned int fit_for_inline:1; /* true if callback function is the same * at each call and flags are always zero */ u32 callback_subprogno; /* valid when fit_for_inline is true */ }; /* Possible states for alu_state member. */ #define BPF_ALU_SANITIZE_SRC (1U << 0) #define BPF_ALU_SANITIZE_DST (1U << 1) #define BPF_ALU_NEG_VALUE (1U << 2) #define BPF_ALU_NON_POINTER (1U << 3) #define BPF_ALU_IMMEDIATE (1U << 4) #define BPF_ALU_SANITIZE (BPF_ALU_SANITIZE_SRC | \ BPF_ALU_SANITIZE_DST) struct bpf_insn_aux_data { union { enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ unsigned long map_ptr_state; /* pointer/poison value for maps */ s32 call_imm; /* saved imm field of call insn */ u32 alu_limit; /* limit for add/sub register with pointer */ struct { u32 map_index; /* index into used_maps[] */ u32 map_off; /* offset from value base address */ }; struct { enum bpf_reg_type reg_type; /* type of pseudo_btf_id */ union { struct { struct btf *btf; u32 btf_id; /* btf_id for struct typed var */ }; u32 mem_size; /* mem_size for non-struct typed var */ }; } btf_var; /* if instruction is a call to bpf_loop this field tracks * the state of the relevant registers to make decision about inlining */ struct bpf_loop_inline_state loop_inline_state; }; union { /* remember the size of type passed to bpf_obj_new to rewrite R1 */ u64 obj_new_size; /* remember the offset of node field within type to rewrite */ u64 insert_off; }; struct btf_struct_meta *kptr_struct_meta; u64 map_key_state; /* constant (32 bit) key tracking for maps */ int ctx_field_size; /* the ctx field size for load insn, maybe 0 */ u32 seen; /* this insn was processed by the verifier at env->pass_cnt */ bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */ bool zext_dst; /* this insn zero extends dst reg */ bool needs_zext; /* alu op needs to clear upper bits */ bool storage_get_func_atomic; /* bpf_*_storage_get() with atomic memory alloc */ bool is_iter_next; /* bpf_iter__next() kfunc call */ bool call_with_percpu_alloc_ptr; /* {this,per}_cpu_ptr() with prog percpu alloc */ u8 alu_state; /* used in combination with alu_limit */ /* below fields are initialized once */ unsigned int orig_idx; /* original instruction index */ bool jmp_point; bool prune_point; /* ensure we check state equivalence and save state checkpoint and * this instruction, regardless of any heuristics */ bool force_checkpoint; /* true if instruction is a call to a helper function that * accepts callback function as a parameter. */ bool calls_callback; }; #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ #define MAX_USED_BTFS 64 /* max number of BTFs accessed by one BPF program */ #define BPF_VERIFIER_TMP_LOG_SIZE 1024 struct bpf_verifier_log { /* Logical start and end positions of a "log window" of the verifier log. * start_pos == 0 means we haven't truncated anything. * Once truncation starts to happen, start_pos + len_total == end_pos, * except during log reset situations, in which (end_pos - start_pos) * might get smaller than len_total (see bpf_vlog_reset()). * Generally, (end_pos - start_pos) gives number of useful data in * user log buffer. */ u64 start_pos; u64 end_pos; char __user *ubuf; u32 level; u32 len_total; u32 len_max; char kbuf[BPF_VERIFIER_TMP_LOG_SIZE]; }; #define BPF_LOG_LEVEL1 1 #define BPF_LOG_LEVEL2 2 #define BPF_LOG_STATS 4 #define BPF_LOG_FIXED 8 #define BPF_LOG_LEVEL (BPF_LOG_LEVEL1 | BPF_LOG_LEVEL2) #define BPF_LOG_MASK (BPF_LOG_LEVEL | BPF_LOG_STATS | BPF_LOG_FIXED) #define BPF_LOG_KERNEL (BPF_LOG_MASK + 1) /* kernel internal flag */ #define BPF_LOG_MIN_ALIGNMENT 8U #define BPF_LOG_ALIGNMENT 40U static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) { return log && log->level; } #define BPF_MAX_SUBPROGS 256 struct bpf_subprog_arg_info { enum bpf_arg_type arg_type; union { u32 mem_size; u32 btf_id; }; }; struct bpf_subprog_info { /* 'start' has to be the first field otherwise find_subprog() won't work */ u32 start; /* insn idx of function entry point */ u32 linfo_idx; /* The idx to the main_prog->aux->linfo */ u16 stack_depth; /* max. stack depth used by this function */ u16 stack_extra; bool has_tail_call: 1; bool tail_call_reachable: 1; bool has_ld_abs: 1; bool is_cb: 1; bool is_async_cb: 1; bool is_exception_cb: 1; bool args_cached: 1; u8 arg_cnt; struct bpf_subprog_arg_info args[MAX_BPF_FUNC_REG_ARGS]; }; struct bpf_verifier_env; struct backtrack_state { struct bpf_verifier_env *env; u32 frame; u32 reg_masks[MAX_CALL_FRAMES]; u64 stack_masks[MAX_CALL_FRAMES]; }; struct bpf_id_pair { u32 old; u32 cur; }; struct bpf_idmap { u32 tmp_id_gen; struct bpf_id_pair map[BPF_ID_MAP_SIZE]; }; struct bpf_idset { u32 count; u32 ids[BPF_ID_MAP_SIZE]; }; /* single container for all structs * one verifier_env per bpf_check() call */ struct bpf_verifier_env { u32 insn_idx; u32 prev_insn_idx; struct bpf_prog *prog; /* eBPF program being verified */ const struct bpf_verifier_ops *ops; struct module *attach_btf_mod; /* The owner module of prog->aux->attach_btf */ struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */ int stack_size; /* number of states to be processed */ bool strict_alignment; /* perform strict pointer alignment checks */ bool test_state_freq; /* test verifier with different pruning frequency */ bool test_reg_invariants; /* fail verification on register invariants violations */ struct bpf_verifier_state *cur_state; /* current verifier state */ struct bpf_verifier_state_list **explored_states; /* search pruning optimization */ struct bpf_verifier_state_list *free_list; struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ struct btf_mod_pair used_btfs[MAX_USED_BTFS]; /* array of BTF's used by BPF program */ u32 used_map_cnt; /* number of used maps */ u32 used_btf_cnt; /* number of used BTF objects */ u32 id_gen; /* used to generate unique reg IDs */ u32 hidden_subprog_cnt; /* number of hidden subprogs */ int exception_callback_subprog; bool explore_alu_limits; bool allow_ptr_leaks; /* Allow access to uninitialized stack memory. Writes with fixed offset are * always allowed, so this refers to reads (with fixed or variable offset), * to writes with variable offset and to indirect (helper) accesses. */ bool allow_uninit_stack; bool bpf_capable; bool bypass_spec_v1; bool bypass_spec_v4; bool seen_direct_write; bool seen_exception; struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ const struct bpf_line_info *prev_linfo; struct bpf_verifier_log log; struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 2]; /* max + 2 for the fake and exception subprogs */ union { struct bpf_idmap idmap_scratch; struct bpf_idset idset_scratch; }; struct { int *insn_state; int *insn_stack; int cur_stack; } cfg; struct backtrack_state bt; struct bpf_jmp_history_entry *cur_hist_ent; u32 pass_cnt; /* number of times do_check() was called */ u32 subprog_cnt; /* number of instructions analyzed by the verifier */ u32 prev_insn_processed, insn_processed; /* number of jmps, calls, exits analyzed so far */ u32 prev_jmps_processed, jmps_processed; /* total verification time */ u64 verification_time; /* maximum number of verifier states kept in 'branching' instructions */ u32 max_states_per_insn; /* total number of allocated verifier states */ u32 total_states; /* some states are freed during program analysis. * this is peak number of states. this number dominates kernel * memory consumption during verification */ u32 peak_states; /* longest register parentage chain walked for liveness marking */ u32 longest_mark_read_walk; bpfptr_t fd_array; /* bit mask to keep track of whether a register has been accessed * since the last time the function state was printed */ u32 scratched_regs; /* Same as scratched_regs but for stack slots */ u64 scratched_stack_slots; u64 prev_log_pos, prev_insn_print_pos; /* buffer used to generate temporary string representations, * e.g., in reg_type_str() to generate reg_type string */ char tmp_str_buf[TMP_STR_BUF_LEN]; }; static inline struct bpf_func_info_aux *subprog_aux(struct bpf_verifier_env *env, int subprog) { return &env->prog->aux->func_info_aux[subprog]; } static inline struct bpf_subprog_info *subprog_info(struct bpf_verifier_env *env, int subprog) { return &env->subprog_info[subprog]; } __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, va_list args); __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, const char *fmt, ...); __printf(2, 3) void bpf_log(struct bpf_verifier_log *log, const char *fmt, ...); int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level, char __user *log_buf, u32 log_size); void bpf_vlog_reset(struct bpf_verifier_log *log, u64 new_pos); int bpf_vlog_finalize(struct bpf_verifier_log *log, u32 *log_size_actual); __printf(3, 4) void verbose_linfo(struct bpf_verifier_env *env, u32 insn_off, const char *prefix_fmt, ...); static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env) { struct bpf_verifier_state *cur = env->cur_state; return cur->frame[cur->curframe]; } static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env) { return cur_func(env)->regs; } int bpf_prog_offload_verifier_prep(struct bpf_prog *prog); int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx); int bpf_prog_offload_finalize(struct bpf_verifier_env *env); void bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off, struct bpf_insn *insn); void bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt); /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */ static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog, struct btf *btf, u32 btf_id) { if (tgt_prog) return ((u64)tgt_prog->aux->id << 32) | btf_id; else return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id; } /* unpack the IDs from the key as constructed above */ static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id) { if (obj_id) *obj_id = key >> 32; if (btf_id) *btf_id = key & 0x7FFFFFFF; } int bpf_check_attach_target(struct bpf_verifier_log *log, const struct bpf_prog *prog, const struct bpf_prog *tgt_prog, u32 btf_id, struct bpf_attach_target_info *tgt_info); void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab); int mark_chain_precision(struct bpf_verifier_env *env, int regno); #define BPF_BASE_TYPE_MASK GENMASK(BPF_BASE_TYPE_BITS - 1, 0) /* extract base type from bpf_{arg, return, reg}_type. */ static inline u32 base_type(u32 type) { return type & BPF_BASE_TYPE_MASK; } /* extract flags from an extended type. See bpf_type_flag in bpf.h. */ static inline u32 type_flag(u32 type) { return type & ~BPF_BASE_TYPE_MASK; } /* only use after check_attach_btf_id() */ static inline enum bpf_prog_type resolve_prog_type(const struct bpf_prog *prog) { return prog->type == BPF_PROG_TYPE_EXT ? prog->aux->dst_prog->type : prog->type; } static inline bool bpf_prog_check_recur(const struct bpf_prog *prog) { switch (resolve_prog_type(prog)) { case BPF_PROG_TYPE_TRACING: return prog->expected_attach_type != BPF_TRACE_ITER; case BPF_PROG_TYPE_STRUCT_OPS: case BPF_PROG_TYPE_LSM: return false; default: return true; } } #define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | PTR_TRUSTED | NON_OWN_REF) static inline bool bpf_type_has_unsafe_modifiers(u32 type) { return type_flag(type) & ~BPF_REG_TRUSTED_MODIFIERS; } static inline bool type_is_ptr_alloc_obj(u32 type) { return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC; } static inline bool type_is_non_owning_ref(u32 type) { return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF; } static inline bool type_is_pkt_pointer(enum bpf_reg_type type) { type = base_type(type); return type == PTR_TO_PACKET || type == PTR_TO_PACKET_META; } static inline bool type_is_sk_pointer(enum bpf_reg_type type) { return type == PTR_TO_SOCKET || type == PTR_TO_SOCK_COMMON || type == PTR_TO_TCP_SOCK || type == PTR_TO_XDP_SOCK; } static inline void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno) { env->scratched_regs |= 1U << regno; } static inline void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi) { env->scratched_stack_slots |= 1ULL << spi; } static inline bool reg_scratched(const struct bpf_verifier_env *env, u32 regno) { return (env->scratched_regs >> regno) & 1; } static inline bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno) { return (env->scratched_stack_slots >> regno) & 1; } static inline bool verifier_state_scratched(const struct bpf_verifier_env *env) { return env->scratched_regs || env->scratched_stack_slots; } static inline void mark_verifier_state_clean(struct bpf_verifier_env *env) { env->scratched_regs = 0U; env->scratched_stack_slots = 0ULL; } /* Used for printing the entire verifier state. */ static inline void mark_verifier_state_scratched(struct bpf_verifier_env *env) { env->scratched_regs = ~0U; env->scratched_stack_slots = ~0ULL; } static inline bool bpf_stack_narrow_access_ok(int off, int fill_size, int spill_size) { #ifdef __BIG_ENDIAN off -= spill_size - fill_size; #endif return !(off % BPF_REG_SIZE); } const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type); const char *dynptr_type_str(enum bpf_dynptr_type type); const char *iter_type_str(const struct btf *btf, u32 btf_id); const char *iter_state_str(enum bpf_iter_state state); void print_verifier_state(struct bpf_verifier_env *env, const struct bpf_func_state *state, bool print_all); void print_insn_state(struct bpf_verifier_env *env, const struct bpf_func_state *state); #endif /* _LINUX_BPF_VERIFIER_H */