diff options
Diffstat (limited to 'include/linux/bpf_verifier.h')
| -rw-r--r-- | include/linux/bpf_verifier.h | 717 |
1 files changed, 640 insertions, 77 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index e83ef6f6bf43..256274acb1d8 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -5,6 +5,7 @@ #define _LINUX_BPF_VERIFIER_H 1 #include <linux/bpf.h> /* for enum bpf_reg_type */ +#include <linux/btf.h> /* for struct btf and btf_id() */ #include <linux/filter.h> /* for MAX_BPF_STACK */ #include <linux/tnum.h> @@ -17,6 +18,13 @@ * 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 +/* Patch buffer size */ +#define INSN_BUF_SIZE 32 /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that @@ -40,27 +48,109 @@ enum bpf_reg_liveness { REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */ }; +#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. + * Or constant delta between "linked" scalars with the same ID. + */ + s32 off; union { /* valid when type == PTR_TO_PACKET */ - u16 range; + int range; /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | * PTR_TO_MAP_VALUE_OR_NULL */ - struct bpf_map *map_ptr; + 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; + }; - u32 btf_id; /* for PTR_TO_BTF_ID */ + /* for PTR_TO_BTF_ID */ + struct { + struct btf *btf; + u32 btf_id; + }; - u32 mem_size; /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */ + 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_<type> 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; + + /* For irq stack slots */ + struct { + enum { + IRQ_NATIVE_KFUNC, + IRQ_LOCK_KFUNC, + } kfunc_class; + } irq; /* Max size from any of the above. */ - unsigned long raw; + struct { + unsigned long raw1; + unsigned long raw2; + } raw; + + u32 subprogno; /* for PTR_TO_FUNC */ }; - /* Fixed part of pointer offset, pointer types only */ - s32 off; + /* 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 @@ -69,7 +159,18 @@ struct bpf_reg_state { * 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. + */ + /* + * Upper bit of ID is used to remember relationship between "linked" + * registers. Example: + * r1 = r2; both will have r1->id == r2->id == N + * r1 += 10; r1->id == N | BPF_ADD_CONST and r1->off == 10 */ +#define BPF_ADD_CONST (1U << 31) u32 id; /* PTR_TO_SOCKET and PTR_TO_TCP_SOCK could be a ptr returned * from a pointer-cast helper, bpf_sk_fullsock() and @@ -111,26 +212,6 @@ struct bpf_reg_state { * allowed and has the same effect as bpf_sk_release(sk). */ u32 ref_obj_id; - /* 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 */ /* parentage chain for liveness checking */ struct bpf_reg_state *parent; /* Inside the callee two registers can be both PTR_TO_STACK like @@ -155,16 +236,40 @@ enum bpf_stack_slot_type { 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, + STACK_IRQ_FLAG, }; #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 { + /* Each reference object has a type. Ensure REF_TYPE_PTR is zero to + * default to pointer reference on zero initialization of a state. + */ + enum ref_state_type { + REF_TYPE_PTR = (1 << 1), + REF_TYPE_IRQ = (1 << 2), + REF_TYPE_LOCK = (1 << 3), + REF_TYPE_RES_LOCK = (1 << 4), + REF_TYPE_RES_LOCK_IRQ = (1 << 5), + REF_TYPE_LOCK_MASK = REF_TYPE_LOCK | REF_TYPE_RES_LOCK | REF_TYPE_RES_LOCK_IRQ, + } type; /* Track each reference created with a unique id, even if the same * instruction creates the reference multiple times (eg, via CALL). */ @@ -173,6 +278,15 @@ struct bpf_reference_state { * is used purely to inform the user of a reference leak. */ int insn_idx; + /* Use to keep track of the source object of a lock, to ensure + * it matches on unlock. + */ + void *ptr; +}; + +struct bpf_retval_range { + s32 minval; + s32 maxval; }; /* state of the program: @@ -187,28 +301,91 @@ struct bpf_func_state { * 0 = main function, 1 = first callee. */ u32 frameno; - /* subprog number == index within subprog_stack_depth + /* 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; - int allocated_stack; + /* 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; }; -struct bpf_idx_pair { - u32 prev_idx; +#define MAX_CALL_FRAMES 8 + +/* instruction history flags, used in bpf_insn_hist_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), + + INSN_F_DST_REG_STACK = BIT(10), /* dst_reg is PTR_TO_STACK */ + INSN_F_SRC_REG_STACK = BIT(11), /* src_reg is PTR_TO_STACK */ + /* total 12 bits are used now. */ +}; + +static_assert(INSN_F_FRAMENO_MASK + 1 >= MAX_CALL_FRAMES); +static_assert(INSN_F_SPI_MASK + 1 >= MAX_BPF_STACK / 8); + +struct bpf_insn_hist_entry { u32 idx; + /* insn idx can't be bigger than 1 million */ + u32 prev_idx : 20; + /* special INSN_F_xxx flags */ + u32 flags : 12; + /* additional registers that need precision tracking when this + * jump is backtracked, vector of six 10-bit records + */ + u64 linked_regs; }; -#define MAX_CALL_FRAMES 8 +/* 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; + /* Acquired reference states */ + struct bpf_reference_state *refs; /* * 'branches' field is the number of branches left to explore: * 0 - all possible paths from this state reached bpf_exit or @@ -245,7 +422,7 @@ struct bpf_verifier_state { * 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 - * equvalency, so two states being 'states_equal' does not mean + * 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(). @@ -257,51 +434,121 @@ struct bpf_verifier_state { u32 branches; u32 insn_idx; u32 curframe; - u32 active_spin_lock; + + u32 acquired_refs; + u32 active_locks; + u32 active_preempt_locks; + u32 active_irq_id; + u32 active_lock_id; + void *active_lock_ptr; + bool active_rcu_lock; + bool speculative; + bool in_sleepable; /* first and last insn idx of this verifier state */ u32 first_insn_idx; u32 last_insn_idx; - /* 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]. + /* 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; + /* Sub-range of env->insn_hist[] corresponding to this state's + * instruction history. + * Backtracking is using it to go from last to first. + * For most states instruction history is short, 0-3 instructions. * For loops can go up to ~40. */ - struct bpf_idx_pair *jmp_history; - u32 jmp_history_cnt; + u32 insn_hist_start; + u32 insn_hist_end; + u32 dfs_depth; + u32 callback_unroll_depth; + u32 may_goto_depth; + /* 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. + */ + u32 used_as_loop_entry; }; -#define bpf_get_spilled_reg(slot, frame) \ +#define bpf_get_spilled_reg(slot, frame, mask) \ (((slot < frame->allocated_stack / BPF_REG_SIZE) && \ - (frame->stack[slot].slot_type[0] == STACK_SPILL)) \ + ((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) \ - for (iter = 0, reg = bpf_get_spilled_reg(iter, frame); \ +#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)) + 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 list_head node; + u32 miss_cnt; + u32 hit_cnt:31; + u32 in_free_list:1; +}; + +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 */ +}; + +/* pointer and state for maps */ +struct bpf_map_ptr_state { + struct bpf_map *map_ptr; + bool poison; + bool unpriv; }; /* Possible states for alu_state member. */ -#define BPF_ALU_SANITIZE_SRC 1U -#define BPF_ALU_SANITIZE_DST 2U +#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 */ + struct bpf_map_ptr_state map_ptr_state; s32 call_imm; /* saved imm field of call insn */ u32 alu_limit; /* limit for add/sub register with pointer */ struct { @@ -311,64 +558,164 @@ struct bpf_insn_aux_data { struct { enum bpf_reg_type reg_type; /* type of pseudo_btf_id */ union { - u32 btf_id; /* btf_id for struct typed var */ + 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 */ - int sanitize_stack_off; /* stack slot to be cleared */ 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_<type>_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 */ + /* true if STX or LDX instruction is a part of a spill/fill + * pattern for a bpf_fastcall call. + */ + u8 fastcall_pattern:1; + /* for CALL instructions, a number of spill/fill pairs in the + * bpf_fastcall pattern. + */ + u8 fastcall_spills_num:3; + u8 arg_prog:4; /* 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; + /* registers alive before this instruction. */ + u16 live_regs_before; }; #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 { - u32 level; - char kbuf[BPF_VERIFIER_TMP_LOG_SIZE]; + /* 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 len_used; + u32 level; u32 len_total; + u32 len_max; + char kbuf[BPF_VERIFIER_TMP_LOG_SIZE]; }; -static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log) -{ - return log->len_used >= log->len_total - 1; -} - #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) +#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 && log->ubuf && !bpf_verifier_log_full(log)) || - log->level == BPF_LOG_KERNEL); + 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; + }; +}; + +enum priv_stack_mode { + PRIV_STACK_UNKNOWN, + NO_PRIV_STACK, + PRIV_STACK_ADAPTIVE, +}; + 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 */ - bool has_tail_call; - bool tail_call_reachable; - bool has_ld_abs; + u16 stack_extra; + /* offsets in range [stack_depth .. fastcall_stack_off) + * are used for bpf_fastcall spills and fills. + */ + s16 fastcall_stack_off; + 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; + /* true if bpf_fastcall stack region is used by functions that can't be inlined */ + bool keep_fastcall_stack: 1; + bool changes_pkt_data: 1; + bool might_sleep: 1; + + enum priv_stack_mode priv_stack_mode; + 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 @@ -379,31 +726,58 @@ struct bpf_verifier_env { 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; + /* Search pruning optimization, array of list_heads for + * lists of struct bpf_verifier_state_list. + */ + struct list_head *explored_states; + struct list_head free_list; /* list of struct bpf_verifier_state_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; - bool allow_ptr_to_map_access; + /* 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 + 1]; + 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; + /* vector of instruction indexes sorted in post-order */ + int *insn_postorder; int cur_stack; + /* current position in the insn_postorder vector */ + int cur_postorder; } cfg; + struct backtrack_state bt; + struct bpf_insn_hist_entry *insn_hist; + struct bpf_insn_hist_entry *cur_hist_ent; + u32 insn_hist_cap; u32 pass_cnt; /* number of times do_check() was called */ u32 subprog_cnt; /* number of instructions analyzed by the verifier */ @@ -423,14 +797,62 @@ struct bpf_verifier_env { u32 peak_states; /* longest register parentage chain walked for liveness marking */ u32 longest_mark_read_walk; + u32 free_list_size; + u32 explored_states_size; + 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 temporary hold constants as scalar registers */ + struct bpf_reg_state fake_reg[2]; + /* 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]; + struct bpf_insn insn_buf[INSN_BUF_SIZE]; + struct bpf_insn epilogue_buf[INSN_BUF_SIZE]; }; +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, ...); + +#define verifier_bug_if(cond, env, fmt, args...) \ + ({ \ + bool __cond = (cond); \ + if (unlikely(__cond)) { \ + BPF_WARN_ONCE(1, "verifier bug: " fmt "(" #cond ")\n", ##args); \ + bpf_log(&env->log, "verifier bug: " fmt "(" #cond ")\n", ##args); \ + } \ + (__cond); \ + }) +#define verifier_bug(env, fmt, args...) verifier_bug_if(1, env, fmt, ##args) static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env) { @@ -454,14 +876,23 @@ bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off, void bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt); -int check_ctx_reg(struct bpf_verifier_env *env, - const struct bpf_reg_state *reg, int regno); - /* 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, - u32 btf_id) + struct btf *btf, u32 btf_id) { - return tgt_prog ? (((u64)tgt_prog->aux->id) << 32 | btf_id) : 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, @@ -469,5 +900,137 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, 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->saved_dst_prog_type) ? + prog->aux->saved_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: + return prog->aux->jits_use_priv_stack; + 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 bool type_may_be_null(u32 type) +{ + return type & PTR_MAYBE_NULL; +} + +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_verifier_state *vstate, + u32 frameno, bool print_all); +void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_state *vstate, + u32 frameno); #endif /* _LINUX_BPF_VERIFIER_H */ |