diff options
Diffstat (limited to 'include/linux/bpf_verifier.h')
| -rw-r--r-- | include/linux/bpf_verifier.h | 101 |
1 files changed, 85 insertions, 16 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index b8d200f60a40..7e61c395fddf 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -15,11 +15,11 @@ * 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 (1ULL << 31) +#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 INT_MAX +#define BPF_MAX_VAR_SIZ (1 << 29) /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that @@ -76,6 +76,14 @@ struct bpf_reg_state { s64 smax_value; /* maximum possible (s64)value */ u64 umin_value; /* minimum possible (u64)value */ u64 umax_value; /* maximum possible (u64)value */ + /* 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. + * This field must be second to last, for states_equal() reasons. + */ + u32 frameno; /* This field must be last, for states_equal() reasons. */ enum bpf_reg_liveness live; }; @@ -83,19 +91,46 @@ struct bpf_reg_state { 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_MISC, /* BPF program wrote some data into this slot */ + STACK_ZERO, /* BPF program wrote constant zero */ }; #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */ +struct bpf_stack_state { + struct bpf_reg_state spilled_ptr; + u8 slot_type[BPF_REG_SIZE]; +}; + /* state of the program: * type of all registers and stack info */ -struct bpf_verifier_state { +struct bpf_func_state { struct bpf_reg_state regs[MAX_BPF_REG]; - u8 stack_slot_type[MAX_BPF_STACK]; - struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE]; struct bpf_verifier_state *parent; + /* 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_stack_depth + * zero == main subprog + */ + u32 subprogno; + + /* should be second to last. See copy_func_state() */ + int allocated_stack; + struct bpf_stack_state *stack; +}; + +#define MAX_CALL_FRAMES 8 +struct bpf_verifier_state { + /* call stack tracking */ + struct bpf_func_state *frame[MAX_CALL_FRAMES]; + struct bpf_verifier_state *parent; + u32 curframe; }; /* linked list of verifier states used to prune search */ @@ -108,40 +143,74 @@ struct bpf_insn_aux_data { union { enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ struct bpf_map *map_ptr; /* pointer for call insn into lookup_elem */ + s32 call_imm; /* saved imm field of call insn */ }; int ctx_field_size; /* the ctx field size for load insn, maybe 0 */ - int converted_op_size; /* the valid value width after perceived conversion */ + bool seen; /* this insn was processed by the verifier */ }; #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ -struct bpf_verifier_env; -struct bpf_ext_analyzer_ops { - int (*insn_hook)(struct bpf_verifier_env *env, - int insn_idx, int prev_insn_idx); +#define BPF_VERIFIER_TMP_LOG_SIZE 1024 + +struct bpf_verifier_log { + u32 level; + char kbuf[BPF_VERIFIER_TMP_LOG_SIZE]; + char __user *ubuf; + u32 len_used; + u32 len_total; }; +static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log) +{ + return log->len_used >= log->len_total - 1; +} + +static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) +{ + return log->level && log->ubuf && !bpf_verifier_log_full(log); +} + +#define BPF_MAX_SUBPROGS 256 + /* single container for all structs * one verifier_env per bpf_check() call */ struct bpf_verifier_env { struct bpf_prog *prog; /* eBPF program being verified */ + const struct bpf_verifier_ops *ops; 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 */ - struct bpf_verifier_state cur_state; /* current verifier state */ + struct bpf_verifier_state *cur_state; /* current verifier state */ struct bpf_verifier_state_list **explored_states; /* search pruning optimization */ - const struct bpf_ext_analyzer_ops *analyzer_ops; /* external analyzer ops */ - void *analyzer_priv; /* pointer to external analyzer's private data */ struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ u32 used_map_cnt; /* number of used maps */ u32 id_gen; /* used to generate unique reg IDs */ bool allow_ptr_leaks; bool seen_direct_write; struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ + struct bpf_verifier_log log; + u32 subprog_starts[BPF_MAX_SUBPROGS]; + /* computes the stack depth of each bpf function */ + u16 subprog_stack_depth[BPF_MAX_SUBPROGS + 1]; + u32 subprog_cnt; }; -int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, - void *priv); +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, ...); + +static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env) +{ + struct bpf_verifier_state *cur = env->cur_state; + + return cur->frame[cur->curframe]->regs; +} + +int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env); +int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, + int insn_idx, int prev_insn_idx); #endif /* _LINUX_BPF_VERIFIER_H */ |