On Wed, Sep 14, 2016 at 08:00:13PM +0100, Jakub Kicinski wrote: > Advanced JIT compilers and translators may want to use > eBPF verifier as a base for parsers or to perform custom > checks and validations. > > Add ability for external users to invoke the verifier > and provide callbacks to be invoked for every intruction > checked. For now only add most basic callback for > per-instruction pre-interpretation checks is added. More > advanced users may also like to have per-instruction post > callback and state comparison callback. > > Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com> > --- > include/linux/bpf_parser.h | 89 ++++++++++++++++++++++++++++++ > kernel/bpf/verifier.c | 134 > +++++++++++++++++++++++---------------------- > 2 files changed, 158 insertions(+), 65 deletions(-) > create mode 100644 include/linux/bpf_parser.h > > diff --git a/include/linux/bpf_parser.h b/include/linux/bpf_parser.h > new file mode 100644 > index 000000000000..daa53b204f4d > --- /dev/null > +++ b/include/linux/bpf_parser.h
'bpf parser' is a bit misleading name, since it can be interpreted as parser written in bpf. Also the header file containes verifier bits, therefore I think the better name would be bpf_verifier.h ? > @@ -0,0 +1,89 @@ > +/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of version 2 of the GNU General Public > + * License as published by the Free Software Foundation. > + */ > +#ifndef _LINUX_BPF_PARSER_H > +#define _LINUX_BPF_PARSER_H 1 > + > +#include <linux/bpf.h> /* for enum bpf_reg_type */ > +#include <linux/filter.h> /* for MAX_BPF_STACK */ > + > +struct reg_state { > + enum bpf_reg_type type; > + union { > + /* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE > */ > + s64 imm; > + > + /* valid when type == PTR_TO_PACKET* */ > + struct { > + u32 id; > + u16 off; > + u16 range; > + }; > + > + /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | > + * PTR_TO_MAP_VALUE_OR_NULL > + */ > + struct bpf_map *map_ptr; > + }; > +}; > + > +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 */ > +}; > + > +#define BPF_REG_SIZE 8 /* size of eBPF register in bytes */ > + > +/* state of the program: > + * type of all registers and stack info > + */ > +struct verifier_state { > + struct reg_state regs[MAX_BPF_REG]; > + u8 stack_slot_type[MAX_BPF_STACK]; > + struct reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE]; > +}; > + > +/* linked list of verifier states used to prune search */ > +struct verifier_state_list { > + struct verifier_state state; > + struct verifier_state_list *next; > +}; > + > +struct bpf_insn_aux_data { > + enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ > +}; > + > +#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program > */ > + > +struct verifier_env; > +struct bpf_ext_parser_ops { > + int (*insn_hook)(struct verifier_env *env, > + int insn_idx, int prev_insn_idx); > +}; How about calling this bpf_ext_analyzer_ops and main entry bpf_analyzer() ? I think it will better convey what it's doing. > + > +/* single container for all structs > + * one verifier_env per bpf_check() call > + */ > +struct verifier_env { > + struct bpf_prog *prog; /* eBPF program being verified */ > + struct verifier_stack_elem *head; /* stack of verifier states to be > processed */ > + int stack_size; /* number of states to be processed */ > + struct verifier_state cur_state; /* current verifier state */ > + struct verifier_state_list **explored_states; /* search pruning > optimization */ > + const struct bpf_ext_parser_ops *pops; /* external parser ops */ > + void *ppriv; /* pointer to external parser's private data */ a bit hard to review, since move and addition is in one patch. I think ppriv and pops are too obscure names. May be analyzer_ops and analyzer_priv ? Conceptually looks good.
