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bpf: Compare BTF types of functions arguments with actual types

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Make the verifier check that BTF types of function arguments match actual types
passed into top-level BPF program and into BPF-to-BPF calls. If types match
such BPF programs and sub-programs will have full support of BPF trampoline. If
types mismatch the trampoline has to be conservative. It has to save/restore
five program arguments and assume 64-bit scalars.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-17-ast@kernel.org
This commit is contained in:
Alexei Starovoitov
2019-11-14 10:57:16 -08:00
committed by Daniel Borkmann
parent 91cc1a9974
commit 8c1b6e69dc
5 changed files with 107 additions and 3 deletions
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8
include/linux/bpf.h
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@@ -480,6 +480,10 @@ static inline int bpf_trampoline_unlink_prog(struct bpf_prog *prog)
static inline void bpf_trampoline_put(struct bpf_trampoline *tr) {}
#endif
struct bpf_func_info_aux {
bool unreliable;
};
struct bpf_prog_aux {
atomic_t refcnt;
u32 used_map_cnt;
@@ -494,6 +498,7 @@ struct bpf_prog_aux {
bool verifier_zext; /* Zero extensions has been inserted by verifier. */
bool offload_requested;
bool attach_btf_trace; /* true if attaching to BTF-enabled raw tp */
bool func_proto_unreliable;
enum bpf_tramp_prog_type trampoline_prog_type;
struct bpf_trampoline *trampoline;
struct hlist_node tramp_hlist;
@@ -518,6 +523,7 @@ struct bpf_prog_aux {
struct bpf_prog_offload *offload;
struct btf *btf;
struct bpf_func_info *func_info;
struct bpf_func_info_aux *func_info_aux;
/* bpf_line_info loaded from userspace. linfo->insn_off
* has the xlated insn offset.
* Both the main and sub prog share the same linfo.
@@ -890,6 +896,8 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
const char *func_name,
struct btf_func_model *m);
int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog);
#else /* !CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{