diff options
| author | Alexei Starovoitov <ast@fb.com> | 2016-04-06 19:39:21 -0700 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:05 +0300 |
| commit | 29ca8572685fca0108c1217828cdaf02242cd913 (patch) | |
| tree | 0839f8d696c572ca93467d70d9f99a79d5458767 /kernel/bpf | |
| parent | 5337e36330c39bcab3f19f024ed092c456201037 (diff) | |
bpf: simplify verifier register state assignments
verifier is using the following structure to track the state of registers:
struct reg_state {
enum bpf_reg_type type;
union {
int imm;
struct bpf_map *map_ptr;
};
};
and later on in states_equal() does memcmp(&old->regs[i], &cur->regs[i],..)
to find equivalent states.
Throughout the code of verifier there are assignements to 'imm' and 'map_ptr'
fields and it's not obvious that most of the assignments into 'imm' don't
need to clear extra 4 bytes (like mark_reg_unknown_value() does) to make sure
that memcmp doesn't go over junk left from 'map_ptr' assignment.
Simplify the code by converting 'int' into 'long'
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8233021538d3..6c5d7cd4cb0e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -142,7 +142,7 @@ struct reg_state { enum bpf_reg_type type; union { /* valid when type == CONST_IMM | PTR_TO_STACK */ - int imm; + long imm; /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | * PTR_TO_MAP_VALUE_OR_NULL @@ -263,7 +263,7 @@ static void print_verifier_state(struct verifier_env *env) continue; verbose(" R%d=%s", i, reg_type_str[t]); if (t == CONST_IMM || t == PTR_TO_STACK) - verbose("%d", env->cur_state.regs[i].imm); + verbose("%ld", env->cur_state.regs[i].imm); else if (t == CONST_PTR_TO_MAP || t == PTR_TO_MAP_VALUE || t == PTR_TO_MAP_VALUE_OR_NULL) verbose("(ks=%d,vs=%d)", @@ -480,7 +480,6 @@ static void init_reg_state(struct reg_state *regs) for (i = 0; i < MAX_BPF_REG; i++) { regs[i].type = NOT_INIT; regs[i].imm = 0; - regs[i].map_ptr = NULL; } /* frame pointer */ @@ -495,7 +494,6 @@ static void mark_reg_unknown_value(struct reg_state *regs, u32 regno) BUG_ON(regno >= MAX_BPF_REG); regs[regno].type = UNKNOWN_VALUE; regs[regno].imm = 0; - regs[regno].map_ptr = NULL; } enum reg_arg_type { |