diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2021-05-28 13:38:01 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-03 08:38:06 +0200 |
| commit | 8ab6572e2081f82eef28a972af86676467192225 (patch) | |
| tree | 8aa1a8bdc18f9c9ce72b4bd503f367ff9470ad01 /kernel | |
| parent | 167743a5eae1c586aa408c6fac4429224e4e4663 (diff) | |
bpf: Rework ptr_limit into alu_limit and add common error path
commit b658bbb844e28f1862867f37e8ca11a8e2aa94a3 upstream.
Small refactor with no semantic changes in order to consolidate the max
ptr_limit boundary check.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[OP: backport to 4.19]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cdef8c7769ef..adc833c6088f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2731,12 +2731,12 @@ static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, const struct bpf_reg_state *off_reg, - u32 *ptr_limit, u8 opcode) + u32 *alu_limit, u8 opcode) { bool off_is_neg = off_reg->smin_value < 0; bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || (opcode == BPF_SUB && !off_is_neg); - u32 off, max; + u32 off, max = 0, ptr_limit = 0; if (!tnum_is_const(off_reg->var_off) && (off_reg->smin_value < 0) != (off_reg->smax_value < 0)) @@ -2750,22 +2750,27 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, max = MAX_BPF_STACK + mask_to_left; off = ptr_reg->off + ptr_reg->var_off.value; if (mask_to_left) - *ptr_limit = MAX_BPF_STACK + off; + ptr_limit = MAX_BPF_STACK + off; else - *ptr_limit = -off - 1; - return *ptr_limit >= max ? -ERANGE : 0; + ptr_limit = -off - 1; + break; case PTR_TO_MAP_VALUE: max = ptr_reg->map_ptr->value_size; if (mask_to_left) { - *ptr_limit = ptr_reg->umax_value + ptr_reg->off; + ptr_limit = ptr_reg->umax_value + ptr_reg->off; } else { off = ptr_reg->smin_value + ptr_reg->off; - *ptr_limit = ptr_reg->map_ptr->value_size - off - 1; + ptr_limit = ptr_reg->map_ptr->value_size - off - 1; } - return *ptr_limit >= max ? -ERANGE : 0; + break; default: return -EINVAL; } + + if (ptr_limit >= max) + return -ERANGE; + *alu_limit = ptr_limit; + return 0; } static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, |