[PATCH 5.11 118/122] bpf: Move off_reg into sanitize_ptr_alu

Greg Kroah-Hartman
2021-04-19T13:17:09Z

From: Daniel Borkmann <daniel@iogearbox.net>

[ Upstream commit 6f55b2f2a1178856c19bbce2f71449926e731914 ]

Small refactor to drag off_reg into sanitize_ptr_alu(), so we later on can
use off_reg for generalizing some of the checks for all pointer types.

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: Sasha Levin <sashal@kernel.org>
---
kernel/bpf/verifier.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index fe473e565092..afb2ae55c9a7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5463,11 +5463,12 @@ static int sanitize_val_alu(struct bpf_verifier_env *env,
static int sanitize_ptr_alu(struct bpf_verifier_env *env,
struct bpf_insn *insn,
const struct bpf_reg_state *ptr_reg,
- struct bpf_reg_state *dst_reg,
- bool off_is_neg)
+ const struct bpf_reg_state *off_reg,
+ struct bpf_reg_state *dst_reg)
{
struct bpf_verifier_state *vstate = env->cur_state;
struct bpf_insn_aux_data *aux = cur_aux(env);
+ bool off_is_neg = off_reg->smin_value < 0;
bool ptr_is_dst_reg = ptr_reg == dst_reg;
u8 opcode = BPF_OP(insn->code);
u32 alu_state, alu_limit;
@@ -5602,7 +5603,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,

switch (opcode) {
case BPF_ADD:
- ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg);
if (ret < 0) {
verbose(env, "R%d tried to add from different maps, paths, or prohibited types\n", dst);
return ret;
@@ -5657,7 +5658,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
}
break;
case BPF_SUB:
- ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg);
if (ret < 0) {
verbose(env, "R%d tried to sub from different maps, paths, or prohibited types\n", dst);
return ret;
--
2.30.2