bpf: Move off_reg into sanitize_ptr_alu

commit 6f55b2f2a1178856c19bbce2f71449926e731914 upstream.

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>
[fllinden@amazon.com: fix minor contextual conflict for 4.14]
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f28ba90a43a7ff61a53b408f2e74d1f2ca8485c7..434829d4438be621c9dfacfee014801510c0efb7 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2094,11 +2094,12 @@ 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;
@@ -2224,7 +2225,7 @@ 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("R%d tried to add from different maps, paths, or prohibited types\n", dst);
                        return ret;
@@ -2279,7 +2280,7 @@ 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("R%d tried to sub from different maps, paths, or prohibited types\n", dst);
                        return ret;