[bpf-next,v1,1/8] bpf/verifier: Factor out atomic_ptr_type_ok()

Commit Message

Peilin Ye Jan. 25, 2025, 2:17 a.m. UTC

Factor out atomic_ptr_type_ok() as a helper function to be used later.

Signed-off-by: Peilin Ye <[e-mail]>
---
 kernel/bpf/verifier.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9971c03adfd5..0935b72fe716 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6116,6 +6116,26 @@  static bool is_arena_reg(struct bpf_verifier_env *env, int regno)
 	return reg->type == PTR_TO_ARENA;
 }
 
+/* Return false if @regno contains a pointer whose type isn't supported for
+ * atomic instruction @insn.
+ */
+static bool atomic_ptr_type_ok(struct bpf_verifier_env *env, int regno,
+			       struct bpf_insn *insn)
+{
+	if (is_ctx_reg(env, regno))
+		return false;
+	if (is_pkt_reg(env, regno))
+		return false;
+	if (is_flow_key_reg(env, regno))
+		return false;
+	if (is_sk_reg(env, regno))
+		return false;
+	if (is_arena_reg(env, regno))
+		return bpf_jit_supports_insn(insn, true);
+
+	return true;
+}
+
 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
 #ifdef CONFIG_NET
 	[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
@@ -7572,11 +7592,7 @@  static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
 		return -EACCES;
 	}
 
-	if (is_ctx_reg(env, insn->dst_reg) ||
-	    is_pkt_reg(env, insn->dst_reg) ||
-	    is_flow_key_reg(env, insn->dst_reg) ||
-	    is_sk_reg(env, insn->dst_reg) ||
-	    (is_arena_reg(env, insn->dst_reg) && !bpf_jit_supports_insn(insn, true))) {
+	if (!atomic_ptr_type_ok(env, insn->dst_reg, insn)) {
 		verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
 			insn->dst_reg,
 			reg_type_str(env, reg_state(env, insn->dst_reg)->type));