bpf: Reuse canonical string formatter for ctx errs

The array "reg_type_str" provides canonical formatting of register
types, however a couple of places would previously check whether a
register represented the context and write the name "context" directly.
An upcoming commit will add another pointer type to these statements, so
to provide more accurate error messages in the verifier, update these
error messages to use "reg_type_str" instead.

Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abf567200574..8b4e70eeced2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1763,8 +1763,7 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
 	if (is_ctx_reg(env, insn->dst_reg) ||
 	    is_pkt_reg(env, insn->dst_reg)) {
 		verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
-			insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
-			"context" : "packet");
+			insn->dst_reg, reg_type_str[insn->dst_reg]);
 		return -EACCES;
 	}
 
@@ -4871,8 +4870,8 @@ static int do_check(struct bpf_verifier_env *env)
 				return err;
 
 			if (is_ctx_reg(env, insn->dst_reg)) {
-				verbose(env, "BPF_ST stores into R%d context is not allowed\n",
-					insn->dst_reg);
+				verbose(env, "BPF_ST stores into R%d %s is not allowed\n",
+					insn->dst_reg, reg_type_str[insn->dst_reg]);
 				return -EACCES;
 			}