Thread (19 messages) 19 messages, 3 authors, 2021-02-26
STALE1952d REVIEWED: 4 (4M)
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[PATCH bpf-next v4 02/12] bpf: factor out verbose_invalid_scalar()

From: Yonghong Song <hidden>
Date: 2021-02-26 05:14:14
Subsystem: bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds

Factor out the function verbose_invalid_scalar() to verbose
print if a scalar is not in a tnum range. There is no
functionality change and the function will be used by
later patch which introduced bpf_for_each_map_elem().

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <redacted>
---
 kernel/bpf/verifier.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9cb182e91162..9b48c966fe15 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -390,6 +390,24 @@ __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
 	env->prev_linfo = linfo;
 }
 
+static void verbose_invalid_scalar(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg,
+				   struct tnum *range, const char *ctx,
+				   const char *reg_name)
+{
+	char tn_buf[48];
+
+	verbose(env, "At %s the register %s ", ctx, reg_name);
+	if (!tnum_is_unknown(reg->var_off)) {
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "has value %s", tn_buf);
+	} else {
+		verbose(env, "has unknown scalar value");
+	}
+	tnum_strn(tn_buf, sizeof(tn_buf), *range);
+	verbose(env, " should have been in %s\n", tn_buf);
+}
+
 static bool type_is_pkt_pointer(enum bpf_reg_type type)
 {
 	return type == PTR_TO_PACKET ||
@@ -8455,17 +8473,7 @@ static int check_return_code(struct bpf_verifier_env *env)
 	}
 
 	if (!tnum_in(range, reg->var_off)) {
-		char tn_buf[48];
-
-		verbose(env, "At program exit the register R0 ");
-		if (!tnum_is_unknown(reg->var_off)) {
-			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
-			verbose(env, "has value %s", tn_buf);
-		} else {
-			verbose(env, "has unknown scalar value");
-		}
-		tnum_strn(tn_buf, sizeof(tn_buf), range);
-		verbose(env, " should have been in %s\n", tn_buf);
+		verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
 		return -EINVAL;
 	}
 
-- 
2.24.1
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