From: Joe Stringer <joe@wand.net.nz>
Date: Tue, 2 Oct 2018 13:35:31 -0700
Subject: bpf: Reuse canonical string formatter for ctx errs
Patch-mainline: v4.20-rc1
Git-commit: 9d2be44a7f33d5ec4fbd3368317bcf5f404bb8f7
References: bsc#1109837

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 kernel/bpf/verifier.c                       |    7 +++----
 tools/testing/selftests/bpf/test_verifier.c |   10 +++++-----
 2 files changed, 8 insertions(+), 9 deletions(-)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1732,8 +1732,7 @@ static int check_xadd(struct bpf_verifie
 	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;
 	}
 
@@ -4835,8 +4834,8 @@ static int do_check(struct bpf_verifier_
 				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;
 			}
 
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -3275,7 +3275,7 @@ static struct bpf_test tests[] = {
 			BPF_ST_MEM(BPF_DW, BPF_REG_1, offsetof(struct __sk_buff, mark), 0),
 			BPF_EXIT_INSN(),
 		},
-		.errstr = "BPF_ST stores into R1 context is not allowed",
+		.errstr = "BPF_ST stores into R1 inv is not allowed",
 		.result = REJECT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	},
@@ -3287,7 +3287,7 @@ static struct bpf_test tests[] = {
 				     BPF_REG_0, offsetof(struct __sk_buff, mark), 0),
 			BPF_EXIT_INSN(),
 		},
-		.errstr = "BPF_XADD stores into R1 context is not allowed",
+		.errstr = "BPF_XADD stores into R1 inv is not allowed",
 		.result = REJECT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	},
@@ -5150,7 +5150,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "R2 leaks addr into mem",
 		.result_unpriv = REJECT,
 		.result = REJECT,
-		.errstr = "BPF_XADD stores into R1 context is not allowed",
+		.errstr = "BPF_XADD stores into R1 inv is not allowed",
 	},
 	{
 		"leak pointer into ctx 2",
@@ -5165,7 +5165,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "R10 leaks addr into mem",
 		.result_unpriv = REJECT,
 		.result = REJECT,
-		.errstr = "BPF_XADD stores into R1 context is not allowed",
+		.errstr = "BPF_XADD stores into R1 inv is not allowed",
 	},
 	{
 		"leak pointer into ctx 3",
@@ -12026,7 +12026,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = REJECT,
-		.errstr = "BPF_XADD stores into R2 packet",
+		.errstr = "BPF_XADD stores into R2 ctx",
 		.prog_type = BPF_PROG_TYPE_XDP,
 	},
 	{