[SRU Bionic 3/3] bpf, selftests: Fix up some test_verifier cases for unprivileged

[Thadeu Lima de Souza Cascardo]

From: Piotr Krysiuk <piotras at gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1920995

Fix up test_verifier error messages for the case where the original error
message changed, or for the case where pointer alu errors differ between
privileged and unprivileged tests. Also, add alternative tests for keeping
coverage of the original verifier rejection error message (fp alu), and
newly reject map_ptr += rX where rX == 0 given we now forbid alu on these
types for unprivileged. All test_verifier cases pass after the change. The
test case fixups were kept separate to ease backporting of core changes.

Signed-off-by: Piotr Krysiuk <piotras at gmail.com>
Co-developed-by: Daniel Borkmann <daniel at iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel at iogearbox.net>
Acked-by: Alexei Starovoitov <ast at kernel.org>
(backported from commit 0a13e3537ea67452d549a6a80da3776d6b7dedb3 net.git)
[cascardo: picked up and adjusted context and identation only for
 the bounds_detection segment]
[cascardo: also apply hunk with fix for stack arithmetic, adding of fp]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
---
 tools/testing/selftests/bpf/test_verifier.c | 42 ++++++++++++++++-----
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 3b3ebf1d1f27..a7331a6d34c1 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2246,7 +2246,7 @@ static struct bpf_test tests[] = {
 		.result = ACCEPT,
 	},
 	{
-		"unpriv: adding of fp",
+		"unpriv: adding of fp, reg",
 		.insns = {
 			BPF_MOV64_IMM(BPF_REG_0, 0),
 			BPF_MOV64_IMM(BPF_REG_1, 0),
@@ -2254,6 +2254,19 @@ static struct bpf_test tests[] = {
 			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -8),
 			BPF_EXIT_INSN(),
 		},
+		.errstr_unpriv = "R1 tried to add from different maps, paths, or prohibited types",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+	},
+	{
+		"unpriv: adding of fp, imm",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0),
+			BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -8),
+			BPF_EXIT_INSN(),
+		},
 		.errstr_unpriv = "R1 stack pointer arithmetic goes out of range",
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
@@ -8987,8 +9000,9 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R0 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "R0 tried to subtract pointer from scalar",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 2",
@@ -9001,6 +9015,8 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
 			BPF_EXIT_INSN(),
 		},
+		.errstr_unpriv = "R1 tried to sub from different maps, paths, or prohibited types",
+		.result_unpriv = REJECT,
 		.result = ACCEPT,
 	},
 	{
@@ -9011,8 +9027,9 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R0 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "R0 tried to subtract pointer from scalar",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 4",
@@ -9025,6 +9042,8 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
 			BPF_EXIT_INSN(),
 		},
+		.errstr_unpriv = "R1 tried to sub from different maps, paths, or prohibited types",
+		.result_unpriv = REJECT,
 		.result = ACCEPT,
 	},
 	{
@@ -9035,8 +9054,9 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R0 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "R0 tried to subtract pointer from scalar",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 6",
@@ -9047,8 +9067,9 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R0 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "R0 tried to subtract pointer from scalar",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 7",
@@ -9060,8 +9081,9 @@ static struct bpf_test tests[] = {
 				    offsetof(struct __sk_buff, mark)),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R1 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "dereference of modified ctx ptr",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 8",
@@ -9073,8 +9095,9 @@ static struct bpf_test tests[] = {
 				    offsetof(struct __sk_buff, mark)),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R1 tried to add from different maps, paths, or prohibited types",
 		.errstr = "dereference of modified ctx ptr",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 9",
@@ -9084,8 +9107,9 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
+		.errstr_unpriv = "R0 tried to sub from different maps, paths, or prohibited types",
 		.errstr = "R0 tried to subtract pointer from scalar",
+		.result = REJECT,
 	},
 	{
 		"check deducing bounds from const, 10",
@@ -9097,8 +9121,8 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
 			BPF_EXIT_INSN(),
 		},
-		.result = REJECT,
 		.errstr = "math between ctx pointer and register with unbounded min value is not allowed",
+		.result = REJECT,
 	},
 	{
 		"bpf_exit with invalid return code. test1",
-- 
2.27.0