bpf, selftests: Fix up some test_verifier cases for unprivileged

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@gmail.com>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>

4 files changed, 59 insertions, 10 deletions

diff --git a/tools/testing/selftests/bpf/verifier/bounds_deduction.c b/tools/testing/selftests/bpf/verifier/bounds_deduction.c
index 1fd07a4f27ac..c162498a64fc 100644
--- a/tools/testing/selftests/bpf/verifier/bounds_deduction.c
+++ b/tools/testing/selftests/bpf/verifier/bounds_deduction.c
@@ -6,8 +6,9 @@
 		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",
@@ -20,6 +21,8 @@
 		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,
 	.retval = 1,
 },
@@ -31,8 +34,9 @@
 		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",
@@ -45,6 +49,8 @@
 		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,
 },
 {
@@ -55,8 +61,9 @@
 		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",
@@ -67,8 +74,9 @@
 		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",
@@ -80,8 +88,9 @@
 			    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,
 	.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
 },
 {
@@ -94,8 +103,9 @@
 			    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,
 	.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
 },
 {
@@ -106,8 +116,9 @@
 		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",
@@ -119,6 +130,6 @@
 		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,
 },
diff --git a/tools/testing/selftests/bpf/verifier/map_ptr.c b/tools/testing/selftests/bpf/verifier/map_ptr.c
index b117bdd3806d..6f610cfddae5 100644
--- a/tools/testing/selftests/bpf/verifier/map_ptr.c
+++ b/tools/testing/selftests/bpf/verifier/map_ptr.c
@@ -75,6 +75,8 @@
 	BPF_EXIT_INSN(),
 	},
 	.fixup_map_hash_16b = { 4 },
+	.result_unpriv = REJECT,
+	.errstr_unpriv = "R1 tried to add from different maps, paths, or prohibited types",
 	.result = ACCEPT,
 },
 {
@@ -91,5 +93,7 @@
 	BPF_EXIT_INSN(),
 	},
 	.fixup_map_hash_16b = { 4 },
+	.result_unpriv = REJECT,
+	.errstr_unpriv = "R1 tried to add from different maps, paths, or prohibited types",
 	.result = ACCEPT,
 },
diff --git a/tools/testing/selftests/bpf/verifier/unpriv.c b/tools/testing/selftests/bpf/verifier/unpriv.c
index b018ad71e0a8..3e32400c4b44 100644
--- a/tools/testing/selftests/bpf/verifier/unpriv.c
+++ b/tools/testing/selftests/bpf/verifier/unpriv.c
@@ -497,7 +497,7 @@
 	.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),
@@ -505,6 +505,19 @@
 	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,
diff --git a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
index ed4e76b24649..feb91266db39 100644
--- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
+++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
@@ -169,7 +169,7 @@
 	.fixup_map_array_48b = { 1 },
 	.result = ACCEPT,
 	.result_unpriv = REJECT,
-	.errstr_unpriv = "R2 tried to add from different maps or paths",
+	.errstr_unpriv = "R2 tried to add from different maps, paths, or prohibited types",
 	.retval = 0,
 },
 {
@@ -517,6 +517,27 @@
 	.retval = 0xabcdef12,
 },
 {
+	"map access: value_ptr += N, value_ptr -= N known scalar",
+	.insns = {
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_LD_MAP_FD(BPF_REG_1, 0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
+	BPF_MOV32_IMM(BPF_REG_1, 0x12345678),
+	BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 2),
+	BPF_MOV64_IMM(BPF_REG_1, 2),
+	BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_array_48b = { 3 },
+	.result = ACCEPT,
+	.retval = 0x12345678,
+},
+{
 	"map access: unknown scalar += value_ptr, 1",
 	.insns = {
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),