[PATCH bpf-next v3 3/3] selftests/bpf: Add tests for LDX/STX/ST sanitize

[Hao Sun]

Add tests for LDX/STX/ST instrumentation in each possible case.
Five cases for STX/ST, nice cases for LDX. All new/existing
selftests can pass.

A slab-out-of-bounds read report is also availble, which is
achieved by exploiting CVE-2022-23222 and can be reproduced
in Linux v5.10: https://pastebin.com/raw/Ee1Cw492

Signed-off-by: Hao Sun <sunhao.th@xxxxxxxxx>
---
 .../selftests/bpf/verifier/sanitize_st_ldx.c  | 317 ++++++++++++++++++
 1 file changed, 317 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/verifier/sanitize_st_ldx.c

diff --git a/tools/testing/selftests/bpf/verifier/sanitize_st_ldx.c b/tools/testing/selftests/bpf/verifier/sanitize_st_ldx.c
new file mode 100644
index 000000000000..dfd53f97eb95
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/sanitize_st_ldx.c
@@ -0,0 +1,317 @@
+#ifdef CONFIG_BPF_PROG_KASAN
+
+#define __BACKUP_REG(n) \
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_##n, INSN_OFF_MASK)
+#define BACKUP_SCRATCH_REGS                                                 \
+	__BACKUP_REG(1), __BACKUP_REG(2), __BACKUP_REG(3), __BACKUP_REG(4), \
+		__BACKUP_REG(5)
+
+#define __RESTORE_REG(n) \
+	BPF_LDX_MEM(BPF_DW, BPF_REG_##n, BPF_REG_10, INSN_OFF_MASK)
+#define RESTORE_SCRATCH_REGS                                  \
+	__RESTORE_REG(1), __RESTORE_REG(2), __RESTORE_REG(3), \
+		__RESTORE_REG(4), __RESTORE_REG(5)
+
+{
+	"sanitize stx: dst is R1, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 1),
+	},
+},
+{
+	"sanitize stx: dst is R1",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, -8, 1),
+	},
+},
+{
+	"sanitize stx: dst is other regs, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 1),
+	},
+},
+{
+	"sanitize stx: dst is other regs",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, -8, 1),
+	},
+},
+{
+	"sanitize stx: dst is R10",
+	.insns = {
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.unexpected_insns = {
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	},
+},
+{
+	"sanitize ldx: src is R1, dst is R0, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
+	},
+},
+{
+	"sanitize ldx: src is R1, dst is R0",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+	},
+},
+{
+	"sanitize ldx: src is R1, dst is others, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0),
+	},
+},
+{
+	"sanitize ldx: src is R1, dst is others",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_1, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, -8),
+	},
+},
+{
+	"sanitize ldx: src is others, dst is R0, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0),
+	},
+},
+{
+	"sanitize ldx: src is others, dst is R0",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -8),
+	},
+},
+{
+	"sanitize ldx: src is others, dst is others, off is zero",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, 0),
+	},
+},
+{
+	"sanitize ldx: src is others, dst is others",
+	.insns = {
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+	BPF_ST_MEM(BPF_DW, BPF_REG_2, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.expected_insns = {
+	BACKUP_SCRATCH_REGS,
+	BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	RESTORE_SCRATCH_REGS,
+	BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -8),
+	},
+},
+{
+	"sanitize LDX: SRC is R10",
+	.insns = {
+	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 1),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+	.unexpected_insns = {
+	BPF_EMIT_CALL(INSN_IMM_MASK),
+	},
+},
+#endif /* CONFIG_BPF_PROG_KASAN */
-- 
2.38.1