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

Hao Sun
2022-11-23T14:17:25Z

Add tests for LDX/STX/ST instrumentation in each possible case.
Four cases for STX/ST, include dst_reg equals to R0, R1, R10,
other regs, respectively, ten 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@gmail.com>
---
.../selftests/bpf/verifier/sanitize_st_ldx.c | 323 ++++++++++++++++++
1 file changed, 323 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..3fd571abc5cc
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/sanitize_st_ldx.c
@@ -0,0 +1,323 @@
+#ifdef CONFIG_BPF_PROG_KASAN
+{
+ "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_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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+ BPF_ST_MEM(BPF_DW, BPF_REG_1, -8, 1),
+ },
+},
+{
+ "sanitize stx: dst is R0",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, -8, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, -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 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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, -8, 1),
+ },
+},
+{
+ "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 = {
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ },
+},
+{
+ "sanitize ldx: src is R1, 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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ 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 R1, dst is other regs",
+ .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_2, BPF_REG_1, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 1, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 2),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .retval = 1,
+ .expected_insns = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -8),
+ },
+},
+{
+ "sanitize ldx: src is R0, dst is R1",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, -8, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -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 = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, -8),
+ },
+},
+{
+ "sanitize ldx: src is R0, dst is R0",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, -8, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, -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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, -8),
+ },
+},
+{
+ "sanitize ldx: src is R0, dst is other regs",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, -8, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 1, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 2),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .retval = 1,
+ .expected_insns = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, -8),
+ },
+},
+{
+ "sanitize ldx: src is other regs, 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 = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -8),
+ },
+},
+{
+ "sanitize ldx: src is other regs, dst is R1",
+ .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 = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ 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 other regs, dst is self",
+ .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_2, BPF_REG_2, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 1, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 2),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .retval = 1,
+ .expected_insns = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_2, -8),
+ },
+},
+{
+ "sanitize ldx: src is other regs, 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_3, BPF_REG_2, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 1, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 2),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .retval = 1,
+ .expected_insns = {
+ BPF_MOV64_REG(MAX_BPF_REG, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_EMIT_CALL(INSN_IMM_MASK),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_3),
+ BPF_MOV64_REG(BPF_REG_1, MAX_BPF_REG),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_2, -8),
+ },
+},
+#endif /* CONFIG_BPF_PROG_KASAN */
--
2.38.1