tools/testing/selftests/bpf/verifier/bpf_st_mem.c

{
	"BPF_ST_MEM stack imm non-zero",
	.insns = {
	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 42),
	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
	BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, -42),
	/* if value is tracked correctly R0 is zero */
	BPF_EXIT_INSN(),
	},
	.result = ACCEPT,
	/* Use prog type that requires return value in range [0, 1] */
	.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
	.expected_attach_type = BPF_SK_LOOKUP,
	.runs = -1,
},
{
	"BPF_ST_MEM stack imm zero",
	.insns = {
	/* mark stack 0000 0000 */
	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
	/* read and sum a few bytes */
	BPF_MOV64_IMM(BPF_REG_0, 0),
	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -8),
	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -4),
	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -1),
	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
	/* if value is tracked correctly R0 is zero */
	BPF_EXIT_INSN(),
	},
	.result = ACCEPT,
	/* Use prog type that requires return value in range [0, 1] */
	.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
	.expected_attach_type = BPF_SK_LOOKUP,
	.runs = -1,
},
{
	"BPF_ST_MEM stack imm zero, variable offset",
	.insns = {
	/* set fp[-16], fp[-24] to zeros */
	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
	BPF_ST_MEM(BPF_DW, BPF_REG_10, -24, 0),
	/* r0 = random value in range [-32, -15] */
	BPF_EMIT_CALL(BPF_FUNC_get_prandom_u32),
	BPF_JMP_IMM(BPF_JLE, BPF_REG_0, 16, 2),
	BPF_MOV64_IMM(BPF_REG_0, 0),
	BPF_EXIT_INSN(),
	BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 32),
	/* fp[r0] = 0, make a variable offset write of zero,
	 *             this should preserve zero marks on stack.
	 */
	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_10),
	BPF_ST_MEM(BPF_B, BPF_REG_0, 0, 0),
	/* r0 = fp[-20], if variable offset write was tracked correctly
	 *               r0 would be a known zero.
	 */
	BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_10, -20),
	/* Would fail return code verification if r0 range is not tracked correctly. */
	BPF_EXIT_INSN(),
	},
	.result = ACCEPT,
	/* Use prog type that requires return value in range [0, 1] */
	.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
	.expected_attach_type = BPF_SK_LOOKUP,
	.runs = -1,
},
{
	"BPF_ST_MEM stack imm sign",
	/* Check if verifier correctly reasons about sign of an
	 * immediate spilled to stack by BPF_ST instruction.
	 *
	 *   fp[-8] = -44;
	 *   r0 = fp[-8];
	 *   if r0 s< 0 goto ret0;
	 *   r0 = -1;
	 *   exit;
	 * ret0:
	 *   r0 = 0;
	 *   exit;
	 */
	.insns = {
	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, -44),
	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
	BPF_JMP_IMM(BPF_JSLT, BPF_REG_0, 0, 2),
	BPF_MOV64_IMM(BPF_REG_0, -1),
	BPF_EXIT_INSN(),
	BPF_MOV64_IMM(BPF_REG_0, 0),
	BPF_EXIT_INSN(),
	},
	/* Use prog type that requires return value in range [0, 1] */
	.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
	.expected_attach_type = BPF_SK_LOOKUP,
	.result = VERBOSE_ACCEPT,
	.runs = -1,
	.errstr = "0: (7a) *(u64 *)(r10 -8) = -44        ; R10=fp0 fp-8_w=-44\
	2: (c5) if r0 s< 0x0 goto pc+2\
	R0_w=-44",
},