2a33c5a25e
A test case to verify that variable offset BPF_ST instruction
preserves STACK_ZERO marks when writes zeros, e.g. in the following
situation:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now variable offset pointer to stack
*(u8*)(r0) = 0 ; BPF_ST writing zero, STACK_ZERO mark for
; fp[-8] should be preserved.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-5-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
{
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"BPF_ST_MEM stack imm non-zero",
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.insns = {
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 42),
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BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, -42),
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/* if value is tracked correctly R0 is zero */
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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/* Use prog type that requires return value in range [0, 1] */
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.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
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.expected_attach_type = BPF_SK_LOOKUP,
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.runs = -1,
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},
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{
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"BPF_ST_MEM stack imm zero",
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.insns = {
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/* mark stack 0000 0000 */
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
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/* read and sum a few bytes */
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -8),
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
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BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -4),
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
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BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_10, -1),
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
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/* if value is tracked correctly R0 is zero */
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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/* Use prog type that requires return value in range [0, 1] */
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.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
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.expected_attach_type = BPF_SK_LOOKUP,
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.runs = -1,
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},
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{
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"BPF_ST_MEM stack imm zero, variable offset",
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.insns = {
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/* set fp[-16], fp[-24] to zeros */
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -24, 0),
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/* r0 = random value in range [-32, -15] */
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BPF_EMIT_CALL(BPF_FUNC_get_prandom_u32),
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BPF_JMP_IMM(BPF_JLE, BPF_REG_0, 16, 2),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 32),
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/* fp[r0] = 0, make a variable offset write of zero,
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* this should preserve zero marks on stack.
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*/
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_10),
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BPF_ST_MEM(BPF_B, BPF_REG_0, 0, 0),
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/* r0 = fp[-20], if variable offset write was tracked correctly
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* r0 would be a known zero.
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*/
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BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_10, -20),
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/* Would fail return code verification if r0 range is not tracked correctly. */
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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/* Use prog type that requires return value in range [0, 1] */
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.prog_type = BPF_PROG_TYPE_SK_LOOKUP,
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.expected_attach_type = BPF_SK_LOOKUP,
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.runs = -1,
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},
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