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selftests/bpf: add tests for stack_zero tracking

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adjust two tests, since verifier got smarter
and add new one to test stack_zero logic

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov 2017-12-14 17:55:09 -08:00 committed by Daniel Borkmann
parent cc2b14d510
commit d98588cef0
1 changed files with 64 additions and 2 deletions
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66
tools/testing/selftests/bpf/test_verifier.c
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@ -5649,7 +5649,7 @@ static struct bpf_test tests[] = {
"helper access to variable memory: size > 0 not allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_2, 1),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
@ -5884,7 +5884,7 @@ static struct bpf_test tests[] = {
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_2, 1),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 63),
@ -9056,6 +9056,68 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"calls: caller stack init to zero or map_value_or_null",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
/* fetch map_value_or_null or const_zero from stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
/* store into map_value */
BPF_ST_MEM(BPF_W, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
/* if (ctx == 0) return; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 8),
/* else bpf_map_lookup() and *(fp - 8) = r0 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
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_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map1 = { 13 },
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"calls: stack init to zero and pruning",
.insns = {
/* first make allocated_stack 16 byte */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
/* now fork the execution such that the false branch
* of JGT insn will be verified second and it skisp zero
* init of fp-8 stack slot. If stack liveness marking
* is missing live_read marks from call map_lookup
* processing then pruning will incorrectly assume
* that fp-8 stack slot was unused in the fall-through
* branch and will accept the program incorrectly
*/
BPF_JMP_IMM(BPF_JGT, BPF_REG_1, 2, 2),
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 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_EXIT_INSN(),
},
.fixup_map2 = { 6 },
.errstr = "invalid indirect read from stack off -8+0 size 8",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
},
};
static int probe_filter_length(const struct bpf_insn *fp)