selftests/bpf: additional stack depth tests

to test inner logic of stack depth tracking

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 41dcc7d..b5a7a6c 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -8764,6 +8764,127 @@ static struct bpf_test tests[] = {
                .result = REJECT,
        },
        {
+               "calls: stack depth check using three frames. test1",
+               .insns = {
+                       /* main */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 5), /* call B */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -32, 0),
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_EXIT_INSN(),
+                       /* A */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
+                       BPF_EXIT_INSN(),
+                       /* B */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -3), /* call A */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .prog_type = BPF_PROG_TYPE_XDP,
+               /* stack_main=32, stack_A=256, stack_B=64
+                * and max(main+A, main+A+B) < 512
+                */
+               .result = ACCEPT,
+       },
+       {
+               "calls: stack depth check using three frames. test2",
+               .insns = {
+                       /* main */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 5), /* call B */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -32, 0),
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_EXIT_INSN(),
+                       /* A */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
+                       BPF_EXIT_INSN(),
+                       /* B */
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -3), /* call A */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .prog_type = BPF_PROG_TYPE_XDP,
+               /* stack_main=32, stack_A=64, stack_B=256
+                * and max(main+A, main+A+B) < 512
+                */
+               .result = ACCEPT,
+       },
+       {
+               "calls: stack depth check using three frames. test3",
+               .insns = {
+                       /* main */
+                       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 6), /* call A */
+                       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 8), /* call B */
+                       BPF_JMP_IMM(BPF_JGE, BPF_REG_6, 0, 1),
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_EXIT_INSN(),
+                       /* A */
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_1, 10, 1),
+                       BPF_EXIT_INSN(),
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -224, 0),
+                       BPF_JMP_IMM(BPF_JA, 0, 0, -3),
+                       /* B */
+                       BPF_JMP_IMM(BPF_JGT, BPF_REG_1, 2, 1),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -6), /* call A */
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .prog_type = BPF_PROG_TYPE_XDP,
+               /* stack_main=64, stack_A=224, stack_B=256
+                * and max(main+A, main+A+B) > 512
+                */
+               .errstr = "combined stack",
+               .result = REJECT,
+       },
+       {
+               "calls: stack depth check using three frames. test4",
+               /* void main(void) {
+                *   func1(0);
+                *   func1(1);
+                *   func2(1);
+                * }
+                * void func1(int alloc_or_recurse) {
+                *   if (alloc_or_recurse) {
+                *     frame_pointer[-300] = 1;
+                *   } else {
+                *     func2(alloc_or_recurse);
+                *   }
+                * }
+                * void func2(int alloc_or_recurse) {
+                *   if (alloc_or_recurse) {
+                *     frame_pointer[-300] = 1;
+                *   }
+                * }
+                */
+               .insns = {
+                       /* main */
+                       BPF_MOV64_IMM(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 6), /* call A */
+                       BPF_MOV64_IMM(BPF_REG_1, 1),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
+                       BPF_MOV64_IMM(BPF_REG_1, 1),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 7), /* call B */
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_EXIT_INSN(),
+                       /* A */
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 2),
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call B */
+                       BPF_EXIT_INSN(),
+                       /* B */
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
+                       BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
+                       BPF_EXIT_INSN(),
+               },
+               .prog_type = BPF_PROG_TYPE_XDP,
+               .result = REJECT,
+               .errstr = "combined stack",
+       },
+       {
                "calls: spill into caller stack frame",
                .insns = {
                        BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),