bpf: add couple of test cases for div/mod by zero

Add couple of missing test cases for eBPF div/mod by zero to the
new test_verifier prog runtime feature. Also one for an empty prog
and only exit.

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

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 6c22edb..efca10d 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -102,6 +102,93 @@ static struct bpf_test tests[] = {
                .retval = -3,
        },
        {
+               "DIV32 by 0, zero check 1",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_MOV32_IMM(BPF_REG_1, 0),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU32_REG(BPF_DIV, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "DIV32 by 0, zero check 2",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_LD_IMM64(BPF_REG_1, 0xffffffff00000000LL),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU32_REG(BPF_DIV, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "DIV64 by 0, zero check",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_MOV32_IMM(BPF_REG_1, 0),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU64_REG(BPF_DIV, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "MOD32 by 0, zero check 1",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_MOV32_IMM(BPF_REG_1, 0),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU32_REG(BPF_MOD, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "MOD32 by 0, zero check 2",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_LD_IMM64(BPF_REG_1, 0xffffffff00000000LL),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU32_REG(BPF_MOD, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "MOD64 by 0, zero check",
+               .insns = {
+                       BPF_MOV32_IMM(BPF_REG_0, 42),
+                       BPF_MOV32_IMM(BPF_REG_1, 0),
+                       BPF_MOV32_IMM(BPF_REG_2, 1),
+                       BPF_ALU64_REG(BPF_MOD, BPF_REG_2, BPF_REG_1),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .retval = 0,
+       },
+       {
+               "empty prog",
+               .insns = {
+               },
+               .errstr = "last insn is not an exit or jmp",
+               .result = REJECT,
+       },
+       {
+               "only exit insn",
+               .insns = {
+                       BPF_EXIT_INSN(),
+               },
+               .errstr = "R0 !read_ok",
+               .result = REJECT,
+       },
+       {
                "unreachable",
                .insns = {
                        BPF_EXIT_INSN(),