If the result of the division is LLONG_MIN, current tests do not detect
the error since the return value is truncated to a 32-bit value and ends
up being 0.
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
---
.../testing/selftests/bpf/verifier/div_overflow.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/verifier/div_overflow.c b/tools/testing/selftests/bpf/verifier/div_overflow.c
index bd3f38dbe796..acab4f00819f 100644
--- a/tools/testing/selftests/bpf/verifier/div_overflow.c
+++ b/tools/testing/selftests/bpf/verifier/div_overflow.c
@@ -29,8 +29,11 @@
"DIV64 overflow, check 1",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, -1),
- BPF_LD_IMM64(BPF_REG_0, LLONG_MIN),
- BPF_ALU64_REG(BPF_DIV, BPF_REG_0, BPF_REG_1),
+ BPF_LD_IMM64(BPF_REG_2, LLONG_MIN),
+ BPF_ALU64_REG(BPF_DIV, BPF_REG_2, BPF_REG_1),
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_2, 1),
+ BPF_MOV32_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
@@ -40,8 +43,11 @@
{
"DIV64 overflow, check 2",
.insns = {
- BPF_LD_IMM64(BPF_REG_0, LLONG_MIN),
- BPF_ALU64_IMM(BPF_DIV, BPF_REG_0, -1),
+ BPF_LD_IMM64(BPF_REG_1, LLONG_MIN),
+ BPF_ALU64_IMM(BPF_DIV, BPF_REG_1, -1),
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_1, 1),
+ BPF_MOV32_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
--
2.21.0
