These two tests are based on the work done for f23cc643f9ba. The first test is
just a basic one to make sure we don't allow AND'ing negative values, even if it
would result in a valid index for the array. The second is a cleaned up version
of the original testcase provided by Jann Horn that resulted in the commit.
Signed-off-by: Josef Bacik <jba...@fb.com>
---
tools/testing/selftests/bpf/test_verifier.c | 55 +++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c
b/tools/testing/selftests/bpf/test_verifier.c
index 853d7e4..44404f1 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2905,6 +2905,61 @@ static struct bpf_test tests[] = {
.result = REJECT,
.errstr = "invalid bpf_context access",
},
+ {
+ "invalid and of negative number",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 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_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_IMM(BPF_REG_1, 6),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_1, -4),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 2),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ BPF_ST_MEM(BPF_DW, BPF_REG_0, 0,
+ offsetof(struct test_val, foo)),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map2 = { 3 },
+ .errstr_unpriv = "R0 pointer arithmetic prohibited",
+ .errstr = "R0 min value is negative, either use unsigned index
or do a if (index >=0) check.",
+ .result = REJECT,
+ .result_unpriv = REJECT,
+ },
+ {
+ "invalid range check",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 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_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 12),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
+ BPF_MOV64_IMM(BPF_REG_9, 1),
+ BPF_ALU32_IMM(BPF_MOD, BPF_REG_1, 2),
+ BPF_ALU32_IMM(BPF_ADD, BPF_REG_1, 1),
+ BPF_ALU32_REG(BPF_AND, BPF_REG_9, BPF_REG_1),
+ BPF_ALU32_IMM(BPF_ADD, BPF_REG_9, 1),
+ BPF_ALU32_IMM(BPF_RSH, BPF_REG_9, 1),
+ BPF_MOV32_IMM(BPF_REG_3, 1),
+ BPF_ALU32_REG(BPF_SUB, BPF_REG_3, BPF_REG_9),
+ BPF_ALU32_IMM(BPF_MUL, BPF_REG_3, 0x10000000),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_3),
+ BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_3, 0),
+ BPF_MOV64_REG(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map2 = { 3 },
+ .errstr_unpriv = "R0 pointer arithmetic prohibited",
+ .errstr = "R0 min value is negative, either use unsigned index
or do a if (index >=0) check.",
+ .result = REJECT,
+ .result_unpriv = REJECT,
+ }
};
static int probe_filter_length(const struct bpf_insn *fp)
--
2.7.4
