From: Youlin Li liulin063@gmail.com

[ Upstream commit 475244f5e06beeda7b557d9dde46a5f439bf3379 ]

Add a test case to ensure that released pointer registers will not be leaked into the map.

Before fix:

./test_verifier 984 984/u reference tracking: try to leak released ptr reg FAIL Unexpected success to load! verification time 67 usec stack depth 4 processed 23 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 984/p reference tracking: try to leak released ptr reg OK Summary: 1 PASSED, 0 SKIPPED, 1 FAILED

After fix:

./test_verifier 984 984/u reference tracking: try to leak released ptr reg OK 984/p reference tracking: try to leak released ptr reg OK Summary: 2 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Youlin Li liulin063@gmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20221103093440.3161-2-liulin063@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../selftests/bpf/verifier/ref_tracking.c | 36 +++++++++++++++++++ 1 file changed, 36 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c index 3b6ee009c00b..4a768b130d61 100644 --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c @@ -905,3 +905,39 @@ .result_unpriv = REJECT, .errstr_unpriv = "unknown func", }, +{ + "reference tracking: try to leak released ptr reg", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_MOV64_REG(BPF_REG_9, BPF_REG_0), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_2, 8), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_ringbuf_reserve), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), + + BPF_MOV64_REG(BPF_REG_1, BPF_REG_8), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_ringbuf_discard), + BPF_MOV64_IMM(BPF_REG_0, 0), + + BPF_STX_MEM(BPF_DW, BPF_REG_9, BPF_REG_8, 0), + BPF_EXIT_INSN() + }, + .fixup_map_array_48b = { 4 }, + .fixup_map_ringbuf = { 11 }, + .result = ACCEPT, + .result_unpriv = REJECT, + .errstr_unpriv = "R8 !read_ok" +},