From: Daniel Borkmann daniel@iogearbox.net
commit b1a7288dedc6caf9023f2676b4f5ed34cf0d4029 upstream.
Add a test case which tries to taint map value pointer arithmetic into a unknown scalar with subsequent export through the map.
Before fix:
# ./test_verifier 1186 #1186/u map access: trying to leak tained dst reg FAIL Unexpected success to load! verification time 24 usec stack depth 8 processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 #1186/p map access: trying to leak tained dst reg FAIL Unexpected success to load! verification time 8 usec stack depth 8 processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 Summary: 0 PASSED, 0 SKIPPED, 2 FAILED
After fix:
# ./test_verifier 1186 #1186/u map access: trying to leak tained dst reg OK #1186/p map access: trying to leak tained dst reg OK Summary: 2 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann daniel@iogearbox.net Reviewed-by: John Fastabend john.fastabend@gmail.com Acked-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/bpf/verifier/value_ptr_arith.c | 23 +++++++++++++++++ 1 file changed, 23 insertions(+)
--- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c +++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c @@ -849,6 +849,29 @@ .errstr_unpriv = "R0 pointer -= pointer prohibited", }, { + "map access: trying to leak tained dst reg", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + 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_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_0), + BPF_MOV32_IMM(BPF_REG_1, 0xFFFFFFFF), + BPF_MOV32_REG(BPF_REG_1, BPF_REG_1), + BPF_ALU64_REG(BPF_SUB, BPF_REG_2, BPF_REG_1), + BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_array_48b = { 4 }, + .result = REJECT, + .errstr = "math between map_value pointer and 4294967295 is not allowed", +}, +{ "32bit pkt_ptr -= scalar", .insns = { BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,