From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Stringer Subject: [RFC bpf-next 08/11] selftests/bpf: Add tests for reference tracking Date: Wed, 9 May 2018 14:07:06 -0700 Message-ID: <20180509210709.7201-9-joe@wand.net.nz> References: <20180509210709.7201-1-joe@wand.net.nz> Cc: netdev@vger.kernel.org, ast@kernel.org, john.fastabend@gmail.com, kafai@fb.com To: daniel@iogearbox.net Return-path: Received: from mail-oi0-f66.google.com ([209.85.218.66]:34817 "EHLO mail-oi0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965585AbeEIVHc (ORCPT ); Wed, 9 May 2018 17:07:32 -0400 Received: by mail-oi0-f66.google.com with SMTP id a6-v6so32786369oia.2 for ; Wed, 09 May 2018 14:07:32 -0700 (PDT) In-Reply-To: <20180509210709.7201-1-joe@wand.net.nz> Sender: netdev-owner@vger.kernel.org List-ID: reference tracking: leak potential reference reference tracking: leak potential reference on stack reference tracking: leak potential reference on stack 2 reference tracking: zero potential reference reference tracking: copy and zero potential references reference tracking: release reference without check reference tracking: release reference reference tracking: release reference twice reference tracking: release reference twice inside branch reference tracking: alloc, check, free in one subbranch reference tracking: alloc, check, free in both subbranches reference tracking in call: free reference in subprog reference tracking in call: free reference in subprog and outside reference tracking in call: alloc & leak reference in subprog reference tracking in call: alloc in subprog, release outside reference tracking in call: sk_ptr leak into caller stack reference tracking in call: sk_ptr spill into caller stack Signed-off-by: Joe Stringer --- tools/testing/selftests/bpf/test_verifier.c | 359 ++++++++++++++++++++++++++++ 1 file changed, 359 insertions(+) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 53439f40e1de..150c7c19eb51 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -3,6 +3,7 @@ * * Copyright (c) 2014 PLUMgrid, http://plumgrid.com * Copyright (c) 2017 Facebook + * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public @@ -152,6 +153,23 @@ static void bpf_fill_jump_around_ld_abs(struct bpf_test *self) insn[i] = BPF_EXIT_INSN(); } +#define BPF_SK_LOOKUP \ + /* struct bpf_sock_tuple tuple = {} */ \ + BPF_MOV64_IMM(BPF_REG_2, 0), \ + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -8), \ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -16), \ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -24), \ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -32), \ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -40), \ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -48), \ + /* sk = sk_lookup(ctx, &tuple, sizeof tuple, 0, 0) */ \ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), \ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -48), \ + BPF_MOV64_IMM(BPF_REG_3, 44), \ + BPF_MOV64_IMM(BPF_REG_4, 0), \ + BPF_MOV64_IMM(BPF_REG_5, 0), \ + BPF_EMIT_CALL(BPF_FUNC_sk_lookup) + static struct bpf_test tests[] = { { "add+sub+mul", @@ -11974,6 +11992,347 @@ static struct bpf_test tests[] = { .result = ACCEPT, .retval = 10, }, + { + "reference tracking: leak potential reference", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), /* leak reference */ + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: leak potential reference on stack", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: leak potential reference on stack 2", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_4, 0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: zero potential reference", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_IMM(BPF_REG_0, 0), /* leak reference */ + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: copy and zero potential references", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_7, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_7, 0), /* leak reference */ + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: release reference without check", + .insns = { + BPF_SK_LOOKUP, + /* reference in r0 may be NULL */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "type=sock_or_null expected=sock", + .result = REJECT, + }, + { + "reference tracking: release reference", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, + { + "reference tracking: release reference 2", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, + { + "reference tracking: release reference twice", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "type=inv expected=sock", + .result = REJECT, + }, + { + "reference tracking: release reference twice inside branch", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4), /* goto end */ + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "type=inv expected=sock", + .result = REJECT, + }, + { + "reference tracking: alloc, check, free in one subbranch", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct __sk_buff, data)), + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, + offsetof(struct __sk_buff, data_end)), + BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 16), + /* if (offsetof(skb, mark) > data_len) exit; */ + BPF_JMP_REG(BPF_JLE, BPF_REG_0, BPF_REG_3, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_2, + offsetof(struct __sk_buff, mark)), + BPF_SK_LOOKUP, + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 1), /* mark == 0? */ + /* Leak reference in R0 */ + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3), /* sk NULL? */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking: alloc, check, free in both subbranches", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct __sk_buff, data)), + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, + offsetof(struct __sk_buff, data_end)), + BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 16), + /* if (offsetof(skb, mark) > data_len) exit; */ + BPF_JMP_REG(BPF_JLE, BPF_REG_0, BPF_REG_3, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_2, + offsetof(struct __sk_buff, mark)), + BPF_SK_LOOKUP, + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 5), /* mark == 0? */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3), /* sk NULL? */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3), /* sk NULL? */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, + { + "reference tracking in call: free reference in subprog", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), /* unchecked reference */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_1), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 0, 2), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, + { + "reference tracking in call: free reference in subprog and outside", + .insns = { + BPF_SK_LOOKUP, + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), /* unchecked reference */ + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_1), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 0, 2), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "type=inv expected=sock", + .result = REJECT, + }, + { + "reference tracking in call: alloc & leak reference in subprog", + .insns = { + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_MOV64_REG(BPF_REG_6, BPF_REG_4), + BPF_SK_LOOKUP, + /* spill unchecked sk_ptr into stack of caller */ + BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking in call: alloc in subprog, release outside", + .insns = { + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_SK_LOOKUP, + BPF_EXIT_INSN(), /* return sk */ + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .retval = POINTER_VALUE, + .result = ACCEPT, + }, + { + "reference tracking in call: sk_ptr leak into caller stack", + .insns = { + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_5, BPF_REG_4, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5), + /* spill unchecked sk_ptr into stack of caller */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, -8), + BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_5, 0), + BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_0, 0), + BPF_EXIT_INSN(), + + /* subprog 2 */ + BPF_SK_LOOKUP, + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, + }, + { + "reference tracking in call: sk_ptr spill into caller stack", + .insns = { + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + + /* subprog 1 */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_5, BPF_REG_4, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 9), + /* spill unchecked sk_ptr into stack of caller */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, -8), + BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_5, 0), + BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3), + /* now the sk_ptr is verified, free the reference */ + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_4, 0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + + /* subprog 2 */ + BPF_SK_LOOKUP, + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, }; static int probe_filter_length(const struct bpf_insn *fp) -- 2.14.1