From fdbaa0beb78b7c8847e261fe2c32816e9d1c54cc Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 19 Dec 2018 13:01:01 -0800 Subject: bpf: Ensure line_info.insn_off cannot point to insn with zero code This patch rejects a line_info if the bpf insn code referred by line_info.insn_off is 0. F.e. a broken userspace tool might generate a line_info.insn_off that points to the second 8 bytes of a BPF_LD_IMM64. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e0e77ffeefb8..5c64281d566e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4980,6 +4980,14 @@ static int check_btf_line(struct bpf_verifier_env *env, goto err_free; } + if (!prog->insnsi[linfo[i].insn_off].code) { + verbose(env, + "Invalid insn code at line_info[%u].insn_off\n", + i); + err = -EINVAL; + goto err_free; + } + if (!btf_name_by_offset(btf, linfo[i].line_off) || !btf_name_by_offset(btf, linfo[i].file_name_off)) { verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i); -- cgit v1.2.3 From e30f5640e32455e02ba08983ebe0b46054f1f6f0 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 19 Dec 2018 13:01:02 -0800 Subject: bpf: Add BPF_LD_IMM64 to the line_info test This patch adds a BPF_LD_IMM64 case to the line_info test to ensure the kernel rejects linfo_info.insn_off pointing to the 2nd 8 bytes of the BPF_LD_IMM64. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/test_btf.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c index 8024b7d4c354..8bcd38010582 100644 --- a/tools/testing/selftests/bpf/test_btf.c +++ b/tools/testing/selftests/bpf/test_btf.c @@ -4253,6 +4253,33 @@ static struct prog_info_raw_test { .expected_prog_load_failure = true, }, +{ + .descr = "line_info (Zero bpf insn code)", + .raw_types = { + BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 64, 8), /* [2] */ + BTF_TYPEDEF_ENC(NAME_TBD, 2), /* [3] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0int\0unsigned long\0u64\0u64 a=1;\0return a;"), + .insns = { + BPF_LD_IMM64(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + .func_info_cnt = 0, + .line_info = { + BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10), + BPF_LINE_INFO_ENC(1, 0, 0, 2, 9), + BPF_LINE_INFO_ENC(2, 0, NAME_TBD, 3, 8), + BTF_END_RAW, + }, + .line_info_rec_size = sizeof(struct bpf_line_info), + .nr_jited_ksyms = 1, + .err_str = "Invalid insn code at line_info[1]", + .expected_prog_load_failure = true, +}, + { .descr = "line_info (No subprog. zero tailing line_info", .raw_types = { -- cgit v1.2.3