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| author |   Gianluca Borello <g.borello@gmail.com> | 2016-12-03 12:31:33 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2016-12-05 13:40:05 -0500 |
| commit | 3c839744b33782b930c5c61df35511ede5e5a574 (patch) | |
| tree | 950a0b8dd43c23f87e636bacd3074a5076818d93 /tools/testing | |
| parent | r8169: Add support for restarting auto-negotiation (diff) | |
| download | linux-dev-3c839744b33782b930c5c61df35511ede5e5a574.tar.xz linux-dev-3c839744b33782b930c5c61df35511ede5e5a574.zip | |
bpf: Preserve const register type on const OR alu ops
Occasionally, clang (e.g. version 3.8.1) translates a sum between two
constant operands using a BPF_OR instead of a BPF_ADD. The verifier is
currently not handling this scenario, and the destination register type
becomes UNKNOWN_VALUE even if it's still storing a constant. As a result,
the destination register cannot be used as argument to a helper function
expecting a ARG_CONST_STACK_*, limiting some use cases.
Modify the verifier to handle this case, and add a few tests to make sure
all combinations are supported, and stack boundaries are still verified
even with BPF_OR.
Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/.gitignore | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 60 |
2 files changed, 61 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore index 3c59f96e3ed8..071431bedde8 100644 --- a/tools/testing/selftests/bpf/.gitignore +++ b/tools/testing/selftests/bpf/.gitignore @@ -1,2 +1,3 @@ test_verifier test_maps +test_lru_map diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 5da2e9d7689c..8d71e44b319d 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -2683,6 +2683,66 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R0 pointer arithmetic prohibited", .result_unpriv = REJECT, }, + { + "constant register |= constant should keep constant type", + .insns = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -48), + BPF_MOV64_IMM(BPF_REG_2, 34), + BPF_ALU64_IMM(BPF_OR, BPF_REG_2, 13), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "constant register |= constant should not bypass stack boundary checks", + .insns = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -48), + BPF_MOV64_IMM(BPF_REG_2, 34), + BPF_ALU64_IMM(BPF_OR, BPF_REG_2, 24), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .errstr = "invalid stack type R1 off=-48 access_size=58", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "constant register |= constant register should keep constant type", + .insns = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -48), + BPF_MOV64_IMM(BPF_REG_2, 34), + BPF_MOV64_IMM(BPF_REG_4, 13), + BPF_ALU64_REG(BPF_OR, BPF_REG_2, BPF_REG_4), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "constant register |= constant register should not bypass stack boundary checks", + .insns = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -48), + BPF_MOV64_IMM(BPF_REG_2, 34), + BPF_MOV64_IMM(BPF_REG_4, 24), + BPF_ALU64_REG(BPF_OR, BPF_REG_2, BPF_REG_4), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .errstr = "invalid stack type R1 off=-48 access_size=58", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, }; static int probe_filter_length(const struct bpf_insn *fp) |