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author | Daniel Borkmann <daniel@iogearbox.net> | 2018-01-10 20:04:37 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-17 09:45:25 +0100 |
commit | a2e0b5db9b581f78155bd4999b5bb2d0d8037eda (patch) | |
tree | 34077f0f12225786243522d52c47b925f7415383 /tools | |
parent | 67c05d9414512e1f9040d29e37e3d5533d8c51dd (diff) | |
download | linux-stable-a2e0b5db9b581f78155bd4999b5bb2d0d8037eda.tar.gz linux-stable-a2e0b5db9b581f78155bd4999b5bb2d0d8037eda.tar.bz2 linux-stable-a2e0b5db9b581f78155bd4999b5bb2d0d8037eda.zip |
bpf: arsh is not supported in 32 bit alu thus reject it
commit 7891a87efc7116590eaba57acc3c422487802c6f upstream.
The following snippet was throwing an 'unknown opcode cc' warning
in BPF interpreter:
0: (18) r0 = 0x0
2: (7b) *(u64 *)(r10 -16) = r0
3: (cc) (u32) r0 s>>= (u32) r0
4: (95) exit
Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
generation, not all of them do and interpreter does neither. We can
leave existing ones and implement it later in bpf-next for the
remaining ones, but reject this properly in verifier for the time
being.
Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 7a2d221c4702..1241487de93f 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -273,6 +273,46 @@ static struct bpf_test tests[] = { .result = REJECT, }, { + "arsh32 on imm", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_ALU32_IMM(BPF_ARSH, BPF_REG_0, 5), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "BPF_ARSH not supported for 32 bit ALU", + }, + { + "arsh32 on reg", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_MOV64_IMM(BPF_REG_1, 5), + BPF_ALU32_REG(BPF_ARSH, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "BPF_ARSH not supported for 32 bit ALU", + }, + { + "arsh64 on imm", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_ALU64_IMM(BPF_ARSH, BPF_REG_0, 5), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + }, + { + "arsh64 on reg", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_MOV64_IMM(BPF_REG_1, 5), + BPF_ALU64_REG(BPF_ARSH, BPF_REG_0, BPF_REG_1), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + }, + { "no bpf_exit", .insns = { BPF_ALU64_REG(BPF_MOV, BPF_REG_0, BPF_REG_2), |