diff options
| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-05-12 09:25:16 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-05-13 06:13:08 +0300 |
| commit | 343f845b375989f1753f605902931fa939aa2223 (patch) | |
| tree | fd2f63ee5b1cf7921993a4f9a0f35c80ac2e5485 /arch | |
| parent | e3d8ecb70e16412b14fb11c1b68ecb533bd4ea64 (diff) | |
| download | linux-343f845b375989f1753f605902931fa939aa2223.tar.xz | |
x86: bpf_jit: fix FROM_BE16 and FROM_LE16/32 instructions
FROM_BE16:
'ror %reg, 8' doesn't clear upper bits of the register,
so use additional 'movzwl' insn to zero extend 16 bits into 64
FROM_LE16:
should zero extend lower 16 bits into 64 bit
FROM_LE32:
should zero extend lower 32 bits into 64 bit
Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 987514396c1e..99f76103c6b7 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -559,6 +559,13 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, if (is_ereg(dst_reg)) EMIT1(0x41); EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8); + + /* emit 'movzwl eax, ax' */ + if (is_ereg(dst_reg)) + EMIT3(0x45, 0x0F, 0xB7); + else + EMIT2(0x0F, 0xB7); + EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); break; case 32: /* emit 'bswap eax' to swap lower 4 bytes */ @@ -577,6 +584,27 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, break; case BPF_ALU | BPF_END | BPF_FROM_LE: + switch (imm32) { + case 16: + /* emit 'movzwl eax, ax' to zero extend 16-bit + * into 64 bit + */ + if (is_ereg(dst_reg)) + EMIT3(0x45, 0x0F, 0xB7); + else + EMIT2(0x0F, 0xB7); + EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); + break; + case 32: + /* emit 'mov eax, eax' to clear upper 32-bits */ + if (is_ereg(dst_reg)) + EMIT1(0x45); + EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg)); + break; + case 64: + /* nop */ + break; + } break; /* ST: *(u8*)(dst_reg + off) = imm */ |