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| author | Xi Wang <xi.wang@gmail.com> | 2015-06-26 03:39:15 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-06-26 15:15:39 +0200 |
| commit | d63903bbc30c7ccad040851dfdb4da12d9a17bcf (patch) | |
| tree | 6ddc09f1a2289e833b51b373049649f416a586bf /arch/arm64/net | |
| parent | arm64: bpf: fix out-of-bounds read in bpf2a64_offset() (diff) | |
| download | linux-d63903bbc30c7ccad040851dfdb4da12d9a17bcf.tar.xz linux-d63903bbc30c7ccad040851dfdb4da12d9a17bcf.zip | |
arm64: bpf: fix endianness conversion bugs
Upper bits should be zeroed in endianness conversion:
- even when there's no need to change endianness (i.e., BPF_FROM_BE
on big endian or BPF_FROM_LE on little endian);
- after rev16.
This patch fixes such bugs by emitting extra instructions to clear
upper bits.
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler")
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/net')
| -rw-r--r-- | arch/arm64/net/bpf_jit.h | 4 | ||||
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 22 |
2 files changed, 24 insertions, 2 deletions
diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h index de0a81a539a0..98a26ce82d26 100644 --- a/arch/arm64/net/bpf_jit.h +++ b/arch/arm64/net/bpf_jit.h @@ -110,6 +110,10 @@ /* Rd = Rn >> shift; signed */ #define A64_ASR(sf, Rd, Rn, shift) A64_SBFM(sf, Rd, Rn, shift, (sf) ? 63 : 31) +/* Zero extend */ +#define A64_UXTH(sf, Rd, Rn) A64_UBFM(sf, Rd, Rn, 0, 15) +#define A64_UXTW(sf, Rd, Rn) A64_UBFM(sf, Rd, Rn, 0, 31) + /* Move wide (immediate) */ #define A64_MOVEW(sf, Rd, imm16, shift, type) \ aarch64_insn_gen_movewide(Rd, imm16, shift, \ diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index c81ddd4ff7f7..c047598b09e0 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -289,23 +289,41 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) case BPF_ALU | BPF_END | BPF_FROM_BE: #ifdef CONFIG_CPU_BIG_ENDIAN if (BPF_SRC(code) == BPF_FROM_BE) - break; + goto emit_bswap_uxt; #else /* !CONFIG_CPU_BIG_ENDIAN */ if (BPF_SRC(code) == BPF_FROM_LE) - break; + goto emit_bswap_uxt; #endif switch (imm) { case 16: emit(A64_REV16(is64, dst, dst), ctx); + /* zero-extend 16 bits into 64 bits */ + emit(A64_UXTH(is64, dst, dst), ctx); break; case 32: emit(A64_REV32(is64, dst, dst), ctx); + /* upper 32 bits already cleared */ break; case 64: emit(A64_REV64(dst, dst), ctx); break; } break; +emit_bswap_uxt: + switch (imm) { + case 16: + /* zero-extend 16 bits into 64 bits */ + emit(A64_UXTH(is64, dst, dst), ctx); + break; + case 32: + /* zero-extend 32 bits into 64 bits */ + emit(A64_UXTW(is64, dst, dst), ctx); + break; + case 64: + /* nop */ + break; + } + break; /* dst = imm */ case BPF_ALU | BPF_MOV | BPF_K: case BPF_ALU64 | BPF_MOV | BPF_K: |