Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zi Shen Lim , Alexei Starovoitov , Catalin Marinas , Xi Wang , Will Deacon Subject: [PATCH 4.0 093/148] arm64: bpf: fix signedness bug in loading 64-bit immediate Date: Wed, 3 Jun 2015 21:09:23 +0900 Message-Id: <20150603114209.415765698@linuxfoundation.org> In-Reply-To: <20150603114205.337615117@linuxfoundation.org> References: <20150603114205.337615117@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xi Wang commit 1e4df6b7208140f3c49f316d33a409d3a161f350 upstream. Consider "(u64)insn1.imm << 32 | imm" in the arm64 JIT. Since imm is signed 32-bit, it is sign-extended to 64-bit, losing the high 32 bits. The fix is to convert imm to u32 first, which will be zero-extended to u64 implicitly. Cc: Zi Shen Lim Cc: Alexei Starovoitov Cc: Catalin Marinas Fixes: 30d3d94cc3d5 ("arm64: bpf: add 'load 64-bit immediate' instruction") Signed-off-by: Xi Wang [will: removed non-arm64 bits and redundant casting] Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -487,7 +487,7 @@ emit_cond_jmp: return -EINVAL; } - imm64 = (u64)insn1.imm << 32 | imm; + imm64 = (u64)insn1.imm << 32 | (u32)imm; emit_a64_mov_i64(dst, imm64, ctx); return 1;