From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 392CDC4167B for ; Wed, 28 Dec 2022 16:04:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233077AbiL1QEK (ORCPT ); Wed, 28 Dec 2022 11:04:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234356AbiL1QDu (ORCPT ); Wed, 28 Dec 2022 11:03:50 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F925192A9 for ; Wed, 28 Dec 2022 08:03:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 05FBDB81730 for ; Wed, 28 Dec 2022 16:03:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EC06C433EF; Wed, 28 Dec 2022 16:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672243426; bh=Lmcw3TOe2AlptIzFhBZvvS38VLzYip5lBfUY/kKNdNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RGxKovDCZL+2GG9uhg/JoI7BDJZEXG1xDxljWES9jxscQiYY6HOBS7ZOic8p5xV9H KYnGNySU1CmyU/rwbpntWq4hmHCu3uZBHnyyytdfUNbuG8Skmd3oLww9niAQ8nt5C5 jAKjrPuvUAiDfUfPNjyUasWaTnz32NFue9VhA32I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Pu Lehui , Daniel Borkmann , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Sasha Levin Subject: [PATCH 6.1 0491/1146] riscv, bpf: Emit fixed-length instructions for BPF_PSEUDO_FUNC Date: Wed, 28 Dec 2022 15:33:50 +0100 Message-Id: <20221228144343.520406287@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pu Lehui [ Upstream commit b54b6003612a376e7be32cbc5c1af3754bbbbb3d ] For BPF_PSEUDO_FUNC instruction, verifier will refill imm with correct addresses of bpf_calls and then run last pass of JIT. Since the emit_imm of RV64 is variable-length, which will emit appropriate length instructions accorroding to the imm, it may broke ctx->offset, and lead to unpredictable problem, such as inaccurate jump. So let's fix it with fixed-length instructions. Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Suggested-by: Björn Töpel Signed-off-by: Pu Lehui Signed-off-by: Daniel Borkmann Reviewed-by: Björn Töpel Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20221206091410.1584784-1-pulehui@huaweicloud.com Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp64.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 00df3a8f92ac..f2417ac54edd 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -136,6 +136,25 @@ static bool in_auipc_jalr_range(s64 val) val < ((1L << 31) - (1L << 11)); } +/* Emit fixed-length instructions for address */ +static int emit_addr(u8 rd, u64 addr, bool extra_pass, struct rv_jit_context *ctx) +{ + u64 ip = (u64)(ctx->insns + ctx->ninsns); + s64 off = addr - ip; + s64 upper = (off + (1 << 11)) >> 12; + s64 lower = off & 0xfff; + + if (extra_pass && !in_auipc_jalr_range(off)) { + pr_err("bpf-jit: target offset 0x%llx is out of range\n", off); + return -ERANGE; + } + + emit(rv_auipc(rd, upper), ctx); + emit(rv_addi(rd, rd, lower), ctx); + return 0; +} + +/* Emit variable-length instructions for 32-bit and 64-bit imm */ static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx) { /* Note that the immediate from the add is sign-extended, @@ -1050,7 +1069,15 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, u64 imm64; imm64 = (u64)insn1.imm << 32 | (u32)imm; - emit_imm(rd, imm64, ctx); + if (bpf_pseudo_func(insn)) { + /* fixed-length insns for extra jit pass */ + ret = emit_addr(rd, imm64, extra_pass, ctx); + if (ret) + return ret; + } else { + emit_imm(rd, imm64, ctx); + } + return 1; } -- 2.35.1