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 959B4C4332F for ; Wed, 24 Nov 2021 12:23:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243699AbhKXM0P (ORCPT ); Wed, 24 Nov 2021 07:26:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:38266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244518AbhKXMXi (ORCPT ); Wed, 24 Nov 2021 07:23:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3E0D96120E; Wed, 24 Nov 2021 12:14:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637756054; bh=F0dvnfFGDPeti9fsmyFM/15EssZg5XjdLeJBjQ1tXXg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vX0W+PH6qxZz9jtO1i7aJ2P3da9AlXhR89084rWpeG+27qILhDGV2YdQpveJkAsx2 ENxsv/su40IHYEpXv+QCuLm7iutvSz4kkRJX7kIYggVXVBolhEciY0HZg33Eje821z UWVtcUgpPler/TPy+Uoi/zPwaqMD4mxGT+4Po02E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Michael Ellerman , "Naveen N. Rao" , Johan Almbladh , Christophe Leroy , Song Liu Subject: [PATCH 4.9 154/207] powerpc/bpf: Validate branch ranges Date: Wed, 24 Nov 2021 12:57:05 +0100 Message-Id: <20211124115708.996302576@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115703.941380739@linuxfoundation.org> References: <20211124115703.941380739@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Naveen N. Rao" upstream commit 3832ba4e283d7052b783dab8311df7e3590fed93 Add checks to ensure that we never emit branch instructions with truncated branch offsets. Suggested-by: Michael Ellerman Signed-off-by: Naveen N. Rao Tested-by: Johan Almbladh Reviewed-by: Christophe Leroy Acked-by: Song Liu Acked-by: Johan Almbladh Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/71d33a6b7603ec1013c9734dd8bdd4ff5e929142.1633464148.git.naveen.n.rao@linux.vnet.ibm.com [expand is_offset_in_[cond_]branch_range() helpers, drop ppc32 changes] Signed-off-by: Naveen N. Rao Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/net/bpf_jit.h | 25 +++++++++++++++++++------ arch/powerpc/net/bpf_jit_comp64.c | 10 +++++++--- 2 files changed, 26 insertions(+), 9 deletions(-) --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -177,13 +177,26 @@ #define PPC_NEG(d, a) EMIT(PPC_INST_NEG | ___PPC_RT(d) | ___PPC_RA(a)) /* Long jump; (unconditional 'branch') */ -#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \ - (((dest) - (ctx->idx * 4)) & 0x03fffffc)) +#define PPC_JMP(dest) \ + do { \ + long offset = (long)(dest) - (ctx->idx * 4); \ + if (offset < -0x2000000 || offset > 0x1fffffc || offset & 0x3) { \ + pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_INST_BRANCH | (offset & 0x03fffffc)); \ + } while (0) /* "cond" here covers BO:BI fields. */ -#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \ - (((cond) & 0x3ff) << 16) | \ - (((dest) - (ctx->idx * 4)) & \ - 0xfffc)) +#define PPC_BCC_SHORT(cond, dest) \ + do { \ + long offset = (long)(dest) - (ctx->idx * 4); \ + if (offset < -0x8000 || offset > 0x7fff || offset & 0x3) { \ + pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc)); \ + } while (0) + /* Sign-extended 32-bit immediate load */ #define PPC_LI32(d, i) do { \ if ((int)(uintptr_t)(i) >= -32768 && \ --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -239,7 +239,7 @@ static void bpf_jit_emit_func_call(u32 * PPC_BLRL(); } -static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) +static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) { /* * By now, the eBPF program has already setup parameters in r3, r4 and r5 @@ -300,7 +300,9 @@ static void bpf_jit_emit_tail_call(u32 * bpf_jit_emit_common_epilogue(image, ctx); PPC_BCTR(); + /* out: */ + return 0; } /* Assemble the body code between the prologue & epilogue */ @@ -310,7 +312,7 @@ static int bpf_jit_build_body(struct bpf { const struct bpf_insn *insn = fp->insnsi; int flen = fp->len; - int i; + int i, ret; /* Start of epilogue code - will only be valid 2nd pass onwards */ u32 exit_addr = addrs[flen]; @@ -938,7 +940,9 @@ common_load: */ case BPF_JMP | BPF_CALL | BPF_X: ctx->seen |= SEEN_TAILCALL; - bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); + ret = bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); + if (ret < 0) + return ret; break; default: