From nobody Thu Nov 28 14:45:41 2024 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15FE31CDFDD for ; Tue, 1 Oct 2024 16:07:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727798854; cv=none; b=Xh33uZj/7hHucyApfLOipfi8p1fzriT1bZomZp7FMoAlnDKDMYcAf6FtO797Pgp9QF3uexOyZE2XCLz6qIeWO9bKfHA83t1rRe37aeL5p4PerOXOXz5b1y2Clbntf63mlJ6AKg1V+GCQtzHwyhkO8SoEA8wylwTyQSKUOEKIF5E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727798854; c=relaxed/simple; bh=APcwzNL4Tw+gpJWkjaTtuJn7di2b1KEkyKTochQibbc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DQVDH/noywpBSiJtNVAqxbONd4z5ShHYsK8H30pIuwVuhYXA5GXMftVmz1ngOF1YUU7JQmtNqBnN1DaDzlu7sHxwAdaFfX2u2cBG7VsU4iMDLoMjzSqcohdldR/svkje5NSHf5OyaVJr4m1lChc9kx9v41sfBF8PbpHJn/mcgEo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com; spf=pass smtp.mailfrom=rivosinc.com; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b=gBz9iBX9; arc=none smtp.client-ip=209.85.216.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="gBz9iBX9" Received: by mail-pj1-f42.google.com with SMTP id 98e67ed59e1d1-2e0b0142bbfso3662468a91.1 for ; Tue, 01 Oct 2024 09:07:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1727798850; x=1728403650; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=Jf2x3pfGFzhqVTB4n6XHdAtkUN+75WMOXWy8ywZVarA=; b=gBz9iBX9w2ucDfvIaw8vE8zXfq3/DrGNBg44yZRUqfOjsGhKHBsOsJ+crPqHwAc/dL 9w/8M2tjWbGZafcVsOhtGqMeoQApPEXE7PQLveENzvc/7izPXOXP/m1wVE5aq64wqVtt I8oiuuaCpi2ZZk8BD/3kTkUrkv5+dMNqJkZvcI1ooiadXpU0ioS1tV7/PBzby5l3tvOD dEJwCJh9Zrb4nv2hvIWM9CKOkHYrL06YdAHY0SHtCxovOsX2vHwdJNiFGITK2JVOKVPt 5xHbCcp8jyAISSI389Jkhc3tNsgjVlaoBZgH3L0pBmuTa4HO05VO65x1+MJjVdj/EZEd cQfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727798850; x=1728403650; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Jf2x3pfGFzhqVTB4n6XHdAtkUN+75WMOXWy8ywZVarA=; b=alJBBoTgNkUQZMRh9HldMQ0Ib7o0GUO8mjCNThg/+ZGlGoTpy9YEA2UEeiBAixRyE/ iPiTh5ymwILCo+mAXry1V09DPTxOLgNY0+dfHM1sNx+TOCbe1mQs8GoxxaMTB+Kuj1FR QlOH7WqF464oxbo5cbv8sjqPBguMkv2fc3Q4TNPUOEPOpn8q3nITA1t68ci7pgtvxs6+ dTfnUoHPDPRezcnYj+U9QYQz8Kipwwuo/LKTLIvMRtXnyN97sUb0yBsuhZMF1Wtj2U06 VrylT9v4BeviLf4ujgMhtgaB1XmhD2YPjANak3qxQSCDCfThvKEkOFSOueuAb8eA25ot WkTg== X-Gm-Message-State: AOJu0YxLk4bieIpmHJdI9klr4ncwGAtWF9sGebOlkB1QhMq5acXoKDY9 zBM+ecW4UYG/jp8vzxXaJEW1K08jY/w8Ue3uCXHVdkj+hj2pPrPzHDulX5NP/pk= X-Google-Smtp-Source: AGHT+IGob07HibDqMTkhNXqspOJCbfYZqD3T/Q2DpzNezAZ4leoJ5tWyryGCIql/xTbKFf++6QnddA== X-Received: by 2002:a17:90b:11cf:b0:2da:88b3:cff8 with SMTP id 98e67ed59e1d1-2e1851c6ec4mr154101a91.6.1727798850248; Tue, 01 Oct 2024 09:07:30 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e06e1d7d47sm13843973a91.28.2024.10.01.09.07.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Oct 2024 09:07:28 -0700 (PDT) From: Deepak Gupta Date: Tue, 01 Oct 2024 09:06:16 -0700 Subject: [PATCH 11/33] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241001-v5_user_cfi_series-v1-11-3ba65b6e550f@rivosinc.com> References: <20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@rivosinc.com> In-Reply-To: <20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@rivosinc.com> To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Rob Herring , Krzysztof Kozlowski , Arnd Bergmann , Christian Brauner , Peter Zijlstra , Oleg Nesterov , Eric Biederman , Kees Cook , Jonathan Corbet , Shuah Khan Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, alistair.francis@wdc.com, richard.henderson@linaro.org, jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com, charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, alexghiti@rivosinc.com, samitolvanen@google.com, broonie@kernel.org, rick.p.edgecombe@intel.com, Deepak Gupta X-Mailer: b4 0.14.0 `arch_calc_vm_prot_bits` is implemented on risc-v to return VM_READ | VM_WRITE if PROT_WRITE is specified. Similarly `riscv_sys_mmap` is updated to convert all incoming PROT_WRITE to (PROT_WRITE | PROT_READ). This is to make sure that any existing apps using PROT_WRITE still work. Earlier `protection_map[VM_WRITE]` used to pick read-write PTE encodings. Now `protection_map[VM_WRITE]` will always pick PAGE_SHADOWSTACK PTE encodings for shadow stack. Above changes ensure that existing apps continue to work because underneath kernel will be picking `protection_map[VM_WRITE|VM_READ]` PTE encodings. Signed-off-by: Deepak Gupta --- arch/riscv/include/asm/mman.h | 24 ++++++++++++++++++++++++ arch/riscv/include/asm/pgtable.h | 1 + arch/riscv/kernel/sys_riscv.c | 10 ++++++++++ arch/riscv/mm/init.c | 2 +- mm/mmap.c | 1 + 5 files changed, 37 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.h new file mode 100644 index 000000000000..ef9fedf32546 --- /dev/null +++ b/arch/riscv/include/asm/mman.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include +#include +#include + +static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, + unsigned long pkey __always_unused) +{ + unsigned long ret =3D 0; + + /* + * If PROT_WRITE was specified, force it to VM_READ | VM_WRITE. + * Only VM_WRITE means shadow stack. + */ + if (prot & PROT_WRITE) + ret =3D (VM_READ | VM_WRITE); + return ret; +} +#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pk= ey) + +#endif /* ! __ASM_MMAN_H__ */ diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgta= ble.h index e79f15293492..4948a1f18ae8 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -177,6 +177,7 @@ extern struct pt_alloc_ops pt_ops __meminitdata; #define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) #define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \ _PAGE_EXEC | _PAGE_WRITE) +#define PAGE_SHADOWSTACK __pgprot(_PAGE_BASE | _PAGE_WRITE) =20 #define PAGE_COPY PAGE_READ #define PAGE_COPY_EXEC PAGE_READ_EXEC diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c index d77afe05578f..43a448bf254b 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -7,6 +7,7 @@ =20 #include #include +#include =20 static long riscv_sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, @@ -16,6 +17,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigned = long len, if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) return -EINVAL; =20 + /* + * If PROT_WRITE is specified then extend that to PROT_READ + * protection_map[VM_WRITE] is now going to select shadow stack encodings. + * So specifying PROT_WRITE actually should select protection_map [VM_WRI= TE | VM_READ] + * If user wants to create shadow stack then they should use `map_shadow_= stack` syscall. + */ + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) + prot |=3D PROT_READ; + return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - page_shift_offset)); } diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 0e8c20adcd98..964810aeb405 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -326,7 +326,7 @@ pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(P= AGE_SIZE); static const pgprot_t protection_map[16] =3D { [VM_NONE] =3D PAGE_NONE, [VM_READ] =3D PAGE_READ, - [VM_WRITE] =3D PAGE_COPY, + [VM_WRITE] =3D PAGE_SHADOWSTACK, [VM_WRITE | VM_READ] =3D PAGE_COPY, [VM_EXEC] =3D PAGE_EXEC, [VM_EXEC | VM_READ] =3D PAGE_READ_EXEC, diff --git a/mm/mmap.c b/mm/mmap.c index dd4b35a25aeb..b56f1e8cbfc6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -47,6 +47,7 @@ #include #include #include +#include =20 #include #include --=20 2.45.0