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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" , "Jann Horn" , "Conor Dooley" From: =?utf-8?q?Radim_Kr=C4=8Dm=C3=A1=C5=99?= References: <20250314-v5_user_cfi_series-v12-0-e51202b53138@rivosinc.com> <20250314-v5_user_cfi_series-v12-6-e51202b53138@rivosinc.com> In-Reply-To: <20250314-v5_user_cfi_series-v12-6-e51202b53138@rivosinc.com> 2025-03-14T14:39:25-07:00, Deepak Gupta : > diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.= h > +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. > + */ This function also changes PROT_WX to VM_RWX, which is effectively not changing anything, but I think it deserves an explicit intent. (At least in the commit message.) > + if (prot & PROT_WRITE) > + ret =3D (VM_READ | VM_WRITE); > + return ret; > +} > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.= c > @@ -16,6 +17,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigne= d long len, > + /* > + * If PROT_WRITE is specified then extend that to PROT_READ > + * protection_map[VM_WRITE] is now going to select shadow stack encodin= gs. > + * So specifying PROT_WRITE actually should select protection_map [VM_W= RITE | VM_READ] > + * If user wants to create shadow stack then they should use `map_shado= w_stack` syscall. > + */ > + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) > + prot |=3D PROT_READ; Why isn't the previous hunk be enough? (Or why don't we do just this?) riscv_sys_mmap() eventually calls arch_calc_vm_prot_bits(), so I'd rather fix each code path just once. Thanks. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C1EDBC3601E for ; Thu, 10 Apr 2025 11:18:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References:From:To:Cc: Subject:Message-Id:Date:Mime-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=VPVXh7mawQxKnJg1cUlnh7bfUueLnc02bqq2e8S9K1w=; b=Z/VMPAq1q5K3ZT cGkqUMx8kl4DNfDcwFCNVKy0Dl0pM22z+/zYhriZnybVcu4asSKWkzM9T0pRFLm0l/zwRmXLrcpYw OGBjKkLySn5L6Mfc05LQzvsAoR2Tp3jHKRL7sdndB0l6onf5+NrSB12vHGa7+9+rbpCrimVUInmWD KdPNZndo/2lsPrmh1eUcuJesGEK8G4d87tOGeT+KIzLg679ppWl9N40QkwbWTW+/srFCkcAP+x4KG ogzGzVnkLkKqt3Fh2paJe8Pvf2nWNvF/x+IzZAAtNWHREg0LEsySopgWg82ssXjRu1KN2mf6gLsq7 gJ+JjeeGCaWAbHFNFNzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2pvS-0000000AFNg-3RJu; Thu, 10 Apr 2025 11:18:30 +0000 Received: from mail-wm1-x333.google.com ([2a00:1450:4864:20::333]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2ol9-0000000A1yn-1CzM for linux-riscv@lists.infradead.org; Thu, 10 Apr 2025 10:03:48 +0000 Received: by mail-wm1-x333.google.com with SMTP id 5b1f17b1804b1-43ce4e47a85so857625e9.0 for ; Thu, 10 Apr 2025 03:03:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ventanamicro.com; s=google; t=1744279425; x=1744884225; darn=lists.infradead.org; h=in-reply-to:references:from:to:cc:subject:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=yuhlYfO+SCuG1tPDw0icZEsvUHv3NYtA5HOyZj159xM=; b=GfzS321x5lx6VMC2dMybIIwmsimssQf7DZS1IxFbY1l0ezquG9l/xXpz8O9wPuUPva NnwVtZTG5z0Tp0fJPgpTz2mHdx8yM0+YSyBN8ldgfP+1DEu9A20J+n8zCH/jbGMjxcSx wqq8y/zB8odOF9BzPcKSdeuwbXJ16so6Ir3R/Y8Q4LEfoqW9Ud+QHfI0QjSP6sm9YV/b 2OeXd1wTmCWeMu1sLanixy5HqLdyLnd6YLhn0a/bpzfZ+9msFnGG2Wh3dUNbWC3ubl00 I/f46hlPekETYCiveFovjktl8i5odyhBmXoJpNjrxqo3CnrKCeX1k1wVat16aFHziIuk af4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744279425; x=1744884225; h=in-reply-to:references:from:to:cc:subject:message-id:date :content-transfer-encoding:mime-version:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=yuhlYfO+SCuG1tPDw0icZEsvUHv3NYtA5HOyZj159xM=; b=knldl0YOUp2LfHqVseUcR6eOy0V0ZYPx+cgg9JoP9xjCcDJNXddCQSOJREMkNnehqe 1oj0kLAtPHDIxLLQwr5IAhnfHol8IusWR79ThwMgrXhGmmeWclfUp+wIFZgGPX/R3Dt6 AM4VOgMhEz6EIkfvc0wwzujVq+1RAOpLFhmcZGIuBIVITw9Dsz1gbNxQedgawqAjBSoR mzVxPPr1235I50HJnpgxWXp8JQamqF3m+8/oTphUQtLJBSLZDfKYRqLcZ+EFZ+OwhrMH 5HZxb24vt26iIGJkECJZgB98FNLH6gET0b9M1/Kpzx39pTNTFIIKm81DDk+tozyFd7VC 00GA== X-Forwarded-Encrypted: i=1; AJvYcCUtvmy1RwoIh1d3eQyKvJZ1aS/VJKfCnO+Vkem/2LUH9rCnWGPkeMytdJH2yLuZlpkya8EnhXm5lN7VXA==@lists.infradead.org X-Gm-Message-State: AOJu0Yz5UMbXKWn/tsJl3YKPrOpsnO8G+lw6d3aSzlxrndjTWXH9n+z9 AOXiNWb/qD4q2vLqawLG8QT0XAJMYcFVmQJqnpUAw7U77vRDINfqKFN7v7aAUq8= X-Gm-Gg: ASbGncuf2qldTj4neK6Ulcxcf66MrXYq1dp941QSUW6ieAqHJ06mug+ksBH8Oz6a6+6 bjvdcYvPPkoOYgThM3f0Ja0k3SZuhvJgA0JL+FvrQDKqbjeB7y1ylZ/H8qOWeMHMH9TzGtjG4Bk V5ctS2p0jlkwC2tOKzIXIqY+7x4FqPiXYkAIe++ojsaRqEH2yCwTlYZRqggixPret7u4/3CjRCZ Ys5yyv4/jtLOaNr3Ni/NpO4lF+pjxdfUP6tPDZ4v6uZTmppefiU2Gmr4k0stEtLLqMWWM0oTFuG lZyxH9MrFVO+kyNGUQBWFbKUA6vGFxjvG+ykTJqvzrQZbptm X-Google-Smtp-Source: AGHT+IFucTZsmmGzPkhUaQ2Z/vAwZtrI/ji5V2QIPWKukl3A8249XbRp5GqSbF4sFE7Q2Qv5hdQlbA== X-Received: by 2002:a05:600c:3d0c:b0:439:a1ce:5669 with SMTP id 5b1f17b1804b1-43f1ed4a7a9mr22097145e9.5.1744279425469; Thu, 10 Apr 2025 03:03:45 -0700 (PDT) Received: from localhost ([2a02:8308:a00c:e200:7d22:13bb:e539:15ee]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-39d893773a0sm4273653f8f.25.2025.04.10.03.03.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Apr 2025 03:03:45 -0700 (PDT) Mime-Version: 1.0 Date: Thu, 10 Apr 2025 12:03:44 +0200 Message-Id: Subject: Re: [PATCH v12 06/28] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Cc: , , , , , , , , , , , , , , , , , , , , , "Zong Li" , "linux-riscv" To: "Deepak Gupta" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Dave Hansen" , , "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" , "Jann Horn" , "Conor Dooley" From: =?utf-8?q?Radim_Kr=C4=8Dm=C3=A1=C5=99?= References: <20250314-v5_user_cfi_series-v12-0-e51202b53138@rivosinc.com> <20250314-v5_user_cfi_series-v12-6-e51202b53138@rivosinc.com> In-Reply-To: <20250314-v5_user_cfi_series-v12-6-e51202b53138@rivosinc.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250410_030347_324582_DE445D54 X-CRM114-Status: GOOD ( 12.13 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 2025-03-14T14:39:25-07:00, Deepak Gupta : > diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.h > +static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, > + unsigned long pkey __always_unused) > +{ > + unsigned long ret = 0; > + > + /* > + * If PROT_WRITE was specified, force it to VM_READ | VM_WRITE. > + * Only VM_WRITE means shadow stack. > + */ This function also changes PROT_WX to VM_RWX, which is effectively not changing anything, but I think it deserves an explicit intent. (At least in the commit message.) > + if (prot & PROT_WRITE) > + ret = (VM_READ | VM_WRITE); > + return ret; > +} > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c > @@ -16,6 +17,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, > + /* > + * 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_WRITE | 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 |= PROT_READ; Why isn't the previous hunk be enough? (Or why don't we do just this?) riscv_sys_mmap() eventually calls arch_calc_vm_prot_bits(), so I'd rather fix each code path just once. Thanks. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv