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b=GjEhGyGK3NikUXJvD6X3msh6CJMLkJ+zXObx3D6+LvMSYvDXrrX/on8/Vb2ccqDCJ c0liPvhk4ohuyS2mUOdZQ1LlEuWZLR6K4n2dDnbFfckcUlA29ijBTBpHIwFW+B75+s 4bFyGOmueXYBkU/PLMlerOVQbtqbYpEwSNiDUYw0wVDe8fiY/VXEL4pKrFvc0w2ycR aFT9SNfHF6mK17AVYL41HSlGg0a/KLxDtZakreGghtLRk/IF/0yb2pFMjzk7yPta/J eGoSGGZoAC8rbY7aeHBGLpilC+cX+Wf0q9m1wkbr6bZ73BWGwb1X8eciJ0liDZCf6D NfQzy0r9pDMjA== Date: Mon, 24 Feb 2025 10:55:26 -0800 From: Kees Cook To: Dave Hansen Cc: Jeff Xu , akpm@linux-foundation.org, jannh@google.com, torvalds@linux-foundation.org, vbabka@suse.cz, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, adhemerval.zanella@linaro.org, oleg@redhat.com, avagin@gmail.com, benjamin@sipsolutions.net, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, jorgelo@chromium.org, sroettger@google.com, hch@lst.de, ojeda@kernel.org, thomas.weissschuh@linutronix.de, adobriyan@gmail.com, johannes@sipsolutions.net, pedro.falcato@gmail.com, hca@linux.ibm.com, willy@infradead.org, anna-maria@linutronix.de, mark.rutland@arm.com, linus.walleij@linaro.org, Jason@zx2c4.com, deller@gmx.de, rdunlap@infradead.org, davem@davemloft.net, peterx@redhat.com, f.fainelli@gmail.com, gerg@kernel.org, dave.hansen@linux.intel.com, mingo@kernel.org, ardb@kernel.org, mhocko@suse.com, 42.hyeyoo@gmail.com, peterz@infradead.org, ardb@google.com, enh@google.com, rientjes@google.com, groeck@chromium.org, mpe@ellerman.id.au, aleksandr.mikhalitsyn@canonical.com, mike.rapoport@gmail.com Subject: Re: [PATCH v6 1/7] mseal, system mappings: kernel config and header change Message-ID: <202502241053.1FF33D5B0@keescook> References: <20250224174513.3600914-1-jeffxu@google.com> <20250224174513.3600914-2-jeffxu@google.com> <443992d7-f694-4e46-b120-545350a5d598@intel.com> <385e1498-2444-4a7a-a1b0-0013b0b8fd68@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <385e1498-2444-4a7a-a1b0-0013b0b8fd68@intel.com> X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 8AD96100006 X-Stat-Signature: 9z6zkiz4anq89a6bmxxmgkpo6i7pewmq X-HE-Tag: 1740423331-189043 X-HE-Meta: U2FsdGVkX19m2Yh9rYehq7TwLCbHrxJ1X1EeoYbQELjI5U+bqZUfeKaezwRAMjJA/FeQB/X8zrJB8qALJ3052+ue5N7BVQGmNoRcaQFxXOc5VDOelmx68CjdbunV6GE5i080hVhh09+0HZj6DSn54FbRYFFtSwe886iuplLT//qdK1KbmeTlqkNATA3yf+mJoafLEPExyQn8CCIyvGZARkuIFppj4jMh6rpc67WlocW0p5H82NDRkvfWiYOxgGkiuyjTDPgvuPXR0xg66h+5y0BXzjxsbZFD1CNygVfBk3Vhk7qg52Oar5GNymIaVPMRIYDdzEH1yw79t3LeimK29yKDtQ0PNRNK1OsuF2UUoeyU2aaRMU1dSq5rRzp5Ch0cT2NzBB/JhovkgrXeBfxl64cjTOe1MySua2EyCJyg4P6lvCZ/sliKG5zl9dEmKeCnzvItOeiG8gkoFQMaVuySx7LoyZIADwUexb041osrjlFebjnzqyfblgheYyzuJnmbA2jxCy2qaAH2KxFWDlpmo1RCMM3JViTL8beRbTm8JFVXynrbB9/jU5ojh2ih1t5UXbehYQBvNANANk0rIoODSqGHkB7g8XK2k7V2hhXLvFr0RHbIqa0dmQVgGlFeZN7mQU7GN+8sX1dkReZ5kB+e7t/KhtS19s421fKOKikgUOCFVoXcZKheYU0g6mKYGDe7SJTX/d8DMwB//1zkp7PUVYxHjD2DvhDffwFjtq11AszaA+nxMas9SUvf/bcKDcM6QXfXKDQ55KEt1DZOku1RGehD/NSCQfkbmAZAX3J6wirJFR9ROYVPh6eXxUwukQxEaDRnMoLns8MJT7PPBDjr9LqOt8c2gQPrWuFsshYS+JtItbarXRZwD5sr+26B/6jmALvIumAV/FuVWots6iYcr99lUaqsNeVgeGb5jZOj2IEcNZJno+K8RylchhYUP45lcETQF3cripmP8zpkD2q AlcDXGhk uAMbDSnmIbYxB+YrVppdu2zBKOjn8DCPqPOynmsuFST8YCGLmuSTOYiwqeB9wEFD6thu4g/mYUd0G+T0MfNNZKChBZhE3lddc3+JApRt4YAIs5u6DABpNGSN4UBdSsC0tKq8aEJRyquyanRIy+zY3XvjV0InZl3nXdXNJYyvJsAsAjcWz27PMhJotHzgLrI5yN0dq3qxZAugeBWoRcTRAaVqnnxaIDUMAL3QFmd2BzEVWJYfWrT8UVNJhMH3N7XSn3p3KJOSiL/B245MpJvXob9hRaKlOz9XlTndXuOvLoZyBxAJADQKaf50uUnf9FpKb7KNq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Feb 24, 2025 at 10:52:13AM -0800, Dave Hansen wrote: > On 2/24/25 10:44, Jeff Xu wrote: > > For example: > > Consider the case below in src/third_party/kernel/v6.6/fs/proc/task_mmu.c, > > > > #ifdef CONFIG_64BIT > > [ilog2(VM_SEALED)] = "sl", > > #endif > > > > Redefining VM_SEALED to VM_NONE for 32 bit won't detect the problem > > in case that "#ifdef CONFIG_64BIT" line is missing. > > > > Please note, this has been like this since the first version of > > mseal() RFC patch, and I prefer to keep it this way. > > That logic is reasonable. But it's different from the _vast_ majority of > other flags. > > So what justifies VM_SEALED being so different? It's leading to pretty > objectively ugly code in this series. Note that VM_SEALED is the "is this VMA sealed?" bit itself. The define for "should we perform system mapping sealing?" is intentionally separate here, so that it can be Kconfig and per-arch toggled, etc. As for the name, I have no strong opinion. Perhaps VM_SEALED_SYSTEM_MAPPING ? -Kees -- Kees Cook