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Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH 01/12] mm, slab: ignore hardened usercopy parameters when disabled Content-Language: en-US To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Kees Cook , Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg , Roman Gushchin , Andrew Morton , Linus Torvalds , Matthew Wilcox , patches@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kees Cook References: <20221121171202.22080-1-vbabka@suse.cz> <20221121171202.22080-2-vbabka@suse.cz> <206E0154-63A6-45CF-8E19-BD01B35AEF0B@kernel.org> <0058169a-1659-7ab1-edff-de9ebadcf236@suse.cz> From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=rIeXXCIl; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=jzhQoJTT; spf=pass (imf27.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; 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dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=rIeXXCIl; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=jzhQoJTT; spf=pass (imf27.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Rspam-User: X-HE-Tag: 1669289203-274550 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: On 11/24/22 12:16, Hyeonggon Yoo wrote: >> /* Fail closed on bad usersize of useroffset values. */ >> - if (WARN_ON(!usersize && useroffset) || >> + if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) || >> + WARN_ON(!usersize && useroffset) || >> WARN_ON(size < usersize || size - usersize < useroffset)) >> usersize = useroffset = 0; > > I think this change is no longer needed as slab_unmergeable() > now does not check usersize when CONFIG_HARDENED_USERCOPY=n? True, but the code here still follows by if (!usersize) s = __kmem_cache_alias(name, size, align, flags, ctor); So it seemed simplest just to leave it like that.