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b=N8LO++w9rRwOTrK4vLzeFY2Fb+lpuYIW/Pmm2iLhyrBEKAWK14PMp9gmu2REMsfHn RPF3R+ZKNCuC7aryhLYSQeEI2e7t+7tyCXWgbRU0QLeT/6U5KEISX6W75KzRUnC7Rs uDKXdH8iw82itjYR8Zq/czLiWHwV8e0hRkdTpAaxEw7EZmvQ+MJfn6aknwjmtdIZeK dqAcECA9OzzaInq7gL7Ooet8RDKmPi6J36kpyBbnbngqfOsjXQa88Zjuaxfdk7AWBu 7we6iXQsYtis/9i5jEjNh1tyqE3DuSHaOrxZxRk+2esnfMhFhsuZawqeBFCt5kp7tt CQ1sRC3iF1JtA== Date: Mon, 5 Aug 2024 13:21:36 -0700 From: Kees Cook To: Christian Brauner Cc: Mateusz Guzik , viro@zeniv.linux.org.uk, jack@suse.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, josef@toxicpanda.com, wojciech.gladysz@infogain.com, ebiederm@xmission.com, linux-mm@kvack.org Subject: Re: [PATCH] exec: drop a racy path_noexec check Message-ID: <202408051320.A5A8674C@keescook> References: <20240805-fehlbesetzung-nilpferd-1ed58783ad4d@brauner> <20240805131721.765484-1-mjguzik@gmail.com> <20240805-denkspiel-unruhen-c0ec00f5d370@brauner> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240805-denkspiel-unruhen-c0ec00f5d370@brauner> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 9924780014 X-Stat-Signature: zp1d86znwu5y6ocm4ftdd6jkek9mo6f6 X-Rspam-User: X-HE-Tag: 1722889301-695811 X-HE-Meta: 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 MoCWy36Q uaFqGxXSb+VEwOPubpFl34ZWVfApgK8PxjPeqnr21WPpK3SRVxhscYZW+th8ChG+TN4kKmu244PobRVWYgOF5P9ieC8fl9fQNKQ9u3YXK5UlxmFtOFs/nzIcrrAXBP4kHpWgAhGB2noNy2T5qo/cpkWJeMLqfGPA0fO+bGWFajWYLUh+AkjLxwEnmPfES4KthCZOypZe/t57T1PASfoBCYtvC7gEqJDTOLqWO8vLy+nSin73EV+YVGbU2g6AtjsjuQcGZ7dmsb0NSo2U= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000955, 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, Aug 05, 2024 at 05:35:35PM +0200, Christian Brauner wrote: > But having it in there isn't wrong. In procfs permission/eligibility > checks often are checked as close to the open as possible. Worst case > it's something similar here. But it's certainly wrong to splat about it. Right, please keep the redundant check, but we can downgrade it from a WARN. It's caught stuff in the past, so I'd like to retain it until we really do feel safe enough to let it go. -- Kees Cook