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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20250911050149.GW31600@ZenIV> References: <20250911050149.GW31600@ZenIV> To: Al Viro Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, Linus Torvalds , Christian Brauner , Jan Kara , NeilBrown , linux-security-module@vger.kernel.org, Namjae Jeon Subject: Re: [PATCHES] simple part of ->d_name stuff Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1910270.1757570384.1@warthog.procyon.org.uk> Date: Thu, 11 Sep 2025 06:59:44 +0100 Message-ID: <1910271.1757570384@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Al Viro wrote: > Rules for ->d_name access are rather unpleasant and so's > verifying that they are followed. There is a relatively simple part, > though - nobody outside of fs/dcache.c has any business modifying > that thing. > > So let's make sure that all functions we are passing > &dentry->d_name are taking const struct qstr * and replace > ->d_name with an anon union of struct qstr *__d_name and > const struct qstr *d_name. > > It is *not* enough to guarantee that another thread will > not call __d_move() right under you - checking the requirements > for that is the hard part. It does make it easy to verify that > nothing else accidentally starts changing it. > > This stuff lives in > git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #work.qstr > Branch is -rc4-based, individual patches in followups. > > Please, review. If nobody objects, I'll put that in #for-next. Reviewed-by: David Howells