From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="dyq5Ib/b"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="6sIF1/RV" Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95FCB101 for ; Thu, 23 Nov 2023 20:21:30 -0800 (PST) Received: from imap2.dmz-prg2.suse.org (imap2.dmz-prg2.suse.org [10.150.64.98]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id EBFFE219BA; Thu, 23 Nov 2023 16:28:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1700756897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rwSvm5vQA21r+qzTnLssiD/xzgui83BIo5DkyWTsbjk=; b=dyq5Ib/beKXQWSGCbOezV4OIdYB58PLceBPQvIweUppISgKIyDP2AJLUnJubwN9QItN66p SXy3y83xe7nIQu1DN71AGwaP8i+/CI4jrYscaot5VMdoJIjS2ZWdGVuU2qYSDwxZM6FyBL rUWpXEgoxTWEoKGu7LWDMCEliVgcM6k= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1700756897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rwSvm5vQA21r+qzTnLssiD/xzgui83BIo5DkyWTsbjk=; b=6sIF1/RVS5a/GT8aOhTuKlCoCXj9tTN/9BUhlf4cAKEyKKxA3nRaVkGb/fraVensPhhSXF caN4haOfY2enZICg== Received: from imap2.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id D4BBE13A82; Thu, 23 Nov 2023 16:28:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap2.dmz-prg2.suse.org with ESMTPSA id ue+aM6F9X2XlGgAAn2gu4w (envelope-from ); Thu, 23 Nov 2023 16:28:17 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 39222A07D9; Thu, 23 Nov 2023 17:28:17 +0100 (CET) Date: Thu, 23 Nov 2023 17:28:17 +0100 From: Jan Kara To: Amir Goldstein Cc: Christian Brauner , Jan Kara , Josef Bacik , David Howells , Jens Axboe , Miklos Szeredi , Al Viro , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 01/16] ovl: add permission hooks outside of do_splice_direct() Message-ID: <20231123162817.dxqcr4ws657v6mvn@quack3> References: <20231122122715.2561213-1-amir73il@gmail.com> <20231122122715.2561213-2-amir73il@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231122122715.2561213-2-amir73il@gmail.com> Authentication-Results: smtp-out1.suse.de; none X-Spam-Score: -2.60 X-Spam-Level: X-Spamd-Result: default: False [-2.60 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; RCPT_COUNT_SEVEN(0.00)[9]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,suse.cz:email]; FREEMAIL_TO(0.00)[gmail.com]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-3.00)[100.00%] On Wed 22-11-23 14:27:00, Amir Goldstein wrote: > The main callers of do_splice_direct() also call rw_verify_area() for > the entire range that is being copied, e.g. by vfs_copy_file_range() > or do_sendfile() before calling do_splice_direct(). > > The only caller that does not have those checks for entire range is > ovl_copy_up_file(). In preparation for removing the checks inside > do_splice_direct(), add rw_verify_area() call in ovl_copy_up_file(). > > For extra safety, perform minimal sanity checks from rw_verify_area() > for non negative offsets also in the copy up do_splice_direct() loop > without calling the file permission hooks. > > This is needed for fanotify "pre content" events. > > Reviewed-by: Josef Bacik > Signed-off-by: Amir Goldstein Looks good. Feel free to add: Reviewed-by: Jan Kara Honza > --- > fs/overlayfs/copy_up.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > > diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c > index 4382881b0709..106f8643af3b 100644 > --- a/fs/overlayfs/copy_up.c > +++ b/fs/overlayfs/copy_up.c > @@ -230,6 +230,19 @@ static int ovl_copy_fileattr(struct inode *inode, const struct path *old, > return ovl_real_fileattr_set(new, &newfa); > } > > +static int ovl_verify_area(loff_t pos, loff_t pos2, loff_t len, loff_t totlen) > +{ > + loff_t tmp; > + > + if (WARN_ON_ONCE(pos != pos2)) > + return -EIO; > + if (WARN_ON_ONCE(pos < 0 || len < 0 || totlen < 0)) > + return -EIO; > + if (WARN_ON_ONCE(check_add_overflow(pos, len, &tmp))) > + return -EIO; > + return 0; > +} > + > static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, > struct file *new_file, loff_t len) > { > @@ -244,13 +257,20 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, > int error = 0; > > ovl_path_lowerdata(dentry, &datapath); > - if (WARN_ON(datapath.dentry == NULL)) > + if (WARN_ON_ONCE(datapath.dentry == NULL) || > + WARN_ON_ONCE(len < 0)) > return -EIO; > > old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY); > if (IS_ERR(old_file)) > return PTR_ERR(old_file); > > + error = rw_verify_area(READ, old_file, &old_pos, len); > + if (!error) > + error = rw_verify_area(WRITE, new_file, &new_pos, len); > + if (error) > + goto out_fput; > + > /* Try to use clone_file_range to clone up within the same fs */ > ovl_start_write(dentry); > cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0); > @@ -309,6 +329,10 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, > } > } > > + error = ovl_verify_area(old_pos, new_pos, this_len, len); > + if (error) > + break; > + > ovl_start_write(dentry); > bytes = do_splice_direct(old_file, &old_pos, > new_file, &new_pos, > -- > 2.34.1 > -- Jan Kara SUSE Labs, CR