From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 13 Dec 2023 14:47:11 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rDPZu-002DdH-22 for lore@lore.pengutronix.de; Wed, 13 Dec 2023 14:47:11 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rDPZu-0005Ta-Qp for lore@pengutronix.de; Wed, 13 Dec 2023 14:47:11 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=k2yRzODqnUluC1JSlQDvDjEegMmDgAfamESYPaO/I+4=; b=4U+E4FHjIVDVhuwVLh0jvp8OaH CvSyXifEnBDyUkrsFKZ43ghqqyaI/40oTEAQ7zpgralKM08mIiYbkm/siuAOmC5ZjGIx7LK/THLh+ KcSKSIzCGxc0RpEy3shg5my7zpZbFFzpiDYPl4ryNvAiuxuIitAuvaMTvUvyeAiiWbHUfRC7eZ9J+ 0YqcUGZCugANXqOI2aCUQwEk0eFlqKU4x8y9ckvqsWLPk5tIuIQZS8pu2RqHOGj80zjnJKjM75pNc 8Pat2G0jcM/Q50XGvkn3wg3+mABH7WP+q6tIyO24xFtrVSjvmZzP3vKpwtXhTyniztKW1Ab5p6Ptc E4EV5Kjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rDPYh-00Erev-2X; Wed, 13 Dec 2023 13:45:55 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rDPYe-00EreQ-28 for barebox@lists.infradead.org; Wed, 13 Dec 2023 13:45:54 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rDPYZ-00045Q-Go; Wed, 13 Dec 2023 14:45:47 +0100 Received: from [2a0a:edc0:2:b01:1d::c0] (helo=ptx.whiteo.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rDPYZ-00FaFO-13; Wed, 13 Dec 2023 14:45:47 +0100 Received: from sha by ptx.whiteo.stw.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1rDPYY-006nUa-V3; Wed, 13 Dec 2023 14:45:46 +0100 Date: Wed, 13 Dec 2023 14:45:46 +0100 From: Sascha Hauer To: Ahmad Fatoum Cc: barebox@lists.infradead.org, Yann Sionneau Message-ID: <20231213134546.GJ1318922@pengutronix.de> References: <20231122170323.15175-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231122170323.15175-1-a.fatoum@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231213_054552_720088_A2C710E2 X-CRM114-Status: GOOD ( 26.20 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH v2 1/3] fs: add open O_TMPFILE support X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On Wed, Nov 22, 2023 at 06:03:21PM +0100, Ahmad Fatoum wrote: > barebox dentry cache is never cleared with the assumption that there > should be enough RAM anyway to cache all lookups until boot. > > When fuzzing barebox however, there is no limit to how many dentries > are added to the cache. This is e.g. problematic when fuzzing the FIT > parser: FIT images can have compressed payloads. Compressed payloads are > passed to uncompress_buf_to_buf, which uses a new random file in ramfs > as destination. A fuzzer would thus create a dentry for every iteration, > rapidly depleting memory. > > A general solution for that would be dropping the dentry cache on memory > pressure. In the special case of uncompress_buf_to_buf, it would already > be enough though to sidestep the dentry cache and create an anonymous > file. Linux provides this with the O_TMPFILE option, so let's add the > equivalent to barebox. > > Signed-off-by: Ahmad Fatoum > --- > v1 -> v2: > - don't use uninitialized fsdrv > --- > fs/fs.c | 29 +++++++++++++++++++++++++++++ > include/fcntl.h | 3 +++ > 2 files changed, 32 insertions(+) Applied, thanks Sascha > > diff --git a/fs/fs.c b/fs/fs.c > index 1800d6826ddc..68e7873e9c54 100644 > --- a/fs/fs.c > +++ b/fs/fs.c > @@ -2539,6 +2539,35 @@ int open(const char *pathname, int flags, ...) > const char *s; > struct filename *filename; > > + if (flags & O_TMPFILE) { > + fsdev = get_fsdevice_by_path(pathname); > + if (!fsdev) { > + errno = ENOENT; > + return -errno; > + } > + > + if (fsdev->driver != ramfs_driver) { > + errno = EOPNOTSUPP; > + return -errno; > + } > + > + f = get_file(); > + if (!f) { > + errno = EMFILE; > + return -errno; > + } > + > + f->path = NULL; > + f->dentry = NULL; > + f->f_inode = new_inode(&fsdev->sb); > + f->f_inode->i_mode = S_IFREG; > + f->flags = flags; > + f->size = 0; > + f->fsdev = fsdev; > + > + return f->no; > + } > + > filename = getname(pathname); > if (IS_ERR(filename)) > return PTR_ERR(filename); > diff --git a/include/fcntl.h b/include/fcntl.h > index 2e7c0eed3479..1b4cd8ad3783 100644 > --- a/include/fcntl.h > +++ b/include/fcntl.h > @@ -16,6 +16,9 @@ > #define O_APPEND 00002000 > #define O_DIRECTORY 00200000 /* must be a directory */ > #define O_NOFOLLOW 00400000 /* don't follow links */ > +#define __O_TMPFILE 020000000 > + > +#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) > > /* barebox additional flags */ > #define O_RWSIZE_MASK 017000000 > -- > 2.39.2 > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |