From: "Stephan Müller" <smueller@chronox.de> To: Nicolai Stange <nstange@suse.de> Cc: Arnd Bergmann <arnd@arndb.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-crypto@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>, linux-api@vger.kernel.org, "Eric W. Biederman" <ebiederm@xmission.com>, "Alexander E. Patrakov" <patrakov@gmail.com>, "Ahmed S. Darwish" <darwish.07@gmail.com>, "Theodore Y. Ts'o" <tytso@mit.edu>, Willy Tarreau <w@1wt.eu>, Matthew Garrett <mjg59@srcf.ucam.org>, Vito Caputo <vcaputo@pengaru.com>, Andreas Dilger <adilger.kernel@dilger.ca>, Jan Kara <jack@suse.cz>, Ray Strode <rstrode@redhat.com>, William Jon McCann <mccann@jhu.edu>, zhangjs <zachary@baishancloud.com>, Andy Lutomirski <luto@kernel.org>, Florian Weimer <fweimer@redhat.com>, Lennart Poettering <mzxreary@0pointer.de>, "Peter, Matthias" <matthias.peter@bsi.bund.de>, Marcelo Henrique Cerri <marcelo.cerri@canonical.com>, Roman Drahtmueller <draht@schaltsekun.de>, Neil Horman <nhorman@redhat.com> Subject: Re: [PATCH v25 12/12] LRNG - add interface for gathering of raw entropy Date: Thu, 21 Nov 2019 16:18:18 +0100 [thread overview] Message-ID: <23500762.5LfuSYdpsK@positron.chronox.de> (raw) In-Reply-To: <87a78pl8xp.fsf@suse.de> Am Donnerstag, 21. November 2019, 13:18:10 CET schrieb Nicolai Stange: Hi Nicolai, > Hi Stephan, > > two general remarks on debugfs usage below > > Stephan Müller <smueller@chronox.de> writes: > > diff --git a/drivers/char/lrng/lrng_testing.c > > b/drivers/char/lrng/lrng_testing.c new file mode 100644 > > index 000000000000..5c33d3bd2172 > > --- /dev/null > > +++ b/drivers/char/lrng/lrng_testing.c > > <snip> > > > +/* > > + * This data structure holds the dentry's of the debugfs files > > establishing + * the interface to user space. > > + */ > > +struct lrng_raw_debugfs { > > + struct dentry *lrng_raw_debugfs_root; /* root dentry */ > > + struct dentry *lrng_raw_debugfs_lrng_raw; /* .../lrng_raw */ > > +}; > > + > > +static struct lrng_raw_debugfs lrng_raw_debugfs; > > + > > +/* DebugFS operations and definition of the debugfs files */ > > +static ssize_t lrng_raw_read(struct file *file, char __user *to, > > + size_t count, loff_t *ppos) > > +{ > > + loff_t pos = *ppos; > > + int ret; > > + > > + if (!count) > > + return 0; > > + lrng_raw_entropy_init(); > > + ret = lrng_raw_extract_user(to, count); > > + lrng_raw_entropy_fini(); > > + if (ret < 0) > > + return ret; > > + count -= ret; > > + *ppos = pos + count; > > + return ret; > > +} > > + > > +/* Module init: allocate memory, register the debugfs files */ > > +static int lrng_raw_debugfs_init(void) > > +{ > > + lrng_raw_debugfs.lrng_raw_debugfs_root = > > + debugfs_create_dir(KBUILD_MODNAME, NULL); > > + if (IS_ERR(lrng_raw_debugfs.lrng_raw_debugfs_root)) { > > + lrng_raw_debugfs.lrng_raw_debugfs_root = NULL; > > + return PTR_ERR(lrng_raw_debugfs.lrng_raw_debugfs_root); > > + } > > I think pointers returned by the debugfs API are not supposed to get > checked for NULL/IS_ERR(), c.f commit ff9fb72bc077 ("debugfs: return > error values, not NULL") or the the output from > > git log --pretty=oneline | grep 'no need to check return value of > debugfs_create' > > (Also the above code is dubious: you're effectively returning > PTR_ERR(NULL)). Removed the check compliant to the mentioned patches. > > > + return 0; > > +} > > + > > +static struct file_operations lrng_raw_name_fops = { > > + .owner = THIS_MODULE, > > + .read = lrng_raw_read, > > +}; > > + > > +static int lrng_raw_debugfs_init_name(void) > > +{ > > + lrng_raw_debugfs.lrng_raw_debugfs_lrng_raw = > > + debugfs_create_file("lrng_raw", 0400, > > + lrng_raw_debugfs.lrng_raw_debugfs_root, > > + NULL, &lrng_raw_name_fops);q > > CONFIG_LRNG_TESTING is a bool and thus, this debugfs file can't ever get > removed. Even if it could, this inode hasn't got any data associated > with it and so file removal would not be a problem for lrng_raw_read(). Correct. > > Please consider using debugfs_create_file_unsafe() instead to save > debugfs from kmalloc()ing a proxy file_operations protecting your fops > against concurrent file removal. Yes, you are correct. Changed. > > > + if (IS_ERR(lrng_raw_debugfs.lrng_raw_debugfs_lrng_raw)) { > > + lrng_raw_debugfs.lrng_raw_debugfs_lrng_raw = NULL; > > + return PTR_ERR(lrng_raw_debugfs.lrng_raw_debugfs_lrng_raw); > > + } > > Same comment regarding return value checking applies here. Same here: I removed the check. With that, I also removed the static variable to maintain the two dentries following the examples seen in other kernel code. Also, the __exit function is removed as we do not need it as you pointed out. Thanks a lot. > > Thanks, > > Nicolai > > > + return 0; > > +} > > + > > +static int __init lrng_raw_init(void) > > +{ > > + int ret = lrng_raw_debugfs_init(); > > + > > + if (ret < 0) > > + return ret; > > + > > + ret = lrng_raw_debugfs_init_name(); > > + if (ret < 0) > > + debugfs_remove_recursive( > > + lrng_raw_debugfs.lrng_raw_debugfs_root); > > + > > + return ret; > > +} > > + > > +static void __exit lrng_raw_exit(void) > > +{ > > + debugfs_remove_recursive(lrng_raw_debugfs.lrng_raw_debugfs_root); > > +} > > + > > +module_init(lrng_raw_init); > > +module_exit(lrng_raw_exit); > > + > > +MODULE_LICENSE("Dual BSD/GPL"); > > +MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); > > +MODULE_DESCRIPTION("Kernel module for gathering raw entropy"); Ciao Stephan
next prev parent reply other threads:[~2019-11-21 15:19 UTC|newest] Thread overview: 162+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-11 18:17 [PATCH v24 00/12] /dev/random - a new approach with full SP800-90B compliance Stephan Müller 2019-11-11 18:18 ` [PATCH v24 01/12] Linux Random Number Generator Stephan Müller 2019-11-11 23:54 ` Thomas Gleixner 2019-11-12 2:25 ` Stephan Müller 2019-11-12 10:16 ` Thomas Gleixner 2019-11-12 22:30 ` kbuild test robot 2019-11-12 23:15 ` Stephan Müller 2019-11-13 0:14 ` kbuild test robot 2019-11-13 0:25 ` Stephan Müller 2019-11-24 4:51 ` Sandy Harris 2019-11-24 9:02 ` Stephan Mueller 2019-11-11 18:19 ` [PATCH v24 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller 2019-11-11 18:20 ` [PATCH v24 03/12] LRNG - /proc interface Stephan Müller 2019-11-11 18:20 ` [PATCH v24 04/12] LRNG - add switchable DRNG support Stephan Müller 2019-11-11 18:21 ` [PATCH v24 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2019-11-11 18:21 ` [PATCH v24 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2019-11-11 18:22 ` [PATCH v24 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2019-11-11 18:23 ` [PATCH v24 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2019-11-11 18:23 ` [PATCH v24 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2019-11-11 18:24 ` [PATCH v24 10/12] LRNG - add TRNG support Stephan Müller 2019-11-11 18:26 ` [PATCH v24 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2019-11-12 19:58 ` Alexander E. Patrakov 2019-11-12 23:11 ` Stephan Müller 2019-11-13 0:36 ` Stephan Müller 2019-11-13 6:02 ` Alexander E. Patrakov 2019-11-14 1:46 ` Stephan Müller 2019-11-11 18:26 ` [PATCH v24 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2019-11-12 20:55 ` kbuild test robot 2019-11-12 23:13 ` Stephan Müller 2019-11-12 13:23 ` [PATCH v24 00/12] /dev/random - a new approach with full SP800-90B compliance Florian Weimer 2019-11-12 22:43 ` Stephan Müller 2019-11-12 15:33 ` Andy Lutomirski 2019-11-12 23:03 ` Stephan Müller 2019-11-12 23:26 ` Stephan Müller 2019-11-13 4:24 ` Stephan Müller 2019-11-13 4:48 ` Andy Lutomirski 2019-11-13 12:16 ` Stephan Müller 2019-11-16 9:32 ` [PATCH v25 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller 2019-11-16 9:33 ` [PATCH v25 01/12] Linux Random Number Generator Stephan Müller 2019-11-16 11:25 ` Thomas Gleixner 2019-11-17 10:30 ` Stephan Müller 2019-11-16 18:13 ` Nicolai Stange 2019-11-17 11:01 ` Stephan Müller 2019-11-16 9:33 ` [PATCH v25 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller 2019-11-16 9:34 ` [PATCH v25 03/12] LRNG - /proc interface Stephan Müller 2019-11-16 16:39 ` Andy Lutomirski 2019-11-17 12:16 ` Stephan Müller 2019-11-19 10:06 ` Andy Lutomirski 2019-11-19 10:55 ` Stephan Mueller 2019-11-19 17:40 ` Andy Lutomirski 2019-11-16 23:36 ` Eric W. Biederman 2019-11-17 11:37 ` Stephan Müller 2019-11-16 9:34 ` [PATCH v25 04/12] LRNG - add switchable DRNG support Stephan Müller 2019-11-16 9:35 ` [PATCH v25 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2019-11-16 9:35 ` [PATCH v25 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2019-11-16 9:35 ` [PATCH v25 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2019-11-16 9:36 ` [PATCH v25 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2019-11-16 9:36 ` [PATCH v25 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2019-11-20 13:33 ` Neil Horman 2019-11-20 20:07 ` Stephan Müller 2019-11-21 14:19 ` Neil Horman 2019-11-21 14:33 ` Stephan Mueller 2019-11-16 9:37 ` [PATCH v25 10/12] LRNG - add TRNG support Stephan Müller 2019-11-16 16:09 ` Andy Lutomirski 2019-11-17 11:10 ` Stephan Müller 2019-11-19 10:07 ` Andy Lutomirski 2019-11-19 10:46 ` Stephan Mueller 2019-11-19 12:41 ` Greg Kroah-Hartman 2019-11-20 8:58 ` Stephan Müller 2019-11-20 9:55 ` Alexander E. Patrakov 2019-11-20 13:29 ` Greg Kroah-Hartman 2019-11-20 19:51 ` Stephan Müller 2019-11-20 19:57 ` Alexander E. Patrakov 2019-11-20 20:32 ` Greg Kroah-Hartman 2019-11-21 13:06 ` Stephan Müller 2019-11-16 9:37 ` [PATCH v25 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2019-11-16 9:38 ` [PATCH v25 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2019-11-16 16:51 ` Andy Lutomirski 2019-11-17 22:55 ` Stephan Müller 2019-11-19 10:04 ` Andy Lutomirski 2019-11-19 17:17 ` Randy Dunlap 2019-11-20 9:01 ` Stephan Müller 2019-11-21 12:18 ` Nicolai Stange 2019-11-21 15:18 ` Stephan Müller [this message] 2019-11-23 20:08 ` [PATCH v26 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller 2019-11-23 20:10 ` [PATCH v26 01/12] Linux Random Number Generator Stephan Müller 2019-11-24 22:44 ` kbuild test robot 2019-11-25 6:29 ` Stephan Mueller 2019-11-23 20:10 ` [PATCH v26 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller 2019-11-23 20:11 ` [PATCH v26 03/12] LRNG - sysctls and /proc interface Stephan Müller 2019-11-23 20:11 ` [PATCH v26 04/12] LRNG - add switchable DRNG support Stephan Müller 2019-11-23 20:31 ` [PATCH v26 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2019-11-23 20:32 ` [PATCH v26 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2019-11-23 20:32 ` [PATCH v26 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2019-11-23 20:33 ` [PATCH v26 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2019-11-23 20:34 ` [PATCH v26 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2019-11-23 20:34 ` [PATCH v26 10/12] LRNG - add TRNG support Stephan Müller 2019-11-23 20:34 ` [PATCH v26 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2019-11-23 20:35 ` [PATCH v26 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2020-01-09 8:29 ` [PATCH v27 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller 2020-01-09 8:30 ` [PATCH v27 01/12] Linux Random Number Generator Stephan Müller 2020-01-16 6:09 ` kbuild test robot 2020-01-16 6:41 ` Stephan Mueller 2020-01-09 8:31 ` [PATCH v27 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller 2020-01-09 8:31 ` [PATCH v27 03/12] LRNG - sysctls and /proc interface Stephan Müller 2020-01-09 8:32 ` [PATCH v27 04/12] LRNG - add switchable DRNG support Stephan Müller 2020-01-11 7:09 ` kbuild test robot 2020-01-12 10:12 ` Stephan Müller 2020-01-09 8:32 ` [PATCH v27 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2020-01-09 8:32 ` [PATCH v27 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2020-01-09 8:33 ` [PATCH v27 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2020-01-09 8:33 ` [PATCH v27 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2020-01-09 8:34 ` [PATCH v27 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2020-01-10 0:24 ` Randy Dunlap 2020-01-10 7:45 ` Stephan Mueller 2020-01-09 8:34 ` [PATCH v27 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2020-01-10 0:20 ` Randy Dunlap 2020-01-10 8:27 ` Stephan Mueller 2020-01-09 8:35 ` [PATCH v27 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2020-01-09 8:35 ` [PATCH v27 12/12] LRNG - add power-on and runtime self-tests Stephan Müller 2020-01-10 0:22 ` Randy Dunlap 2020-01-10 7:48 ` Stephan Mueller 2020-01-13 10:39 ` Dan Carpenter 2020-01-13 10:46 ` Stephan Mueller 2020-01-15 10:31 ` [PATCH v28 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller 2020-01-15 10:31 ` [PATCH v28 01/12] Linux Random Number Generator Stephan Müller 2020-01-16 0:11 ` Randy Dunlap 2020-01-16 7:22 ` Stephan Mueller 2020-01-15 10:32 ` [PATCH v28 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller 2020-01-15 10:32 ` [PATCH v28 03/12] LRNG - sysctls and /proc interface Stephan Müller 2020-01-15 10:32 ` [PATCH v28 04/12] LRNG - add switchable DRNG support Stephan Müller 2020-01-15 10:33 ` [PATCH v28 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2020-01-15 10:33 ` [PATCH v28 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2020-01-16 0:14 ` Randy Dunlap 2020-01-16 6:55 ` Stephan Mueller 2020-01-15 10:34 ` [PATCH v28 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2020-01-16 0:15 ` Randy Dunlap 2020-01-16 6:54 ` Stephan Mueller 2020-01-15 10:34 ` [PATCH v28 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2020-01-15 10:34 ` [PATCH v28 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2020-01-16 0:17 ` Randy Dunlap 2020-01-16 6:51 ` Stephan Mueller 2020-01-15 10:35 ` [PATCH v28 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2020-01-15 10:35 ` [PATCH v28 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2020-01-16 0:18 ` Randy Dunlap 2020-01-16 6:43 ` Stephan Mueller 2020-01-16 6:48 ` Randy Dunlap 2020-01-16 6:52 ` Stephan Mueller 2020-01-15 10:36 ` [PATCH v28 12/12] LRNG - add power-on and runtime self-tests Stephan Müller 2020-01-19 21:12 ` [PATCH v29 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller 2020-01-19 21:13 ` [PATCH v29 01/12] Linux Random Number Generator Stephan Müller 2020-01-19 21:13 ` [PATCH v29 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller 2020-01-19 21:14 ` [PATCH v29 03/12] LRNG - sysctls and /proc interface Stephan Müller 2020-01-19 21:14 ` [PATCH v29 04/12] LRNG - add switchable DRNG support Stephan Müller 2020-01-19 21:15 ` [PATCH v29 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller 2020-01-19 21:16 ` [PATCH v29 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller 2020-01-19 21:16 ` [PATCH v29 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller 2020-01-19 21:17 ` [PATCH v29 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller 2020-01-19 21:18 ` [PATCH v29 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller 2020-01-19 21:18 ` [PATCH v29 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller 2020-01-19 21:19 ` [PATCH v29 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller 2020-01-19 21:20 ` [PATCH v29 12/12] LRNG - add power-on and runtime self-tests Stephan Müller
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