From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261285AbVGDQBu (ORCPT ); Mon, 4 Jul 2005 12:01:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261409AbVGDQBt (ORCPT ); Mon, 4 Jul 2005 12:01:49 -0400 Received: from ms-smtp-05.texas.rr.com ([24.93.47.44]:58285 "EHLO ms-smtp-05-eri0.texas.rr.com") by vger.kernel.org with ESMTP id S261285AbVGDPxo (ORCPT ); Mon, 4 Jul 2005 11:53:44 -0400 Date: Mon, 4 Jul 2005 10:53:21 -0500 From: serge@hallyn.com To: Greg KH Cc: James Morris , Tony Jones , lkml , Chris Wright , Stephen Smalley , Andrew Morton , Michael Halcrow , David Safford , Reiner Sailer , Gerrit Huizenga Subject: Re: [PATCH] securityfs Message-ID: <20050704155321.GA25153@vino.hallyn.com> References: <20050703182505.GA29491@immunix.com> <20050703204423.GA17418@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050703204423.GA17418@kroah.com> User-Agent: Mutt/1.5.8i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting Greg KH (greg@kroah.com): > On Sun, Jul 03, 2005 at 02:53:17PM -0400, James Morris wrote: > > On Sun, 3 Jul 2005, Tony Jones wrote: > > > > > There just isn't enough content to justify a stacker specific filesystem IMHO. > > > > It might be worth thinking about a more general securityfs as part of LSM, > > to be used by stacker and LSM modules. SELinux could use this instead of > > managing its own selinuxfs. > > Good idea. Here's a patch to do just that (compile tested only...) > > Comments? Tested without a hitch. In addition, the attached patch converts seclvl to use the securityfs. Also tested without any problems. (Only meant as proof of concept: Mike, you'll probably want to at least add the passwd_read_file function back in, I assume?) thanks, -serge -- seclvl.c | 226 +++++++++++++++++++++++++++------------------------------------ 1 files changed, 99 insertions(+), 127 deletions(-) Signed-off-by: Serge Hallyn Index: linux-2.6.13-rc1/security/seclvl.c =================================================================== --- linux-2.6.13-rc1.orig/security/seclvl.c 2005-07-02 21:49:34.000000000 -0500 +++ linux-2.6.13-rc1/security/seclvl.c 2005-07-04 07:58:15.000000000 -0500 @@ -119,69 +119,6 @@ } while (0) /** - * kobject stuff - */ - -struct subsystem seclvl_subsys; - -struct seclvl_obj { - char *name; - struct list_head slot_list; - struct kobject kobj; -}; - -/** - * There is a seclvl_attribute struct for each file in sysfs. - * - * In our case, we have one of these structs for "passwd" and another - * for "seclvl". - */ -struct seclvl_attribute { - struct attribute attr; - ssize_t(*show) (struct seclvl_obj *, char *); - ssize_t(*store) (struct seclvl_obj *, const char *, size_t); -}; - -/** - * When this function is called, one of the files in sysfs is being - * written to. attribute->store is a function pointer to whatever the - * struct seclvl_attribute store function pointer points to. It is - * unique for "passwd" and "seclvl". - */ -static ssize_t -seclvl_attr_store(struct kobject *kobj, - struct attribute *attr, const char *buf, size_t len) -{ - struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj); - struct seclvl_attribute *attribute = - container_of(attr, struct seclvl_attribute, attr); - return attribute->store ? attribute->store(obj, buf, len) : -EIO; -} - -static ssize_t -seclvl_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) -{ - struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj); - struct seclvl_attribute *attribute = - container_of(attr, struct seclvl_attribute, attr); - return attribute->show ? attribute->show(obj, buf) : -EIO; -} - -/** - * Callback function pointers for show and store - */ -static struct sysfs_ops seclvlfs_sysfs_ops = { - .show = seclvl_attr_show, - .store = seclvl_attr_store, -}; - -static struct kobj_type seclvl_ktype = { - .sysfs_ops = &seclvlfs_sysfs_ops -}; - -decl_subsys(seclvl, &seclvl_ktype, NULL); - -/** * The actual security level. Ranges between -1 and 2 inclusive. */ static int seclvl; @@ -216,9 +153,15 @@ * Called whenever the user reads the sysfs handle to this kernel * object */ -static ssize_t seclvl_read_file(struct seclvl_obj *obj, char *buff) +#define TMPBUFLEN 12 +static ssize_t seclvl_read_file(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) { - return snprintf(buff, PAGE_SIZE, "%d\n", seclvl); + char tmpbuf[TMPBUFLEN]; + ssize_t length; + + length = scnprintf(tmpbuf, TMPBUFLEN, "%d", seclvl); + return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); } /** @@ -253,57 +196,58 @@ * object (seclvl/seclvl). It expects a single-digit number. */ static ssize_t -seclvl_write_file(struct seclvl_obj *obj, const char *buff, size_t count) +seclvl_write_file(struct file * file, const char __user * buf, + size_t count, loff_t *ppos) { - unsigned long val; - if (count > 2 || (count == 2 && buff[1] != '\n')) { - seclvl_printk(1, KERN_WARNING, "Invalid value passed to " - "seclvl: [%s]\n", buff); + int val; + int err; + char *page; + + if (count > 2) return -EINVAL; + if (*ppos != 0) + return -EINVAL; + + page = (char *) get_zeroed_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + if (copy_from_user(page, buf, count)) { + err = -EFAULT; + goto out; + } + + if (sscanf(page, "%d", &val) != 1) { + err = -EINVAL; + goto out; } - val = buff[0] - 48; + if (seclvl_sanity(val)) { seclvl_printk(1, KERN_WARNING, "Illegal secure level " "requested: [%d]\n", (int)val); - return -EPERM; + err = -EINVAL; + goto out; } + err = count; if (do_seclvl_advance(val)) { seclvl_printk(0, KERN_ERR, "Failure advancing security level " - "to %lu\n", val); + "to %d\n", val); + err = -EINVAL; } - return count; + +out: + free_page((unsigned long)page); + return err; } -/* Generate sysfs_attr_seclvl */ -static struct seclvl_attribute sysfs_attr_seclvl = -__ATTR(seclvl, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_file, - seclvl_write_file); +static struct file_operations seclvl_file_ops = { + .read = seclvl_read_file, + .write = seclvl_write_file, +}; static unsigned char hashedPassword[SHA1_DIGEST_SIZE]; /** - * Called whenever the user reads the sysfs passwd handle. - */ -static ssize_t seclvl_read_passwd(struct seclvl_obj *obj, char *buff) -{ - /* So just how good *is* your password? :-) */ - char tmp[3]; - int i = 0; - buff[0] = '\0'; - if (hideHash) { - /* Security through obscurity */ - return 0; - } - while (i < SHA1_DIGEST_SIZE) { - snprintf(tmp, 3, "%02x", hashedPassword[i]); - strncat(buff, tmp, 2); - i++; - } - strcat(buff, "\n"); - return ((SHA1_DIGEST_SIZE * 2) + 1); -} - -/** * Converts a block of plaintext of into its SHA1 hashed value. * * It would be nice if crypto had a wrapper to do this for us linear @@ -347,12 +291,15 @@ * object. It hashes the password and compares the hashed results. */ static ssize_t -seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count) +passwd_write_file(struct file * file, const char __user * buf, + size_t count, loff_t *ppos) { int i; unsigned char tmp[SHA1_DIGEST_SIZE]; + char *page; int rc; int len; + if (!*passwd && !*sha1_passwd) { seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the " "seclvl module, but neither a plain text " @@ -363,13 +310,26 @@ "maintainer about this event.\n"); return -EINVAL; } - len = strlen(buff); + + if (count < 0 || count >= PAGE_SIZE) + return -ENOMEM; + if (*ppos != 0) { + return -EINVAL; + } + page = (char *)get_zeroed_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + len = -EFAULT; + if (copy_from_user(page, buf, count)) + goto out; + + len = strlen(page); /* ``echo "secret" > seclvl/passwd'' includes a newline */ - if (buff[len - 1] == '\n') { + if (page[len - 1] == '\n') { len--; } /* Hash the password, then compare the hashed values */ - if ((rc = plaintext_to_sha1(tmp, buff, len))) { + if ((rc = plaintext_to_sha1(tmp, page, len))) { seclvl_printk(0, KERN_ERR, "Error hashing password: rc = " "[%d]\n", rc); return rc; @@ -382,13 +342,16 @@ seclvl_printk(0, KERN_INFO, "Password accepted; seclvl reduced to 0.\n"); seclvl = 0; - return count; + len = count; + +out: + free_page((unsigned long)page); + return len; } -/* Generate sysfs_attr_passwd */ -static struct seclvl_attribute sysfs_attr_passwd = -__ATTR(passwd, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_passwd, - seclvl_write_passwd); +static struct file_operations passwd_file_ops = { + .write = passwd_write_file, +}; /** * Explicitely disallow ptrace'ing the init process. @@ -647,22 +610,34 @@ } /** - * Sysfs registrations + * securityfs registrations */ -static int doSysfsRegistrations(void) +struct dentry *dir_ino, *seclvl_ino, *passwd_ino; + +static int seclvlfs_register(void) { - int rc = 0; - if ((rc = subsystem_register(&seclvl_subsys))) { - seclvl_printk(0, KERN_WARNING, - "Error [%d] registering seclvl subsystem\n", rc); - return rc; - } - sysfs_create_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr); + dir_ino = securityfs_create_dir("seclvl", NULL); + if (!dir_ino) + return -EFAULT; + + seclvl_ino = securityfs_create_file("seclvl", S_IRUGO | S_IWUSR, + dir_ino, NULL, &seclvl_file_ops); + if (!seclvl_ino) + goto out_deldir; if (*passwd || *sha1_passwd) { - sysfs_create_file(&seclvl_subsys.kset.kobj, - &sysfs_attr_passwd.attr); + passwd_ino = securityfs_create_file("passwd", S_IRUGO | S_IWUSR, + dir_ino, NULL, &passwd_file_ops); + if (!passwd_ino) + goto out_delf; } return 0; + +out_deldir: + securityfs_remove(dir_ino); +out_delf: + securityfs_remove(seclvl_ino); + + return -EFAULT; } /** @@ -677,8 +652,6 @@ rc = -EINVAL; goto exit; } - sysfs_attr_seclvl.attr.owner = THIS_MODULE; - sysfs_attr_passwd.attr.owner = THIS_MODULE; if (initlvl < -1 || initlvl > 2) { seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel " "[%d].\n", initlvl); @@ -706,7 +679,7 @@ } /* if primary module registered */ secondary = 1; } /* if we registered ourselves with the security framework */ - if ((rc = doSysfsRegistrations())) { + if ((rc = seclvlfs_register())) { seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n"); goto exit; } @@ -724,12 +697,11 @@ */ static void __exit seclvl_exit(void) { - sysfs_remove_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr); + securityfs_remove(seclvl_ino); if (*passwd || *sha1_passwd) { - sysfs_remove_file(&seclvl_subsys.kset.kobj, - &sysfs_attr_passwd.attr); + securityfs_remove(passwd_ino); } - subsystem_unregister(&seclvl_subsys); + securityfs_remove(dir_ino); if (secondary == 1) { mod_unreg_security(MY_NAME, &seclvl_ops); } else if (unregister_security(&seclvl_ops)) {