diff options
| -rw-r--r-- | include/linux/security.h | 5 | ||||
| -rw-r--r-- | security/Kconfig | 1 | ||||
| -rw-r--r-- | security/Makefile | 2 | ||||
| -rw-r--r-- | security/inode.c | 347 | ||||
| -rw-r--r-- | security/seclvl.c | 228 |
5 files changed, 424 insertions, 159 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index 55b02e1..0e43460 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1907,6 +1907,11 @@ extern int register_security (struct security_operations *ops); extern int unregister_security (struct security_operations *ops); extern int mod_reg_security (const char *name, struct security_operations *ops); extern int mod_unreg_security (const char *name, struct security_operations *ops); +extern struct dentry *securityfs_create_file(const char *name, mode_t mode, + struct dentry *parent, void *data, + struct file_operations *fops); +extern struct dentry *securityfs_create_dir(const char *name, struct dentry *parent); +extern void securityfs_remove(struct dentry *dentry); #else /* CONFIG_SECURITY */ diff --git a/security/Kconfig b/security/Kconfig index dcf04a0..64d3f1e 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -35,6 +35,7 @@ config KEYS_DEBUG_PROC_KEYS config SECURITY bool "Enable different security models" + depends on SYSFS help This allows you to choose different security modules to be configured into your kernel. diff --git a/security/Makefile b/security/Makefile index 197cc2f..8cbbf2f 100644 --- a/security/Makefile +++ b/security/Makefile @@ -11,7 +11,7 @@ obj-y += commoncap.o endif # Object file lists -obj-$(CONFIG_SECURITY) += security.o dummy.o +obj-$(CONFIG_SECURITY) += security.o dummy.o inode.o # Must precede capability.o in order to stack properly. obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o obj-$(CONFIG_SECURITY_CAPABILITIES) += commoncap.o capability.o diff --git a/security/inode.c b/security/inode.c new file mode 100644 index 0000000..a596450 --- /dev/null +++ b/security/inode.c @@ -0,0 +1,347 @@ +/* + * inode.c - securityfs + * + * Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * Based on fs/debugfs/inode.c which had the following copyright notice: + * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2004 IBM Inc. + */ + +/* #define DEBUG */ +#include <linux/config.h> +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/pagemap.h> +#include <linux/init.h> +#include <linux/namei.h> +#include <linux/security.h> + +#define SECURITYFS_MAGIC 0x73636673 + +static struct vfsmount *mount; +static int mount_count; + +/* + * TODO: + * I think I can get rid of these default_file_ops, but not quite sure... + */ +static ssize_t default_read_file(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + return 0; +} + +static ssize_t default_write_file(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + return count; +} + +static int default_open(struct inode *inode, struct file *file) +{ + if (inode->u.generic_ip) + file->private_data = inode->u.generic_ip; + + return 0; +} + +static struct file_operations default_file_ops = { + .read = default_read_file, + .write = default_write_file, + .open = default_open, +}; + +static struct inode *get_inode(struct super_block *sb, int mode, dev_t dev) +{ + struct inode *inode = new_inode(sb); + + if (inode) { + inode->i_mode = mode; + inode->i_uid = 0; + inode->i_gid = 0; + inode->i_blksize = PAGE_CACHE_SIZE; + inode->i_blocks = 0; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + switch (mode & S_IFMT) { + default: + init_special_inode(inode, mode, dev); + break; + case S_IFREG: + inode->i_fop = &default_file_ops; + break; + case S_IFDIR: + inode->i_op = &simple_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + break; + } + } + return inode; +} + +/* SMP-safe */ +static int mknod(struct inode *dir, struct dentry *dentry, + int mode, dev_t dev) +{ + struct inode *inode; + int error = -EPERM; + + if (dentry->d_inode) + return -EEXIST; + + inode = get_inode(dir->i_sb, mode, dev); + if (inode) { + d_instantiate(dentry, inode); + dget(dentry); + error = 0; + } + return error; +} + +static int mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + int res; + + mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; + res = mknod(dir, dentry, mode, 0); + if (!res) + dir->i_nlink++; + return res; +} + +static int create(struct inode *dir, struct dentry *dentry, int mode) +{ + mode = (mode & S_IALLUGO) | S_IFREG; + return mknod(dir, dentry, mode, 0); +} + +static inline int positive(struct dentry *dentry) +{ + return dentry->d_inode && !d_unhashed(dentry); +} + +static int fill_super(struct super_block *sb, void *data, int silent) +{ + static struct tree_descr files[] = {{""}}; + + return simple_fill_super(sb, SECURITYFS_MAGIC, files); +} + +static struct super_block *get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + return get_sb_single(fs_type, flags, data, fill_super); +} + +static struct file_system_type fs_type = { + .owner = THIS_MODULE, + .name = "securityfs", + .get_sb = get_sb, + .kill_sb = kill_litter_super, +}; + +static int create_by_name(const char *name, mode_t mode, + struct dentry *parent, + struct dentry **dentry) +{ + int error = 0; + + *dentry = NULL; + + /* If the parent is not specified, we create it in the root. + * We need the root dentry to do this, which is in the super + * block. A pointer to that is in the struct vfsmount that we + * have around. + */ + if (!parent ) { + if (mount && mount->mnt_sb) { + parent = mount->mnt_sb->s_root; + } + } + if (!parent) { + pr_debug("securityfs: Ah! can not find a parent!\n"); + return -EFAULT; + } + + down(&parent->d_inode->i_sem); + *dentry = lookup_one_len(name, parent, strlen(name)); + if (!IS_ERR(dentry)) { + if ((mode & S_IFMT) == S_IFDIR) + error = mkdir(parent->d_inode, *dentry, mode); + else + error = create(parent->d_inode, *dentry, mode); + } else + error = PTR_ERR(dentry); + up(&parent->d_inode->i_sem); + + return error; +} + +/** + * securityfs_create_file - create a file in the securityfs filesystem + * + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this paramater is NULL, then the + * file will be created in the root of the securityfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.u.generic_ip pointer will point to this value on + * the open() call. + * @fops: a pointer to a struct file_operations that should be used for + * this file. + * + * This is the basic "create a file" function for securityfs. It allows for a + * wide range of flexibility in createing a file, or a directory (if you + * want to create a directory, the securityfs_create_dir() function is + * recommended to be used instead.) + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the securityfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, NULL will be returned. + * + * If securityfs is not enabled in the kernel, the value -ENODEV will be + * returned. It is not wise to check for this value, but rather, check for + * NULL or !NULL instead as to eliminate the need for #ifdef in the calling + * code. + */ +struct dentry *securityfs_create_file(const char *name, mode_t mode, + struct dentry *parent, void *data, + struct file_operations *fops) +{ + struct dentry *dentry = NULL; + int error; + + pr_debug("securityfs: creating file '%s'\n",name); + + error = simple_pin_fs("securityfs", &mount, &mount_count); + if (error) { + dentry = ERR_PTR(error); + goto exit; + } + + error = create_by_name(name, mode, parent, &dentry); + if (error) { + dentry = ERR_PTR(error); + simple_release_fs(&mount, &mount_count); + goto exit; + } + + if (dentry->d_inode) { + if (fops) + dentry->d_inode->i_fop = fops; + if (data) + dentry->d_inode->u.generic_ip = data; + } +exit: + return dentry; +} +EXPORT_SYMBOL_GPL(securityfs_create_file); + +/** + * securityfs_create_dir - create a directory in the securityfs filesystem + * + * @name: a pointer to a string containing the name of the directory to + * create. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this paramater is NULL, then the + * directory will be created in the root of the securityfs filesystem. + * + * This function creates a directory in securityfs with the given name. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the securityfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, NULL will be returned. + * + * If securityfs is not enabled in the kernel, the value -ENODEV will be + * returned. It is not wise to check for this value, but rather, check for + * NULL or !NULL instead as to eliminate the need for #ifdef in the calling + * code. + */ +struct dentry *securityfs_create_dir(const char *name, struct dentry *parent) +{ + return securityfs_create_file(name, + S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, + parent, NULL, NULL); +} +EXPORT_SYMBOL_GPL(securityfs_create_dir); + +/** + * securityfs_remove - removes a file or directory from the securityfs filesystem + * + * @dentry: a pointer to a the dentry of the file or directory to be + * removed. + * + * This function removes a file or directory in securityfs that was previously + * created with a call to another securityfs function (like + * securityfs_create_file() or variants thereof.) + * + * This function is required to be called in order for the file to be + * removed, no automatic cleanup of files will happen when a module is + * removed, you are responsible here. + */ +void securityfs_remove(struct dentry *dentry) +{ + struct dentry *parent; + + if (!dentry) + return; + + parent = dentry->d_parent; + if (!parent || !parent->d_inode) + return; + + down(&parent->d_inode->i_sem); + if (positive(dentry)) { + if (dentry->d_inode) { + if (S_ISDIR(dentry->d_inode->i_mode)) + simple_rmdir(parent->d_inode, dentry); + else + simple_unlink(parent->d_inode, dentry); + dput(dentry); + } + } + up(&parent->d_inode->i_sem); + simple_release_fs(&mount, &mount_count); +} +EXPORT_SYMBOL_GPL(securityfs_remove); + +static decl_subsys(security, NULL, NULL); + +static int __init securityfs_init(void) +{ + int retval; + + kset_set_kset_s(&security_subsys, kernel_subsys); + retval = subsystem_register(&security_subsys); + if (retval) + return retval; + + retval = register_filesystem(&fs_type); + if (retval) + subsystem_unregister(&security_subsys); + return retval; +} + +static void __exit securityfs_exit(void) +{ + simple_release_fs(&mount, &mount_count); + unregister_filesystem(&fs_type); + subsystem_unregister(&security_subsys); +} + +core_initcall(securityfs_init); +module_exit(securityfs_exit); +MODULE_LICENSE("GPL"); + diff --git a/security/seclvl.c b/security/seclvl.c index 96b1f21..dc4e17b 100644 --- a/security/seclvl.c +++ b/security/seclvl.c @@ -119,69 +119,6 @@ MODULE_PARM_DESC(hideHash, "When set to 0, reading seclvl/passwd from sysfs " } 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; @@ -213,97 +150,44 @@ static int seclvl_sanity(int reqlvl) } /** - * Called whenever the user reads the sysfs handle to this kernel - * object - */ -static ssize_t seclvl_read_file(struct seclvl_obj *obj, char *buff) -{ - return snprintf(buff, PAGE_SIZE, "%d\n", seclvl); -} - -/** * security level advancement rules: * Valid levels are -1 through 2, inclusive. * From -1, stuck. [ in case compiled into kernel ] * From 0 or above, can only increment. */ -static int do_seclvl_advance(int newlvl) +static void do_seclvl_advance(void *data, u64 val) { - if (newlvl <= seclvl) { - seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl " - "[%d]\n", newlvl); - return -EINVAL; - } + int ret; + int newlvl = (int)val; + + ret = seclvl_sanity(newlvl); + if (ret) + return; + if (newlvl > 2) { seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl " "[%d]\n", newlvl); - return -EINVAL; + return; } if (seclvl == -1) { seclvl_printk(1, KERN_WARNING, "Not allowed to advance to " "seclvl [%d]\n", seclvl); - return -EPERM; + return; } - seclvl = newlvl; - return 0; + seclvl = newlvl; /* would it be more "correct" to set *data? */ + return; } -/** - * Called whenever the user writes to the sysfs handle to this kernel - * 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) +static u64 seclvl_int_get(void *data) { - unsigned long val; - if (count > 2 || (count == 2 && buff[1] != '\n')) { - seclvl_printk(1, KERN_WARNING, "Invalid value passed to " - "seclvl: [%s]\n", buff); - return -EINVAL; - } - val = buff[0] - 48; - if (seclvl_sanity(val)) { - seclvl_printk(1, KERN_WARNING, "Illegal secure level " - "requested: [%d]\n", (int)val); - return -EPERM; - } - if (do_seclvl_advance(val)) { - seclvl_printk(0, KERN_ERR, "Failure advancing security level " - "to %lu\n", val); - } - return count; + return *(int *)data; } -/* 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); +DEFINE_SIMPLE_ATTRIBUTE(seclvl_file_ops, seclvl_int_get, do_seclvl_advance, "%lld\n"); 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 +231,15 @@ plaintext_to_sha1(unsigned char *hash, const char *plaintext, int len) * 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 +250,26 @@ seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count) "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 +282,16 @@ seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count) 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 +550,34 @@ static int processPassword(void) } /** - * 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, &seclvl, &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 +592,6 @@ static int __init seclvl_init(void) 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 +619,7 @@ static int __init seclvl_init(void) } /* 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 +637,11 @@ static int __init seclvl_init(void) */ 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)) { |
