From e47c8fc582a2c9f3cba059e543c4a056cd6bf8c4 Mon Sep 17 00:00:00 2001 From: "Christopher J. PeBenito" Date: Wed, 23 May 2007 09:12:09 -0400 Subject: [PATCH] selinux: add selinuxfs structure for object class discovery The structure is as follows (relative to selinuxfs root): /class/file/index /class/file/perms/read /class/file/perms/write ... Each class is allocated 33 inodes, 1 for the class index and 32 for permissions. Relative to SEL_CLASS_INO_OFFSET, the inode of the index file DIV 33 is the class number. The inode of the permission file % 33 is the index of the permission for that class. Signed-off-by: Christopher J. PeBenito Signed-off-by: James Morris --- security/selinux/include/security.h | 1 + security/selinux/selinuxfs.c | 249 ++++++++++++++++++++++++++++ 2 files changed, 250 insertions(+) diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 731a173f5a5f..83bdd4d2a29e 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -41,6 +41,7 @@ extern int selinux_mls_enabled; int security_load_policy(void * data, size_t len); +#define SEL_VEC_MAX 32 struct av_decision { u32 allowed; u32 decided; diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index cf1acde778de..c9e92daedee2 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -67,6 +67,10 @@ static struct dentry *bool_dir = NULL; static int bool_num = 0; static int *bool_pending_values = NULL; +/* global data for classes */ +static struct dentry *class_dir = NULL; +static unsigned long last_class_ino; + extern void selnl_notify_setenforce(int val); /* Check whether a task is allowed to use a security operation. */ @@ -106,6 +110,7 @@ static unsigned long sel_last_ino = SEL_INO_NEXT - 1; #define SEL_INITCON_INO_OFFSET 0x01000000 #define SEL_BOOL_INO_OFFSET 0x02000000 +#define SEL_CLASS_INO_OFFSET 0x04000000 #define SEL_INO_MASK 0x00ffffff #define TMPBUFLEN 12 @@ -237,6 +242,11 @@ static const struct file_operations sel_policyvers_ops = { /* declaration for sel_write_load */ static int sel_make_bools(void); +static int sel_make_classes(void); + +/* declaration for sel_make_class_dirs */ +static int sel_make_dir(struct inode *dir, struct dentry *dentry, + unsigned long *ino); static ssize_t sel_read_mls(struct file *filp, char __user *buf, size_t count, loff_t *ppos) @@ -287,10 +297,18 @@ static ssize_t sel_write_load(struct file * file, const char __user * buf, goto out; ret = sel_make_bools(); + if (ret) { + length = ret; + goto out1; + } + + ret = sel_make_classes(); if (ret) length = ret; else length = count; + +out1: audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD, "policy loaded auid=%u", audit_get_loginuid(current->audit_context)); @@ -1293,6 +1311,225 @@ static int sel_make_initcon_files(struct dentry *dir) return ret; } +static inline unsigned int sel_div(unsigned long a, unsigned long b) +{ + return a / b - (a % b < 0); +} + +static inline unsigned long sel_class_to_ino(u16 class) +{ + return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET; +} + +static inline u16 sel_ino_to_class(unsigned long ino) +{ + return sel_div(ino & SEL_INO_MASK, SEL_VEC_MAX + 1); +} + +static inline unsigned long sel_perm_to_ino(u16 class, u32 perm) +{ + return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET; +} + +static inline u32 sel_ino_to_perm(unsigned long ino) +{ + return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1); +} + +static ssize_t sel_read_class(struct file * file, char __user *buf, + size_t count, loff_t *ppos) +{ + ssize_t rc, len; + char *page; + unsigned long ino = file->f_path.dentry->d_inode->i_ino; + + page = (char *)__get_free_page(GFP_KERNEL); + if (!page) { + rc = -ENOMEM; + goto out; + } + + len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino)); + rc = simple_read_from_buffer(buf, count, ppos, page, len); + free_page((unsigned long)page); +out: + return rc; +} + +static const struct file_operations sel_class_ops = { + .read = sel_read_class, +}; + +static ssize_t sel_read_perm(struct file * file, char __user *buf, + size_t count, loff_t *ppos) +{ + ssize_t rc, len; + char *page; + unsigned long ino = file->f_path.dentry->d_inode->i_ino; + + page = (char *)__get_free_page(GFP_KERNEL); + if (!page) { + rc = -ENOMEM; + goto out; + } + + len = snprintf(page, PAGE_SIZE,"%d", sel_ino_to_perm(ino)); + rc = simple_read_from_buffer(buf, count, ppos, page, len); + free_page((unsigned long)page); +out: + return rc; +} + +static const struct file_operations sel_perm_ops = { + .read = sel_read_perm, +}; + +static int sel_make_perm_files(char *objclass, int classvalue, + struct dentry *dir) +{ + int i, rc = 0, nperms; + char **perms; + + rc = security_get_permissions(objclass, &perms, &nperms); + if (rc) + goto out; + + for (i = 0; i < nperms; i++) { + struct inode *inode; + struct dentry *dentry; + + dentry = d_alloc_name(dir, perms[i]); + if (!dentry) { + rc = -ENOMEM; + goto out1; + } + + inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO); + if (!inode) { + rc = -ENOMEM; + goto out1; + } + inode->i_fop = &sel_perm_ops; + /* i+1 since perm values are 1-indexed */ + inode->i_ino = sel_perm_to_ino(classvalue, i+1); + d_add(dentry, inode); + } + +out1: + for (i = 0; i < nperms; i++) + kfree(perms[i]); + kfree(perms); +out: + return rc; +} + +static int sel_make_class_dir_entries(char *classname, int index, + struct dentry *dir) +{ + struct dentry *dentry = NULL; + struct inode *inode = NULL; + int rc; + + dentry = d_alloc_name(dir, "index"); + if (!dentry) { + rc = -ENOMEM; + goto out; + } + + inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO); + if (!inode) { + rc = -ENOMEM; + goto out; + } + + inode->i_fop = &sel_class_ops; + inode->i_ino = sel_class_to_ino(index); + d_add(dentry, inode); + + dentry = d_alloc_name(dir, "perms"); + if (!dentry) { + rc = -ENOMEM; + goto out; + } + + rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino); + if (rc) + goto out; + + rc = sel_make_perm_files(classname, index, dentry); + +out: + return rc; +} + +static void sel_remove_classes(void) +{ + struct list_head *class_node; + + list_for_each(class_node, &class_dir->d_subdirs) { + struct dentry *class_subdir = list_entry(class_node, + struct dentry, d_u.d_child); + struct list_head *class_subdir_node; + + list_for_each(class_subdir_node, &class_subdir->d_subdirs) { + struct dentry *d = list_entry(class_subdir_node, + struct dentry, d_u.d_child); + + if (d->d_inode) + if (d->d_inode->i_mode & S_IFDIR) + sel_remove_entries(d); + } + + sel_remove_entries(class_subdir); + } + + sel_remove_entries(class_dir); +} + +static int sel_make_classes(void) +{ + int rc = 0, nclasses, i; + char **classes; + + /* delete any existing entries */ + sel_remove_classes(); + + rc = security_get_classes(&classes, &nclasses); + if (rc < 0) + goto out; + + /* +2 since classes are 1-indexed */ + last_class_ino = sel_class_to_ino(nclasses+2); + + for (i = 0; i < nclasses; i++) { + struct dentry *class_name_dir; + + class_name_dir = d_alloc_name(class_dir, classes[i]); + if (!class_name_dir) { + rc = -ENOMEM; + goto out1; + } + + rc = sel_make_dir(class_dir->d_inode, class_name_dir, + &last_class_ino); + if (rc) + goto out1; + + /* i+1 since class values are 1-indexed */ + rc = sel_make_class_dir_entries(classes[i], i+1, + class_name_dir); + if (rc) + goto out1; + } + +out1: + for (i = 0; i < nclasses; i++) + kfree(classes[i]); + kfree(classes); +out: + return rc; +} + static int sel_make_dir(struct inode *dir, struct dentry *dentry, unsigned long *ino) { @@ -1407,6 +1644,18 @@ static int sel_fill_super(struct super_block * sb, void * data, int silent) if (ret) goto err; + dentry = d_alloc_name(sb->s_root, "class"); + if (!dentry) { + ret = -ENOMEM; + goto err; + } + + ret = sel_make_dir(root_inode, dentry, &sel_last_ino); + if (ret) + goto err; + + class_dir = dentry; + out: return ret; err: