We limit the maximum length of any string data (such as domainname and pathnames)
to TOMOYO_MAX_PATHNAME_LEN (which is 4000) bytes to fit within a single page.
Userland programs can obtain the amount of RAM currently used by TOMOYO from /proc interface.
Signed-off-by: Kentaro Takeda <[email protected]>
Signed-off-by: Tetsuo Handa <[email protected]>
---------------
security/tomoyo/include/realpath.h | 46 +++++
security/tomoyo/realpath.c | 445 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 491 insertions(+)
diff -ubBpErN linux-2.6.21.5/security/tomoyo/include/realpath.h linux-2.6.21.5-tomoyo/security/tomoyo/include/realpath.h
--- linux-2.6.21.5/security/tomoyo/include/realpath.h 1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.21.5-tomoyo/security/tomoyo/include/realpath.h 2007-06-05 00:00:00.000000000 +0900
@@ -0,0 +1,46 @@
+/*
+ * security/tomoyo/include/realpath.h
+ *
+ * Get the canonicalized absolute pathnames. The basis for TOMOYO.
+ *
+ * Copyright (C) 2005-2007 NTT DATA CORPORATION
+ *
+ * Version: 2.0 2007/06/05
+ *
+ */
+
+#ifndef _TOMOYO_REALPATH_H
+#define _TOMOYO_REALPATH_H
+
+struct path_info;
+
+/* Returns realpath(3) of the given pathname but ignores chroot'ed root. */
+int tomoyo_realpath_from_dentry2(struct dentry *dentry,
+ struct vfsmount *mnt,
+ char *newname,
+ int newname_len);
+
+/* Returns realpath(3) of the given pathname but ignores chroot'ed root. */
+/* These functions use tomoyo_alloc(), so caller must tomoyo_free() */
+/* if these functions didn't return NULL. */
+char *tomoyo_realpath(const char *pathname);
+char *tomoyo_realpath_nofollow(const char *pathname);
+char *tomoyo_realpath_from_dentry(struct dentry *dentry, struct vfsmount *mnt);
+
+/* Allocate memory for structures. */
+/* The RAM is chunked, so NEVER try to kfree() the returned pointer. */
+void *tomoyo_alloc_element(const unsigned int size);
+
+/* Get used RAM size for tomoyo_alloc_elements(). */
+unsigned int tomoyo_get_memory_used_for_elements(void);
+
+/* Keep the given name on the RAM. */
+/* The RAM is shared, so NEVER try to modify or kfree() the returned name. */
+const struct path_info *tomoyo_save_name(const char *name);
+
+/* Get used RAM size for tomoyo_save_name(). */
+unsigned int tomoyo_get_memory_used_for_save_name(void);
+
+unsigned int tomoyo_get_memory_used_for_dynamic(void);
+
+#endif
diff -ubBpErN linux-2.6.21.5/security/tomoyo/realpath.c linux-2.6.21.5-tomoyo/security/tomoyo/realpath.c
--- linux-2.6.21.5/security/tomoyo/realpath.c 1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.21.5-tomoyo/security/tomoyo/realpath.c 2007-06-14 15:06:37.000000000 +0900
@@ -0,0 +1,445 @@
+/*
+ * security/tomoyo/realpath.c
+ *
+ * Get the canonicalized absolute pathnames.
+ * The basis for TOMOYO Linux.
+ *
+ * Copyright (C) 2005-2007 NTT DATA CORPORATION
+ *
+ * Version: 2.0 2007/06/05
+ */
+
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/utime.h>
+#include <linux/file.h>
+#include <linux/smp_lock.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
+#include <asm/atomic.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/proc_fs.h>
+#include "realpath.h"
+#include "tomoyo.h"
+
+extern int sbin_init_started;
+
+/***** realpath handler *****/
+
+/*
+ * tomoyo_get_absolute_path - return the path of a dentry but ignores chroot'ed root.
+ * @dentry: dentry to report
+ * @vfsmnt: vfsmnt to which the dentry belongs
+ * @buffer: buffer to return value in
+ * @buflen: buffer length
+ *
+ * Caller holds the dcache_lock.
+ * Based on __d_path() in fs/dcache.c
+ *
+ * If dentry is a directory, trailing '/' is appended.
+ * Characters other than ' ' < c < 127 are converted to \ooo style octal string.
+ * Character \ is converted to \\ string.
+ */
+static int tomoyo_get_absolute_path(struct dentry *dentry,
+ struct vfsmount *vfsmnt,
+ char *buffer,
+ int buflen)
+{
+ char *start = buffer;
+ char *end = buffer + buflen;
+ int is_dir = (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode));
+
+ if (buflen < 256) goto out;
+
+ *--end = '\0';
+ buflen--;
+
+ for (;;) {
+ struct dentry *parent;
+
+ if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
+ /* Global root? */
+ spin_lock(&vfsmount_lock);
+ if (vfsmnt->mnt_parent == vfsmnt) {
+ spin_unlock(&vfsmount_lock);
+ break;
+ }
+ dentry = vfsmnt->mnt_mountpoint;
+ vfsmnt = vfsmnt->mnt_parent;
+ spin_unlock(&vfsmount_lock);
+ continue;
+ }
+ if (is_dir) {
+ is_dir = 0;
+ *--end = '/';
+ buflen--;
+ }
+ parent = dentry->d_parent;
+ {
+ const char *sp = dentry->d_name.name;
+ const char *cp = sp + dentry->d_name.len - 1;
+ unsigned char c;
+
+ /* Exception: Use /proc/self/ rather than /proc/\$/ for current process. */
+ if (IS_ROOT(parent) && *sp > '0' && *sp <= '9' && parent->d_sb
+ && parent->d_sb->s_magic == PROC_SUPER_MAGIC) {
+ char *ep;
+ const pid_t pid = (pid_t) simple_strtoul(sp, &ep, 10);
+ if (!*ep && pid == current->tgid) {
+ sp = "self";
+ cp = sp + 3;
+ }
+ if (!*ep && pid == current->pid) {
+ sp = "self";
+ cp = sp + 3;
+ }
+ }
+
+ while (sp <= cp) {
+ c = * (unsigned char *) cp;
+ if (c == '\\') {
+ buflen -= 2;
+ if (buflen < 0) goto out;
+ *--end = '\\';
+ *--end = '\\';
+ } else if (c > ' ' && c < 127) {
+ if (--buflen < 0) goto out;
+ *--end = (char) c;
+ } else {
+ buflen -= 4;
+ if (buflen < 0) goto out;
+ *--end = (c & 7) + '0';
+ *--end = ((c >> 3) & 7) + '0';
+ *--end = (c >> 6) + '0';
+ *--end = '\\';
+ }
+ cp--;
+ }
+ if (--buflen < 0) goto out;
+ *--end = '/';
+ }
+ dentry = parent;
+ }
+ if (*end == '/') {
+ buflen++;
+ end++;
+ }
+ {
+ const char *sp = dentry->d_name.name;
+ const char *cp = sp + dentry->d_name.len - 1;
+ unsigned char c;
+ while (sp <= cp) {
+ c = * (unsigned char *) cp;
+ if (c == '\\') {
+ buflen -= 2;
+ if (buflen < 0) goto out;
+ *--end = '\\';
+ *--end = '\\';
+ } else if (c > ' ' && c < 127) {
+ if (--buflen < 0) goto out;
+ *--end = (char) c;
+ } else {
+ buflen -= 4;
+ if (buflen < 0) goto out;
+ *--end = (c & 7) + '0';
+ *--end = ((c >> 3) & 7) + '0';
+ *--end = (c >> 6) + '0';
+ *--end = '\\';
+ }
+ cp--;
+ }
+ }
+ /* Move the pathname to the top of the buffer. */
+ memmove(start, end, strlen(end) + 1);
+ return 0;
+ out:
+ return -ENOMEM;
+}
+
+/* Returns realpath(3) of the given dentry but ignores chroot'ed root. */
+int tomoyo_realpath_from_dentry2(struct dentry *dentry,
+ struct vfsmount *mnt,
+ char *newname,
+ int newname_len)
+{
+ int error;
+ struct dentry *d_dentry;
+ struct vfsmount *d_mnt;
+ if (!dentry || !mnt || !newname || newname_len <= 0) return -EINVAL;
+ if (!current->fs) {
+ printk("%s: current->fs == NULL for pid=%d\n", __FUNCTION__, current->pid);
+ return -ENOENT;
+ }
+ d_dentry = dget(dentry);
+ d_mnt = mntget(mnt);
+ /***** CRITICAL SECTION START *****/
+ spin_lock(&dcache_lock);
+ error = tomoyo_get_absolute_path(d_dentry, d_mnt, newname, newname_len);
+ spin_unlock(&dcache_lock);
+ /***** CRITICAL SECTION END *****/
+ dput(d_dentry);
+ mntput(d_mnt);
+ return error;
+}
+
+/* Returns realpath(3) of the given pathname but ignores chroot'ed root. */
+/* These functions use tomoyo_alloc(), so caller must tomoyo_free() */
+/* if these functions didn't return NULL. */
+char *tomoyo_realpath_from_dentry(struct dentry *dentry, struct vfsmount *mnt)
+{
+ char *buf = tomoyo_alloc(TOMOYO_MAX_PATHNAME_LEN);
+ if (buf && tomoyo_realpath_from_dentry2(dentry, mnt, buf, TOMOYO_MAX_PATHNAME_LEN - 1) == 0)
+ return buf;
+ tomoyo_free(buf);
+ return NULL;
+}
+
+char *tomoyo_realpath(const char *pathname)
+{
+ struct nameidata nd;
+ if (pathname && path_lookup(pathname, LOOKUP_FOLLOW, &nd) == 0) {
+ char *buf = tomoyo_realpath_from_dentry(nd.dentry, nd.mnt);
+ path_release(&nd);
+ return buf;
+ }
+ return NULL;
+}
+
+char *tomoyo_realpath_nofollow(const char *pathname)
+{
+ struct nameidata nd;
+ if (pathname && path_lookup(pathname, 0, &nd) == 0) {
+ char *buf = tomoyo_realpath_from_dentry(nd.dentry, nd.mnt);
+ path_release(&nd);
+ return buf;
+ }
+ return NULL;
+}
+
+/***** Private memory allocator. *****/
+
+/*
+ * Round up an integer so that the returned pointers are appropriately aligned.
+ * FIXME: Are there more requirements that is needed for assigning value atomically?
+ */
+static inline unsigned int tomoyo_roundup(const unsigned int size) {
+ if (sizeof(void *) >= sizeof(long)) {
+ return ((size + sizeof(void *) - 1) / sizeof(void *)) * sizeof(void *);
+ } else {
+ return ((size + sizeof(long) - 1) / sizeof(long)) * sizeof(long);
+ }
+}
+
+static unsigned int allocated_memory_for_elements = 0;
+
+unsigned int tomoyo_get_memory_used_for_elements(void)
+{
+ return allocated_memory_for_elements;
+}
+
+/* Allocate memory for structures. */
+/* The RAM is chunked, so NEVER try to kfree() the returned pointer. */
+void *tomoyo_alloc_element(const unsigned int size)
+{
+ static DECLARE_MUTEX(lock);
+ static char *buf = NULL;
+ static unsigned int buf_used_len = PAGE_SIZE;
+ char *ptr = NULL;
+ const unsigned int word_aligned_size = tomoyo_roundup(size);
+ if (word_aligned_size > PAGE_SIZE) return NULL;
+ down(&lock);
+ if (buf_used_len + word_aligned_size > PAGE_SIZE) {
+ if ((ptr = kmalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) {
+ printk("ERROR: Out of memory for tomoyo_alloc_element().\n");
+ if (!sbin_init_started) panic("MAC Initialization failed.\n");
+ } else {
+ memset(ptr, 0, PAGE_SIZE);
+ buf = ptr;
+ allocated_memory_for_elements += PAGE_SIZE;
+ buf_used_len = word_aligned_size;
+ ptr = buf;
+ }
+ } else if (word_aligned_size) {
+ int i;
+ ptr = buf + buf_used_len;
+ buf_used_len += word_aligned_size;
+ for (i = 0; i < word_aligned_size; i++) {
+ if (ptr[i]) {
+ printk(KERN_ERR "WARNING: Reserved memory was tainted! "
+ "The system might go wrong.\n");
+ ptr[i] = '\0';
+ }
+ }
+ }
+ up(&lock);
+ return ptr;
+}
+
+/***** Shared memory allocator. *****/
+
+static unsigned int allocated_memory_for_savename = 0;
+
+unsigned int tomoyo_get_memory_used_for_save_name(void)
+{
+ return allocated_memory_for_savename;
+}
+
+#define MAX_HASH 256
+
+struct name_entry {
+ struct name_entry *next; /* Pointer to next record. NULL if none. */
+ struct path_info entry;
+};
+
+struct free_memory_block_list {
+ struct free_memory_block_list *next; /* Pointer to next record. NULL if none. */
+ char *ptr; /* Pointer to a free area. */
+ int len; /* Length of the area. */
+};
+
+/* Keep the given name on the RAM. */
+/* The RAM is shared, so NEVER try to modify or kfree() the returned name. */
+const struct path_info *tomoyo_save_name(const char *name)
+{
+ static struct free_memory_block_list fmb_list = { NULL, NULL, 0 };
+ static struct name_entry name_list[MAX_HASH]; /* The list of names. */
+ static DECLARE_MUTEX(lock);
+ struct name_entry *ptr, *prev = NULL;
+ unsigned int hash;
+ struct free_memory_block_list *fmb = &fmb_list;
+ int len;
+ static int first_call = 1;
+ if (!name) return NULL;
+ len = strlen(name) + 1;
+ if (len > TOMOYO_MAX_PATHNAME_LEN) {
+ printk("ERROR: Name too long for tomoyo_save_name().\n");
+ return NULL;
+ }
+ hash = full_name_hash((const unsigned char *) name, len - 1);
+ down(&lock);
+ if (first_call) {
+ int i;
+ first_call = 0;
+ memset(&name_list, 0, sizeof(name_list));
+ for (i = 0; i < MAX_HASH; i++) {
+ name_list[i].entry.name = "/";
+ tomoyo_fill_path_info(&name_list[i].entry);
+ }
+ if (TOMOYO_MAX_PATHNAME_LEN > PAGE_SIZE) panic("Bad size.");
+ }
+ ptr = &name_list[hash % MAX_HASH];
+ while (ptr) {
+ if (hash == ptr->entry.hash && strcmp(name, ptr->entry.name) == 0) goto out;
+ prev = ptr;
+ ptr = ptr->next;
+ }
+ while (len > fmb->len) {
+ if (fmb->next) {
+ fmb = fmb->next;
+ } else {
+ char *cp;
+ if ((cp = kmalloc(PAGE_SIZE, GFP_KERNEL)) == NULL ||
+ (fmb->next = tomoyo_alloc_element(sizeof(*fmb))) == NULL) {
+ kfree(cp);
+ printk("ERROR: Out of memory for tomoyo_save_name().\n");
+ if (!sbin_init_started) panic("MAC Initialization failed.\n");
+ goto out; /* ptr == NULL */
+ }
+ memset(cp, 0, PAGE_SIZE);
+ allocated_memory_for_savename += PAGE_SIZE;
+ fmb = fmb->next;
+ fmb->ptr = cp;
+ fmb->len = PAGE_SIZE;
+ }
+ }
+ if ((ptr = tomoyo_alloc_element(sizeof(*ptr))) == NULL) goto out;
+ ptr->entry.name = fmb->ptr;
+ memmove(fmb->ptr, name, len);
+ tomoyo_fill_path_info(&ptr->entry);
+ fmb->ptr += len;
+ fmb->len -= len;
+ prev->next = ptr; /* prev != NULL because name_list is not empty. */
+ if (fmb->len == 0) {
+ struct free_memory_block_list *ptr = &fmb_list;
+ while (ptr->next != fmb)
+ ptr = ptr->next;
+ ptr->next = fmb->next;
+ }
+ out:
+ up(&lock);
+ return ptr ? &ptr->entry : NULL;
+}
+
+/***** Dynamic memory allocator. *****/
+
+struct cache_entry {
+ struct list_head list;
+ void *ptr;
+ int size;
+};
+
+static struct kmem_cache *ccs_cachep = NULL;
+
+void tomoyo_realpath_init(void)
+{
+ ccs_cachep = kmem_cache_create("ccs_cache", sizeof(struct cache_entry), 0, 0, NULL, NULL);
+ if (!ccs_cachep) panic("Can't create cache.\n");
+}
+
+static LIST_HEAD(cache_list);
+static spinlock_t cache_list_lock = SPIN_LOCK_UNLOCKED;
+static unsigned int dynamic_memory_size = 0;
+
+unsigned int tomoyo_get_memory_used_for_dynamic(void)
+{
+ return dynamic_memory_size;
+}
+
+void *tomoyo_alloc(const size_t size)
+{
+ void *ret = kmalloc(size, GFP_KERNEL);
+ if (ret) {
+ struct cache_entry *new_entry = kmem_cache_alloc(ccs_cachep, GFP_KERNEL);
+ if (!new_entry) {
+ kfree(ret);
+ ret = NULL;
+ } else {
+ INIT_LIST_HEAD(&new_entry->list);
+ new_entry->ptr = ret;
+ new_entry->size = size;
+ spin_lock(&cache_list_lock);
+ list_add_tail(&new_entry->list, &cache_list);
+ dynamic_memory_size += size;
+ spin_unlock(&cache_list_lock);
+ memset(ret, 0, size);
+ }
+ }
+ return ret;
+}
+
+void tomoyo_free(const void *p)
+{
+ struct list_head *v;
+ struct cache_entry *entry = NULL;
+ if (!p) return;
+ spin_lock(&cache_list_lock);
+ list_for_each(v, &cache_list) {
+ entry = list_entry(v, struct cache_entry, list);
+ if (entry->ptr != p) {
+ entry = NULL;
+ continue;
+ }
+ list_del(&entry->list);
+ dynamic_memory_size -= entry->size;
+ break;
+ }
+ spin_unlock(&cache_list_lock);
+ if (entry) {
+ kfree(p);
+ kmem_cache_free(ccs_cachep, entry);
+ } else {
+ printk("BUG: tomoyo_free() with invalid pointer.\n");
+ }
+}
---------------
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