diff options
| -rw-r--r-- | security/tomoyo/realpath.c | 487 | ||||
| -rw-r--r-- | security/tomoyo/realpath.h | 63 |
2 files changed, 550 insertions, 0 deletions
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c new file mode 100644 index 00000000000..5fd48d23a21 --- /dev/null +++ b/security/tomoyo/realpath.c @@ -0,0 +1,487 @@ +/* + * security/tomoyo/realpath.c + * + * Get the canonicalized absolute pathnames. The basis for TOMOYO. + * + * Copyright (C) 2005-2009 NTT DATA CORPORATION + * + * Version: 2.2.0-pre 2009/02/01 + * + */ + +#include <linux/types.h> +#include <linux/mount.h> +#include <linux/mnt_namespace.h> +#include "common.h" +#include "realpath.h" + +/** + * tomoyo_encode: Convert binary string to ascii string. + * + * @buffer: Buffer for ASCII string. + * @buflen: Size of @buffer. + * @str: Binary string. + * + * Returns 0 on success, -ENOMEM otherwise. + */ +int tomoyo_encode(char *buffer, int buflen, const char *str) +{ + while (1) { + const unsigned char c = *(unsigned char *) str++; + + if (tomoyo_is_valid(c)) { + if (--buflen <= 0) + break; + *buffer++ = (char) c; + if (c != '\\') + continue; + if (--buflen <= 0) + break; + *buffer++ = (char) c; + continue; + } + if (!c) { + if (--buflen <= 0) + break; + *buffer = '\0'; + return 0; + } + buflen -= 4; + if (buflen <= 0) + break; + *buffer++ = '\\'; + *buffer++ = (c >> 6) + '0'; + *buffer++ = ((c >> 3) & 7) + '0'; + *buffer++ = (c & 7) + '0'; + } + return -ENOMEM; +} + +/** + * tomoyo_realpath_from_path2 - Returns realpath(3) of the given dentry but ignores chroot'ed root. + * + * @path: Pointer to "struct path". + * @newname: Pointer to buffer to return value in. + * @newname_len: Size of @newname. + * + * Returns 0 on success, negative value otherwise. + * + * If dentry is a directory, trailing '/' is appended. + * Characters out of 0x20 < c < 0x7F range are converted to + * \ooo style octal string. + * Character \ is converted to \\ string. + */ +int tomoyo_realpath_from_path2(struct path *path, char *newname, + int newname_len) +{ + int error = -ENOMEM; + struct dentry *dentry = path->dentry; + char *sp; + + if (!dentry || !path->mnt || !newname || newname_len <= 2048) + return -EINVAL; + if (dentry->d_op && dentry->d_op->d_dname) { + /* For "socket:[\$]" and "pipe:[\$]". */ + static const int offset = 1536; + sp = dentry->d_op->d_dname(dentry, newname + offset, + newname_len - offset); + } else { + /* Taken from d_namespace_path(). */ + struct path root; + struct path ns_root = { }; + struct path tmp; + + read_lock(¤t->fs->lock); + root = current->fs->root; + path_get(&root); + read_unlock(¤t->fs->lock); + spin_lock(&vfsmount_lock); + if (root.mnt && root.mnt->mnt_ns) + ns_root.mnt = mntget(root.mnt->mnt_ns->root); + if (ns_root.mnt) + ns_root.dentry = dget(ns_root.mnt->mnt_root); + spin_unlock(&vfsmount_lock); + spin_lock(&dcache_lock); + tmp = ns_root; + sp = __d_path(path, &tmp, newname, newname_len); + spin_unlock(&dcache_lock); + path_put(&root); + path_put(&ns_root); + } + if (IS_ERR(sp)) + error = PTR_ERR(sp); + else + error = tomoyo_encode(newname, sp - newname, sp); + /* Append trailing '/' if dentry is a directory. */ + if (!error && dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode) + && *newname) { + sp = newname + strlen(newname); + if (*(sp - 1) != '/') { + if (sp < newname + newname_len - 4) { + *sp++ = '/'; + *sp = '\0'; + } else { + error = -ENOMEM; + } + } + } + if (error) + printk(KERN_WARNING "tomoyo_realpath: Pathname too long.\n"); + return error; +} + +/** + * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root. + * + * @path: Pointer to "struct path". + * + * Returns the realpath of the given @path on success, NULL otherwise. + * + * These functions use tomoyo_alloc(), so the caller must call tomoyo_free() + * if these functions didn't return NULL. + */ +char *tomoyo_realpath_from_path(struct path *path) +{ + char *buf = tomoyo_alloc(sizeof(struct tomoyo_page_buffer)); + + BUILD_BUG_ON(sizeof(struct tomoyo_page_buffer) + <= TOMOYO_MAX_PATHNAME_LEN - 1); + if (!buf) + return NULL; + if (tomoyo_realpath_from_path2(path, buf, + TOMOYO_MAX_PATHNAME_LEN - 1) == 0) + return buf; + tomoyo_free(buf); + return NULL; +} + +/** + * tomoyo_realpath - Get realpath of a pathname. + * + * @pathname: The pathname to solve. + * + * Returns the realpath of @pathname on success, NULL otherwise. + */ +char *tomoyo_realpath(const char *pathname) +{ + struct nameidata nd; + + if (pathname && path_lookup(pathname, LOOKUP_FOLLOW, &nd) == 0) { + char *buf = tomoyo_realpath_from_path(&nd.path); + path_put(&nd.path); + return buf; + } + return NULL; +} + +/** + * tomoyo_realpath_nofollow - Get realpath of a pathname. + * + * @pathname: The pathname to solve. + * + * Returns the realpath of @pathname on success, NULL otherwise. + */ +char *tomoyo_realpath_nofollow(const char *pathname) +{ + struct nameidata nd; + + if (pathname && path_lookup(pathname, 0, &nd) == 0) { + char *buf = tomoyo_realpath_from_path(&nd.path); + path_put(&nd.path); + return buf; + } + return NULL; +} + +/* Memory allocated for non-string data. */ +static unsigned int tomoyo_allocated_memory_for_elements; +/* Quota for holding non-string data. */ +static unsigned int tomoyo_quota_for_elements; + +/** + * tomoyo_alloc_element - Allocate permanent memory for structures. + * + * @size: Size in bytes. + * + * Returns pointer to allocated memory on success, NULL otherwise. + * + * Memory has to be zeroed. + * The RAM is chunked, so NEVER try to kfree() the returned pointer. + */ +void *tomoyo_alloc_element(const unsigned int size) +{ + static char *buf; + static DEFINE_MUTEX(lock); + static unsigned int buf_used_len = PATH_MAX; + char *ptr = NULL; + /*Assumes sizeof(void *) >= sizeof(long) is true. */ + const unsigned int word_aligned_size + = roundup(size, max(sizeof(void *), sizeof(long))); + if (word_aligned_size > PATH_MAX) + return NULL; + /***** EXCLUSIVE SECTION START *****/ + mutex_lock(&lock); + if (buf_used_len + word_aligned_size > PATH_MAX) { + if (!tomoyo_quota_for_elements || + tomoyo_allocated_memory_for_elements + + PATH_MAX <= tomoyo_quota_for_elements) + ptr = kzalloc(PATH_MAX, GFP_KERNEL); + if (!ptr) { + printk(KERN_WARNING "ERROR: Out of memory " + "for tomoyo_alloc_element().\n"); + if (!tomoyo_policy_loaded) + panic("MAC Initialization failed.\n"); + } else { + buf = ptr; + tomoyo_allocated_memory_for_elements += PATH_MAX; + 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]) + continue; + printk(KERN_ERR "WARNING: Reserved memory was tainted! " + "The system might go wrong.\n"); + ptr[i] = '\0'; + } + } + mutex_unlock(&lock); + /***** EXCLUSIVE SECTION END *****/ + return ptr; +} + +/* Memory allocated for string data in bytes. */ +static unsigned int tomoyo_allocated_memory_for_savename; +/* Quota for holding string data in bytes. */ +static unsigned int tomoyo_quota_for_savename; + +/* + * TOMOYO uses this hash only when appending a string into the string + * table. Frequency of appending strings is very low. So we don't need + * large (e.g. 64k) hash size. 256 will be sufficient. + */ +#define TOMOYO_MAX_HASH 256 + +/* Structure for string data. */ +struct tomoyo_name_entry { + struct list_head list; + struct tomoyo_path_info entry; +}; + +/* Structure for available memory region. */ +struct tomoyo_free_memory_block_list { + struct list_head list; + char *ptr; /* Pointer to a free area. */ + int len; /* Length of the area. */ +}; + +/* + * The list for "struct tomoyo_name_entry". + * + * This list is updated only inside tomoyo_save_name(), thus + * no global mutex exists. + */ +static struct list_head tomoyo_name_list[TOMOYO_MAX_HASH]; + +/** + * tomoyo_save_name - Allocate permanent memory for string data. + * + * @name: The string to store into the permernent memory. + * + * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise. + * + * The RAM is shared, so NEVER try to modify or kfree() the returned name. + */ +const struct tomoyo_path_info *tomoyo_save_name(const char *name) +{ + static LIST_HEAD(fmb_list); + static DEFINE_MUTEX(lock); + struct tomoyo_name_entry *ptr; + unsigned int hash; + /* fmb contains available size in bytes. + fmb is removed from the fmb_list when fmb->len becomes 0. */ + struct tomoyo_free_memory_block_list *fmb; + int len; + char *cp; + + if (!name) + return NULL; + len = strlen(name) + 1; + if (len > TOMOYO_MAX_PATHNAME_LEN) { + printk(KERN_WARNING "ERROR: Name too long " + "for tomoyo_save_name().\n"); + return NULL; + } + hash = full_name_hash((const unsigned char *) name, len - 1); + /***** EXCLUSIVE SECTION START *****/ + mutex_lock(&lock); + list_for_each_entry(ptr, &tomoyo_name_list[hash % TOMOYO_MAX_HASH], + list) { + if (hash == ptr->entry.hash && !strcmp(name, ptr->entry.name)) + goto out; + } + list_for_each_entry(fmb, &fmb_list, list) { + if (len <= fmb->len) + goto ready; + } + if (!tomoyo_quota_for_savename || + tomoyo_allocated_memory_for_savename + PATH_MAX + <= tomoyo_quota_for_savename) + cp = kzalloc(PATH_MAX, GFP_KERNEL); + else + cp = NULL; + fmb = kzalloc(sizeof(*fmb), GFP_KERNEL); + if (!cp || !fmb) { + kfree(cp); + kfree(fmb); + printk(KERN_WARNING "ERROR: Out of memory " + "for tomoyo_save_name().\n"); + if (!tomoyo_policy_loaded) + panic("MAC Initialization failed.\n"); + ptr = NULL; + goto out; + } + tomoyo_allocated_memory_for_savename += PATH_MAX; + list_add(&fmb->list, &fmb_list); + fmb->ptr = cp; + fmb->len = PATH_MAX; + ready: + ptr = tomoyo_alloc_element(sizeof(*ptr)); + if (!ptr) + goto out; + ptr->entry.name = fmb->ptr; + memmove(fmb->ptr, name, len); + tomoyo_fill_path_info(&ptr->entry); + fmb->ptr += len; + fmb->len -= len; + list_add_tail(&ptr->list, &tomoyo_name_list[hash % TOMOYO_MAX_HASH]); + if (fmb->len == 0) { + list_del(&fmb->list); + kfree(fmb); + } + out: + mutex_unlock(&lock); + /***** EXCLUSIVE SECTION END *****/ + return ptr ? &ptr->entry : NULL; +} + +/** + * tomoyo_realpath_init - Initialize realpath related code. + * + * Returns 0. + */ +static int __init tomoyo_realpath_init(void) +{ + int i; + + BUILD_BUG_ON(TOMOYO_MAX_PATHNAME_LEN > PATH_MAX); + for (i = 0; i < TOMOYO_MAX_HASH; i++) + INIT_LIST_HEAD(&tomoyo_name_list[i]); + INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list); + tomoyo_kernel_domain.domainname = tomoyo_save_name(TOMOYO_ROOT_NAME); + list_add_tail(&tomoyo_kernel_domain.list, &tomoyo_domain_list); + down_read(&tomoyo_domain_list_lock); + if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain) + panic("Can't register tomoyo_kernel_domain"); + up_read(&tomoyo_domain_list_lock); + return 0; +} + +security_initcall(tomoyo_realpath_init); + +/* Memory allocated for temporary purpose. */ +static atomic_t tomoyo_dynamic_memory_size; + +/** + * tomoyo_alloc - Allocate memory for temporary purpose. + * + * @size: Size in bytes. + * + * Returns pointer to allocated memory on success, NULL otherwise. + */ +void *tomoyo_alloc(const size_t size) +{ + void *p = kzalloc(size, GFP_KERNEL); + if (p) + atomic_add(ksize(p), &tomoyo_dynamic_memory_size); + return p; +} + +/** + * tomoyo_free - Release memory allocated by tomoyo_alloc(). + * + * @p: Pointer returned by tomoyo_alloc(). May be NULL. + * + * Returns nothing. + */ +void tomoyo_free(const void *p) +{ + if (p) { + atomic_sub(ksize(p), &tomoyo_dynamic_memory_size); + kfree(p); + } +} + +/** + * tomoyo_read_memory_counter - Check for memory usage in bytes. + * + * @head: Pointer to "struct tomoyo_io_buffer". + * + * Returns memory usage. + */ +int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head) +{ + if (!head->read_eof) { + const unsigned int shared + = tomoyo_allocated_memory_for_savename; + const unsigned int private + = tomoyo_allocated_memory_for_elements; + const unsigned int dynamic + = atomic_read(&tomoyo_dynamic_memory_size); + char buffer[64]; + + memset(buffer, 0, sizeof(buffer)); + if (tomoyo_quota_for_savename) + snprintf(buffer, sizeof(buffer) - 1, + " (Quota: %10u)", + tomoyo_quota_for_savename); + else + buffer[0] = '\0'; + tomoyo_io_printf(head, "Shared: %10u%s\n", shared, buffer); + if (tomoyo_quota_for_elements) + snprintf(buffer, sizeof(buffer) - 1, + " (Quota: %10u)", + tomoyo_quota_for_elements); + else + buffer[0] = '\0'; + tomoyo_io_printf(head, "Private: %10u%s\n", private, buffer); + tomoyo_io_printf(head, "Dynamic: %10u\n", dynamic); + tomoyo_io_printf(head, "Total: %10u\n", + shared + private + dynamic); + head->read_eof = true; + } + return 0; +} + +/** + * tomoyo_write_memory_quota - Set memory quota. + * + * @head: Pointer to "struct tomoyo_io_buffer". + * + * Returns 0. + */ +int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head) +{ + char *data = head->write_buf; + unsigned int size; + + if (sscanf(data, "Shared: %u", &size) == 1) + tomoyo_quota_for_savename = size; + else if (sscanf(data, "Private: %u", &size) == 1) + tomoyo_quota_for_elements = size; + return 0; +} diff --git a/security/tomoyo/realpath.h b/security/tomoyo/realpath.h new file mode 100644 index 00000000000..0ea541fcb53 --- /dev/null +++ b/security/tomoyo/realpath.h @@ -0,0 +1,63 @@ +/* + * security/tomoyo/realpath.h + * + * Get the canonicalized absolute pathnames. The basis for TOMOYO. + * + * Copyright (C) 2005-2009 NTT DATA CORPORATION + * + * Version: 2.2.0-pre 2009/02/01 + * + */ + +#ifndef _SECURITY_TOMOYO_REALPATH_H +#define _SECURITY_TOMOYO_REALPATH_H + +struct path; +struct tomoyo_path_info; +struct tomoyo_io_buffer; + +/* Convert binary string to ascii string. */ +int tomoyo_encode(char *buffer, int buflen, const char *str); + +/* Returns realpath(3) of the given pathname but ignores chroot'ed root. */ +int tomoyo_realpath_from_path2(struct path *path, char *newname, + int newname_len); + +/* + * Returns realpath(3) of the given pathname but ignores chroot'ed root. + * These functions use tomoyo_alloc(), so the caller must call tomoyo_free() + * if these functions didn't return NULL. + */ +char *tomoyo_realpath(const char *pathname); +/* + * Same with tomoyo_realpath() except that it doesn't follow the final symlink. + */ +char *tomoyo_realpath_nofollow(const char *pathname); +/* Same with tomoyo_realpath() except that the pathname is already solved. */ +char *tomoyo_realpath_from_path(struct path *path); + +/* + * Allocate memory for ACL entry. + * The RAM is chunked, so NEVER try to kfree() the returned pointer. + */ +void *tomoyo_alloc_element(const unsigned int size); + +/* + * Keep the given name on the RAM. + * The RAM is shared, so NEVER try to modify or kfree() the returned name. + */ +const struct tomoyo_path_info *tomoyo_save_name(const char *name); + +/* Allocate memory for temporary use (e.g. permission checks). */ +void *tomoyo_alloc(const size_t size); + +/* Free memory allocated by tomoyo_alloc(). */ +void tomoyo_free(const void *p); + +/* Check for memory usage. */ +int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head); + +/* Set memory quota. */ +int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head); + +#endif /* !defined(_SECURITY_TOMOYO_REALPATH_H) */ |