diff options
Diffstat (limited to 'security/tomoyo/realpath.c')
| -rw-r--r-- | security/tomoyo/realpath.c | 537 |
1 files changed, 252 insertions, 285 deletions
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c index c225c65ce42..a3386d11942 100644 --- a/security/tomoyo/realpath.c +++ b/security/tomoyo/realpath.c @@ -1,361 +1,328 @@ /* * security/tomoyo/realpath.c * - * Get the canonicalized absolute pathnames. The basis for TOMOYO. - * - * Copyright (C) 2005-2009 NTT DATA CORPORATION - * - * Version: 2.2.0 2009/04/01 - * + * Copyright (C) 2005-2011 NTT DATA CORPORATION */ -#include <linux/types.h> -#include <linux/mount.h> -#include <linux/mnt_namespace.h> -#include <linux/fs_struct.h> -#include <linux/hash.h> -#include <linux/magic.h> -#include <linux/slab.h> #include "common.h" +#include <linux/magic.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. + * tomoyo_encode2 - Encode binary string to ascii string. * - * @path: Pointer to "struct path". - * @newname: Pointer to buffer to return value in. - * @newname_len: Size of @newname. + * @str: String in binary format. + * @str_len: Size of @str in byte. * - * Returns 0 on success, negative value otherwise. + * Returns pointer to @str in ascii format on success, NULL 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. + * This function uses kzalloc(), so caller must kfree() if this function + * didn't return NULL. */ -int tomoyo_realpath_from_path2(struct path *path, char *newname, - int newname_len) +char *tomoyo_encode2(const char *str, int str_len) { - int error = -ENOMEM; - struct dentry *dentry = path->dentry; - char *sp; + int i; + int len = 0; + const char *p = str; + char *cp; + char *cp0; - 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 { - struct path ns_root = {.mnt = NULL, .dentry = NULL}; + if (!p) + return NULL; + for (i = 0; i < str_len; i++) { + const unsigned char c = p[i]; - spin_lock(&dcache_lock); - /* go to whatever namespace root we are under */ - sp = __d_path(path, &ns_root, newname, newname_len); - spin_unlock(&dcache_lock); - /* Prepend "/proc" prefix if using internal proc vfs mount. */ - if (!IS_ERR(sp) && (path->mnt->mnt_flags & MNT_INTERNAL) && - (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) { - sp -= 5; - if (sp >= newname) - memcpy(sp, "/proc", 5); - else - sp = ERR_PTR(-ENOMEM); - } + if (c == '\\') + len += 2; + else if (c > ' ' && c < 127) + len++; + else + len += 4; } - 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; - } + len++; + /* Reserve space for appending "/". */ + cp = kzalloc(len + 10, GFP_NOFS); + if (!cp) + return NULL; + cp0 = cp; + p = str; + for (i = 0; i < str_len; i++) { + const unsigned char c = p[i]; + + if (c == '\\') { + *cp++ = '\\'; + *cp++ = '\\'; + } else if (c > ' ' && c < 127) { + *cp++ = c; + } else { + *cp++ = '\\'; + *cp++ = (c >> 6) + '0'; + *cp++ = ((c >> 3) & 7) + '0'; + *cp++ = (c & 7) + '0'; } } - if (error) - printk(KERN_WARNING "tomoyo_realpath: Pathname too long.\n"); - return error; + return cp0; } /** - * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root. + * tomoyo_encode - Encode binary string to ascii string. * - * @path: Pointer to "struct path". + * @str: String in binary format. * - * Returns the realpath of the given @path on success, NULL otherwise. + * Returns pointer to @str in ascii format on success, NULL otherwise. * - * These functions use kzalloc(), so the caller must call kfree() - * if these functions didn't return NULL. + * This function uses kzalloc(), so caller must kfree() if this function + * didn't return NULL. */ -char *tomoyo_realpath_from_path(struct path *path) +char *tomoyo_encode(const char *str) { - char *buf = kzalloc(sizeof(struct tomoyo_page_buffer), GFP_KERNEL); - - 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; - kfree(buf); - return NULL; + return str ? tomoyo_encode2(str, strlen(str)) : NULL; } /** - * tomoyo_realpath - Get realpath of a pathname. + * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root. * - * @pathname: The pathname to solve. + * @path: Pointer to "struct path". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. * - * Returns the realpath of @pathname on success, NULL otherwise. + * Returns the buffer on success, an error code otherwise. + * + * If dentry is a directory, trailing '/' is appended. */ -char *tomoyo_realpath(const char *pathname) +static char *tomoyo_get_absolute_path(struct path *path, char * const buffer, + const int buflen) { - struct path path; - - if (pathname && kern_path(pathname, LOOKUP_FOLLOW, &path) == 0) { - char *buf = tomoyo_realpath_from_path(&path); - path_put(&path); - return buf; + char *pos = ERR_PTR(-ENOMEM); + if (buflen >= 256) { + /* go to whatever namespace root we are under */ + pos = d_absolute_path(path, buffer, buflen - 1); + if (!IS_ERR(pos) && *pos == '/' && pos[1]) { + struct inode *inode = path->dentry->d_inode; + if (inode && S_ISDIR(inode->i_mode)) { + buffer[buflen - 2] = '/'; + buffer[buflen - 1] = '\0'; + } + } } - return NULL; + return pos; } /** - * tomoyo_realpath_nofollow - Get realpath of a pathname. + * tomoyo_get_dentry_path - Get the path of a dentry. * - * @pathname: The pathname to solve. + * @dentry: Pointer to "struct dentry". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. * - * Returns the realpath of @pathname on success, NULL otherwise. + * Returns the buffer on success, an error code otherwise. + * + * If dentry is a directory, trailing '/' is appended. */ -char *tomoyo_realpath_nofollow(const char *pathname) +static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer, + const int buflen) { - struct path path; - - if (pathname && kern_path(pathname, 0, &path) == 0) { - char *buf = tomoyo_realpath_from_path(&path); - path_put(&path); - return buf; + char *pos = ERR_PTR(-ENOMEM); + if (buflen >= 256) { + pos = dentry_path_raw(dentry, buffer, buflen - 1); + if (!IS_ERR(pos) && *pos == '/' && pos[1]) { + struct inode *inode = dentry->d_inode; + if (inode && S_ISDIR(inode->i_mode)) { + buffer[buflen - 2] = '/'; + buffer[buflen - 1] = '\0'; + } + } } - return NULL; + return pos; } -/* Memory allocated for non-string data. */ -static atomic_t tomoyo_policy_memory_size; -/* Quota for holding policy. */ -static unsigned int tomoyo_quota_for_policy; - /** - * tomoyo_memory_ok - Check memory quota. - * - * @ptr: Pointer to allocated memory. + * tomoyo_get_local_path - Get the path of a dentry. * - * Returns true on success, false otherwise. + * @dentry: Pointer to "struct dentry". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. * - * Caller holds tomoyo_policy_lock. - * Memory pointed by @ptr will be zeroed on success. + * Returns the buffer on success, an error code otherwise. */ -bool tomoyo_memory_ok(void *ptr) +static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer, + const int buflen) { - int allocated_len = ptr ? ksize(ptr) : 0; - atomic_add(allocated_len, &tomoyo_policy_memory_size); - if (ptr && (!tomoyo_quota_for_policy || - atomic_read(&tomoyo_policy_memory_size) - <= tomoyo_quota_for_policy)) { - memset(ptr, 0, allocated_len); - return true; + struct super_block *sb = dentry->d_sb; + char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen); + if (IS_ERR(pos)) + return pos; + /* Convert from $PID to self if $PID is current thread. */ + if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') { + char *ep; + const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10); + if (*ep == '/' && pid && pid == + task_tgid_nr_ns(current, sb->s_fs_info)) { + pos = ep - 5; + if (pos < buffer) + goto out; + memmove(pos, "/self", 5); + } + goto prepend_filesystem_name; + } + /* Use filesystem name for unnamed devices. */ + if (!MAJOR(sb->s_dev)) + goto prepend_filesystem_name; + { + struct inode *inode = sb->s_root->d_inode; + /* + * Use filesystem name if filesystem does not support rename() + * operation. + */ + if (!inode->i_op->rename) + goto prepend_filesystem_name; } - printk(KERN_WARNING "ERROR: Out of memory " - "for tomoyo_alloc_element().\n"); - if (!tomoyo_policy_loaded) - panic("MAC Initialization failed.\n"); - return false; + /* Prepend device name. */ + { + char name[64]; + int name_len; + const dev_t dev = sb->s_dev; + name[sizeof(name) - 1] = '\0'; + snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev), + MINOR(dev)); + name_len = strlen(name); + pos -= name_len; + if (pos < buffer) + goto out; + memmove(pos, name, name_len); + return pos; + } + /* Prepend filesystem name. */ +prepend_filesystem_name: + { + const char *name = sb->s_type->name; + const int name_len = strlen(name); + pos -= name_len + 1; + if (pos < buffer) + goto out; + memmove(pos, name, name_len); + pos[name_len] = ':'; + } + return pos; +out: + return ERR_PTR(-ENOMEM); } /** - * tomoyo_memory_free - Free memory for elements. + * tomoyo_get_socket_name - Get the name of a socket. * - * @ptr: Pointer to allocated memory. + * @path: Pointer to "struct path". + * @buffer: Pointer to buffer to return value in. + * @buflen: Sizeof @buffer. + * + * Returns the buffer. */ -void tomoyo_memory_free(void *ptr) +static char *tomoyo_get_socket_name(struct path *path, char * const buffer, + const int buflen) { - atomic_sub(ksize(ptr), &tomoyo_policy_memory_size); - kfree(ptr); + struct inode *inode = path->dentry->d_inode; + struct socket *sock = inode ? SOCKET_I(inode) : NULL; + struct sock *sk = sock ? sock->sk : NULL; + if (sk) { + snprintf(buffer, buflen, "socket:[family=%u:type=%u:" + "protocol=%u]", sk->sk_family, sk->sk_type, + sk->sk_protocol); + } else { + snprintf(buffer, buflen, "socket:[unknown]"); + } + return buffer; } -/* - * tomoyo_name_list is used for holding string data used by TOMOYO. - * Since same string data is likely used for multiple times (e.g. - * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of - * "const struct tomoyo_path_info *". - */ -struct list_head tomoyo_name_list[TOMOYO_MAX_HASH]; -/* Lock for protecting tomoyo_name_list . */ -DEFINE_MUTEX(tomoyo_name_list_lock); - /** - * tomoyo_get_name - Allocate permanent memory for string data. + * 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. * - * @name: The string to store into the permernent memory. + * 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. * - * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise. + * These functions use kzalloc(), so the caller must call kfree() + * if these functions didn't return NULL. */ -const struct tomoyo_path_info *tomoyo_get_name(const char *name) +char *tomoyo_realpath_from_path(struct path *path) { - struct tomoyo_name_entry *ptr; - unsigned int hash; - int len; - int allocated_len; - struct list_head *head; - - if (!name) + char *buf = NULL; + char *name = NULL; + unsigned int buf_len = PAGE_SIZE / 2; + struct dentry *dentry = path->dentry; + struct super_block *sb; + if (!dentry) return NULL; - len = strlen(name) + 1; - hash = full_name_hash((const unsigned char *) name, len - 1); - head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)]; - mutex_lock(&tomoyo_name_list_lock); - list_for_each_entry(ptr, head, list) { - if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name)) + sb = dentry->d_sb; + while (1) { + char *pos; + struct inode *inode; + buf_len <<= 1; + kfree(buf); + buf = kmalloc(buf_len, GFP_NOFS); + if (!buf) + break; + /* To make sure that pos is '\0' terminated. */ + buf[buf_len - 1] = '\0'; + /* Get better name for socket. */ + if (sb->s_magic == SOCKFS_MAGIC) { + pos = tomoyo_get_socket_name(path, buf, buf_len - 1); + goto encode; + } + /* For "pipe:[\$]". */ + if (dentry->d_op && dentry->d_op->d_dname) { + pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1); + goto encode; + } + inode = sb->s_root->d_inode; + /* + * Get local name for filesystems without rename() operation + * or dentry without vfsmount. + */ + if (!path->mnt || !inode->i_op->rename) + pos = tomoyo_get_local_path(path->dentry, buf, + buf_len - 1); + /* Get absolute name for the rest. */ + else { + pos = tomoyo_get_absolute_path(path, buf, buf_len - 1); + /* + * Fall back to local name if absolute name is not + * available. + */ + if (pos == ERR_PTR(-EINVAL)) + pos = tomoyo_get_local_path(path->dentry, buf, + buf_len - 1); + } +encode: + if (IS_ERR(pos)) continue; - atomic_inc(&ptr->users); - goto out; - } - ptr = kzalloc(sizeof(*ptr) + len, GFP_KERNEL); - allocated_len = ptr ? ksize(ptr) : 0; - if (!ptr || (tomoyo_quota_for_policy && - atomic_read(&tomoyo_policy_memory_size) + allocated_len - > tomoyo_quota_for_policy)) { - kfree(ptr); - printk(KERN_WARNING "ERROR: Out of memory " - "for tomoyo_get_name().\n"); - if (!tomoyo_policy_loaded) - panic("MAC Initialization failed.\n"); - ptr = NULL; - goto out; + name = tomoyo_encode(pos); + break; } - atomic_add(allocated_len, &tomoyo_policy_memory_size); - ptr->entry.name = ((char *) ptr) + sizeof(*ptr); - memmove((char *) ptr->entry.name, name, len); - atomic_set(&ptr->users, 1); - tomoyo_fill_path_info(&ptr->entry); - list_add_tail(&ptr->list, head); - out: - mutex_unlock(&tomoyo_name_list_lock); - return ptr ? &ptr->entry : NULL; -} - -/** - * tomoyo_realpath_init - Initialize realpath related code. - */ -void __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_get_name(TOMOYO_ROOT_NAME); - /* - * tomoyo_read_lock() is not needed because this function is - * called before the first "delete" request. - */ - list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list); - if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain) - panic("Can't register tomoyo_kernel_domain"); + kfree(buf); + if (!name) + tomoyo_warn_oom(__func__); + return name; } /** - * tomoyo_read_memory_counter - Check for memory usage in bytes. + * tomoyo_realpath_nofollow - Get realpath of a pathname. * - * @head: Pointer to "struct tomoyo_io_buffer". + * @pathname: The pathname to solve. * - * Returns memory usage. + * Returns the realpath of @pathname on success, NULL otherwise. */ -int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head) +char *tomoyo_realpath_nofollow(const char *pathname) { - if (!head->read_eof) { - const unsigned int policy - = atomic_read(&tomoyo_policy_memory_size); - char buffer[64]; + struct path path; - memset(buffer, 0, sizeof(buffer)); - if (tomoyo_quota_for_policy) - snprintf(buffer, sizeof(buffer) - 1, - " (Quota: %10u)", - tomoyo_quota_for_policy); - else - buffer[0] = '\0'; - tomoyo_io_printf(head, "Policy: %10u%s\n", policy, buffer); - tomoyo_io_printf(head, "Total: %10u\n", policy); - head->read_eof = true; + if (pathname && kern_path(pathname, 0, &path) == 0) { + char *buf = tomoyo_realpath_from_path(&path); + path_put(&path); + return buf; } - 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, "Policy: %u", &size) == 1) - tomoyo_quota_for_policy = size; - return 0; + return NULL; } |