diff options
Diffstat (limited to 'fs/posix_acl.c')
| -rw-r--r-- | fs/posix_acl.c | 610 |
1 files changed, 566 insertions, 44 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 39df95a0ec2..0855f772cd4 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1,10 +1,8 @@ /* - * linux/fs/posix_acl.c + * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org> * - * Copyright (C) 2002 by Andreas Gruenbacher <a.gruenbacher@computer.org> - * - * Fixes from William Schumacher incorporated on 15 March 2001. - * (Reported by Charles Bertsch, <CBertsch@microtest.com>). + * Fixes from William Schumacher incorporated on 15 March 2001. + * (Reported by Charles Bertsch, <CBertsch@microtest.com>). */ /* @@ -14,22 +12,127 @@ #include <linux/kernel.h> #include <linux/slab.h> -#include <asm/atomic.h> +#include <linux/atomic.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/posix_acl.h> -#include <linux/module.h> +#include <linux/posix_acl_xattr.h> +#include <linux/xattr.h> +#include <linux/export.h> +#include <linux/user_namespace.h> -#include <linux/errno.h> +struct posix_acl **acl_by_type(struct inode *inode, int type) +{ + switch (type) { + case ACL_TYPE_ACCESS: + return &inode->i_acl; + case ACL_TYPE_DEFAULT: + return &inode->i_default_acl; + default: + BUG(); + } +} +EXPORT_SYMBOL(acl_by_type); -EXPORT_SYMBOL(posix_acl_alloc); -EXPORT_SYMBOL(posix_acl_clone); -EXPORT_SYMBOL(posix_acl_valid); -EXPORT_SYMBOL(posix_acl_equiv_mode); -EXPORT_SYMBOL(posix_acl_from_mode); -EXPORT_SYMBOL(posix_acl_create_masq); -EXPORT_SYMBOL(posix_acl_chmod_masq); -EXPORT_SYMBOL(posix_acl_permission); +struct posix_acl *get_cached_acl(struct inode *inode, int type) +{ + struct posix_acl **p = acl_by_type(inode, type); + struct posix_acl *acl = ACCESS_ONCE(*p); + if (acl) { + spin_lock(&inode->i_lock); + acl = *p; + if (acl != ACL_NOT_CACHED) + acl = posix_acl_dup(acl); + spin_unlock(&inode->i_lock); + } + return acl; +} +EXPORT_SYMBOL(get_cached_acl); + +struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) +{ + return rcu_dereference(*acl_by_type(inode, type)); +} +EXPORT_SYMBOL(get_cached_acl_rcu); + +void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) +{ + struct posix_acl **p = acl_by_type(inode, type); + struct posix_acl *old; + spin_lock(&inode->i_lock); + old = *p; + rcu_assign_pointer(*p, posix_acl_dup(acl)); + spin_unlock(&inode->i_lock); + if (old != ACL_NOT_CACHED) + posix_acl_release(old); +} +EXPORT_SYMBOL(set_cached_acl); + +void forget_cached_acl(struct inode *inode, int type) +{ + struct posix_acl **p = acl_by_type(inode, type); + struct posix_acl *old; + spin_lock(&inode->i_lock); + old = *p; + *p = ACL_NOT_CACHED; + spin_unlock(&inode->i_lock); + if (old != ACL_NOT_CACHED) + posix_acl_release(old); +} +EXPORT_SYMBOL(forget_cached_acl); + +void forget_all_cached_acls(struct inode *inode) +{ + struct posix_acl *old_access, *old_default; + spin_lock(&inode->i_lock); + old_access = inode->i_acl; + old_default = inode->i_default_acl; + inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; + spin_unlock(&inode->i_lock); + if (old_access != ACL_NOT_CACHED) + posix_acl_release(old_access); + if (old_default != ACL_NOT_CACHED) + posix_acl_release(old_default); +} +EXPORT_SYMBOL(forget_all_cached_acls); + +struct posix_acl *get_acl(struct inode *inode, int type) +{ + struct posix_acl *acl; + + acl = get_cached_acl(inode, type); + if (acl != ACL_NOT_CACHED) + return acl; + + if (!IS_POSIXACL(inode)) + return NULL; + + /* + * A filesystem can force a ACL callback by just never filling the + * ACL cache. But normally you'd fill the cache either at inode + * instantiation time, or on the first ->get_acl call. + * + * If the filesystem doesn't have a get_acl() function at all, we'll + * just create the negative cache entry. + */ + if (!inode->i_op->get_acl) { + set_cached_acl(inode, type, NULL); + return NULL; + } + return inode->i_op->get_acl(inode, type); +} +EXPORT_SYMBOL(get_acl); + +/* + * Init a fresh posix_acl + */ +void +posix_acl_init(struct posix_acl *acl, int count) +{ + atomic_set(&acl->a_refcount, 1); + acl->a_count = count; +} +EXPORT_SYMBOL(posix_acl_init); /* * Allocate a new ACL with the specified number of entries. @@ -40,17 +143,16 @@ posix_acl_alloc(int count, gfp_t flags) const size_t size = sizeof(struct posix_acl) + count * sizeof(struct posix_acl_entry); struct posix_acl *acl = kmalloc(size, flags); - if (acl) { - atomic_set(&acl->a_refcount, 1); - acl->a_count = count; - } + if (acl) + posix_acl_init(acl, count); return acl; } +EXPORT_SYMBOL(posix_acl_alloc); /* * Clone an ACL. */ -struct posix_acl * +static struct posix_acl * posix_acl_clone(const struct posix_acl *acl, gfp_t flags) { struct posix_acl *clone = NULL; @@ -73,7 +175,6 @@ posix_acl_valid(const struct posix_acl *acl) { const struct posix_acl_entry *pa, *pe; int state = ACL_USER_OBJ; - unsigned int id = 0; /* keep gcc happy */ int needs_mask = 0; FOREACH_ACL_ENTRY(pa, acl, pe) { @@ -82,7 +183,6 @@ posix_acl_valid(const struct posix_acl *acl) switch (pa->e_tag) { case ACL_USER_OBJ: if (state == ACL_USER_OBJ) { - id = 0; state = ACL_USER; break; } @@ -91,16 +191,13 @@ posix_acl_valid(const struct posix_acl *acl) case ACL_USER: if (state != ACL_USER) return -EINVAL; - if (pa->e_id == ACL_UNDEFINED_ID || - pa->e_id < id) + if (!uid_valid(pa->e_uid)) return -EINVAL; - id = pa->e_id + 1; needs_mask = 1; break; case ACL_GROUP_OBJ: if (state == ACL_USER) { - id = 0; state = ACL_GROUP; break; } @@ -109,10 +206,8 @@ posix_acl_valid(const struct posix_acl *acl) case ACL_GROUP: if (state != ACL_GROUP) return -EINVAL; - if (pa->e_id == ACL_UNDEFINED_ID || - pa->e_id < id) + if (!gid_valid(pa->e_gid)) return -EINVAL; - id = pa->e_id + 1; needs_mask = 1; break; @@ -138,18 +233,25 @@ posix_acl_valid(const struct posix_acl *acl) return 0; return -EINVAL; } +EXPORT_SYMBOL(posix_acl_valid); /* * Returns 0 if the acl can be exactly represented in the traditional * file mode permission bits, or else 1. Returns -E... on error. */ int -posix_acl_equiv_mode(const struct posix_acl *acl, mode_t *mode_p) +posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) { const struct posix_acl_entry *pa, *pe; - mode_t mode = 0; + umode_t mode = 0; int not_equiv = 0; + /* + * A null ACL can always be presented as mode bits. + */ + if (!acl) + return 0; + FOREACH_ACL_ENTRY(pa, acl, pe) { switch (pa->e_tag) { case ACL_USER_OBJ: @@ -178,30 +280,29 @@ posix_acl_equiv_mode(const struct posix_acl *acl, mode_t *mode_p) *mode_p = (*mode_p & ~S_IRWXUGO) | mode; return not_equiv; } +EXPORT_SYMBOL(posix_acl_equiv_mode); /* * Create an ACL representing the file mode permission bits of an inode. */ struct posix_acl * -posix_acl_from_mode(mode_t mode, gfp_t flags) +posix_acl_from_mode(umode_t mode, gfp_t flags) { struct posix_acl *acl = posix_acl_alloc(3, flags); if (!acl) return ERR_PTR(-ENOMEM); acl->a_entries[0].e_tag = ACL_USER_OBJ; - acl->a_entries[0].e_id = ACL_UNDEFINED_ID; acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; acl->a_entries[1].e_tag = ACL_GROUP_OBJ; - acl->a_entries[1].e_id = ACL_UNDEFINED_ID; acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; acl->a_entries[2].e_tag = ACL_OTHER; - acl->a_entries[2].e_id = ACL_UNDEFINED_ID; acl->a_entries[2].e_perm = (mode & S_IRWXO); return acl; } +EXPORT_SYMBOL(posix_acl_from_mode); /* * Return 0 if current is granted want access to the inode @@ -213,15 +314,17 @@ posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want) const struct posix_acl_entry *pa, *pe, *mask_obj; int found = 0; + want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK; + FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { case ACL_USER_OBJ: /* (May have been checked already) */ - if (inode->i_uid == current_fsuid()) + if (uid_eq(inode->i_uid, current_fsuid())) goto check_perm; break; case ACL_USER: - if (pa->e_id == current_fsuid()) + if (uid_eq(pa->e_uid, current_fsuid())) goto mask; break; case ACL_GROUP_OBJ: @@ -232,7 +335,7 @@ posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want) } break; case ACL_GROUP: - if (in_group_p(pa->e_id)) { + if (in_group_p(pa->e_gid)) { found = 1; if ((pa->e_perm & want) == want) goto mask; @@ -274,12 +377,11 @@ check_perm: * system calls. All permissions that are not granted by the acl are removed. * The permissions in the acl are changed to reflect the mode_p parameter. */ -int -posix_acl_create_masq(struct posix_acl *acl, mode_t *mode_p) +static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) { struct posix_acl_entry *pa, *pe; struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; - mode_t mode = *mode_p; + umode_t mode = *mode_p; int not_equiv = 0; /* assert(atomic_read(acl->a_refcount) == 1); */ @@ -332,8 +434,7 @@ posix_acl_create_masq(struct posix_acl *acl, mode_t *mode_p) /* * Modify the ACL for the chmod syscall. */ -int -posix_acl_chmod_masq(struct posix_acl *acl, mode_t mode) +static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) { struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; struct posix_acl_entry *pa, *pe; @@ -377,3 +478,424 @@ posix_acl_chmod_masq(struct posix_acl *acl, mode_t mode) return 0; } + +int +__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) +{ + struct posix_acl *clone = posix_acl_clone(*acl, gfp); + int err = -ENOMEM; + if (clone) { + err = posix_acl_create_masq(clone, mode_p); + if (err < 0) { + posix_acl_release(clone); + clone = NULL; + } + } + posix_acl_release(*acl); + *acl = clone; + return err; +} +EXPORT_SYMBOL(__posix_acl_create); + +int +__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) +{ + struct posix_acl *clone = posix_acl_clone(*acl, gfp); + int err = -ENOMEM; + if (clone) { + err = __posix_acl_chmod_masq(clone, mode); + if (err) { + posix_acl_release(clone); + clone = NULL; + } + } + posix_acl_release(*acl); + *acl = clone; + return err; +} +EXPORT_SYMBOL(__posix_acl_chmod); + +int +posix_acl_chmod(struct inode *inode, umode_t mode) +{ + struct posix_acl *acl; + int ret = 0; + + if (!IS_POSIXACL(inode)) + return 0; + if (!inode->i_op->set_acl) + return -EOPNOTSUPP; + + acl = get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR_OR_NULL(acl)) { + if (acl == ERR_PTR(-EOPNOTSUPP)) + return 0; + return PTR_ERR(acl); + } + + ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); + if (ret) + return ret; + ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS); + posix_acl_release(acl); + return ret; +} +EXPORT_SYMBOL(posix_acl_chmod); + +int +posix_acl_create(struct inode *dir, umode_t *mode, + struct posix_acl **default_acl, struct posix_acl **acl) +{ + struct posix_acl *p; + int ret; + + if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) + goto no_acl; + + p = get_acl(dir, ACL_TYPE_DEFAULT); + if (IS_ERR(p)) { + if (p == ERR_PTR(-EOPNOTSUPP)) + goto apply_umask; + return PTR_ERR(p); + } + + if (!p) + goto apply_umask; + + *acl = posix_acl_clone(p, GFP_NOFS); + if (!*acl) + return -ENOMEM; + + ret = posix_acl_create_masq(*acl, mode); + if (ret < 0) { + posix_acl_release(*acl); + return -ENOMEM; + } + + if (ret == 0) { + posix_acl_release(*acl); + *acl = NULL; + } + + if (!S_ISDIR(*mode)) { + posix_acl_release(p); + *default_acl = NULL; + } else { + *default_acl = p; + } + return 0; + +apply_umask: + *mode &= ~current_umask(); +no_acl: + *default_acl = NULL; + *acl = NULL; + return 0; +} +EXPORT_SYMBOL_GPL(posix_acl_create); + +/* + * Fix up the uids and gids in posix acl extended attributes in place. + */ +static void posix_acl_fix_xattr_userns( + struct user_namespace *to, struct user_namespace *from, + void *value, size_t size) +{ + posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; + posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; + int count; + kuid_t uid; + kgid_t gid; + + if (!value) + return; + if (size < sizeof(posix_acl_xattr_header)) + return; + if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) + return; + + count = posix_acl_xattr_count(size); + if (count < 0) + return; + if (count == 0) + return; + + for (end = entry + count; entry != end; entry++) { + switch(le16_to_cpu(entry->e_tag)) { + case ACL_USER: + uid = make_kuid(from, le32_to_cpu(entry->e_id)); + entry->e_id = cpu_to_le32(from_kuid(to, uid)); + break; + case ACL_GROUP: + gid = make_kgid(from, le32_to_cpu(entry->e_id)); + entry->e_id = cpu_to_le32(from_kgid(to, gid)); + break; + default: + break; + } + } +} + +void posix_acl_fix_xattr_from_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); +} + +void posix_acl_fix_xattr_to_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); +} + +/* + * Convert from extended attribute to in-memory representation. + */ +struct posix_acl * +posix_acl_from_xattr(struct user_namespace *user_ns, + const void *value, size_t size) +{ + posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; + posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; + int count; + struct posix_acl *acl; + struct posix_acl_entry *acl_e; + + if (!value) + return NULL; + if (size < sizeof(posix_acl_xattr_header)) + return ERR_PTR(-EINVAL); + if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) + return ERR_PTR(-EOPNOTSUPP); + + count = posix_acl_xattr_count(size); + if (count < 0) + return ERR_PTR(-EINVAL); + if (count == 0) + return NULL; + + acl = posix_acl_alloc(count, GFP_NOFS); + if (!acl) + return ERR_PTR(-ENOMEM); + acl_e = acl->a_entries; + + for (end = entry + count; entry != end; acl_e++, entry++) { + acl_e->e_tag = le16_to_cpu(entry->e_tag); + acl_e->e_perm = le16_to_cpu(entry->e_perm); + + switch(acl_e->e_tag) { + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + break; + + case ACL_USER: + acl_e->e_uid = + make_kuid(user_ns, + le32_to_cpu(entry->e_id)); + if (!uid_valid(acl_e->e_uid)) + goto fail; + break; + case ACL_GROUP: + acl_e->e_gid = + make_kgid(user_ns, + le32_to_cpu(entry->e_id)); + if (!gid_valid(acl_e->e_gid)) + goto fail; + break; + + default: + goto fail; + } + } + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} +EXPORT_SYMBOL (posix_acl_from_xattr); + +/* + * Convert from in-memory to extended attribute representation. + */ +int +posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, + void *buffer, size_t size) +{ + posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer; + posix_acl_xattr_entry *ext_entry; + int real_size, n; + + real_size = posix_acl_xattr_size(acl->a_count); + if (!buffer) + return real_size; + if (real_size > size) + return -ERANGE; + + ext_entry = ext_acl->a_entries; + ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); + + for (n=0; n < acl->a_count; n++, ext_entry++) { + const struct posix_acl_entry *acl_e = &acl->a_entries[n]; + ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); + ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); + switch(acl_e->e_tag) { + case ACL_USER: + ext_entry->e_id = + cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); + break; + case ACL_GROUP: + ext_entry->e_id = + cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); + break; + default: + ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); + break; + } + } + return real_size; +} +EXPORT_SYMBOL (posix_acl_to_xattr); + +static int +posix_acl_xattr_get(struct dentry *dentry, const char *name, + void *value, size_t size, int type) +{ + struct posix_acl *acl; + int error; + + if (!IS_POSIXACL(dentry->d_inode)) + return -EOPNOTSUPP; + if (S_ISLNK(dentry->d_inode->i_mode)) + return -EOPNOTSUPP; + + acl = get_acl(dentry->d_inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl == NULL) + return -ENODATA; + + error = posix_acl_to_xattr(&init_user_ns, acl, value, size); + posix_acl_release(acl); + + return error; +} + +static int +posix_acl_xattr_set(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, int type) +{ + struct inode *inode = dentry->d_inode; + struct posix_acl *acl = NULL; + int ret; + + if (!IS_POSIXACL(inode)) + return -EOPNOTSUPP; + if (!inode->i_op->set_acl) + return -EOPNOTSUPP; + + if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) + return value ? -EACCES : 0; + if (!inode_owner_or_capable(inode)) + return -EPERM; + + if (value) { + acl = posix_acl_from_xattr(&init_user_ns, value, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + + if (acl) { + ret = posix_acl_valid(acl); + if (ret) + goto out; + } + } + + ret = inode->i_op->set_acl(inode, acl, type); +out: + posix_acl_release(acl); + return ret; +} + +static size_t +posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size, + const char *name, size_t name_len, int type) +{ + const char *xname; + size_t size; + + if (!IS_POSIXACL(dentry->d_inode)) + return -EOPNOTSUPP; + if (S_ISLNK(dentry->d_inode->i_mode)) + return -EOPNOTSUPP; + + if (type == ACL_TYPE_ACCESS) + xname = POSIX_ACL_XATTR_ACCESS; + else + xname = POSIX_ACL_XATTR_DEFAULT; + + size = strlen(xname) + 1; + if (list && size <= list_size) + memcpy(list, xname, size); + return size; +} + +const struct xattr_handler posix_acl_access_xattr_handler = { + .prefix = POSIX_ACL_XATTR_ACCESS, + .flags = ACL_TYPE_ACCESS, + .list = posix_acl_xattr_list, + .get = posix_acl_xattr_get, + .set = posix_acl_xattr_set, +}; +EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); + +const struct xattr_handler posix_acl_default_xattr_handler = { + .prefix = POSIX_ACL_XATTR_DEFAULT, + .flags = ACL_TYPE_DEFAULT, + .list = posix_acl_xattr_list, + .get = posix_acl_xattr_get, + .set = posix_acl_xattr_set, +}; +EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); + +int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type) +{ + int error; + + if (type == ACL_TYPE_ACCESS) { + error = posix_acl_equiv_mode(acl, &inode->i_mode); + if (error < 0) + return 0; + if (error == 0) + acl = NULL; + } + + inode->i_ctime = CURRENT_TIME; + set_cached_acl(inode, type, acl); + return 0; +} + +int simple_acl_create(struct inode *dir, struct inode *inode) +{ + struct posix_acl *default_acl, *acl; + int error; + + error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); + if (error) + return error; + + set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); + set_cached_acl(inode, ACL_TYPE_ACCESS, acl); + + if (default_acl) + posix_acl_release(default_acl); + if (acl) + posix_acl_release(acl); + return 0; +} |