diff options
Diffstat (limited to 'fs/posix_acl.c')
| -rw-r--r-- | fs/posix_acl.c | 725 |
1 files changed, 368 insertions, 357 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 74dc0f571dc9..e6643db35cce 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -25,6 +25,11 @@ #include <linux/namei.h> #include <linux/mnt_idmapping.h> #include <linux/iversion.h> +#include <linux/security.h> +#include <linux/evm.h> +#include <linux/fsnotify.h> + +#include "internal.h" static struct posix_acl **acl_by_type(struct inode *inode, int type) { @@ -64,7 +69,7 @@ struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) if (acl == ACL_DONT_CACHE) { struct posix_acl *ret; - ret = inode->i_op->get_acl(inode, type, LOOKUP_RCU); + ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU); if (!IS_ERR(ret)) acl = ret; } @@ -106,15 +111,17 @@ void forget_all_cached_acls(struct inode *inode) } EXPORT_SYMBOL(forget_all_cached_acls); -struct posix_acl *get_acl(struct inode *inode, int type) +static struct posix_acl *__get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, struct inode *inode, + int type) { - void *sentinel; + struct posix_acl *sentinel; struct posix_acl **p; struct posix_acl *acl; /* * The sentinel is used to detect when another operation like - * set_cached_acl() or forget_cached_acl() races with get_acl(). + * set_cached_acl() or forget_cached_acl() races with get_inode_acl(). * It is guaranteed that is_uncached_acl(sentinel) is true. */ @@ -133,25 +140,27 @@ struct posix_acl *get_acl(struct inode *inode, int type) * current value of the ACL will not be ACL_NOT_CACHED and so our own * sentinel will not be set; another task will update the cache. We * could wait for that other task to complete its job, but it's easier - * to just call ->get_acl to fetch the ACL ourself. (This is going to - * be an unlikely race.) + * to just call ->get_inode_acl to fetch the ACL ourself. (This is + * going to be an unlikely race.) */ cmpxchg(p, ACL_NOT_CACHED, sentinel); /* - * Normally, the ACL returned by ->get_acl will be cached. + * Normally, the ACL returned by ->get{_inode}_acl will be cached. * A filesystem can prevent that by calling - * forget_cached_acl(inode, type) in ->get_acl. + * forget_cached_acl(inode, type) in ->get{_inode}_acl. * - * If the filesystem doesn't have a get_acl() function at all, we'll - * just create the negative cache entry. + * If the filesystem doesn't have a get{_inode}_ acl() function at all, + * we'll just create the negative cache entry. */ - if (!inode->i_op->get_acl) { + if (dentry && inode->i_op->get_acl) { + acl = inode->i_op->get_acl(mnt_userns, dentry, type); + } else if (inode->i_op->get_inode_acl) { + acl = inode->i_op->get_inode_acl(inode, type, false); + } else { set_cached_acl(inode, type, NULL); return NULL; } - acl = inode->i_op->get_acl(inode, type, false); - if (IS_ERR(acl)) { /* * Remove our sentinel so that we don't block future attempts @@ -169,7 +178,12 @@ struct posix_acl *get_acl(struct inode *inode, int type) posix_acl_release(acl); return acl; } -EXPORT_SYMBOL(get_acl); + +struct posix_acl *get_inode_acl(struct inode *inode, int type) +{ + return __get_acl(&init_user_ns, NULL, inode, type); +} +EXPORT_SYMBOL(get_inode_acl); /* * Init a fresh posix_acl @@ -578,19 +592,20 @@ EXPORT_SYMBOL(__posix_acl_chmod); * posix_acl_chmod - chmod a posix acl * * @mnt_userns: user namespace of the mount @inode was found from - * @inode: inode to check permissions on + * @dentry: dentry to check permissions on * @mode: the new mode of @inode * - * If the inode has been found through an idmapped mount the user namespace of + * If the dentry has been found through an idmapped mount the user namespace of * the vfsmount must be passed through @mnt_userns. This function will then * take care to map the inode according to @mnt_userns before checking * permissions. On non-idmapped mounts or if permission checking is to be * performed on the raw inode simply passs init_user_ns. */ int - posix_acl_chmod(struct user_namespace *mnt_userns, struct inode *inode, + posix_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry, umode_t mode) { + struct inode *inode = d_inode(dentry); struct posix_acl *acl; int ret = 0; @@ -599,7 +614,7 @@ int if (!inode->i_op->set_acl) return -EOPNOTSUPP; - acl = get_acl(inode, ACL_TYPE_ACCESS); + acl = get_inode_acl(inode, ACL_TYPE_ACCESS); if (IS_ERR_OR_NULL(acl)) { if (acl == ERR_PTR(-EOPNOTSUPP)) return 0; @@ -609,7 +624,7 @@ int ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); if (ret) return ret; - ret = inode->i_op->set_acl(mnt_userns, inode, acl, ACL_TYPE_ACCESS); + ret = inode->i_op->set_acl(mnt_userns, dentry, acl, ACL_TYPE_ACCESS); posix_acl_release(acl); return ret; } @@ -629,7 +644,7 @@ posix_acl_create(struct inode *dir, umode_t *mode, if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) return 0; - p = get_acl(dir, ACL_TYPE_DEFAULT); + p = get_inode_acl(dir, ACL_TYPE_DEFAULT); if (!p || p == ERR_PTR(-EOPNOTSUPP)) { *mode &= ~current_umask(); return 0; @@ -732,118 +747,32 @@ static int posix_acl_fix_xattr_common(const void *value, size_t size) return count; } -void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns, - const struct inode *inode, - void *value, size_t size) -{ - struct posix_acl_xattr_header *header = value; - struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; - struct user_namespace *fs_userns = i_user_ns(inode); - int count; - vfsuid_t vfsuid; - vfsgid_t vfsgid; - kuid_t uid; - kgid_t gid; - - if (no_idmapping(mnt_userns, i_user_ns(inode))) - return; - - count = posix_acl_fix_xattr_common(value, size); - if (count <= 0) - return; - - for (end = entry + count; entry != end; entry++) { - switch (le16_to_cpu(entry->e_tag)) { - case ACL_USER: - uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); - vfsuid = make_vfsuid(mnt_userns, fs_userns, uid); - entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, - vfsuid_into_kuid(vfsuid))); - break; - case ACL_GROUP: - gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); - vfsgid = make_vfsgid(mnt_userns, fs_userns, gid); - entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, - vfsgid_into_kgid(vfsgid))); - break; - default: - break; - } - } -} - -static void posix_acl_fix_xattr_userns( - struct user_namespace *to, struct user_namespace *from, - void *value, size_t size) -{ - struct posix_acl_xattr_header *header = value; - struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; - int count; - kuid_t uid; - kgid_t gid; - - count = posix_acl_fix_xattr_common(value, size); - 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); -} - /** - * make_posix_acl - convert POSIX ACLs from uapi to VFS format using the - * provided callbacks to map ACL_{GROUP,USER} entries into the - * appropriate format - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping + * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format + * @userns: the filesystem's idmapping * @value: the uapi representation of POSIX ACLs * @size: the size of @void - * @uid_cb: callback to use for mapping the uid stored in ACL_USER entries - * @gid_cb: callback to use for mapping the gid stored in ACL_GROUP entries * - * The make_posix_acl() helper is an abstraction to translate from uapi format - * into the VFS format allowing the caller to specific callbacks to map - * ACL_{GROUP,USER} entries into the expected format. This is used in - * posix_acl_from_xattr() and vfs_set_acl_prepare() and avoids pointless code - * duplication. + * Filesystems that store POSIX ACLs in the unaltered uapi format should use + * posix_acl_from_xattr() when reading them from the backing store and + * converting them into the struct posix_acl VFS format. The helper is + * specifically intended to be called from the acl inode operation. + * + * The posix_acl_from_xattr() function will map the raw {g,u}id values stored + * in ACL_{GROUP,USER} entries into idmapping in @userns. + * + * Note that posix_acl_from_xattr() does not take idmapped mounts into account. + * If it did it calling it from the get acl inode operation would return POSIX + * ACLs mapped according to an idmapped mount which would mean that the value + * couldn't be cached for the filesystem. Idmapped mounts are taken into + * account on the fly during permission checking or right at the VFS - + * userspace boundary before reporting them to the user. * * Return: Allocated struct posix_acl on success, NULL for a valid header but * without actual POSIX ACL entries, or ERR_PTR() encoded error code. */ -static struct posix_acl *make_posix_acl(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, const void *value, size_t size, - kuid_t (*uid_cb)(struct user_namespace *, struct user_namespace *, - const struct posix_acl_xattr_entry *), - kgid_t (*gid_cb)(struct user_namespace *, struct user_namespace *, - const struct posix_acl_xattr_entry *)) +struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns, + const void *value, size_t size) { const struct posix_acl_xattr_header *header = value; const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; @@ -874,12 +803,14 @@ static struct posix_acl *make_posix_acl(struct user_namespace *mnt_userns, break; case ACL_USER: - acl_e->e_uid = uid_cb(mnt_userns, fs_userns, entry); + acl_e->e_uid = make_kuid(userns, + le32_to_cpu(entry->e_id)); if (!uid_valid(acl_e->e_uid)) goto fail; break; case ACL_GROUP: - acl_e->e_gid = gid_cb(mnt_userns, fs_userns, entry); + acl_e->e_gid = make_kgid(userns, + le32_to_cpu(entry->e_id)); if (!gid_valid(acl_e->e_gid)) goto fail; break; @@ -894,181 +825,6 @@ fail: posix_acl_release(acl); return ERR_PTR(-EINVAL); } - -/** - * vfs_set_acl_prepare_kuid - map ACL_USER uid according to mount- and - * filesystem idmapping - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * @e: a ACL_USER entry in POSIX ACL uapi format - * - * The uid stored as ACL_USER entry in @e is a kuid_t stored as a raw {g,u}id - * value. The vfs_set_acl_prepare_kuid() will recover the kuid_t through - * KUIDT_INIT() and then map it according to the idmapped mount. The resulting - * kuid_t is the value which the filesystem can map up into a raw backing store - * id in the filesystem's idmapping. - * - * This is used in vfs_set_acl_prepare() to generate the proper VFS - * representation of POSIX ACLs with ACL_USER entries during setxattr(). - * - * Return: A kuid in @fs_userns for the uid stored in @e. - */ -static inline kuid_t -vfs_set_acl_prepare_kuid(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - const struct posix_acl_xattr_entry *e) -{ - kuid_t kuid = KUIDT_INIT(le32_to_cpu(e->e_id)); - return from_vfsuid(mnt_userns, fs_userns, VFSUIDT_INIT(kuid)); -} - -/** - * vfs_set_acl_prepare_kgid - map ACL_GROUP gid according to mount- and - * filesystem idmapping - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * @e: a ACL_GROUP entry in POSIX ACL uapi format - * - * The gid stored as ACL_GROUP entry in @e is a kgid_t stored as a raw {g,u}id - * value. The vfs_set_acl_prepare_kgid() will recover the kgid_t through - * KGIDT_INIT() and then map it according to the idmapped mount. The resulting - * kgid_t is the value which the filesystem can map up into a raw backing store - * id in the filesystem's idmapping. - * - * This is used in vfs_set_acl_prepare() to generate the proper VFS - * representation of POSIX ACLs with ACL_GROUP entries during setxattr(). - * - * Return: A kgid in @fs_userns for the gid stored in @e. - */ -static inline kgid_t -vfs_set_acl_prepare_kgid(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - const struct posix_acl_xattr_entry *e) -{ - kgid_t kgid = KGIDT_INIT(le32_to_cpu(e->e_id)); - return from_vfsgid(mnt_userns, fs_userns, VFSGIDT_INIT(kgid)); -} - -/** - * vfs_set_acl_prepare - convert POSIX ACLs from uapi to VFS format taking - * mount and filesystem idmappings into account - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * @value: the uapi representation of POSIX ACLs - * @size: the size of @void - * - * When setting POSIX ACLs with ACL_{GROUP,USER} entries they need to be - * mapped according to the relevant mount- and filesystem idmapping. It is - * important that the ACL_{GROUP,USER} entries in struct posix_acl will be - * mapped into k{g,u}id_t that are supposed to be mapped up in the filesystem - * idmapping. This is crucial since the resulting struct posix_acl might be - * cached filesystem wide. The vfs_set_acl_prepare() function will take care to - * perform all necessary idmappings. - * - * Note, that since basically forever the {g,u}id values encoded as - * ACL_{GROUP,USER} entries in the uapi POSIX ACLs passed via @value contain - * values that have been mapped according to the caller's idmapping. In other - * words, POSIX ACLs passed in uapi format as @value during setxattr() contain - * {g,u}id values in their ACL_{GROUP,USER} entries that should actually have - * been stored as k{g,u}id_t. - * - * This means, vfs_set_acl_prepare() needs to first recover the k{g,u}id_t by - * calling K{G,U}IDT_INIT(). Afterwards they can be interpreted as vfs{g,u}id_t - * through from_vfs{g,u}id() to account for any idmapped mounts. The - * vfs_set_acl_prepare_k{g,u}id() helpers will take care to generate the - * correct k{g,u}id_t. - * - * The filesystem will then receive the POSIX ACLs ready to be cached - * filesystem wide and ready to be written to the backing store taking the - * filesystem's idmapping into account. - * - * Return: Allocated struct posix_acl on success, NULL for a valid header but - * without actual POSIX ACL entries, or ERR_PTR() encoded error code. - */ -struct posix_acl *vfs_set_acl_prepare(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - const void *value, size_t size) -{ - return make_posix_acl(mnt_userns, fs_userns, value, size, - vfs_set_acl_prepare_kuid, - vfs_set_acl_prepare_kgid); -} -EXPORT_SYMBOL(vfs_set_acl_prepare); - -/** - * posix_acl_from_xattr_kuid - map ACL_USER uid into filesystem idmapping - * @mnt_userns: unused - * @fs_userns: the filesystem's idmapping - * @e: a ACL_USER entry in POSIX ACL uapi format - * - * Map the uid stored as ACL_USER entry in @e into the filesystem's idmapping. - * This is used in posix_acl_from_xattr() to generate the proper VFS - * representation of POSIX ACLs with ACL_USER entries. - * - * Return: A kuid in @fs_userns for the uid stored in @e. - */ -static inline kuid_t -posix_acl_from_xattr_kuid(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - const struct posix_acl_xattr_entry *e) -{ - return make_kuid(fs_userns, le32_to_cpu(e->e_id)); -} - -/** - * posix_acl_from_xattr_kgid - map ACL_GROUP gid into filesystem idmapping - * @mnt_userns: unused - * @fs_userns: the filesystem's idmapping - * @e: a ACL_GROUP entry in POSIX ACL uapi format - * - * Map the gid stored as ACL_GROUP entry in @e into the filesystem's idmapping. - * This is used in posix_acl_from_xattr() to generate the proper VFS - * representation of POSIX ACLs with ACL_GROUP entries. - * - * Return: A kgid in @fs_userns for the gid stored in @e. - */ -static inline kgid_t -posix_acl_from_xattr_kgid(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - const struct posix_acl_xattr_entry *e) -{ - return make_kgid(fs_userns, le32_to_cpu(e->e_id)); -} - -/** - * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format - * @fs_userns: the filesystem's idmapping - * @value: the uapi representation of POSIX ACLs - * @size: the size of @void - * - * Filesystems that store POSIX ACLs in the unaltered uapi format should use - * posix_acl_from_xattr() when reading them from the backing store and - * converting them into the struct posix_acl VFS format. The helper is - * specifically intended to be called from the ->get_acl() inode operation. - * - * The posix_acl_from_xattr() function will map the raw {g,u}id values stored - * in ACL_{GROUP,USER} entries into the filesystem idmapping in @fs_userns. The - * posix_acl_from_xattr_k{g,u}id() helpers will take care to generate the - * correct k{g,u}id_t. The returned struct posix_acl can be cached. - * - * Note that posix_acl_from_xattr() does not take idmapped mounts into account. - * If it did it calling is from the ->get_acl() inode operation would return - * POSIX ACLs mapped according to an idmapped mount which would mean that the - * value couldn't be cached for the filesystem. Idmapped mounts are taken into - * account on the fly during permission checking or right at the VFS - - * userspace boundary before reporting them to the user. - * - * Return: Allocated struct posix_acl on success, NULL for a valid header but - * without actual POSIX ACL entries, or ERR_PTR() encoded error code. - */ -struct posix_acl * -posix_acl_from_xattr(struct user_namespace *fs_userns, - const void *value, size_t size) -{ - return make_posix_acl(&init_user_ns, fs_userns, value, size, - posix_acl_from_xattr_kuid, - posix_acl_from_xattr_kgid); -} EXPORT_SYMBOL (posix_acl_from_xattr); /* @@ -1113,35 +869,74 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, } EXPORT_SYMBOL (posix_acl_to_xattr); -static int -posix_acl_xattr_get(const struct xattr_handler *handler, - struct dentry *unused, struct inode *inode, - const char *name, void *value, size_t size) -{ - struct posix_acl *acl; - int error; +/** + * vfs_posix_acl_to_xattr - convert from kernel to userspace representation + * @mnt_userns: user namespace of the mount + * @inode: inode the posix acls are set on + * @acl: the posix acls as represented by the vfs + * @buffer: the buffer into which to convert @acl + * @size: size of @buffer + * + * This converts @acl from the VFS representation in the filesystem idmapping + * to the uapi form reportable to userspace. And mount and caller idmappings + * are handled appropriately. + * + * Return: On success, the size of the stored uapi posix acls, on error a + * negative errno. + */ +static ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns, + struct inode *inode, + const struct posix_acl *acl, void *buffer, + size_t size) - if (!IS_POSIXACL(inode)) - return -EOPNOTSUPP; - if (S_ISLNK(inode->i_mode)) - return -EOPNOTSUPP; +{ + struct posix_acl_xattr_header *ext_acl = buffer; + struct posix_acl_xattr_entry *ext_entry; + struct user_namespace *fs_userns, *caller_userns; + ssize_t real_size, n; + vfsuid_t vfsuid; + vfsgid_t vfsgid; - acl = get_acl(inode, handler->flags); - if (IS_ERR(acl)) - return PTR_ERR(acl); - if (acl == NULL) - return -ENODATA; + real_size = posix_acl_xattr_size(acl->a_count); + if (!buffer) + return real_size; + if (real_size > size) + return -ERANGE; - error = posix_acl_to_xattr(&init_user_ns, acl, value, size); - posix_acl_release(acl); + ext_entry = (void *)(ext_acl + 1); + ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); - return error; + fs_userns = i_user_ns(inode); + caller_userns = current_user_ns(); + 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: + vfsuid = make_vfsuid(mnt_userns, fs_userns, acl_e->e_uid); + ext_entry->e_id = cpu_to_le32(from_kuid( + caller_userns, vfsuid_into_kuid(vfsuid))); + break; + case ACL_GROUP: + vfsgid = make_vfsgid(mnt_userns, fs_userns, acl_e->e_gid); + ext_entry->e_id = cpu_to_le32(from_kgid( + caller_userns, vfsgid_into_kgid(vfsgid))); + break; + default: + ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); + break; + } + } + return real_size; } int -set_posix_acl(struct user_namespace *mnt_userns, struct inode *inode, +set_posix_acl(struct user_namespace *mnt_userns, struct dentry *dentry, int type, struct posix_acl *acl) { + struct inode *inode = d_inode(dentry); + if (!IS_POSIXACL(inode)) return -EOPNOTSUPP; if (!inode->i_op->set_acl) @@ -1157,40 +952,10 @@ set_posix_acl(struct user_namespace *mnt_userns, struct inode *inode, if (ret) return ret; } - return inode->i_op->set_acl(mnt_userns, inode, acl, type); + return inode->i_op->set_acl(mnt_userns, dentry, acl, type); } EXPORT_SYMBOL(set_posix_acl); -static int -posix_acl_xattr_set(const struct xattr_handler *handler, - struct user_namespace *mnt_userns, - struct dentry *unused, struct inode *inode, - const char *name, const void *value, size_t size, - int flags) -{ - struct posix_acl *acl = NULL; - int ret; - - if (value) { - /* - * By the time we end up here the {g,u}ids stored in - * ACL_{GROUP,USER} have already been mapped according to the - * caller's idmapping. The vfs_set_acl_prepare() helper will - * recover them and take idmapped mounts into account. The - * filesystem will receive the POSIX ACLs in the correct - * format ready to be cached or written to the backing store - * taking the filesystem idmapping into account. - */ - acl = vfs_set_acl_prepare(mnt_userns, i_user_ns(inode), - value, size); - if (IS_ERR(acl)) - return PTR_ERR(acl); - } - ret = set_posix_acl(mnt_userns, inode, handler->flags, acl); - posix_acl_release(acl); - return ret; -} - static bool posix_acl_xattr_list(struct dentry *dentry) { @@ -1201,8 +966,6 @@ const struct xattr_handler posix_acl_access_xattr_handler = { .name = XATTR_NAME_POSIX_ACL_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); @@ -1210,15 +973,14 @@ const struct xattr_handler posix_acl_default_xattr_handler = { .name = XATTR_NAME_POSIX_ACL_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 user_namespace *mnt_userns, struct inode *inode, +int simple_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, struct posix_acl *acl, int type) { int error; + struct inode *inode = d_inode(dentry); if (type == ACL_TYPE_ACCESS) { error = posix_acl_update_mode(mnt_userns, inode, @@ -1252,3 +1014,252 @@ int simple_acl_create(struct inode *dir, struct inode *inode) posix_acl_release(acl); return 0; } + +static int vfs_set_acl_idmapped_mnt(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + struct posix_acl *acl) +{ + for (int n = 0; n < acl->a_count; n++) { + struct posix_acl_entry *acl_e = &acl->a_entries[n]; + + switch (acl_e->e_tag) { + case ACL_USER: + acl_e->e_uid = from_vfsuid(mnt_userns, fs_userns, + VFSUIDT_INIT(acl_e->e_uid)); + break; + case ACL_GROUP: + acl_e->e_gid = from_vfsgid(mnt_userns, fs_userns, + VFSGIDT_INIT(acl_e->e_gid)); + break; + } + } + + return 0; +} + +/** + * vfs_set_acl - set posix acls + * @mnt_userns: user namespace of the mount + * @dentry: the dentry based on which to set the posix acls + * @acl_name: the name of the posix acl + * @kacl: the posix acls in the appropriate VFS format + * + * This function sets @kacl. The caller must all posix_acl_release() on @kacl + * afterwards. + * + * Return: On success 0, on error negative errno. + */ +int vfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) +{ + int acl_type; + int error; + struct inode *inode = d_inode(dentry); + struct inode *delegated_inode = NULL; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return -EINVAL; + + if (kacl) { + /* + * If we're on an idmapped mount translate from mount specific + * vfs{g,u}id_t into global filesystem k{g,u}id_t. + * Afterwards we can cache the POSIX ACLs filesystem wide and - + * if this is a filesystem with a backing store - ultimately + * translate them to backing store values. + */ + error = vfs_set_acl_idmapped_mnt(mnt_userns, i_user_ns(inode), kacl); + if (error) + return error; + } + +retry_deleg: + inode_lock(inode); + + /* + * We only care about restrictions the inode struct itself places upon + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. + */ + error = may_write_xattr(mnt_userns, inode); + if (error) + goto out_inode_unlock; + + error = security_inode_set_acl(mnt_userns, dentry, acl_name, kacl); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (inode->i_opflags & IOP_XATTR) + error = set_posix_acl(mnt_userns, dentry, acl_type, kacl); + else if (unlikely(is_bad_inode(inode))) + error = -EIO; + else + error = -EOPNOTSUPP; + if (!error) { + fsnotify_xattr(dentry); + evm_inode_post_set_acl(dentry, acl_name, kacl); + } + +out_inode_unlock: + inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL_GPL(vfs_set_acl); + +/** + * vfs_get_acl - get posix acls + * @mnt_userns: user namespace of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function retrieves @kacl from the filesystem. The caller must all + * posix_acl_release() on @kacl. + * + * Return: On success POSIX ACLs in VFS format, on error negative errno. + */ +struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *acl_name) +{ + struct inode *inode = d_inode(dentry); + struct posix_acl *acl; + int acl_type, error; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return ERR_PTR(-EINVAL); + + /* + * The VFS has no restrictions on reading POSIX ACLs so calling + * something like xattr_permission() isn't needed. Only LSMs get a say. + */ + error = security_inode_get_acl(mnt_userns, dentry, acl_name); + if (error) + return ERR_PTR(error); + + if (!IS_POSIXACL(inode)) + return ERR_PTR(-EOPNOTSUPP); + if (S_ISLNK(inode->i_mode)) + return ERR_PTR(-EOPNOTSUPP); + + acl = __get_acl(mnt_userns, dentry, inode, acl_type); + if (IS_ERR(acl)) + return acl; + if (!acl) + return ERR_PTR(-ENODATA); + + return acl; +} +EXPORT_SYMBOL_GPL(vfs_get_acl); + +/** + * vfs_remove_acl - remove posix acls + * @mnt_userns: user namespace of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function removes posix acls. + * + * Return: On success 0, on error negative errno. + */ +int vfs_remove_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name) +{ + int acl_type; + int error; + struct inode *inode = d_inode(dentry); + struct inode *delegated_inode = NULL; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return -EINVAL; + +retry_deleg: + inode_lock(inode); + + /* + * We only care about restrictions the inode struct itself places upon + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. + */ + error = may_write_xattr(mnt_userns, inode); + if (error) + goto out_inode_unlock; + + error = security_inode_remove_acl(mnt_userns, dentry, acl_name); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (inode->i_opflags & IOP_XATTR) + error = set_posix_acl(mnt_userns, dentry, acl_type, NULL); + else if (unlikely(is_bad_inode(inode))) + error = -EIO; + else + error = -EOPNOTSUPP; + if (!error) { + fsnotify_xattr(dentry); + evm_inode_post_remove_acl(mnt_userns, dentry, acl_name); + } + +out_inode_unlock: + inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL_GPL(vfs_remove_acl); + +int do_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name, const void *kvalue, size_t size) +{ + int error; + struct posix_acl *acl = NULL; + + if (size) { + /* + * Note that posix_acl_from_xattr() uses GFP_NOFS when it + * probably doesn't need to here. + */ + acl = posix_acl_from_xattr(current_user_ns(), kvalue, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + } + + error = vfs_set_acl(mnt_userns, dentry, acl_name, acl); + posix_acl_release(acl); + return error; +} + +ssize_t do_get_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name, void *kvalue, size_t size) +{ + ssize_t error; + struct posix_acl *acl; + + acl = vfs_get_acl(mnt_userns, dentry, acl_name); + if (IS_ERR(acl)) + return PTR_ERR(acl); + + error = vfs_posix_acl_to_xattr(mnt_userns, d_inode(dentry), + acl, kvalue, size); + posix_acl_release(acl); + return error; +} |