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303 lines
6.7 KiB
303 lines
6.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/ext4/acl.c |
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* |
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* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]> |
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*/ |
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#include <linux/quotaops.h> |
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#include "ext4_jbd2.h" |
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#include "ext4.h" |
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#include "xattr.h" |
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#include "acl.h" |
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/* |
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* Convert from filesystem to in-memory representation. |
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*/ |
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static struct posix_acl * |
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ext4_acl_from_disk(const void *value, size_t size) |
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{ |
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const char *end = (char *)value + size; |
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int n, count; |
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struct posix_acl *acl; |
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if (!value) |
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return NULL; |
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if (size < sizeof(ext4_acl_header)) |
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return ERR_PTR(-EINVAL); |
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if (((ext4_acl_header *)value)->a_version != |
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cpu_to_le32(EXT4_ACL_VERSION)) |
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return ERR_PTR(-EINVAL); |
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value = (char *)value + sizeof(ext4_acl_header); |
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count = ext4_acl_count(size); |
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if (count < 0) |
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return ERR_PTR(-EINVAL); |
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if (count == 0) |
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return NULL; |
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acl = posix_acl_alloc(count, GFP_NOFS); |
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if (!acl) |
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return ERR_PTR(-ENOMEM); |
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for (n = 0; n < count; n++) { |
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ext4_acl_entry *entry = |
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(ext4_acl_entry *)value; |
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if ((char *)value + sizeof(ext4_acl_entry_short) > end) |
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goto fail; |
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acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); |
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acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); |
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switch (acl->a_entries[n].e_tag) { |
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case ACL_USER_OBJ: |
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case ACL_GROUP_OBJ: |
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case ACL_MASK: |
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case ACL_OTHER: |
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value = (char *)value + |
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sizeof(ext4_acl_entry_short); |
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break; |
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case ACL_USER: |
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value = (char *)value + sizeof(ext4_acl_entry); |
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if ((char *)value > end) |
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goto fail; |
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acl->a_entries[n].e_uid = |
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make_kuid(&init_user_ns, |
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le32_to_cpu(entry->e_id)); |
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break; |
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case ACL_GROUP: |
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value = (char *)value + sizeof(ext4_acl_entry); |
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if ((char *)value > end) |
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goto fail; |
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acl->a_entries[n].e_gid = |
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make_kgid(&init_user_ns, |
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le32_to_cpu(entry->e_id)); |
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break; |
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default: |
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goto fail; |
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} |
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} |
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if (value != end) |
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goto fail; |
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return acl; |
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fail: |
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posix_acl_release(acl); |
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return ERR_PTR(-EINVAL); |
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} |
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/* |
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* Convert from in-memory to filesystem representation. |
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*/ |
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static void * |
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ext4_acl_to_disk(const struct posix_acl *acl, size_t *size) |
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{ |
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ext4_acl_header *ext_acl; |
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char *e; |
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size_t n; |
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*size = ext4_acl_size(acl->a_count); |
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ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count * |
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sizeof(ext4_acl_entry), GFP_NOFS); |
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if (!ext_acl) |
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return ERR_PTR(-ENOMEM); |
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ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION); |
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e = (char *)ext_acl + sizeof(ext4_acl_header); |
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for (n = 0; n < acl->a_count; n++) { |
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const struct posix_acl_entry *acl_e = &acl->a_entries[n]; |
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ext4_acl_entry *entry = (ext4_acl_entry *)e; |
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entry->e_tag = cpu_to_le16(acl_e->e_tag); |
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entry->e_perm = cpu_to_le16(acl_e->e_perm); |
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switch (acl_e->e_tag) { |
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case ACL_USER: |
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entry->e_id = cpu_to_le32( |
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from_kuid(&init_user_ns, acl_e->e_uid)); |
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e += sizeof(ext4_acl_entry); |
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break; |
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case ACL_GROUP: |
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entry->e_id = cpu_to_le32( |
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from_kgid(&init_user_ns, acl_e->e_gid)); |
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e += sizeof(ext4_acl_entry); |
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break; |
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case ACL_USER_OBJ: |
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case ACL_GROUP_OBJ: |
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case ACL_MASK: |
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case ACL_OTHER: |
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e += sizeof(ext4_acl_entry_short); |
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break; |
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default: |
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goto fail; |
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} |
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} |
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return (char *)ext_acl; |
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fail: |
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kfree(ext_acl); |
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return ERR_PTR(-EINVAL); |
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} |
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/* |
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* Inode operation get_posix_acl(). |
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* |
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* inode->i_rwsem: don't care |
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*/ |
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struct posix_acl * |
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ext4_get_acl(struct inode *inode, int type, bool rcu) |
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{ |
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int name_index; |
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char *value = NULL; |
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struct posix_acl *acl; |
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int retval; |
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if (rcu) |
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return ERR_PTR(-ECHILD); |
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switch (type) { |
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case ACL_TYPE_ACCESS: |
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; |
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break; |
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case ACL_TYPE_DEFAULT: |
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; |
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break; |
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default: |
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BUG(); |
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} |
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retval = ext4_xattr_get(inode, name_index, "", NULL, 0); |
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if (retval > 0) { |
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value = kmalloc(retval, GFP_NOFS); |
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if (!value) |
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return ERR_PTR(-ENOMEM); |
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retval = ext4_xattr_get(inode, name_index, "", value, retval); |
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} |
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if (retval > 0) |
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acl = ext4_acl_from_disk(value, retval); |
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else if (retval == -ENODATA || retval == -ENOSYS) |
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acl = NULL; |
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else |
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acl = ERR_PTR(retval); |
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kfree(value); |
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return acl; |
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} |
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/* |
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* Set the access or default ACL of an inode. |
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* |
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* inode->i_rwsem: down unless called from ext4_new_inode |
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*/ |
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static int |
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__ext4_set_acl(handle_t *handle, struct inode *inode, int type, |
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struct posix_acl *acl, int xattr_flags) |
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{ |
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int name_index; |
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void *value = NULL; |
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size_t size = 0; |
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int error; |
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switch (type) { |
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case ACL_TYPE_ACCESS: |
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; |
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break; |
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case ACL_TYPE_DEFAULT: |
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; |
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if (!S_ISDIR(inode->i_mode)) |
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return acl ? -EACCES : 0; |
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break; |
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default: |
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return -EINVAL; |
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} |
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if (acl) { |
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value = ext4_acl_to_disk(acl, &size); |
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if (IS_ERR(value)) |
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return (int)PTR_ERR(value); |
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} |
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error = ext4_xattr_set_handle(handle, inode, name_index, "", |
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value, size, xattr_flags); |
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kfree(value); |
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if (!error) |
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set_cached_acl(inode, type, acl); |
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return error; |
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} |
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int |
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ext4_set_acl(struct user_namespace *mnt_userns, struct inode *inode, |
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struct posix_acl *acl, int type) |
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{ |
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handle_t *handle; |
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int error, credits, retries = 0; |
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size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0; |
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umode_t mode = inode->i_mode; |
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int update_mode = 0; |
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error = dquot_initialize(inode); |
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if (error) |
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return error; |
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retry: |
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error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */, |
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&credits); |
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if (error) |
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return error; |
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handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); |
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if (IS_ERR(handle)) |
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return PTR_ERR(handle); |
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if ((type == ACL_TYPE_ACCESS) && acl) { |
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error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl); |
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if (error) |
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goto out_stop; |
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if (mode != inode->i_mode) |
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update_mode = 1; |
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} |
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error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */); |
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if (!error && update_mode) { |
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inode->i_mode = mode; |
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inode->i_ctime = current_time(inode); |
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error = ext4_mark_inode_dirty(handle, inode); |
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} |
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out_stop: |
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ext4_journal_stop(handle); |
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if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) |
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goto retry; |
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return error; |
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} |
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/* |
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* Initialize the ACLs of a new inode. Called from ext4_new_inode. |
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* |
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* dir->i_rwsem: down |
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* inode->i_rwsem: up (access to inode is still exclusive) |
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*/ |
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int |
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ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) |
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{ |
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struct posix_acl *default_acl, *acl; |
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int error; |
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error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); |
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if (error) |
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return error; |
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if (default_acl) { |
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error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT, |
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default_acl, XATTR_CREATE); |
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posix_acl_release(default_acl); |
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} else { |
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inode->i_default_acl = NULL; |
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} |
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if (acl) { |
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if (!error) |
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error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, |
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acl, XATTR_CREATE); |
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posix_acl_release(acl); |
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} else { |
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inode->i_acl = NULL; |
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} |
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return error; |
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}
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