| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2008 Christoph Hellwig. |
| * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc. |
| */ |
| |
| #include "xfs.h" |
| #include "xfs_shared.h" |
| #include "xfs_format.h" |
| #include "xfs_log_format.h" |
| #include "xfs_da_format.h" |
| #include "xfs_trans_resv.h" |
| #include "xfs_mount.h" |
| #include "xfs_inode.h" |
| #include "xfs_da_btree.h" |
| #include "xfs_attr.h" |
| #include "xfs_acl.h" |
| #include "xfs_log.h" |
| #include "xfs_xattr.h" |
| |
| #include <linux/posix_acl_xattr.h> |
| |
| /* |
| * Get permission to use log-assisted atomic exchange of file extents. |
| * Callers must not be running any transactions or hold any ILOCKs. |
| */ |
| static inline int |
| xfs_attr_grab_log_assist( |
| struct xfs_mount *mp) |
| { |
| int error = 0; |
| |
| /* xattr update log intent items are already enabled */ |
| if (xfs_sb_version_haslogxattrs(&mp->m_sb)) |
| return 0; |
| |
| /* |
| * Check if the filesystem featureset is new enough to set this log |
| * incompat feature bit. Strictly speaking, the minimum requirement is |
| * a V5 filesystem for the superblock field, but we'll require rmap |
| * or reflink to avoid having to deal with really old kernels. |
| */ |
| if (!xfs_has_reflink(mp) && !xfs_has_rmapbt(mp)) |
| return -EOPNOTSUPP; |
| |
| /* Enable log-assisted xattrs. */ |
| error = xfs_add_incompat_log_feature(mp, |
| XFS_SB_FEAT_INCOMPAT_LOG_XATTRS); |
| if (error) |
| return error; |
| |
| xfs_warn_mount(mp, XFS_OPSTATE_WARNED_LARP, |
| "EXPERIMENTAL logged extended attributes feature in use. Use at your own risk!"); |
| |
| return 0; |
| } |
| |
| static inline bool |
| xfs_attr_want_log_assist( |
| struct xfs_mount *mp) |
| { |
| #ifdef DEBUG |
| /* Logged xattrs require a V5 super for log_incompat */ |
| return xfs_has_crc(mp) && xfs_globals.larp; |
| #else |
| return false; |
| #endif |
| } |
| |
| /* |
| * Set or remove an xattr, having grabbed the appropriate logging resources |
| * prior to calling libxfs. |
| */ |
| int |
| xfs_attr_change( |
| struct xfs_da_args *args) |
| { |
| struct xfs_mount *mp = args->dp->i_mount; |
| int error; |
| |
| ASSERT(!(args->op_flags & XFS_DA_OP_LOGGED)); |
| |
| if (xfs_attr_want_log_assist(mp)) { |
| error = xfs_attr_grab_log_assist(mp); |
| if (error) |
| return error; |
| |
| args->op_flags |= XFS_DA_OP_LOGGED; |
| } |
| |
| return xfs_attr_set(args); |
| } |
| |
| |
| static int |
| xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused, |
| struct inode *inode, const char *name, void *value, size_t size) |
| { |
| struct xfs_da_args args = { |
| .dp = XFS_I(inode), |
| .attr_filter = handler->flags, |
| .name = name, |
| .namelen = strlen(name), |
| .value = value, |
| .valuelen = size, |
| }; |
| int error; |
| |
| if (xfs_ifork_zapped(XFS_I(inode), XFS_ATTR_FORK)) |
| return -EIO; |
| |
| error = xfs_attr_get(&args); |
| if (error) |
| return error; |
| return args.valuelen; |
| } |
| |
| static int |
| xfs_xattr_set(const struct xattr_handler *handler, |
| struct mnt_idmap *idmap, struct dentry *unused, |
| struct inode *inode, const char *name, const void *value, |
| size_t size, int flags) |
| { |
| struct xfs_da_args args = { |
| .dp = XFS_I(inode), |
| .attr_filter = handler->flags, |
| .attr_flags = flags, |
| .name = name, |
| .namelen = strlen(name), |
| .value = (void *)value, |
| .valuelen = size, |
| }; |
| int error; |
| |
| error = xfs_attr_change(&args); |
| if (!error && (handler->flags & XFS_ATTR_ROOT)) |
| xfs_forget_acl(inode, name); |
| return error; |
| } |
| |
| static const struct xattr_handler xfs_xattr_user_handler = { |
| .prefix = XATTR_USER_PREFIX, |
| .flags = 0, /* no flags implies user namespace */ |
| .get = xfs_xattr_get, |
| .set = xfs_xattr_set, |
| }; |
| |
| static const struct xattr_handler xfs_xattr_trusted_handler = { |
| .prefix = XATTR_TRUSTED_PREFIX, |
| .flags = XFS_ATTR_ROOT, |
| .get = xfs_xattr_get, |
| .set = xfs_xattr_set, |
| }; |
| |
| static const struct xattr_handler xfs_xattr_security_handler = { |
| .prefix = XATTR_SECURITY_PREFIX, |
| .flags = XFS_ATTR_SECURE, |
| .get = xfs_xattr_get, |
| .set = xfs_xattr_set, |
| }; |
| |
| const struct xattr_handler * const xfs_xattr_handlers[] = { |
| &xfs_xattr_user_handler, |
| &xfs_xattr_trusted_handler, |
| &xfs_xattr_security_handler, |
| NULL |
| }; |
| |
| static void |
| __xfs_xattr_put_listent( |
| struct xfs_attr_list_context *context, |
| char *prefix, |
| int prefix_len, |
| unsigned char *name, |
| int namelen) |
| { |
| char *offset; |
| int arraytop; |
| |
| if (context->count < 0 || context->seen_enough) |
| return; |
| |
| if (!context->buffer) |
| goto compute_size; |
| |
| arraytop = context->count + prefix_len + namelen + 1; |
| if (arraytop > context->firstu) { |
| context->count = -1; /* insufficient space */ |
| context->seen_enough = 1; |
| return; |
| } |
| offset = context->buffer + context->count; |
| memcpy(offset, prefix, prefix_len); |
| offset += prefix_len; |
| strncpy(offset, (char *)name, namelen); /* real name */ |
| offset += namelen; |
| *offset = '\0'; |
| |
| compute_size: |
| context->count += prefix_len + namelen + 1; |
| return; |
| } |
| |
| static void |
| xfs_xattr_put_listent( |
| struct xfs_attr_list_context *context, |
| int flags, |
| unsigned char *name, |
| int namelen, |
| int valuelen) |
| { |
| char *prefix; |
| int prefix_len; |
| |
| ASSERT(context->count >= 0); |
| |
| if (flags & XFS_ATTR_ROOT) { |
| #ifdef CONFIG_XFS_POSIX_ACL |
| if (namelen == SGI_ACL_FILE_SIZE && |
| strncmp(name, SGI_ACL_FILE, |
| SGI_ACL_FILE_SIZE) == 0) { |
| __xfs_xattr_put_listent( |
| context, XATTR_SYSTEM_PREFIX, |
| XATTR_SYSTEM_PREFIX_LEN, |
| XATTR_POSIX_ACL_ACCESS, |
| strlen(XATTR_POSIX_ACL_ACCESS)); |
| } else if (namelen == SGI_ACL_DEFAULT_SIZE && |
| strncmp(name, SGI_ACL_DEFAULT, |
| SGI_ACL_DEFAULT_SIZE) == 0) { |
| __xfs_xattr_put_listent( |
| context, XATTR_SYSTEM_PREFIX, |
| XATTR_SYSTEM_PREFIX_LEN, |
| XATTR_POSIX_ACL_DEFAULT, |
| strlen(XATTR_POSIX_ACL_DEFAULT)); |
| } |
| #endif |
| |
| /* |
| * Only show root namespace entries if we are actually allowed to |
| * see them. |
| */ |
| if (!capable(CAP_SYS_ADMIN)) |
| return; |
| |
| prefix = XATTR_TRUSTED_PREFIX; |
| prefix_len = XATTR_TRUSTED_PREFIX_LEN; |
| } else if (flags & XFS_ATTR_SECURE) { |
| prefix = XATTR_SECURITY_PREFIX; |
| prefix_len = XATTR_SECURITY_PREFIX_LEN; |
| } else { |
| prefix = XATTR_USER_PREFIX; |
| prefix_len = XATTR_USER_PREFIX_LEN; |
| } |
| |
| __xfs_xattr_put_listent(context, prefix, prefix_len, name, |
| namelen); |
| return; |
| } |
| |
| ssize_t |
| xfs_vn_listxattr( |
| struct dentry *dentry, |
| char *data, |
| size_t size) |
| { |
| struct xfs_attr_list_context context; |
| struct inode *inode = d_inode(dentry); |
| int error; |
| |
| if (xfs_ifork_zapped(XFS_I(inode), XFS_ATTR_FORK)) |
| return -EIO; |
| |
| /* |
| * First read the regular on-disk attributes. |
| */ |
| memset(&context, 0, sizeof(context)); |
| context.dp = XFS_I(inode); |
| context.resynch = 1; |
| context.buffer = size ? data : NULL; |
| context.bufsize = size; |
| context.firstu = context.bufsize; |
| context.put_listent = xfs_xattr_put_listent; |
| |
| error = xfs_attr_list(&context); |
| if (error) |
| return error; |
| if (context.count < 0) |
| return -ERANGE; |
| |
| return context.count; |
| } |