diff options
Diffstat (limited to '')
-rw-r--r-- | fs/xfs/xfs_acl.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c new file mode 100644 index 000000000..b744c6205 --- /dev/null +++ b/fs/xfs/xfs_acl.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2008, Christoph Hellwig + * All Rights Reserved. + */ +#include "xfs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_inode.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_attr.h" +#include "xfs_trace.h" +#include "xfs_error.h" +#include "xfs_acl.h" +#include "xfs_trans.h" +#include "xfs_xattr.h" + +#include <linux/posix_acl_xattr.h> + +/* + * Locking scheme: + * - all ACL updates are protected by inode->i_mutex, which is taken before + * calling into this file. + */ + +STATIC struct posix_acl * +xfs_acl_from_disk( + struct xfs_mount *mp, + const struct xfs_acl *aclp, + int len, + int max_entries) +{ + struct posix_acl_entry *acl_e; + struct posix_acl *acl; + const struct xfs_acl_entry *ace; + unsigned int count, i; + + if (len < sizeof(*aclp)) { + XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, + len); + return ERR_PTR(-EFSCORRUPTED); + } + + count = be32_to_cpu(aclp->acl_cnt); + if (count > max_entries || XFS_ACL_SIZE(count) != len) { + XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp, + len); + return ERR_PTR(-EFSCORRUPTED); + } + + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < count; i++) { + acl_e = &acl->a_entries[i]; + ace = &aclp->acl_entry[i]; + + /* + * The tag is 32 bits on disk and 16 bits in core. + * + * Because every access to it goes through the core + * format first this is not a problem. + */ + acl_e->e_tag = be32_to_cpu(ace->ae_tag); + acl_e->e_perm = be16_to_cpu(ace->ae_perm); + + switch (acl_e->e_tag) { + case ACL_USER: + acl_e->e_uid = make_kuid(&init_user_ns, + be32_to_cpu(ace->ae_id)); + break; + case ACL_GROUP: + acl_e->e_gid = make_kgid(&init_user_ns, + be32_to_cpu(ace->ae_id)); + break; + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + break; + default: + goto fail; + } + } + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} + +STATIC void +xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) +{ + const struct posix_acl_entry *acl_e; + struct xfs_acl_entry *ace; + int i; + + aclp->acl_cnt = cpu_to_be32(acl->a_count); + for (i = 0; i < acl->a_count; i++) { + ace = &aclp->acl_entry[i]; + acl_e = &acl->a_entries[i]; + + ace->ae_tag = cpu_to_be32(acl_e->e_tag); + switch (acl_e->e_tag) { + case ACL_USER: + ace->ae_id = cpu_to_be32( + from_kuid(&init_user_ns, acl_e->e_uid)); + break; + case ACL_GROUP: + ace->ae_id = cpu_to_be32( + from_kgid(&init_user_ns, acl_e->e_gid)); + break; + default: + ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID); + break; + } + + ace->ae_perm = cpu_to_be16(acl_e->e_perm); + } +} + +struct posix_acl * +xfs_get_acl(struct inode *inode, int type, bool rcu) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct posix_acl *acl = NULL; + struct xfs_da_args args = { + .dp = ip, + .attr_filter = XFS_ATTR_ROOT, + .valuelen = XFS_ACL_MAX_SIZE(mp), + }; + int error; + + if (rcu) + return ERR_PTR(-ECHILD); + + trace_xfs_get_acl(ip); + + switch (type) { + case ACL_TYPE_ACCESS: + args.name = SGI_ACL_FILE; + break; + case ACL_TYPE_DEFAULT: + args.name = SGI_ACL_DEFAULT; + break; + default: + BUG(); + } + args.namelen = strlen(args.name); + + /* + * If the attribute doesn't exist make sure we have a negative cache + * entry, for any other error assume it is transient. + */ + error = xfs_attr_get(&args); + if (!error) { + acl = xfs_acl_from_disk(mp, args.value, args.valuelen, + XFS_ACL_MAX_ENTRIES(mp)); + } else if (error != -ENOATTR) { + acl = ERR_PTR(error); + } + + kmem_free(args.value); + return acl; +} + +int +__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_da_args args = { + .dp = ip, + .attr_filter = XFS_ATTR_ROOT, + }; + int error; + + switch (type) { + case ACL_TYPE_ACCESS: + args.name = SGI_ACL_FILE; + break; + case ACL_TYPE_DEFAULT: + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + args.name = SGI_ACL_DEFAULT; + break; + default: + return -EINVAL; + } + args.namelen = strlen(args.name); + + if (acl) { + args.valuelen = XFS_ACL_SIZE(acl->a_count); + args.value = kvzalloc(args.valuelen, GFP_KERNEL); + if (!args.value) + return -ENOMEM; + xfs_acl_to_disk(args.value, acl); + } + + error = xfs_attr_change(&args); + kmem_free(args.value); + + /* + * If the attribute didn't exist to start with that's fine. + */ + if (!acl && error == -ENOATTR) + error = 0; + if (!error) + set_cached_acl(inode, type, acl); + return error; +} + +static int +xfs_acl_set_mode( + struct inode *inode, + umode_t mode) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct xfs_trans *tp; + int error; + + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); + if (error) + return error; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); + inode->i_mode = mode; + inode->i_ctime = current_time(inode); + xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); + + if (xfs_has_wsync(mp)) + xfs_trans_set_sync(tp); + return xfs_trans_commit(tp); +} + +int +xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode, + struct posix_acl *acl, int type) +{ + umode_t mode; + bool set_mode = false; + int error = 0; + + if (!acl) + goto set_acl; + + error = -E2BIG; + if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) + return error; + + if (type == ACL_TYPE_ACCESS) { + error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl); + if (error) + return error; + set_mode = true; + } + + set_acl: + /* + * We set the mode after successfully updating the ACL xattr because the + * xattr update can fail at ENOSPC and we don't want to change the mode + * if the ACL update hasn't been applied. + */ + error = __xfs_set_acl(inode, acl, type); + if (!error && set_mode && mode != inode->i_mode) + error = xfs_acl_set_mode(inode, mode); + return error; +} + +/* + * Invalidate any cached ACLs if the user has bypassed the ACL interface. + * We don't validate the content whatsoever so it is caller responsibility to + * provide data in valid format and ensure i_mode is consistent. + */ +void +xfs_forget_acl( + struct inode *inode, + const char *name) +{ + if (!strcmp(name, SGI_ACL_FILE)) + forget_cached_acl(inode, ACL_TYPE_ACCESS); + else if (!strcmp(name, SGI_ACL_DEFAULT)) + forget_cached_acl(inode, ACL_TYPE_DEFAULT); +} |