2f6f0654ab
- In setxattr if we are setting a posix acl convert uids and gids from the current user namespace into the initial user namespace, before the xattrs are passed to the underlying filesystem. Untranslatable uids and gids are represented as -1 which posix_acl_from_xattr will represent as INVALID_UID or INVALID_GID. posix_acl_valid will fail if an acl from userspace has any INVALID_UID or INVALID_GID values. In net this guarantees that untranslatable posix acls will not be stored by filesystems. - In getxattr if we are reading a posix acl convert uids and gids from the initial user namespace into the current user namespace. Uids and gids that can not be tranlsated into the current user namespace will be represented as -1. - Replace e_id in struct posix_acl_entry with an anymouns union of e_uid and e_gid. For the short term retain the e_id field until all of the users are converted. - Don't set struct posix_acl.e_id in the cases where the acl type does not use e_id. Greatly reducing the use of ACL_UNDEFINED_ID. - Rework the ordering checks in posix_acl_valid so that I use kuid_t and kgid_t types throughout the code, and so that I don't need arithmetic on uid and gid types. Cc: Theodore Tso <tytso@mit.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
178 lines
4.1 KiB
C
178 lines
4.1 KiB
C
/*
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File: linux/posix_acl.h
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(C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
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*/
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#ifndef __LINUX_POSIX_ACL_H
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#define __LINUX_POSIX_ACL_H
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#include <linux/bug.h>
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#include <linux/slab.h>
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#include <linux/rcupdate.h>
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#define ACL_UNDEFINED_ID (-1)
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/* a_type field in acl_user_posix_entry_t */
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#define ACL_TYPE_ACCESS (0x8000)
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#define ACL_TYPE_DEFAULT (0x4000)
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/* e_tag entry in struct posix_acl_entry */
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#define ACL_USER_OBJ (0x01)
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#define ACL_USER (0x02)
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#define ACL_GROUP_OBJ (0x04)
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#define ACL_GROUP (0x08)
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#define ACL_MASK (0x10)
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#define ACL_OTHER (0x20)
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/* permissions in the e_perm field */
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#define ACL_READ (0x04)
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#define ACL_WRITE (0x02)
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#define ACL_EXECUTE (0x01)
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//#define ACL_ADD (0x08)
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//#define ACL_DELETE (0x10)
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struct posix_acl_entry {
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short e_tag;
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unsigned short e_perm;
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union {
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kuid_t e_uid;
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kgid_t e_gid;
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#ifndef CONFIG_UIDGID_STRICT_TYPE_CHECKS
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unsigned int e_id;
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#endif
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};
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};
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struct posix_acl {
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union {
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atomic_t a_refcount;
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struct rcu_head a_rcu;
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};
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unsigned int a_count;
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struct posix_acl_entry a_entries[0];
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};
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#define FOREACH_ACL_ENTRY(pa, acl, pe) \
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for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
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/*
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* Duplicate an ACL handle.
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*/
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static inline struct posix_acl *
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posix_acl_dup(struct posix_acl *acl)
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{
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if (acl)
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atomic_inc(&acl->a_refcount);
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return acl;
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}
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/*
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* Free an ACL handle.
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*/
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static inline void
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posix_acl_release(struct posix_acl *acl)
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{
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if (acl && atomic_dec_and_test(&acl->a_refcount))
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kfree_rcu(acl, a_rcu);
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}
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/* posix_acl.c */
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extern void posix_acl_init(struct posix_acl *, int);
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extern struct posix_acl *posix_acl_alloc(int, gfp_t);
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extern int posix_acl_valid(const struct posix_acl *);
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extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
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extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
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extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
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extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
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extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
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extern struct posix_acl *get_posix_acl(struct inode *, int);
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extern int set_posix_acl(struct inode *, int, struct posix_acl *);
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#ifdef CONFIG_FS_POSIX_ACL
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static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
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{
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switch (type) {
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case ACL_TYPE_ACCESS:
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return &inode->i_acl;
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case ACL_TYPE_DEFAULT:
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return &inode->i_default_acl;
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default:
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BUG();
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}
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}
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static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *acl = ACCESS_ONCE(*p);
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if (acl) {
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spin_lock(&inode->i_lock);
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acl = *p;
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if (acl != ACL_NOT_CACHED)
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acl = posix_acl_dup(acl);
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spin_unlock(&inode->i_lock);
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}
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return acl;
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}
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static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
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{
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return rcu_dereference(*acl_by_type(inode, type));
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}
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static inline void set_cached_acl(struct inode *inode,
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int type,
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struct posix_acl *acl)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *old;
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spin_lock(&inode->i_lock);
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old = *p;
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rcu_assign_pointer(*p, posix_acl_dup(acl));
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spin_unlock(&inode->i_lock);
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if (old != ACL_NOT_CACHED)
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posix_acl_release(old);
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}
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static inline void forget_cached_acl(struct inode *inode, int type)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *old;
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spin_lock(&inode->i_lock);
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old = *p;
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*p = ACL_NOT_CACHED;
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spin_unlock(&inode->i_lock);
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if (old != ACL_NOT_CACHED)
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posix_acl_release(old);
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}
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static inline void forget_all_cached_acls(struct inode *inode)
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{
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struct posix_acl *old_access, *old_default;
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spin_lock(&inode->i_lock);
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old_access = inode->i_acl;
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old_default = inode->i_default_acl;
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inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
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spin_unlock(&inode->i_lock);
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if (old_access != ACL_NOT_CACHED)
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posix_acl_release(old_access);
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if (old_default != ACL_NOT_CACHED)
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posix_acl_release(old_default);
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}
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#endif
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static inline void cache_no_acl(struct inode *inode)
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{
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#ifdef CONFIG_FS_POSIX_ACL
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inode->i_acl = NULL;
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inode->i_default_acl = NULL;
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#endif
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}
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#endif /* __LINUX_POSIX_ACL_H */
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