295 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (c) 2008, Christoph Hellwig4 * All Rights Reserved.5 */6#include "xfs.h"7#include "xfs_shared.h"8#include "xfs_format.h"9#include "xfs_log_format.h"10#include "xfs_trans_resv.h"11#include "xfs_mount.h"12#include "xfs_inode.h"13#include "xfs_da_format.h"14#include "xfs_da_btree.h"15#include "xfs_attr.h"16#include "xfs_trace.h"17#include "xfs_error.h"18#include "xfs_acl.h"19#include "xfs_trans.h"20#include "xfs_xattr.h"21 22#include <linux/posix_acl_xattr.h>23 24/*25 * Locking scheme:26 * - all ACL updates are protected by inode->i_mutex, which is taken before27 * calling into this file.28 */29 30STATIC struct posix_acl *31xfs_acl_from_disk(32 struct xfs_mount *mp,33 const struct xfs_acl *aclp,34 int len,35 int max_entries)36{37 struct posix_acl_entry *acl_e;38 struct posix_acl *acl;39 const struct xfs_acl_entry *ace;40 unsigned int count, i;41 42 if (len < sizeof(*aclp)) {43 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,44 len);45 return ERR_PTR(-EFSCORRUPTED);46 }47 48 count = be32_to_cpu(aclp->acl_cnt);49 if (count > max_entries || XFS_ACL_SIZE(count) != len) {50 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,51 len);52 return ERR_PTR(-EFSCORRUPTED);53 }54 55 acl = posix_acl_alloc(count, GFP_KERNEL);56 if (!acl)57 return ERR_PTR(-ENOMEM);58 59 for (i = 0; i < count; i++) {60 acl_e = &acl->a_entries[i];61 ace = &aclp->acl_entry[i];62 63 /*64 * The tag is 32 bits on disk and 16 bits in core.65 *66 * Because every access to it goes through the core67 * format first this is not a problem.68 */69 acl_e->e_tag = be32_to_cpu(ace->ae_tag);70 acl_e->e_perm = be16_to_cpu(ace->ae_perm);71 72 switch (acl_e->e_tag) {73 case ACL_USER:74 acl_e->e_uid = make_kuid(&init_user_ns,75 be32_to_cpu(ace->ae_id));76 break;77 case ACL_GROUP:78 acl_e->e_gid = make_kgid(&init_user_ns,79 be32_to_cpu(ace->ae_id));80 break;81 case ACL_USER_OBJ:82 case ACL_GROUP_OBJ:83 case ACL_MASK:84 case ACL_OTHER:85 break;86 default:87 goto fail;88 }89 }90 return acl;91 92fail:93 posix_acl_release(acl);94 return ERR_PTR(-EINVAL);95}96 97STATIC void98xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)99{100 const struct posix_acl_entry *acl_e;101 struct xfs_acl_entry *ace;102 int i;103 104 aclp->acl_cnt = cpu_to_be32(acl->a_count);105 for (i = 0; i < acl->a_count; i++) {106 ace = &aclp->acl_entry[i];107 acl_e = &acl->a_entries[i];108 109 ace->ae_tag = cpu_to_be32(acl_e->e_tag);110 switch (acl_e->e_tag) {111 case ACL_USER:112 ace->ae_id = cpu_to_be32(113 from_kuid(&init_user_ns, acl_e->e_uid));114 break;115 case ACL_GROUP:116 ace->ae_id = cpu_to_be32(117 from_kgid(&init_user_ns, acl_e->e_gid));118 break;119 default:120 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);121 break;122 }123 124 ace->ae_perm = cpu_to_be16(acl_e->e_perm);125 }126}127 128struct posix_acl *129xfs_get_acl(struct inode *inode, int type, bool rcu)130{131 struct xfs_inode *ip = XFS_I(inode);132 struct xfs_mount *mp = ip->i_mount;133 struct posix_acl *acl = NULL;134 struct xfs_da_args args = {135 .dp = ip,136 .attr_filter = XFS_ATTR_ROOT,137 .valuelen = XFS_ACL_MAX_SIZE(mp),138 };139 int error;140 141 if (rcu)142 return ERR_PTR(-ECHILD);143 144 trace_xfs_get_acl(ip);145 146 switch (type) {147 case ACL_TYPE_ACCESS:148 args.name = SGI_ACL_FILE;149 break;150 case ACL_TYPE_DEFAULT:151 args.name = SGI_ACL_DEFAULT;152 break;153 default:154 BUG();155 }156 args.namelen = strlen(args.name);157 158 /*159 * If the attribute doesn't exist make sure we have a negative cache160 * entry, for any other error assume it is transient.161 */162 error = xfs_attr_get(&args);163 if (!error) {164 acl = xfs_acl_from_disk(mp, args.value, args.valuelen,165 XFS_ACL_MAX_ENTRIES(mp));166 } else if (error != -ENOATTR) {167 acl = ERR_PTR(error);168 }169 170 kvfree(args.value);171 return acl;172}173 174int175__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)176{177 struct xfs_inode *ip = XFS_I(inode);178 struct xfs_da_args args = {179 .dp = ip,180 .attr_filter = XFS_ATTR_ROOT,181 };182 int error;183 184 switch (type) {185 case ACL_TYPE_ACCESS:186 args.name = SGI_ACL_FILE;187 break;188 case ACL_TYPE_DEFAULT:189 if (!S_ISDIR(inode->i_mode))190 return acl ? -EACCES : 0;191 args.name = SGI_ACL_DEFAULT;192 break;193 default:194 return -EINVAL;195 }196 args.namelen = strlen(args.name);197 198 if (acl) {199 args.valuelen = XFS_ACL_SIZE(acl->a_count);200 args.value = kvzalloc(args.valuelen, GFP_KERNEL);201 if (!args.value)202 return -ENOMEM;203 xfs_acl_to_disk(args.value, acl);204 error = xfs_attr_change(&args, XFS_ATTRUPDATE_UPSERT);205 kvfree(args.value);206 } else {207 error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE);208 /*209 * If the attribute didn't exist to start with that's fine.210 */211 if (error == -ENOATTR)212 error = 0;213 }214 215 if (!error)216 set_cached_acl(inode, type, acl);217 return error;218}219 220static int221xfs_acl_set_mode(222 struct inode *inode,223 umode_t mode)224{225 struct xfs_inode *ip = XFS_I(inode);226 struct xfs_mount *mp = ip->i_mount;227 struct xfs_trans *tp;228 int error;229 230 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);231 if (error)232 return error;233 234 xfs_ilock(ip, XFS_ILOCK_EXCL);235 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);236 inode->i_mode = mode;237 inode_set_ctime_current(inode);238 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);239 240 if (xfs_has_wsync(mp))241 xfs_trans_set_sync(tp);242 return xfs_trans_commit(tp);243}244 245int246xfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,247 struct posix_acl *acl, int type)248{249 umode_t mode;250 bool set_mode = false;251 int error = 0;252 struct inode *inode = d_inode(dentry);253 254 if (!acl)255 goto set_acl;256 257 error = -E2BIG;258 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))259 return error;260 261 if (type == ACL_TYPE_ACCESS) {262 error = posix_acl_update_mode(idmap, inode, &mode, &acl);263 if (error)264 return error;265 set_mode = true;266 }267 268 set_acl:269 /*270 * We set the mode after successfully updating the ACL xattr because the271 * xattr update can fail at ENOSPC and we don't want to change the mode272 * if the ACL update hasn't been applied.273 */274 error = __xfs_set_acl(inode, acl, type);275 if (!error && set_mode && mode != inode->i_mode)276 error = xfs_acl_set_mode(inode, mode);277 return error;278}279 280/*281 * Invalidate any cached ACLs if the user has bypassed the ACL interface.282 * We don't validate the content whatsoever so it is caller responsibility to283 * provide data in valid format and ensure i_mode is consistent.284 */285void286xfs_forget_acl(287 struct inode *inode,288 const char *name)289{290 if (!strcmp(name, SGI_ACL_FILE))291 forget_cached_acl(inode, ACL_TYPE_ACCESS);292 else if (!strcmp(name, SGI_ACL_DEFAULT))293 forget_cached_acl(inode, ACL_TYPE_DEFAULT);294}295