/* * Copyright (c) 2001-2002,2005 Silicon Graphics, Inc. * All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "xfs.h" #include "xfs_fs.h" #include "xfs_types.h" #include "xfs_bit.h" #include "xfs_inum.h" #include "xfs_ag.h" #include "xfs_dir.h" #include "xfs_dir2.h" #include "xfs_bmap_btree.h" #include "xfs_alloc_btree.h" #include "xfs_ialloc_btree.h" #include "xfs_dir_sf.h" #include "xfs_dir2_sf.h" #include "xfs_attr_sf.h" #include "xfs_dinode.h" #include "xfs_inode.h" #include "xfs_btree.h" #include "xfs_acl.h" #include "xfs_mac.h" #include "xfs_attr.h" #include <linux/posix_acl_xattr.h> STATIC int xfs_acl_setmode(vnode_t *, xfs_acl_t *, int *); STATIC void xfs_acl_filter_mode(mode_t, xfs_acl_t *); STATIC void xfs_acl_get_endian(xfs_acl_t *); STATIC int xfs_acl_access(uid_t, gid_t, xfs_acl_t *, mode_t, cred_t *); STATIC int xfs_acl_invalid(xfs_acl_t *); STATIC void xfs_acl_sync_mode(mode_t, xfs_acl_t *); STATIC void xfs_acl_get_attr(vnode_t *, xfs_acl_t *, int, int, int *); STATIC void xfs_acl_set_attr(vnode_t *, xfs_acl_t *, int, int *); STATIC int xfs_acl_allow_set(vnode_t *, int); kmem_zone_t *xfs_acl_zone; /* * Test for existence of access ACL attribute as efficiently as possible. */ int xfs_acl_vhasacl_access( vnode_t *vp) { int error; xfs_acl_get_attr(vp, NULL, _ACL_TYPE_ACCESS, ATTR_KERNOVAL, &error); return (error == 0); } /* * Test for existence of default ACL attribute as efficiently as possible. */ int xfs_acl_vhasacl_default( vnode_t *vp) { int error; if (!VN_ISDIR(vp)) return 0; xfs_acl_get_attr(vp, NULL, _ACL_TYPE_DEFAULT, ATTR_KERNOVAL, &error); return (error == 0); } /* * Convert from extended attribute representation to in-memory for XFS. */ STATIC int posix_acl_xattr_to_xfs( posix_acl_xattr_header *src, size_t size, xfs_acl_t *dest) { posix_acl_xattr_entry *src_entry; xfs_acl_entry_t *dest_entry; int n; if (!src || !dest) return EINVAL; if (size < sizeof(posix_acl_xattr_header)) return EINVAL; if (src->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) return EOPNOTSUPP; memset(dest, 0, sizeof(xfs_acl_t)); dest->acl_cnt = posix_acl_xattr_count(size); if (dest->acl_cnt < 0 || dest->acl_cnt > XFS_ACL_MAX_ENTRIES) return EINVAL; /* * acl_set_file(3) may request that we set default ACLs with * zero length -- defend (gracefully) against that here. */ if (!dest->acl_cnt) return 0; src_entry = (posix_acl_xattr_entry *)((char *)src + sizeof(*src)); dest_entry = &dest->acl_entry[0]; for (n = 0; n < dest->acl_cnt; n++, src_entry++, dest_entry++) { dest_entry->ae_perm = le16_to_cpu(src_entry->e_perm); if (_ACL_PERM_INVALID(dest_entry->ae_perm)) return EINVAL; dest_entry->ae_tag = le16_to_cpu(src_entry->e_tag); switch(dest_entry->ae_tag) { case ACL_USER: case ACL_GROUP: dest_entry->ae_id = le32_to_cpu(src_entry->e_id); break; case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: dest_entry->ae_id = ACL_UNDEFINED_ID; break; default: return EINVAL; } } if (xfs_acl_invalid(dest)) return EINVAL; return 0; } /* * Comparison function called from xfs_sort(). * Primary key is ae_tag, secondary key is ae_id. */ STATIC int xfs_acl_entry_compare( const void *va, const void *vb) { xfs_acl_entry_t *a = (xfs_acl_entry_t *)va, *b = (xfs_acl_entry_t *)vb; if (a->ae_tag == b->ae_tag) return (a->ae_id - b->ae_id); return (a->ae_tag - b->ae_tag); } /* * Convert from in-memory XFS to extended attribute representation. */ STATIC int posix_acl_xfs_to_xattr( xfs_acl_t *src, posix_acl_xattr_header *dest, size_t size) { int n; size_t new_size = posix_acl_xattr_size(src->acl_cnt); posix_acl_xattr_entry *dest_entry; xfs_acl_entry_t *src_entry; if (size < new_size) return -ERANGE; /* Need to sort src XFS ACL by <ae_tag,ae_id> */ xfs_sort(src->acl_entry, src->acl_cnt, sizeof(src->acl_entry[0]), xfs_acl_entry_compare); dest->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); dest_entry = &dest->a_entries[0]; src_entry = &src->acl_entry[0]; for (n = 0; n < src->acl_cnt; n++, dest_entry++, src_entry++) { dest_entry->e_perm = cpu_to_le16(src_entry->ae_perm); if (_ACL_PERM_INVALID(src_entry->ae_perm)) return -EINVAL; dest_entry->e_tag = cpu_to_le16(src_entry->ae_tag); switch (src_entry->ae_tag) { case ACL_USER: case ACL_GROUP: dest_entry->e_id = cpu_to_le32(src_entry->ae_id); break; case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: dest_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); break; default: return -EINVAL; } } return new_size; } int xfs_acl_vget( vnode_t *vp, void *acl, size_t size, int kind) { int error; xfs_acl_t *xfs_acl = NULL; posix_acl_xattr_header *ext_acl = acl; int flags = 0; VN_HOLD(vp); if(size) { if (!(_ACL_ALLOC(xfs_acl))) { error = ENOMEM; goto out; } memset(xfs_acl, 0, sizeof(xfs_acl_t)); } else flags = ATTR_KERNOVAL; xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error); if (error) goto out; if (!size) { error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES); } else { if (xfs_acl_invalid(xfs_acl)) { error = EINVAL; goto out; } if (kind == _ACL_TYPE_ACCESS) { vattr_t va; va.va_mask = XFS_AT_MODE; VOP_GETATTR(vp, &va, 0, sys_cred, error); if (error) goto out; xfs_acl_sync_mode(va.va_mode, xfs_acl); } error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size); } out: VN_RELE(vp); if(xfs_acl) _ACL_FREE(xfs_acl); return -error; } int xfs_acl_vremove( vnode_t *vp, int kind) { int error; VN_HOLD(vp); error = xfs_acl_allow_set(vp, kind); if (!error) { VOP_ATTR_REMOVE(vp, kind == _ACL_TYPE_DEFAULT? SGI_ACL_DEFAULT: SGI_ACL_FILE, ATTR_ROOT, sys_cred, error); if (error == ENOATTR) error = 0; /* 'scool */ } VN_RELE(vp); return -error; } int xfs_acl_vset( vnode_t *vp, void *acl, size_t size, int kind) { posix_acl_xattr_header *ext_acl = acl; xfs_acl_t *xfs_acl; int error; int basicperms = 0; /* more than std unix perms? */ if (!acl) return -EINVAL; if (!(_ACL_ALLOC(xfs_acl))) return -ENOMEM; error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl); if (error) { _ACL_FREE(xfs_acl); return -error; } if (!xfs_acl->acl_cnt) { _ACL_FREE(xfs_acl); return 0; } VN_HOLD(vp); error = xfs_acl_allow_set(vp, kind); if (error) goto out; /* Incoming ACL exists, set file mode based on its value */ if (kind == _ACL_TYPE_ACCESS) xfs_acl_setmode(vp, xfs_acl, &basicperms); /* * If we have more than std unix permissions, set up the actual attr. * Otherwise, delete any existing attr. This prevents us from * having actual attrs for permissions that can be stored in the * standard permission bits. */ if (!basicperms) { xfs_acl_set_attr(vp, xfs_acl, kind, &error); } else { xfs_acl_vremove(vp, _ACL_TYPE_ACCESS); } out: VN_RELE(vp); _ACL_FREE(xfs_acl); return -error; } int xfs_acl_iaccess( xfs_inode_t *ip, mode_t mode, cred_t *cr) { xfs_acl_t *acl; int rval; if (!(_ACL_ALLOC(acl))) return -1; /* If the file has no ACL return -1. */ rval = sizeof(xfs_acl_t); if (xfs_attr_fetch(ip, SGI_ACL_FILE, SGI_ACL_FILE_SIZE, (char *)acl, &rval, ATTR_ROOT | ATTR_KERNACCESS, cr)) { _ACL_FREE(acl); return -1; } xfs_acl_get_endian(acl); /* If the file has an empty ACL return -1. */ if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) { _ACL_FREE(acl); return -1; } /* Synchronize ACL with mode bits */ xfs_acl_sync_mode(ip->i_d.di_mode, acl); rval = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr); _ACL_FREE(acl); return rval; } STATIC int xfs_acl_allow_set( vnode_t *vp, int kind) { vattr_t va; int error; if (vp->v_inode.i_flags & (S_IMMUTABLE|S_APPEND)) return EPERM; if (kind == _ACL_TYPE_DEFAULT && !VN_ISDIR(vp)) return ENOTDIR; if (vp->v_vfsp->vfs_flag & VFS_RDONLY) return EROFS; va.va_mask = XFS_AT_UID; VOP_GETATTR(vp, &va, 0, NULL, error); if (error) return error; if (va.va_uid != current->fsuid && !capable(CAP_FOWNER)) return EPERM; return error; } /* * The access control process to determine the access permission: * if uid == file owner id, use the file owner bits. * if gid == file owner group id, use the file group bits. * scan ACL for a maching user or group, and use matched entry * permission. Use total permissions of all matching group entries, * until all acl entries are exhausted. The final permission produced * by matching acl entry or entries needs to be & with group permission. * if not owner, owning group, or matching entry in ACL, use file * other bits. */ STATIC int xfs_acl_capability_check( mode_t mode, cred_t *cr) { if ((mode & ACL_READ) && !capable_cred(cr, CAP_DAC_READ_SEARCH)) return EACCES; if ((mode & ACL_WRITE) && !capable_cred(cr, CAP_DAC_OVERRIDE)) return EACCES; if ((mode & ACL_EXECUTE) && !capable_cred(cr, CAP_DAC_OVERRIDE)) return EACCES; return 0; } /* * Note: cr is only used here for the capability check if the ACL test fails. * It is not used to find out the credentials uid or groups etc, as was * done in IRIX. It is assumed that the uid and groups for the current * thread are taken from "current" instead of the cr parameter. */ STATIC int xfs_acl_access( uid_t fuid, gid_t fgid, xfs_acl_t *fap, mode_t md, cred_t *cr) { xfs_acl_entry_t matched; int i, allows; int maskallows = -1; /* true, but not 1, either */ int seen_userobj = 0; matched.ae_tag = 0; /* Invalid type */ matched.ae_perm = 0; md >>= 6; /* Normalize the bits for comparison */ for (i = 0; i < fap->acl_cnt; i++) { /* * Break out if we've got a user_obj entry or * a user entry and the mask (and have processed USER_OBJ) */ if (matched.ae_tag == ACL_USER_OBJ) break; if (matched.ae_tag == ACL_USER) { if (maskallows != -1 && seen_userobj) break; if (fap->acl_entry[i].ae_tag != ACL_MASK && fap->acl_entry[i].ae_tag != ACL_USER_OBJ) continue; } /* True if this entry allows the requested access */ allows = ((fap->acl_entry[i].ae_perm & md) == md); switch (fap->acl_entry[i].ae_tag) { case ACL_USER_OBJ: seen_userobj = 1; if (fuid != current->fsuid) continue; matched.ae_tag = ACL_USER_OBJ; matched.ae_perm = allows; break; case ACL_USER: if (fap->acl_entry[i].ae_id != current->fsuid) continue; matched.ae_tag = ACL_USER; matched.ae_perm = allows; break; case ACL_GROUP_OBJ: if ((matched.ae_tag == ACL_GROUP_OBJ || matched.ae_tag == ACL_GROUP) && !allows) continue; if (!in_group_p(fgid)) continue; matched.ae_tag = ACL_GROUP_OBJ; matched.ae_perm = allows; break; case ACL_GROUP: if ((matched.ae_tag == ACL_GROUP_OBJ || matched.ae_tag == ACL_GROUP) && !allows) continue; if (!in_group_p(fap->acl_entry[i].ae_id)) continue; matched.ae_tag = ACL_GROUP; matched.ae_perm = allows; break; case ACL_MASK: maskallows = allows; break; case ACL_OTHER: if (matched.ae_tag != 0) continue; matched.ae_tag = ACL_OTHER; matched.ae_perm = allows; break; } } /* * First possibility is that no matched entry allows access. * The capability to override DAC may exist, so check for it. */ switch (matched.ae_tag) { case ACL_OTHER: case ACL_USER_OBJ: if (matched.ae_perm) return 0; break; case ACL_USER: case ACL_GROUP_OBJ: case ACL_GROUP: if (maskallows && matched.ae_perm) return 0; break; case 0: break; } return xfs_acl_capability_check(md, cr); } /* * ACL validity checker. * This acl validation routine checks each ACL entry read in makes sense. */ STATIC int xfs_acl_invalid( xfs_acl_t *aclp) { xfs_acl_entry_t *entry, *e; int user = 0, group = 0, other = 0, mask = 0; int mask_required = 0; int i, j; if (!aclp) goto acl_invalid; if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES) goto acl_invalid; for (i = 0; i < aclp->acl_cnt; i++) { entry = &aclp->acl_entry[i]; switch (entry->ae_tag) { case ACL_USER_OBJ: if (user++) goto acl_invalid; break; case ACL_GROUP_OBJ: if (group++) goto acl_invalid; break; case ACL_OTHER: if (other++) goto acl_invalid; break; case ACL_USER: case ACL_GROUP: for (j = i + 1; j < aclp->acl_cnt; j++) { e = &aclp->acl_entry[j]; if (e->ae_id == entry->ae_id && e->ae_tag == entry->ae_tag) goto acl_invalid; } mask_required++; break; case ACL_MASK: if (mask++) goto acl_invalid; break; default: goto acl_invalid; } } if (!user || !group || !other || (mask_required && !mask)) goto acl_invalid; else return 0; acl_invalid: return EINVAL; } /* * Do ACL endian conversion. */ STATIC void xfs_acl_get_endian( xfs_acl_t *aclp) { xfs_acl_entry_t *ace, *end; INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt); end = &aclp->acl_entry[0]+aclp->acl_cnt; for (ace = &aclp->acl_entry[0]; ace < end; ace++) { INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag); INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id); INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm); } } /* * Get the ACL from the EA and do endian conversion. */ STATIC void xfs_acl_get_attr( vnode_t *vp, xfs_acl_t *aclp, int kind, int flags, int *error) { int len = sizeof(xfs_acl_t); ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1); flags |= ATTR_ROOT; VOP_ATTR_GET(vp, kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE : SGI_ACL_DEFAULT, (char *)aclp, &len, flags, sys_cred, *error); if (*error || (flags & ATTR_KERNOVAL)) return; xfs_acl_get_endian(aclp); } /* * Set the EA with the ACL and do endian conversion. */ STATIC void xfs_acl_set_attr( vnode_t *vp, xfs_acl_t *aclp, int kind, int *error) { xfs_acl_entry_t *ace, *newace, *end; xfs_acl_t *newacl; int len; if (!(_ACL_ALLOC(newacl))) { *error = ENOMEM; return; } len = sizeof(xfs_acl_t) - (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt)); end = &aclp->acl_entry[0]+aclp->acl_cnt; for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0]; ace < end; ace++, newace++) { INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag); INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id); INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm); } INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt); VOP_ATTR_SET(vp, kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE: SGI_ACL_DEFAULT, (char *)newacl, len, ATTR_ROOT, sys_cred, *error); _ACL_FREE(newacl); } int xfs_acl_vtoacl( vnode_t *vp, xfs_acl_t *access_acl, xfs_acl_t *default_acl) { vattr_t va; int error = 0; if (access_acl) { /* * Get the Access ACL and the mode. If either cannot * be obtained for some reason, invalidate the access ACL. */ xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error); if (!error) { /* Got the ACL, need the mode... */ va.va_mask = XFS_AT_MODE; VOP_GETATTR(vp, &va, 0, sys_cred, error); } if (error) access_acl->acl_cnt = XFS_ACL_NOT_PRESENT; else /* We have a good ACL and the file mode, synchronize. */ xfs_acl_sync_mode(va.va_mode, access_acl); } if (default_acl) { xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error); if (error) default_acl->acl_cnt = XFS_ACL_NOT_PRESENT; } return error; } /* * This function retrieves the parent directory's acl, processes it * and lets the child inherit the acl(s) that it should. */ int xfs_acl_inherit( vnode_t *vp, vattr_t *vap, xfs_acl_t *pdaclp) { xfs_acl_t *cacl; int error = 0; int basicperms = 0; /* * If the parent does not have a default ACL, or it's an * invalid ACL, we're done. */ if (!vp) return 0; if (!pdaclp || xfs_acl_invalid(pdaclp)) return 0; /* * Copy the default ACL of the containing directory to * the access ACL of the new file and use the mode that * was passed in to set up the correct initial values for * the u::,g::[m::], and o:: entries. This is what makes * umask() "work" with ACL's. */ if (!(_ACL_ALLOC(cacl))) return ENOMEM; memcpy(cacl, pdaclp, sizeof(xfs_acl_t)); xfs_acl_filter_mode(vap->va_mode, cacl); xfs_acl_setmode(vp, cacl, &basicperms); /* * Set the Default and Access ACL on the file. The mode is already * set on the file, so we don't need to worry about that. * * If the new file is a directory, its default ACL is a copy of * the containing directory's default ACL. */ if (VN_ISDIR(vp)) xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error); if (!error && !basicperms) xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error); _ACL_FREE(cacl); return error; } /* * Set up the correct mode on the file based on the supplied ACL. This * makes sure that the mode on the file reflects the state of the * u::,g::[m::], and o:: entries in the ACL. Since the mode is where * the ACL is going to get the permissions for these entries, we must * synchronize the mode whenever we set the ACL on a file. */ STATIC int xfs_acl_setmode( vnode_t *vp, xfs_acl_t *acl, int *basicperms) { vattr_t va; xfs_acl_entry_t *ap; xfs_acl_entry_t *gap = NULL; int i, error, nomask = 1; *basicperms = 1; if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) return 0; /* * Copy the u::, g::, o::, and m:: bits from the ACL into the * mode. The m:: bits take precedence over the g:: bits. */ va.va_mask = XFS_AT_MODE; VOP_GETATTR(vp, &va, 0, sys_cred, error); if (error) return error; va.va_mask = XFS_AT_MODE; va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO); ap = acl->acl_entry; for (i = 0; i < acl->acl_cnt; ++i) { switch (ap->ae_tag) { case ACL_USER_OBJ: va.va_mode |= ap->ae_perm << 6; break; case ACL_GROUP_OBJ: gap = ap; break; case ACL_MASK: /* more than just standard modes */ nomask = 0; va.va_mode |= ap->ae_perm << 3; *basicperms = 0; break; case ACL_OTHER: va.va_mode |= ap->ae_perm; break; default: /* more than just standard modes */ *basicperms = 0; break; } ap++; } /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */ if (gap && nomask) va.va_mode |= gap->ae_perm << 3; VOP_SETATTR(vp, &va, 0, sys_cred, error); return error; } /* * The permissions for the special ACL entries (u::, g::[m::], o::) are * actually stored in the file mode (if there is both a group and a mask, * the group is stored in the ACL entry and the mask is stored on the file). * This allows the mode to remain automatically in sync with the ACL without * the need for a call-back to the ACL system at every point where the mode * could change. This function takes the permissions from the specified mode * and places it in the supplied ACL. * * This implementation draws its validity from the fact that, when the ACL * was assigned, the mode was copied from the ACL. * If the mode did not change, therefore, the mode remains exactly what was * taken from the special ACL entries at assignment. * If a subsequent chmod() was done, the POSIX spec says that the change in * mode must cause an update to the ACL seen at user level and used for * access checks. Before and after a mode change, therefore, the file mode * most accurately reflects what the special ACL entries should permit/deny. * * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly, * the existing mode bits will override whatever is in the * ACL. Similarly, if there is a pre-existing ACL that was * never in sync with its mode (owing to a bug in 6.5 and * before), it will now magically (or mystically) be * synchronized. This could cause slight astonishment, but * it is better than inconsistent permissions. * * The supplied ACL is a template that may contain any combination * of special entries. These are treated as place holders when we fill * out the ACL. This routine does not add or remove special entries, it * simply unites each special entry with its associated set of permissions. */ STATIC void xfs_acl_sync_mode( mode_t mode, xfs_acl_t *acl) { int i, nomask = 1; xfs_acl_entry_t *ap; xfs_acl_entry_t *gap = NULL; /* * Set ACL entries. POSIX1003.1eD16 requires that the MASK * be set instead of the GROUP entry, if there is a MASK. */ for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) { switch (ap->ae_tag) { case ACL_USER_OBJ: ap->ae_perm = (mode >> 6) & 0x7; break; case ACL_GROUP_OBJ: gap = ap; break; case ACL_MASK: nomask = 0; ap->ae_perm = (mode >> 3) & 0x7; break; case ACL_OTHER: ap->ae_perm = mode & 0x7; break; default: break; } } /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */ if (gap && nomask) gap->ae_perm = (mode >> 3) & 0x7; } /* * When inheriting an Access ACL from a directory Default ACL, * the ACL bits are set to the intersection of the ACL default * permission bits and the file permission bits in mode. If there * are no permission bits on the file then we must not give them * the ACL. This is what what makes umask() work with ACLs. */ STATIC void xfs_acl_filter_mode( mode_t mode, xfs_acl_t *acl) { int i, nomask = 1; xfs_acl_entry_t *ap; xfs_acl_entry_t *gap = NULL; /* * Set ACL entries. POSIX1003.1eD16 requires that the MASK * be merged with GROUP entry, if there is a MASK. */ for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) { switch (ap->ae_tag) { case ACL_USER_OBJ: ap->ae_perm &= (mode >> 6) & 0x7; break; case ACL_GROUP_OBJ: gap = ap; break; case ACL_MASK: nomask = 0; ap->ae_perm &= (mode >> 3) & 0x7; break; case ACL_OTHER: ap->ae_perm &= mode & 0x7; break; default: break; } } /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */ if (gap && nomask) gap->ae_perm &= (mode >> 3) & 0x7; }