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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/xfs/xfs_acl.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/xfs/xfs_acl.c')
-rw-r--r-- | fs/xfs/xfs_acl.c | 937 |
1 files changed, 937 insertions, 0 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c new file mode 100644 index 000000000000..8d01dce8c532 --- /dev/null +++ b/fs/xfs/xfs_acl.c @@ -0,0 +1,937 @@ +/* + * Copyright (c) 2001-2002 Silicon Graphics, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 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. + * + * Further, this software is distributed without any warranty that it is + * free of the rightful claim of any third person regarding infringement + * or the like. Any license provided herein, whether implied or + * otherwise, applies only to this software file. Patent licenses, if + * any, provided herein do not apply to combinations of this program with + * other software, or any other product whatsoever. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, + * Mountain View, CA 94043, or: + * + * http://www.sgi.com + * + * For further information regarding this notice, see: + * + * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ + */ + +#include "xfs.h" + +#include "xfs_inum.h" +#include "xfs_dir.h" +#include "xfs_dir2.h" +#include "xfs_alloc_btree.h" +#include "xfs_bmap_btree.h" +#include "xfs_ialloc_btree.h" +#include "xfs_btree.h" +#include "xfs_attr_sf.h" +#include "xfs_dir_sf.h" +#include "xfs_dir2_sf.h" +#include "xfs_dinode.h" +#include "xfs_inode.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 (vp->v_type != VDIR) + 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 qsort(). + * 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> */ + qsort(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 && vp->v_type != VDIR) + 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 */ + 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 (vp->v_type == VDIR) + 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; +} |