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emacs/lib/acl-internal.c
Eli Zaretskii cae528457c ; Add 2023 to copyright years.
2023-01-01 05:31:12 -05:00

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/* Test whether a file has a nontrivial ACL. -*- coding: utf-8 -*-
Copyright (C) 2002-2003, 2005-2023 Free Software Foundation, Inc.
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, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will 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, see <https://www.gnu.org/licenses/>.
Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible. */
#include <config.h>
#include "acl.h"
#include "acl-internal.h"
#if USE_ACL && HAVE_ACL_GET_FILE /* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */
# if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */
/* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.
Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial. */
int
acl_extended_nontrivial (acl_t acl)
{
/* acl is non-trivial if it is non-empty. */
return (acl_entries (acl) > 0);
}
# else /* Linux, FreeBSD, IRIX, Tru64, Cygwin >= 2.5 */
/* ACL is an ACL, from a file, stored as type ACL_TYPE_ACCESS.
Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.
Return -1 and set errno upon failure to determine it. */
int
acl_access_nontrivial (acl_t acl)
{
/* acl is non-trivial if it has some entries other than for "user::",
"group::", and "other::". Normally these three should be present
at least, allowing us to write
return (3 < acl_entries (acl));
but the following code is more robust. */
# if HAVE_ACL_FIRST_ENTRY /* Linux, FreeBSD, Cygwin >= 2.5 */
acl_entry_t ace;
int got_one;
for (got_one = acl_get_entry (acl, ACL_FIRST_ENTRY, &ace);
got_one > 0;
got_one = acl_get_entry (acl, ACL_NEXT_ENTRY, &ace))
{
acl_tag_t tag;
if (acl_get_tag_type (ace, &tag) < 0)
return -1;
if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER))
return 1;
}
return got_one;
# elif HAVE_ACL_TO_SHORT_TEXT /* IRIX */
/* Don't use acl_get_entry: it is undocumented. */
int count = acl->acl_cnt;
int i;
for (i = 0; i < count; i++)
{
acl_entry_t ace = &acl->acl_entry[i];
acl_tag_t tag = ace->ae_tag;
if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ
|| tag == ACL_OTHER_OBJ))
return 1;
}
return 0;
# elif HAVE_ACL_FREE_TEXT /* Tru64 */
/* Don't use acl_get_entry: it takes only one argument and does not work. */
int count = acl->acl_num;
acl_entry_t ace;
for (ace = acl->acl_first; count > 0; ace = ace->next, count--)
{
acl_tag_t tag;
acl_perm_t perm;
tag = ace->entry->acl_type;
if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER))
return 1;
perm = ace->entry->acl_perm;
/* On Tru64, perm can also contain non-standard bits such as
PERM_INSERT, PERM_DELETE, PERM_MODIFY, PERM_LOOKUP, ... */
if ((perm & ~(ACL_READ | ACL_WRITE | ACL_EXECUTE)) != 0)
return 1;
}
return 0;
# else
errno = ENOSYS;
return -1;
# endif
}
int
acl_default_nontrivial (acl_t acl)
{
/* acl is non-trivial if it is non-empty. */
return (acl_entries (acl) > 0);
}
# endif
#elif USE_ACL && HAVE_FACL && defined GETACL /* Solaris, Cygwin < 2.5, not HP-UX */
/* Test an ACL retrieved with GETACL.
Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_nontrivial (int count, aclent_t *entries)
{
int i;
for (i = 0; i < count; i++)
{
aclent_t *ace = &entries[i];
/* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat().
If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat().
We don't need to check ace->a_id in these cases. */
if (!(ace->a_type == USER_OBJ
|| ace->a_type == GROUP_OBJ
|| ace->a_type == OTHER_OBJ
/* Note: Cygwin does not return a CLASS_OBJ ("mask:") entry
sometimes. */
|| ace->a_type == CLASS_OBJ))
return 1;
}
return 0;
}
# ifdef ACE_GETACL
/* A shortcut for a bitmask. */
# define NEW_ACE_WRITEA_DATA (NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA)
/* Test an ACL retrieved with ACE_GETACL.
Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_ace_nontrivial (int count, ace_t *entries)
{
int i;
/* The flags in the ace_t structure changed in a binary incompatible way
when ACL_NO_TRIVIAL etc. were introduced in <sys/acl.h> version 1.15.
How to distinguish the two conventions at runtime?
In the old convention, usually three ACEs have a_flags = ACE_OWNER /
ACE_GROUP / ACE_OTHER, in the range 0x0100..0x0400. In the new
convention, these values are not used. */
int old_convention = 0;
for (i = 0; i < count; i++)
if (entries[i].a_flags & (OLD_ACE_OWNER | OLD_ACE_GROUP | OLD_ACE_OTHER))
{
old_convention = 1;
break;
}
if (old_convention)
/* Running on Solaris 10. */
for (i = 0; i < count; i++)
{
ace_t *ace = &entries[i];
/* Note:
If ace->a_flags = ACE_OWNER, ace->a_who is the st_uid from stat().
If ace->a_flags = ACE_GROUP, ace->a_who is the st_gid from stat().
We don't need to check ace->a_who in these cases. */
if (!(ace->a_type == OLD_ALLOW
&& (ace->a_flags == OLD_ACE_OWNER
|| ace->a_flags == OLD_ACE_GROUP
|| ace->a_flags == OLD_ACE_OTHER)))
return 1;
}
else
{
/* Running on Solaris 10 (newer version) or Solaris 11. */
unsigned int access_masks[6] =
{
0, /* owner@ deny */
0, /* owner@ allow */
0, /* group@ deny */
0, /* group@ allow */
0, /* everyone@ deny */
0 /* everyone@ allow */
};
for (i = 0; i < count; i++)
{
ace_t *ace = &entries[i];
unsigned int index1;
unsigned int index2;
if (ace->a_type == NEW_ACE_ACCESS_ALLOWED_ACE_TYPE)
index1 = 1;
else if (ace->a_type == NEW_ACE_ACCESS_DENIED_ACE_TYPE)
index1 = 0;
else
return 1;
if (ace->a_flags == NEW_ACE_OWNER)
index2 = 0;
else if (ace->a_flags == (NEW_ACE_GROUP | NEW_ACE_IDENTIFIER_GROUP))
index2 = 2;
else if (ace->a_flags == NEW_ACE_EVERYONE)
index2 = 4;
else
return 1;
access_masks[index1 + index2] |= ace->a_access_mask;
}
/* The same bit shouldn't be both allowed and denied. */
if (access_masks[0] & access_masks[1])
return 1;
if (access_masks[2] & access_masks[3])
return 1;
if (access_masks[4] & access_masks[5])
return 1;
/* Check minimum masks. */
if ((NEW_ACE_WRITE_NAMED_ATTRS
| NEW_ACE_WRITE_ATTRIBUTES
| NEW_ACE_WRITE_ACL
| NEW_ACE_WRITE_OWNER)
& ~ access_masks[1])
return 1;
access_masks[1] &= ~(NEW_ACE_WRITE_NAMED_ATTRS
| NEW_ACE_WRITE_ATTRIBUTES
| NEW_ACE_WRITE_ACL
| NEW_ACE_WRITE_OWNER);
if ((NEW_ACE_READ_NAMED_ATTRS
| NEW_ACE_READ_ATTRIBUTES
| NEW_ACE_READ_ACL
| NEW_ACE_SYNCHRONIZE)
& ~ access_masks[5])
return 1;
access_masks[5] &= ~(NEW_ACE_READ_NAMED_ATTRS
| NEW_ACE_READ_ATTRIBUTES
| NEW_ACE_READ_ACL
| NEW_ACE_SYNCHRONIZE);
/* Check the allowed or denied bits. */
switch ((access_masks[0] | access_masks[1])
& ~(NEW_ACE_READ_NAMED_ATTRS
| NEW_ACE_READ_ATTRIBUTES
| NEW_ACE_READ_ACL
| NEW_ACE_SYNCHRONIZE))
{
case 0:
case NEW_ACE_READ_DATA:
case NEW_ACE_WRITEA_DATA:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA:
case NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
break;
default:
return 1;
}
switch ((access_masks[2] | access_masks[3])
& ~(NEW_ACE_READ_NAMED_ATTRS
| NEW_ACE_READ_ATTRIBUTES
| NEW_ACE_READ_ACL
| NEW_ACE_SYNCHRONIZE))
{
case 0:
case NEW_ACE_READ_DATA:
case NEW_ACE_WRITEA_DATA:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA:
case NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
break;
default:
return 1;
}
switch ((access_masks[4] | access_masks[5])
& ~(NEW_ACE_WRITE_NAMED_ATTRS
| NEW_ACE_WRITE_ATTRIBUTES
| NEW_ACE_WRITE_ACL
| NEW_ACE_WRITE_OWNER))
{
case 0:
case NEW_ACE_READ_DATA:
case NEW_ACE_WRITEA_DATA:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA:
case NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
case NEW_ACE_READ_DATA | NEW_ACE_WRITEA_DATA | NEW_ACE_EXECUTE:
break;
default:
return 1;
}
/* Check that the NEW_ACE_WRITE_DATA and NEW_ACE_APPEND_DATA bits are
either both allowed or both denied. */
if (((access_masks[0] & NEW_ACE_WRITE_DATA) != 0)
!= ((access_masks[0] & NEW_ACE_APPEND_DATA) != 0))
return 1;
if (((access_masks[2] & NEW_ACE_WRITE_DATA) != 0)
!= ((access_masks[2] & NEW_ACE_APPEND_DATA) != 0))
return 1;
if (((access_masks[4] & NEW_ACE_WRITE_DATA) != 0)
!= ((access_masks[4] & NEW_ACE_APPEND_DATA) != 0))
return 1;
}
return 0;
}
# endif
#elif USE_ACL && HAVE_GETACL /* HP-UX */
/* Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_nontrivial (int count, struct acl_entry *entries)
{
int i;
if (count > 3)
return 1;
for (i = 0; i < count; i++)
{
struct acl_entry *ace = &entries[i];
if (ace->uid != ACL_NSUSER && ace->gid != ACL_NSGROUP)
return 1;
}
return 0;
}
# if HAVE_ACLV_H /* HP-UX >= 11.11 */
/* Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
aclv_nontrivial (int count, struct acl *entries)
{
int i;
for (i = 0; i < count; i++)
{
struct acl *ace = &entries[i];
/* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat().
If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat().
We don't need to check ace->a_id in these cases. */
if (!(ace->a_type == USER_OBJ /* no need to check ace->a_id here */
|| ace->a_type == GROUP_OBJ /* no need to check ace->a_id here */
|| ace->a_type == CLASS_OBJ
|| ace->a_type == OTHER_OBJ))
return 1;
}
return 0;
}
# endif
#elif USE_ACL && (HAVE_ACLX_GET || HAVE_STATACL) /* AIX */
/* Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_nontrivial (struct acl *a)
{
/* The normal way to iterate through an ACL is like this:
struct acl_entry *ace;
for (ace = a->acl_ext; ace != acl_last (a); ace = acl_nxt (ace))
{
struct ace_id *aei;
switch (ace->ace_type)
{
case ACC_PERMIT:
case ACC_DENY:
case ACC_SPECIFY:
...;
}
for (aei = ace->ace_id; aei != id_last (ace); aei = id_nxt (aei))
...
}
*/
return (acl_last (a) != a->acl_ext ? 1 : 0);
}
# if HAVE_ACLX_GET && defined ACL_AIX_WIP /* newer AIX */
/* Return 1 if the given ACL is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_nfs4_nontrivial (nfs4_acl_int_t *a)
{
# if 1 /* let's try this first */
return (a->aclEntryN > 0 ? 1 : 0);
# else
int count = a->aclEntryN;
int i;
for (i = 0; i < count; i++)
{
nfs4_ace_int_t *ace = &a->aclEntry[i];
if (!((ace->flags & ACE4_ID_SPECIAL) != 0
&& (ace->aceWho.special_whoid == ACE4_WHO_OWNER
|| ace->aceWho.special_whoid == ACE4_WHO_GROUP
|| ace->aceWho.special_whoid == ACE4_WHO_EVERYONE)
&& ace->aceType == ACE4_ACCESS_ALLOWED_ACE_TYPE
&& ace->aceFlags == 0
&& (ace->aceMask & ~(ACE4_READ_DATA | ACE4_LIST_DIRECTORY
| ACE4_WRITE_DATA | ACE4_ADD_FILE
| ACE4_EXECUTE)) == 0))
return 1;
}
return 0;
# endif
}
# endif
#elif USE_ACL && HAVE_ACLSORT /* NonStop Kernel */
/* Test an ACL retrieved with ACL_GET.
Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
Return 0 if it is trivial, i.e. equivalent to a simple stat() mode. */
int
acl_nontrivial (int count, struct acl *entries)
{
int i;
for (i = 0; i < count; i++)
{
struct acl *ace = &entries[i];
/* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat().
If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat().
We don't need to check ace->a_id in these cases. */
if (!(ace->a_type == USER_OBJ /* no need to check ace->a_id here */
|| ace->a_type == GROUP_OBJ /* no need to check ace->a_id here */
|| ace->a_type == CLASS_OBJ
|| ace->a_type == OTHER_OBJ))
return 1;
}
return 0;
}
#endif
void
free_permission_context (struct permission_context *ctx)
{
#if USE_ACL
# if HAVE_ACL_GET_FILE /* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */
if (ctx->acl)
acl_free (ctx->acl);
# if !HAVE_ACL_TYPE_EXTENDED
if (ctx->default_acl)
acl_free (ctx->default_acl);
# endif
# elif defined GETACL /* Solaris, Cygwin < 2.5 */
free (ctx->entries);
# ifdef ACE_GETACL
free (ctx->ace_entries);
# endif
# elif HAVE_GETACL /* HP-UX */
# if HAVE_ACLV_H
# endif
# elif HAVE_STATACL /* older AIX */
# elif HAVE_ACLSORT /* NonStop Kernel */
# endif
#endif
}
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