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Apply umask on "standard" Cygwin ACL 

* sec_acl.cc (get_posix_access): Check for Cygwin "standard" ACL.
        Apply umask, if so.  Align comments.
        * security.cc (set_created_file_access): Fix permission masking by
        incoming requested file mode.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2015-04-21 11:49:38 +02:00
parent b364582734
commit a8ec1e804e
3 changed files with 54 additions and 23 deletions
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7
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,10 @@
2015-04-21 Corinna Vinschen <corinna@vinschen.de>
* sec_acl.cc (get_posix_access): Check for Cygwin "standard" ACL.
Apply umask, if so. Align comments.
* security.cc (set_created_file_access): Fix permission masking by
incoming requested file mode.
2015-04-20 Corinna Vinschen <corinna@vinschen.de> 2015-04-20 Corinna Vinschen <corinna@vinschen.de>
* sec_acl.cc (set_posix_access): Apply mask only in terms of execute bit * sec_acl.cc (set_posix_access): Apply mask only in terms of execute bit

28
winsup/cygwin/sec_acl.cc
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@ -549,6 +549,7 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
bool owner_eq_group; bool owner_eq_group;
bool just_created = false; bool just_created = false;
bool standard_ACEs_only = true;
bool new_style = false; bool new_style = false;
bool saw_user_obj = false; bool saw_user_obj = false;
bool saw_group_obj = false; bool saw_group_obj = false;
@ -802,6 +803,17 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
class_perm |= lacl[pos].a_perm; class_perm |= lacl[pos].a_perm;
} }
} }
/* For a newly created file, we'd like to know if we're running
with a standard ACL, one only consisting of POSIX perms, plus
SYSTEM and Admins as maximum non-POSIX perms entries. If it's
a standard ACL, we apply umask. That's not entirely correct,
but it's probably the best we can do. */
else if (type & (USER | GROUP)
&& just_created
&& standard_ACEs_only
&& ace_sid != well_known_system_sid
&& ace_sid != well_known_admins_sid)
standard_ACEs_only = false;
} }
} }
if ((ace->Header.AceFlags & SUB_CONTAINERS_AND_OBJECTS_INHERIT)) if ((ace->Header.AceFlags & SUB_CONTAINERS_AND_OBJECTS_INHERIT))
@ -884,19 +896,19 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
lacl[pos].a_id = ILLEGAL_GID; lacl[pos].a_id = ILLEGAL_GID;
lacl[pos].a_perm = lacl[1].a_perm; /* == group perms */ lacl[pos].a_perm = lacl[1].a_perm; /* == group perms */
} }
/* If this is a just created file, and there are no default permissions /* If this is a just created file, and this is an ACL with only standard
(probably no inherited ACEs so created from a default DACL), assign entries, or if standard POSIX permissions are missing (probably no
the permissions specified by the file creation mask. The values get inherited ACEs so created from a default DACL), assign the permissions
masked by the actually requested permissions by the caller. specified by the file creation mask. The values get masked by the
See POSIX 1003.1e draft 17. */ actually requested permissions by the caller per POSIX 1003.1e draft 17. */
if (just_created) if (just_created)
{ {
mode_t perms = (S_IRWXU | S_IRWXG | S_IRWXO) & ~cygheap->umask; mode_t perms = (S_IRWXU | S_IRWXG | S_IRWXO) & ~cygheap->umask;
if (!saw_user_obj) if (standard_ACEs_only || !saw_user_obj)
lacl[0].a_perm = (perms >> 6) & S_IRWXO; lacl[0].a_perm = (perms >> 6) & S_IRWXO;
if (!saw_group_obj) if (standard_ACEs_only || !saw_group_obj)
lacl[1].a_perm = (perms >> 3) & S_IRWXO; lacl[1].a_perm = (perms >> 3) & S_IRWXO;
if (!saw_other_obj) if (standard_ACEs_only || !saw_other_obj)
lacl[2].a_perm = perms & S_IRWXO; lacl[2].a_perm = perms & S_IRWXO;
} }
/* Ensure that the default acl contains at least /* Ensure that the default acl contains at least

42
winsup/cygwin/security.cc
View File

@ -468,22 +468,34 @@ set_created_file_access (HANDLE handle, path_conv &pc, mode_t attr)
if ((nentries = get_posix_access (sd, &attr_rd, &uid, &gid, if ((nentries = get_posix_access (sd, &attr_rd, &uid, &gid,
aclp, MAX_ACL_ENTRIES)) >= 0) aclp, MAX_ACL_ENTRIES)) >= 0)
{ {
/* Symlinks always get the request POSIX perms. */
if (S_ISLNK (attr)) if (S_ISLNK (attr))
attr_rd = 0777; {
/* Overwrite ACL permissions as required by POSIX 1003.1e /* Symlinks always get the request POSIX perms. */
draft 17. */ aclp[0].a_perm = (attr >> 6) & S_IRWXO;
aclp[0].a_perm = ((attr & attr_rd) >> 6) & S_IRWXO; if ((idx = searchace (aclp, nentries, GROUP_OBJ)) >= 0)
/* Deliberate deviation from POSIX 1003.1e here. We're not aclp[idx].a_perm = (attr >> 3) & S_IRWXO;
writing CLASS_OBJ *or* GROUP_OBJ, but both. Otherwise we're if (nentries > MIN_ACL_ENTRIES
going to be in constant trouble with user expectations. */ && (idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0)
if ((idx = searchace (aclp, nentries, GROUP_OBJ)) >= 0) aclp[idx].a_perm = (attr >> 3) & S_IRWXO;
aclp[idx].a_perm = ((attr & attr_rd) >> 3) & S_IRWXO; if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0)
if (nentries > MIN_ACL_ENTRIES aclp[idx].a_perm = attr & S_IRWXO;
&& (idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0) }
aclp[idx].a_perm = ((attr & attr_rd) >> 3) & S_IRWXO; else
if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0) {
aclp[idx].a_perm = (attr & attr_rd) & S_IRWXO; /* Overwrite ACL permissions as required by POSIX 1003.1e
draft 17. */
aclp[0].a_perm &= (attr >> 6) & S_IRWXO;
/* Deliberate deviation from POSIX 1003.1e here. We're not
writing CLASS_OBJ *or* GROUP_OBJ, but both. Otherwise we're
going to be in constant trouble with user expectations. */
if ((idx = searchace (aclp, nentries, GROUP_OBJ)) >= 0)
aclp[idx].a_perm &= (attr >> 3) & S_IRWXO;
if (nentries > MIN_ACL_ENTRIES
&& (idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0)
aclp[idx].a_perm &= (attr >> 3) & S_IRWXO;
if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0)
aclp[idx].a_perm &= attr & S_IRWXO;
}
/* Construct appropriate inherit attribute for new directories. /* Construct appropriate inherit attribute for new directories.
Basically we do this only for the sake of non-Cygwin applications. Basically we do this only for the sake of non-Cygwin applications.
Cygwin applications don't need these. Additionally, if the Cygwin applications don't need these. Additionally, if the