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[newlib-cygwin] Apply umask on "standard" Cygwin ACL
- From: Corinna Vinschen <corinna at sourceware dot org>
- To: cygwin-cvs at sourceware dot org
- Date: 21 Apr 2015 09:49:49 -0000
- Subject: [newlib-cygwin] Apply umask on "standard" Cygwin ACL
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a8ec1e804ee9ba2d6f8304731e593dcf167c9836
commit a8ec1e804ee9ba2d6f8304731e593dcf167c9836
Author: Corinna Vinschen <corinna@vinschen.de>
Date: Tue Apr 21 11:49:38 2015 +0200
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>
Diff:
---
winsup/cygwin/ChangeLog | 7 +++++++
winsup/cygwin/sec_acl.cc | 28 ++++++++++++++++++++--------
winsup/cygwin/security.cc | 42 +++++++++++++++++++++++++++---------------
3 files changed, 54 insertions(+), 23 deletions(-)
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index dda1a95..998cb4b 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -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>
* sec_acl.cc (set_posix_access): Apply mask only in terms of execute bit
diff --git a/winsup/cygwin/sec_acl.cc b/winsup/cygwin/sec_acl.cc
index bddd21c..7d97fca 100644
--- a/winsup/cygwin/sec_acl.cc
+++ b/winsup/cygwin/sec_acl.cc
@@ -549,6 +549,7 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
bool owner_eq_group;
bool just_created = false;
+ bool standard_ACEs_only = true;
bool new_style = false;
bool saw_user_obj = false;
bool saw_group_obj = false;
@@ -802,6 +803,17 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
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))
@@ -884,19 +896,19 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
lacl[pos].a_id = ILLEGAL_GID;
lacl[pos].a_perm = lacl[1].a_perm; /* == group perms */
}
- /* If this is a just created file, and there are no default permissions
- (probably no inherited ACEs so created from a default DACL), assign
- the permissions specified by the file creation mask. The values get
- masked by the actually requested permissions by the caller.
- See POSIX 1003.1e draft 17. */
+ /* If this is a just created file, and this is an ACL with only standard
+ entries, or if standard POSIX permissions are missing (probably no
+ inherited ACEs so created from a default DACL), assign the permissions
+ specified by the file creation mask. The values get masked by the
+ actually requested permissions by the caller per POSIX 1003.1e draft 17. */
if (just_created)
{
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;
- if (!saw_group_obj)
+ if (standard_ACEs_only || !saw_group_obj)
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;
}
/* Ensure that the default acl contains at least
diff --git a/winsup/cygwin/security.cc b/winsup/cygwin/security.cc
index 6d891c1..5fca674 100644
--- a/winsup/cygwin/security.cc
+++ b/winsup/cygwin/security.cc
@@ -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,
aclp, MAX_ACL_ENTRIES)) >= 0)
{
- /* Symlinks always get the request POSIX perms. */
if (S_ISLNK (attr))
- attr_rd = 0777;
- /* Overwrite ACL permissions as required by POSIX 1003.1e
- draft 17. */
- aclp[0].a_perm = ((attr & attr_rd) >> 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 & attr_rd) >> 3) & S_IRWXO;
- if (nentries > MIN_ACL_ENTRIES
- && (idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0)
- aclp[idx].a_perm = ((attr & attr_rd) >> 3) & S_IRWXO;
- if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0)
- aclp[idx].a_perm = (attr & attr_rd) & S_IRWXO;
+ {
+ /* Symlinks always get the request POSIX perms. */
+ aclp[0].a_perm = (attr >> 6) & S_IRWXO;
+ 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;
+ }
+ else
+ {
+ /* 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.
Basically we do this only for the sake of non-Cygwin applications.
Cygwin applications don't need these. Additionally, if the