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Fix reading/writing Samba ACLs using RFC2307 mapping 

When using RFC2307 uid/gid-mapping on Samba shares, the POSIX ACL contains
the Windows SIDs.  When writing back such an ACL we have to map the
Windows SIDs back to the corresponding Samba SIDs representing the UNIX
uid/gid value.  When reading Samba SIDs, make sure never to evaluate a
UNIX user account as group.

	* sec_acl.cc (set_posix_access): Convert Windows SIDs to
	RFC2307-mapped Sambe UNIX SIDs.
	* sec_helper.cc (cygpsid::get_id): Skip UNIX user accounts when
	trying to evaluate a SID as group.  Skip UNIX group accounts when
	trying to evaluate a SID as user.
	* cygheap.h (cygheap_ugid_cache::reverse_get): New method to
	get nfs id from cygwin id.
	(cygheap_ugid_cache::reverse_get_uid): Wrapper for uids.
	(cygheap_ugid_cache::reverse_get_gid): Wrapper for gids.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2016-03-12 17:56:21 +01:00
parent 018fa93e2b
commit fc180edcf4
3 changed files with 82 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
winsup/cygwin/cygheap.h
View File

@ -508,6 +508,13 @@ class cygheap_ugid_cache
return _map[i].cyg_id;
return (uint32_t) -1;
}
uint32_t reverse_get (uint32_t id) const
{
for (uint32_t i = 0; i < _cnt; ++i)
if (_map[i].cyg_id == id)
return _map[i].nfs_id;
return (uint32_t) -1;
}
void add (uint32_t nfs_id, uint32_t cyg_id)
{
if (_cnt >= _max)
@ -523,6 +530,8 @@ class cygheap_ugid_cache
public:
uid_t get_uid (uid_t uid) const { return uids.get (uid); }
gid_t get_gid (gid_t gid) const { return gids.get (gid); }
uid_t reverse_get_uid (uid_t uid) const { return uids.reverse_get (uid); }
gid_t reverse_get_gid (gid_t gid) const { return gids.reverse_get (gid); }
void add_uid (uid_t nfs_uid, uid_t cyg_uid) { uids.add (nfs_uid, cyg_uid); }
void add_gid (gid_t nfs_gid, gid_t cyg_gid) { gids.add (nfs_gid, cyg_gid); }
};

59
winsup/cygwin/sec_acl.cc
View File

@ -138,7 +138,8 @@ set_posix_access (mode_t attr, uid_t uid, gid_t gid,
{
SECURITY_DESCRIPTOR sd;
cyg_ldap cldap;
PSID owner, group;
PSID owner = NULL, group = NULL;
cygsid smb_owner, smb_group;
NTSTATUS status;
tmp_pathbuf tp;
cygpsid *aclsid;
@ -157,9 +158,27 @@ set_posix_access (mode_t attr, uid_t uid, gid_t gid,
modified by inheritable ACEs. */
RtlSetControlSecurityDescriptor (&sd, SE_DACL_PROTECTED, SE_DACL_PROTECTED);
/* Fetch owner and group and set in security descriptor. */
owner = sidfromuid (uid, &cldap);
group = sidfromgid (gid, &cldap);
/* Fetch owner and group and set in security descriptor.
For Samba we check if there's an RFC2307 mapping in place, otherwise
we're trying to create an ACL with the wrong Windows SIDs rather than
the correct Unix SIDs. Same happens below for mapping other USER and
GROUP SIDs. */
if (is_samba)
{
uint32_t smb_uid, smb_gid;
smb_uid = cygheap->ugid_cache.reverse_get_uid (uid);
if (smb_uid != ILLEGAL_UID)
owner = smb_owner.create (22, 2, 1, smb_uid);
smb_gid = cygheap->ugid_cache.reverse_get_gid (gid);
if (smb_gid != ILLEGAL_GID)
group = smb_group.create (22, 2, 2, smb_gid);
}
if (!owner)
owner = sidfromuid (uid, &cldap);
if (!group)
group = sidfromgid (gid, &cldap);
if (!owner || !group)
{
set_errno (EINVAL);
@ -224,7 +243,21 @@ set_posix_access (mode_t attr, uid_t uid, gid_t gid,
break;
case USER:
case DEF_USER:
aclsid[idx] = sidfromuid (aclbufp[idx].a_id, &cldap);
aclsid[idx] = NO_SID;
if (is_samba)
{
uint32_t smb_uid;
cygsid *smb_sid;
smb_uid = cygheap->ugid_cache.reverse_get_uid (aclbufp[idx].a_id);
if (smb_uid != ILLEGAL_UID)
{
smb_sid = (cygsid *) alloca (sizeof (cygsid));
aclsid[idx] = smb_sid->create (22, 2, 1, smb_uid);
}
}
if (!aclsid[idx])
aclsid[idx] = sidfromuid (aclbufp[idx].a_id, &cldap);
break;
case GROUP_OBJ:
aclsid[idx] = group;
@ -235,7 +268,21 @@ set_posix_access (mode_t attr, uid_t uid, gid_t gid,
break;
case GROUP:
case DEF_GROUP:
aclsid[idx] = sidfromgid (aclbufp[idx].a_id, &cldap);
aclsid[idx] = NO_SID;
if (is_samba)
{
uint32_t smb_gid;
cygsid *smb_sid;
smb_gid = cygheap->ugid_cache.reverse_get_gid (aclbufp[idx].a_id);
if (smb_gid != ILLEGAL_GID)
{
smb_sid = (cygsid *) alloca (sizeof (cygsid));
aclsid[idx] = smb_sid->create (22, 2, 2, smb_gid);
}
}
if (!aclsid[idx])
aclsid[idx] = sidfromgid (aclbufp[idx].a_id, &cldap);
break;
case CLASS_OBJ:
case DEF_CLASS_OBJ:

32
winsup/cygwin/sec_helper.cc
View File

@ -117,21 +117,28 @@ cygpsid::get_id (BOOL search_grp, int *type, cyg_ldap *pldap)
id = myself->gid;
else if (sid_id_auth (psid) == 22 && cygheap->pg.nss_grp_db ())
{
/* Samba UNIX group. Try to map to Cygwin gid. If there's no
/* Samba UNIX group? Try to map to Cygwin gid. If there's no
mapping in the cache, try to fetch it from the configured
RFC 2307 domain (see last comment in cygheap_domain_info::init()
for more information) and add it to the mapping cache. */
gid_t gid = sid_sub_auth_rid (psid);
gid_t map_gid = cygheap->ugid_cache.get_gid (gid);
if (map_gid == ILLEGAL_GID)
for more information) and add it to the mapping cache.
If this is a user, not a group, make sure to skip the subsequent
internal_getgrsid call, otherwise we end up with a fake group
entry for a UNIX user account. */
if (sid_sub_auth (psid, 0) == 2)
{
if (pldap->open (cygheap->dom.get_rfc2307_domain ()) == NO_ERROR)
map_gid = pldap->remap_gid (gid);
if (map_gid == ILLEGAL_GID)
map_gid = MAP_UNIX_TO_CYGWIN_ID (gid);
cygheap->ugid_cache.add_gid (gid, map_gid);
gid_t gid = sid_sub_auth_rid (psid);
gid_t map_gid = cygheap->ugid_cache.get_gid (gid);
if (map_gid == ILLEGAL_GID)
{
if (pldap->open (cygheap->dom.get_rfc2307_domain ())
== NO_ERROR)
map_gid = pldap->remap_gid (gid);
if (map_gid == ILLEGAL_GID)
map_gid = MAP_UNIX_TO_CYGWIN_ID (gid);
cygheap->ugid_cache.add_gid (gid, map_gid);
}
id = (uid_t) map_gid;
}
id = (uid_t) map_gid;
}
else if ((gr = internal_getgrsid (*this, pldap)))
id = gr->gr_gid;
@ -147,7 +154,8 @@ cygpsid::get_id (BOOL search_grp, int *type, cyg_ldap *pldap)
struct passwd *pw;
if (*this == cygheap->user.sid ())
id = myself->uid;
else if (sid_id_auth (psid) == 22 && cygheap->pg.nss_pwd_db ())
else if (sid_id_auth (psid) == 22 && sid_sub_auth (psid, 0) == 1
&& cygheap->pg.nss_pwd_db ())
{
/* Samba UNIX user. See comment above. */
uid_t uid = sid_sub_auth_rid (psid);