[PATCH] Fix bug 10252 - make our access-based enumeration work exactly like Windows.

Jeremy Allison jra at samba.org
Wed Oct 14 00:10:47 UTC 2015


This took much longer to fix than it should have
- fighting the test suite to access a specific
share, and discovering that Windows only does
access-based enumeration on wildcard directory
listings, not specific filenames :-).

Please review and push if happy !

Cheers,

	Jeremy.
-------------- next part --------------
From 2c9f36128a781d32e16e25528eb9ca293469ba43 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Tue, 13 Oct 2015 16:49:41 -0700
Subject: [PATCH 1/3] s3: smbd: Fix our access-based enumeration on "hide
 unreadable" to match Windows.

Torture test to follow.

https://bugzilla.samba.org/show_bug.cgi?id=10252

Signed-off-by: Jeremy Allison <jra at samba.org>
---
 source3/smbd/dir.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 61 insertions(+), 3 deletions(-)

diff --git a/source3/smbd/dir.c b/source3/smbd/dir.c
index eebf9b1..3f99f88 100644
--- a/source3/smbd/dir.c
+++ b/source3/smbd/dir.c
@@ -1343,6 +1343,15 @@ bool get_dir_entry(TALLOC_CTX *ctx,
 static bool user_can_read_file(connection_struct *conn,
 			       struct smb_filename *smb_fname)
 {
+	NTSTATUS status;
+	uint32_t rejected_share_access = 0;
+	uint32_t rejected_mask = 0;
+	struct security_descriptor *sd = NULL;
+	uint32_t access_mask = FILE_READ_DATA|
+				FILE_READ_EA|
+				FILE_READ_ATTRIBUTES|
+				SEC_STD_READ_CONTROL;
+
 	/*
 	 * Never hide files from the root user.
 	 * We use (uid_t)0 here not sec_initial_uid()
@@ -1353,10 +1362,59 @@ static bool user_can_read_file(connection_struct *conn,
 		return True;
 	}
 
-	return NT_STATUS_IS_OK(smbd_check_access_rights(conn,
-				smb_fname,
+	/*
+	 * We can't directly use smbd_check_access_rights()
+	 * here, as this implicitly grants FILE_READ_ATTRIBUTES
+	 * which the Windows access-based-enumeration code
+	 * explicitly checks for on the file security descriptor.
+	 * See bug:
+	 *
+	 * https://bugzilla.samba.org/show_bug.cgi?id=10252
+	 *
+	 * and the smb2.acl2.ACCESSBASED test for details.
+	 */
+
+	rejected_share_access = access_mask & ~(conn->share_access);
+	if (rejected_share_access) {
+		DEBUG(10, ("rejected share access 0x%x "
+			"on %s (0x%x)\n",
+			(unsigned int)access_mask,
+			smb_fname_str_dbg(smb_fname),
+			(unsigned int)rejected_share_access ));
+		return false;
+        }
+
+	status = SMB_VFS_GET_NT_ACL(conn,
+			smb_fname->base_name,
+			(SECINFO_OWNER |
+			 SECINFO_GROUP |
+			 SECINFO_DACL),
+			talloc_tos(),
+			&sd);
+
+	if (!NT_STATUS_IS_OK(status)) {
+                DEBUG(10, ("Could not get acl "
+			"on %s: %s\n",
+			smb_fname_str_dbg(smb_fname),
+			nt_errstr(status)));
+		return false;
+        }
+
+	status = se_file_access_check(sd,
+				get_current_nttok(conn),
 				false,
-				FILE_READ_DATA));
+				access_mask,
+				&rejected_mask);
+
+        TALLOC_FREE(sd);
+
+	if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
+		DEBUG(10,("rejected bits 0x%x read access for %s\n",
+			(unsigned int)rejected_mask,
+			smb_fname_str_dbg(smb_fname) ));
+		return false;
+        }
+	return true;
 }
 
 /*******************************************************************
-- 
2.6.0.rc2.230.g3dd15c0


From b84a37dee050101ab9b1b7bcc920aa4845ddd0bf Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Fri, 9 Oct 2015 15:08:05 -0700
Subject: [PATCH 2/3] lib: cli: Add accessor function smb2cli_tcon_flags() to
 get tcon flags.

We need this to see if a share supports access-based enumeration.

https://bugzilla.samba.org/show_bug.cgi?id=10252

Signed-off-by: Jeremy Allison <jra at samba.org>
---
 libcli/smb/smbXcli_base.c | 5 +++++
 libcli/smb/smbXcli_base.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/libcli/smb/smbXcli_base.c b/libcli/smb/smbXcli_base.c
index c1e9e58..6fe4816 100644
--- a/libcli/smb/smbXcli_base.c
+++ b/libcli/smb/smbXcli_base.c
@@ -5991,6 +5991,11 @@ uint32_t smb2cli_tcon_capabilities(struct smbXcli_tcon *tcon)
 	return tcon->smb2.capabilities;
 }
 
+uint32_t smb2cli_tcon_flags(struct smbXcli_tcon *tcon)
+{
+	return tcon->smb2.flags;
+}
+
 void smb2cli_tcon_set_values(struct smbXcli_tcon *tcon,
 			     struct smbXcli_session *session,
 			     uint32_t tcon_id,
diff --git a/libcli/smb/smbXcli_base.h b/libcli/smb/smbXcli_base.h
index cf93135..e4cfb10 100644
--- a/libcli/smb/smbXcli_base.h
+++ b/libcli/smb/smbXcli_base.h
@@ -442,6 +442,7 @@ bool smb1cli_tcon_set_values(struct smbXcli_tcon *tcon,
 			     const char *fs_type);
 uint32_t smb2cli_tcon_current_id(struct smbXcli_tcon *tcon);
 uint32_t smb2cli_tcon_capabilities(struct smbXcli_tcon *tcon);
+uint32_t smb2cli_tcon_flags(struct smbXcli_tcon *tcon);
 void smb2cli_tcon_set_values(struct smbXcli_tcon *tcon,
 			     struct smbXcli_session *session,
 			     uint32_t tcon_id,
-- 
2.6.0.rc2.230.g3dd15c0


From 6ef937cb864ebd6a63038fa3eb573ba35c5306f2 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Tue, 13 Oct 2015 15:33:47 -0700
Subject: [PATCH 3/3] s4: torture: Add SMB2 access-based enumeration test.
 Passes against Win2k12R2.

https://bugzilla.samba.org/show_bug.cgi?id=10252

Signed-off-by: Jeremy Allison <jra at samba.org>
---
 selftest/knownfail          |   1 +
 source4/torture/smb2/acls.c | 230 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 231 insertions(+)

diff --git a/selftest/knownfail b/selftest/knownfail
index bf73176..0d74933 100644
--- a/selftest/knownfail
+++ b/selftest/knownfail
@@ -147,6 +147,7 @@
 ^samba4.smb2.acls.*.generic
 ^samba4.smb2.acls.*.inheritflags
 ^samba4.smb2.acls.*.owner
+^samba4.smb2.acls.*.ACCESSBASED
 ^samba4.ldap.dirsync.python.ad_dc_ntvfs..__main__.ExtendedDirsyncTests.test_dirsync_deleted_items
 #^samba4.ldap.dirsync.python.ad_dc_ntvfs..__main__.ExtendedDirsyncTests.*
 ^samba4.libsmbclient.opendir.opendir # This requires netbios browsing
diff --git a/source4/torture/smb2/acls.c b/source4/torture/smb2/acls.c
index 37052c6..8066bc9 100644
--- a/source4/torture/smb2/acls.c
+++ b/source4/torture/smb2/acls.c
@@ -20,13 +20,17 @@
 */
 
 #include "includes.h"
+#include "lib/cmdline/popt_common.h"
 #include "libcli/smb2/smb2.h"
 #include "libcli/smb2/smb2_calls.h"
+#include "libcli/smb/smbXcli_base.h"
 #include "torture/torture.h"
+#include "libcli/resolve/resolve.h"
 #include "torture/util.h"
 #include "torture/smb2/proto.h"
 #include "libcli/security/security.h"
 #include "librpc/gen_ndr/ndr_security.h"
+#include "lib/param/param.h"
 
 #define CHECK_STATUS(status, correct) do { \
 	if (!NT_STATUS_EQUAL(status, correct)) { \
@@ -1855,6 +1859,231 @@ done:
 }
 #endif
 
+/**
+ * SMB2 connect with explicit share
+ **/
+static bool torture_smb2_con_share(struct torture_context *tctx,
+                           const char *share,
+                           struct smb2_tree **tree)
+{
+        struct smbcli_options options;
+        NTSTATUS status;
+        const char *host = torture_setting_string(tctx, "host", NULL);
+        struct cli_credentials *credentials = cmdline_credentials;
+
+        lpcfg_smbcli_options(tctx->lp_ctx, &options);
+
+        status = smb2_connect_ext(tctx,
+                                  host,
+                                  lpcfg_smb_ports(tctx->lp_ctx),
+                                  share,
+                                  lpcfg_resolve_context(tctx->lp_ctx),
+                                  credentials,
+                                  0,
+                                  tree,
+                                  tctx->ev,
+                                  &options,
+                                  lpcfg_socket_options(tctx->lp_ctx),
+                                  lpcfg_gensec_settings(tctx, tctx->lp_ctx)
+                                  );
+        if (!NT_STATUS_IS_OK(status)) {
+                printf("Failed to connect to SMB2 share \\\\%s\\%s - %s\n",
+                       host, share, nt_errstr(status));
+                return false;
+        }
+        return true;
+}
+
+static bool test_access_based(struct torture_context *tctx,
+				struct smb2_tree *tree)
+{
+	struct smb2_tree *tree1 = NULL;
+	NTSTATUS status;
+	struct smb2_create io;
+	const char *fname = BASEDIR "\\testfile";
+	bool ret = true;
+	struct smb2_handle fhandle, dhandle;
+	union smb_fileinfo q;
+	union smb_setfileinfo set;
+	struct security_descriptor *sd, *sd_orig=NULL;
+	const char *owner_sid;
+	uint32_t flags = 0;
+	/*
+	 * Can't test without SEC_STD_READ_CONTROL as we
+	 * own the file and implicitly have SEC_STD_READ_CONTROL.
+	*/
+	uint32_t access_masks[] = {
+		/* Full READ access. */
+		SEC_STD_READ_CONTROL|FILE_READ_DATA|
+		FILE_READ_ATTRIBUTES|FILE_READ_EA,
+
+		/* Missing FILE_READ_EA. */
+		SEC_STD_READ_CONTROL|FILE_READ_DATA|
+		FILE_READ_ATTRIBUTES,
+
+		/* Missing FILE_READ_ATTRIBUTES. */
+		SEC_STD_READ_CONTROL|FILE_READ_DATA|
+		FILE_READ_EA,
+
+		/* Missing FILE_READ_DATA. */
+		SEC_STD_READ_CONTROL|
+		FILE_READ_ATTRIBUTES|FILE_READ_EA,
+	};
+	unsigned int i;
+	unsigned int count;
+	struct smb2_find f;
+	union smb_search_data *d;
+
+	ZERO_STRUCT(fhandle);
+	ZERO_STRUCT(dhandle);
+
+	if (!torture_smb2_con_share(tctx, "hideunread", &tree1)) {
+		torture_result(tctx, TORTURE_FAIL, "(%s) Unable to connect "
+			"to share 'hideunread'\n",
+                       __location__);
+		ret = false;
+		goto done;
+	}
+
+	flags = smb2cli_tcon_flags(tree1->smbXcli);
+
+	smb2_util_unlink(tree1, fname);
+	smb2_deltree(tree1, BASEDIR);
+
+	torture_comment(tctx, "TESTING ACCESS BASED ENUMERATION\n");
+
+	if ((flags & SMB2_SHAREFLAG_ACCESS_BASED_DIRECTORY_ENUM)==0) {
+		torture_result(tctx, TORTURE_FAIL, "(%s) No access enumeration "
+			"on share 'hideunread'\n",
+                       __location__);
+		ret = false;
+		goto done;
+	}
+
+	if (!smb2_util_setup_dir(tctx, tree1, BASEDIR)) {
+		torture_result(tctx, TORTURE_FAIL, "(%s) Unable to setup %s\n",
+                       __location__, BASEDIR);
+		ret = false;
+		goto done;
+	}
+
+	/* Get a handle to the BASEDIR directory. */
+	status = torture_smb2_testdir(tree1, BASEDIR, &dhandle);
+	CHECK_STATUS(status, NT_STATUS_OK);
+	smb2_util_close(tree1, dhandle);
+	ZERO_STRUCT(dhandle);
+
+	ZERO_STRUCT(io);
+	io.level = RAW_OPEN_SMB2;
+	io.in.create_flags = 0;
+	io.in.desired_access = SEC_RIGHTS_FILE_ALL;
+	io.in.create_options = 0;
+	io.in.file_attributes = FILE_ATTRIBUTE_NORMAL;
+	io.in.share_access = 0;
+	io.in.alloc_size = 0;
+	io.in.create_disposition = NTCREATEX_DISP_CREATE;
+	io.in.impersonation_level = NTCREATEX_IMPERSONATION_ANONYMOUS;
+	io.in.security_flags = 0;
+	io.in.fname = fname;
+
+	status = smb2_create(tree1, tctx, &io);
+	CHECK_STATUS(status, NT_STATUS_OK);
+	fhandle = io.out.file.handle;
+
+	torture_comment(tctx, "get the original sd\n");
+	q.query_secdesc.level = RAW_FILEINFO_SEC_DESC;
+	q.query_secdesc.in.file.handle = fhandle;
+	q.query_secdesc.in.secinfo_flags = SECINFO_DACL | SECINFO_OWNER;
+	status = smb2_getinfo_file(tree1, tctx, &q);
+	CHECK_STATUS(status, NT_STATUS_OK);
+	sd_orig = q.query_secdesc.out.sd;
+
+	owner_sid = dom_sid_string(tctx, sd_orig->owner_sid);
+
+	torture_comment(tctx, "owner_sid is %s\n", owner_sid);
+
+	/* Setup for the search. */
+	ZERO_STRUCT(f);
+	f.in.pattern            = "*";
+	f.in.continue_flags     = SMB2_CONTINUE_FLAG_REOPEN;
+	f.in.max_response_size  = 0x1000;
+	f.in.level              = SMB2_FIND_DIRECTORY_INFO;
+
+	for (i = 0; i < ARRAY_SIZE(access_masks); i++) {
+
+		sd = security_descriptor_dacl_create(tctx,
+					0, NULL, NULL,
+					owner_sid,
+					SEC_ACE_TYPE_ACCESS_ALLOWED,
+					access_masks[i]|SEC_STD_SYNCHRONIZE,
+					0,
+					NULL);
+
+		set.set_secdesc.level = RAW_SFILEINFO_SEC_DESC;
+		set.set_secdesc.in.file.handle = fhandle;
+		set.set_secdesc.in.secinfo_flags = SECINFO_DACL;
+		set.set_secdesc.in.sd = sd;
+		status = smb2_setinfo_file(tree1, &set);
+		CHECK_STATUS(status, NT_STATUS_OK);
+
+		/* Now see if we can see the file in a directory listing. */
+
+		/* Re-open dhandle. */
+		status = torture_smb2_testdir(tree1, BASEDIR, &dhandle);
+		CHECK_STATUS(status, NT_STATUS_OK);
+		f.in.file.handle = dhandle;
+
+		count = 0;
+		d = NULL;
+		status = smb2_find_level(tree1, tree1, &f, &count, &d);
+		TALLOC_FREE(d);
+
+		CHECK_STATUS(status, NT_STATUS_OK);
+
+		smb2_util_close(tree1, dhandle);
+		ZERO_STRUCT(dhandle);
+
+		if (i == 0) {
+			/* We should see the first sd. */
+			if (count != 3) {
+				torture_result(tctx, TORTURE_FAIL,
+					"(%s) Normal SD - Unable "
+					"to see file %s\n",
+					__location__,
+					BASEDIR);
+				ret = false;
+				goto done;
+			}
+		} else {
+			/* But no others. */
+			if (count != 2) {
+				torture_result(tctx, TORTURE_FAIL,
+					"(%s) SD 0x%x - can "
+					"see file %s\n",
+					__location__,
+					access_masks[i],
+					BASEDIR);
+				ret = false;
+				goto done;
+			}
+		}
+	}
+
+done:
+
+	if (tree1) {
+		smb2_util_close(tree1, fhandle);
+		smb2_util_close(tree1, dhandle);
+		smb2_util_unlink(tree1, fname);
+		smb2_deltree(tree1, BASEDIR);
+		smb2_tdis(tree1);
+		smb2_logoff(tree1->session);
+	}
+	smb2_tdis(tree);
+	smb2_logoff(tree->session);
+	return ret;
+}
+
 /*
    basic testing of SMB2 ACLs
 */
@@ -1872,6 +2101,7 @@ struct torture_suite *torture_smb2_acls_init(void)
 	/* XXX This test does not work against XP or Vista. */
 	torture_suite_add_1smb2_test(suite, "GETSET", test_sd_get_set);
 #endif
+	torture_suite_add_1smb2_test(suite, "ACCESSBASED", test_access_based);
 
 	suite->description = talloc_strdup(suite, "SMB2-ACLS tests");
 
-- 
2.6.0.rc2.230.g3dd15c0



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