samba/CVE-2019-10197-6.patch
2019-12-25 16:07:00 +08:00

88 lines
2.9 KiB
Diff

From 501e034aa5b6ba50bf14e41c59674fbbc28a2e9c Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze@samba.org>
Date: Thu, 11 Jul 2019 17:02:15 +0200
Subject: [PATCH 6/6] CVE-2019-10197: smbd: split change_to_user_impersonate()
out of change_to_user_internal()
This makes sure we always call chdir_current_service() even
when we still impersonated the user. Which is important
in order to run the SMB* request within the correct working directory
and only if the user has permissions to enter that directory.
It makes sure we always update conn->lastused_count
in chdir_current_service() for each request.
Note that vfs_ChDir() (called from chdir_current_service())
maintains its own cache and avoids calling SMB_VFS_CHDIR()
if possible.
It means we still avoid syscalls if we get a multiple requests
for the same session/tcon tuple.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14035
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
---
selftest/knownfail.d/CVE-2019-10197 | 1 -
source3/smbd/uid.c | 21 +++++++++++++++++----
2 files changed, 17 insertions(+), 5 deletions(-)
delete mode 100644 selftest/knownfail.d/CVE-2019-10197
diff --git a/selftest/knownfail.d/CVE-2019-10197 b/selftest/knownfail.d/CVE-2019-10197
deleted file mode 100644
index f7056bbf3ad4..000000000000
--- a/selftest/knownfail.d/CVE-2019-10197
+++ /dev/null
@@ -1 +0,0 @@
-^samba3.blackbox.smbclient_s3.*.noperm.share.regression
diff --git a/source3/smbd/uid.c b/source3/smbd/uid.c
index 50868ba8572a..5c39baade5cf 100644
--- a/source3/smbd/uid.c
+++ b/source3/smbd/uid.c
@@ -306,9 +306,9 @@ static void print_impersonation_info(connection_struct *conn)
stack, but modify the current_user entries.
****************************************************************************/
-static bool change_to_user_internal(connection_struct *conn,
- const struct auth_session_info *session_info,
- uint64_t vuid)
+static bool change_to_user_impersonate(connection_struct *conn,
+ const struct auth_session_info *session_info,
+ uint64_t vuid)
{
int snum;
gid_t gid;
@@ -321,7 +321,6 @@ static bool change_to_user_internal(connection_struct *conn,
if ((current_user.conn == conn) &&
(current_user.vuid == vuid) &&
- (current_user.need_chdir == conn->tcon_done) &&
(current_user.ut.uid == session_info->unix_token->uid))
{
DBG_INFO("Skipping user change - already user\n");
@@ -426,6 +425,20 @@ static bool change_to_user_internal(connection_struct *conn,
current_user.conn = conn;
current_user.vuid = vuid;
+ return true;
+}
+
+static bool change_to_user_internal(connection_struct *conn,
+ const struct auth_session_info *session_info,
+ uint64_t vuid)
+{
+ bool ok;
+
+ ok = change_to_user_impersonate(conn, session_info, vuid);
+ if (!ok) {
+ return false;
+ }
+
current_user.need_chdir = conn->tcon_done;
current_user.done_chdir = false;
--
2.17.1