From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: Zihan Xi <zihanx@nebusec.ai>,
	Vega <vega@nebusec.ai>,
	Luxing Yin <root@tr0jan.top>,
	Frank Sorenson <sorenson@redhat.com>,
	Paulo Alcantara <pc@manguebit.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.6.y 2/2] smb: client: clean up failed cached directory opens
Date: Wed, 30 Sep 2026 12:08:51 -0400
Message-ID: <20260930160851.2985631-2-sashal@kernel.org>
In-Reply-To: <20260930160851.2985631-1-sashal@kernel.org>
References: <2026092937-truce-superhero-2529@gregkh>
 <20260930160851.2985631-1-sashal@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: Zihan Xi <zihanx@nebusec.ai>

[ Upstream commit d2ff5fb93ea83034025850266b5eed391f96b825 ]

open_cached_dir() sends CREATE and QUERY_INFO as a compound request. If
the CREATE succeeds but a later command returns an error, the function
must retain the CREATE FID so common cleanup can issue SMB2_close(). It
also must not treat a response error as a valid CREATE.

Validate the CREATE response before using its fields, record the FIDs, and
mark the handle open before handling errors from later compound commands.
Move the -EREMCHG reconnect handling before response validation so a
missing response does not hide the reconnect request. Count the handle
when it is marked open; confirmed close responses decrement the counter,
while existing close retry behavior remains best effort on transport
failures.

Fixes: b0f6df737a1c ("cifs: cache FILE_ALL_INFO for the shared root handle")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/cached_dir.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index fbc746813a6f2..bb1358d649499 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -8,6 +8,7 @@
 #include <linux/namei.h>
 #include "cifsglob.h"
 #include "cifsproto.h"
+#include "../common/smb2status.h"
 #include "cifs_debug.h"
 #include "smb2proto.h"
 #include "cached_dir.h"
@@ -294,25 +295,37 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 	rc = compound_send_recv(xid, ses, server,
 				flags, 2, rqst,
 				resp_buftype, rsp_iov);
-	if (rc) {
-		if (rc == -EREMCHG) {
-			tcon->need_reconnect = true;
-			pr_warn_once("server share %s deleted\n",
-				     tcon->tree_name);
-		}
-		goto oshr_free;
+	if (rc == -EREMCHG) {
+		tcon->need_reconnect = true;
+		pr_warn_once("server share %s deleted\n",
+			     tcon->tree_name);
 	}
-	cfid->is_open = true;
 
-	spin_lock(&cfids->cfid_list_lock);
+	if (!rsp_iov[0].iov_base || rsp_iov[0].iov_len < sizeof(*o_rsp)) {
+		if (!rc)
+			rc = -EIO;
+		goto oshr_free;
+	}
 
 	o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
+	if (o_rsp->hdr.Status != STATUS_SUCCESS) {
+		if (!rc)
+			rc = -EIO;
+		goto oshr_free;
+	}
+
 	oparms.fid->persistent_fid = o_rsp->PersistentFileId;
 	oparms.fid->volatile_fid = o_rsp->VolatileFileId;
 #ifdef CONFIG_CIFS_DEBUG2
 	oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
 #endif /* CIFS_DEBUG2 */
+	cfid->is_open = true;
+	atomic_inc(&tcon->num_remote_opens);
 
+	if (rc)
+		goto oshr_free;
+
+	spin_lock(&cfids->cfid_list_lock);
 
 	if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) {
 		spin_unlock(&cfids->cfid_list_lock);
@@ -378,7 +391,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 		close_cached_dir(cfid);
 	} else {
 		*ret_cfid = cfid;
-		atomic_inc(&tcon->num_remote_opens);
 	}
 	kfree(utf16_path);
 
-- 
2.53.0