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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Namjae Jeon <linkinjeon@kernel.org>,
	Steve French <stfrench@microsoft.com>,
	Sasha Levin <sashal@kernel.org>,
	sfrench@samba.org,
	linux-cifs@vger.kernel.org
Subject: [PATCH AUTOSEL 6.1 52/53] ksmbd: fix potential circular locking issue in smb2_set_ea()
Date: Mon, 22 Jan 2024 10:08:53 -0500
Message-ID: <20240122150949.994249-52-sashal@kernel.org>
In-Reply-To: <20240122150949.994249-1-sashal@kernel.org>
References: <20240122150949.994249-1-sashal@kernel.org>
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From: Namjae Jeon <linkinjeon@kernel.org>

[ Upstream commit 6fc0a265e1b932e5e97a038f99e29400a93baad0 ]

smb2_set_ea() can be called in parent inode lock range.
So add get_write argument to smb2_set_ea() not to call nested
mnt_want_write().

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/server/smb2pdu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 6e5ed0ac578a..8d4e2c666c34 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2309,11 +2309,12 @@ static noinline int create_smb2_pipe(struct ksmbd_work *work)
  * @eabuf:	set info command buffer
  * @buf_len:	set info command buffer length
  * @path:	dentry path for get ea
+ * @get_write:	get write access to a mount
  *
  * Return:	0 on success, otherwise error
  */
 static int smb2_set_ea(struct smb2_ea_info *eabuf, unsigned int buf_len,
-		       const struct path *path)
+		       const struct path *path, bool get_write)
 {
 	struct user_namespace *user_ns = mnt_user_ns(path->mnt);
 	char *attr_name = NULL, *value;
@@ -3001,7 +3002,7 @@ int smb2_open(struct ksmbd_work *work)
 
 			rc = smb2_set_ea(&ea_buf->ea,
 					 le32_to_cpu(ea_buf->ccontext.DataLength),
-					 &path);
+					 &path, false);
 			if (rc == -EOPNOTSUPP)
 				rc = 0;
 			else if (rc)
@@ -5990,7 +5991,7 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 			return -EINVAL;
 
 		return smb2_set_ea((struct smb2_ea_info *)req->Buffer,
-				   buf_len, &fp->filp->f_path);
+				   buf_len, &fp->filp->f_path, true);
 	}
 	case FILE_POSITION_INFORMATION:
 	{
-- 
2.43.0