linux-kernel - [PATCH 5.15 048/107] cifs: fix small mempool leak in SMB2

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Date:   Tue,  6 Sep 2022 15:30:29 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Enzo Matsumiya <ematsumiya@...e.de>,
        Ronnie Sahlberg <lsahlber@...hat.com>,
        Steve French <stfrench@...rosoft.com>
Subject: [PATCH 5.15 048/107] cifs: fix small mempool leak in SMB2_negotiate()

From: Enzo Matsumiya <ematsumiya@...e.de>

commit 27893dfc1285f80f80f46b3b8c95f5d15d2e66d0 upstream.

In some cases of failure (dialect mismatches) in SMB2_negotiate(), after
the request is sent, the checks would return -EIO when they should be
rather setting rc = -EIO and jumping to neg_exit to free the response
buffer from mempool.

Signed-off-by: Enzo Matsumiya <ematsumiya@...e.de>
Cc: stable@...r.kernel.org
Reviewed-by: Ronnie Sahlberg <lsahlber@...hat.com>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/cifs/smb2pdu.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -933,16 +933,17 @@ SMB2_negotiate(const unsigned int xid, s
 	} else if (rc != 0)
 		goto neg_exit;
 
+	rc = -EIO;
 	if (strcmp(server->vals->version_string,
 		   SMB3ANY_VERSION_STRING) == 0) {
 		if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2.1 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
 			/* ops set to 3.0 by default for default so update */
 			server->ops = &smb311_operations;
@@ -953,7 +954,7 @@ SMB2_negotiate(const unsigned int xid, s
 		if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
 			/* ops set to 3.0 by default for default so update */
 			server->ops = &smb21_operations;
@@ -967,7 +968,7 @@ SMB2_negotiate(const unsigned int xid, s
 		/* if requested single dialect ensure returned dialect matched */
 		cifs_server_dbg(VFS, "Invalid 0x%x dialect returned: not requested\n",
 				le16_to_cpu(rsp->DialectRevision));
-		return -EIO;
+		goto neg_exit;
 	}
 
 	cifs_dbg(FYI, "mode 0x%x\n", rsp->SecurityMode);
@@ -985,9 +986,10 @@ SMB2_negotiate(const unsigned int xid, s
 	else {
 		cifs_server_dbg(VFS, "Invalid dialect returned by server 0x%x\n",
 				le16_to_cpu(rsp->DialectRevision));
-		rc = -EIO;
 		goto neg_exit;
 	}
+
+	rc = 0;
 	server->dialect = le16_to_cpu(rsp->DialectRevision);
 
 	/*