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Commit 2a71a47e authored by Ross Lagerwall's avatar Ross Lagerwall Committed by Greg Kroah-Hartman
Browse files

cifs: Fix potential OOB access of lock element array 



commit b9a74cde94957d82003fb9f7ab4777938ca851cd upstream.

If maxBuf is small but non-zero, it could result in a zero sized lock
element array which we would then try and access OOB.

Signed-off-by: default avatarRoss Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7dcc5b36

fs/cifs/file.c

+4 −4
Original line number Diff line number Diff line
@@ -1120,10 +1120,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile) 


	/*

	 * Accessing maxBuf is racy with cifs_reconnect - need to store value

	 * and check it for zero before using.

	 * and check it before using.

	 */

	max_buf = tcon->ses->server->maxBuf;

	if (!max_buf) {

	if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {

		free_xid(xid);

		return -EINVAL;

	}
@@ -1460,10 +1460,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, 


	/*

	 * Accessing maxBuf is racy with cifs_reconnect - need to store value

	 * and check it for zero before using.

	 * and check it before using.

	 */

	max_buf = tcon->ses->server->maxBuf;

	if (!max_buf)

	if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))

		return -EINVAL;



	max_num = (max_buf - sizeof(struct smb_hdr)) /

fs/cifs/smb2file.c

+2 −2
Original line number Diff line number Diff line
@@ -122,10 +122,10 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock, 


	/*

	 * Accessing maxBuf is racy with cifs_reconnect - need to store value

	 * and check it for zero before using.

	 * and check it before using.

	 */

	max_buf = tcon->ses->server->maxBuf;

	if (!max_buf)

	if (max_buf < sizeof(struct smb2_lock_element))

		return -EINVAL;



	max_num = max_buf / sizeof(struct smb2_lock_element);