From a2d9daad1d2dfbd307ab158044d1c323d7babbde Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Fri, 20 Oct 2017 14:49:38 +0200 Subject: SMB: fix validate negotiate info uninitialised memory use An undersize validate negotiate info server response causes the client to use uninitialised memory for struct validate_negotiate_info_rsp comparisons of Dialect, SecurityMode and/or Capabilities members. Link: https://bugzilla.samba.org/show_bug.cgi?id=13092 Fixes: 7db0a6efdc3e ("SMB3: Work around mount failure when using SMB3 dialect to Macs") Signed-off-by: David Disseldorp Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French --- fs/cifs/smb2pdu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 6b03e2d45d8e..ba58af747b43 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -727,7 +727,8 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon) rsplen); /* relax check since Mac returns max bufsize allowed on ioctl */ - if (rsplen > CIFSMaxBufSize) + if ((rsplen > CIFSMaxBufSize) + || (rsplen < sizeof(struct validate_negotiate_info_rsp))) goto err_rsp_free; } -- cgit v1.2.3