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From: David Disseldorp <ddiss-l3A5Bk7waGM@public.gmane.org>
To: Shu Wang <shuwang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	sfrench-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org,
	linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org
Cc: David Disseldorp <ddiss-l3A5Bk7waGM@public.gmane.org>
Subject: [PATCH 2/2] SMB: fix validate negotiate info uninitialised memory use
Date: Fri, 20 Oct 2017 14:49:38 +0200	[thread overview]
Message-ID: <20171020124938.9913-3-ddiss@suse.de> (raw)
In-Reply-To: <20171020124938.9913-1-ddiss-l3A5Bk7waGM@public.gmane.org>

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 <ddiss-l3A5Bk7waGM@public.gmane.org>
---
 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 052ab5dee6b6..c836de2f79b2 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;
 	}
 
-- 
2.13.6

  parent reply	other threads:[~2017-10-20 12:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-20 10:20 [PATCH] SMB: fix memory leak in smb3_validate_negotiate shuwang
     [not found] ` <20171020102033.22936-1-shuwang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-10-20 12:49   ` David Disseldorp
     [not found]     ` <20171020124938.9913-1-ddiss-l3A5Bk7waGM@public.gmane.org>
2017-10-20 12:49       ` [PATCH 1/2] SMB: fix leak of validate negotiate info response buffer David Disseldorp
     [not found]         ` <20171020124938.9913-2-ddiss-l3A5Bk7waGM@public.gmane.org>
2017-10-21  2:49           ` Shu Wang
     [not found]             ` <61197467.18033621.1508554198404.JavaMail.zimbra-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-10-22 14:16               ` David Disseldorp
2017-10-20 12:49       ` David Disseldorp [this message]
     [not found]         ` <20171020124938.9913-3-ddiss-l3A5Bk7waGM@public.gmane.org>
2017-10-25 18:04           ` [PATCH 2/2] SMB: fix validate negotiate info uninitialised memory use Pavel Shilovsky

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