Bug 14569

Summary:	BCC_LE macro in cifspdu.h
Product:	File System	Reporter:	Juro (jurobystricky)
Component:	CIFS	Assignee:	Jeff Layton (jlayton)
Status:	RESOLVED DUPLICATE
Severity:	high	CC:	jlayton
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.31	Subsystem:
Regression:	No	Bisected commit-id:

Description Juro 2009-11-09 18:16:23 UTC

BCC_LE macro in "cifspdu.h" is not well defined. The sizeof(structure smb_hdr)
is odd (go ahead, count the bytes) and the BCC_LE attempts to do a 16 bit
access from an odd address. This renders the whole CIFS pretty much unusable on
all CPUs that cannot handle misaligned accesses.
The macro should use "unaligned" access.

Comment 1 Jeff Layton 2009-11-09 18:58:37 UTC

No objection to fixing it so that it works better on such architectures. Care to offer up a patch or explanation of how you think it should work?

Comment 2 Juro 2009-11-09 20:14:52 UTC

(In reply to comment #1)
> No objection to fixing it so that it works better on such architectures. Care
> to offer up a patch or explanation of how you think it should work?

The macro BCC_LE is used in several files, sometimes to read and sometimes to write a 16 bit le value.
The best I could come was to split the macro into two macros:

#define BCC_LE_GET(smb_var) get_unaligned_le16((char*)smb_var + sizeof(struct smb_hdr)+(2*smb_var->WordCount))


#define BCC_LE_PUT(smb_var) put_unaligned_le16((char*)smb_var + sizeof(struct smb_hdr)+(2*smb_var->WordCount))

and change the files "connect.c","netmisc.c","transport.c" and "sess.c" to
use the new macros.

It is quite likely there is a better way to do this.

Comment 3 Jeff Layton 2010-09-03 12:11:58 UTC

If you're still interested in fixing this, could you spin up patches against recent mainline git (or even better, against Steve French's tree). Then please post them to linux-cifs@vger.kernel.org so we can review them. Thanks!

Comment 4 Jeff Layton 2011-01-15 13:16:49 UTC


*** This bug has been marked as a duplicate of bug 11115 ***