Commit 08123408 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
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smb: client: handle max length for SMB symlinks 



We can't use PATH_MAX for SMB symlinks because

  (1) Windows Server will fail FSCTL_SET_REPARSE_POINT with
      STATUS_IO_REPARSE_DATA_INVALID when input buffer is larger than
      16K, as specified in MS-FSA 2.1.5.10.37.

  (2) The client won't be able to parse large SMB responses that
      includes SMB symlink path within SMB2_CREATE or SMB2_IOCTL
      responses.

Fix this by defining a maximum length value (4060) for SMB symlinks
that both client and server can handle.

Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 9f544d26

fs/smb/client/reparse.c

+4 −1
Original line number Diff line number Diff line
@@ -35,6 +35,9 @@ int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode, 
	u16 len, plen;

	int rc = 0;



	if (strlen(symname) > REPARSE_SYM_PATH_MAX)

		return -ENAMETOOLONG;



	sym = kstrdup(symname, GFP_KERNEL);

	if (!sym)

		return -ENOMEM;
@@ -64,7 +67,7 @@ int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode, 
	if (rc < 0)

		goto out;



	plen = 2 * UniStrnlen((wchar_t *)path, PATH_MAX);

	plen = 2 * UniStrnlen((wchar_t *)path, REPARSE_SYM_PATH_MAX);

	len = sizeof(*buf) + plen * 2;

	buf = kzalloc(len, GFP_KERNEL);

	if (!buf) {

fs/smb/client/reparse.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include "fs_context.h"

#include "cifsglob.h"



#define REPARSE_SYM_PATH_MAX 4060



/*

 * Used only by cifs.ko to ignore reparse points from files when client or

 * server doesn't support FSCTL_GET_REPARSE_POINT.