Commit 32f31918 authored by Steve French's avatar Steve French
Browse files

smb3: workaround negprot bug in some Samba servers 



Mount can now fail to older Samba servers due to a server
bug handling padding at the end of the last negotiate
context (negotiate contexts typically are rounded up to 8
bytes by adding padding if needed). This server bug can
be avoided by switching the order of negotiate contexts,
placing a negotiate context at the end that does not
require padding (prior to the recent netname context fix
this was the case on the client).

Fixes: 73130a7b ("smb3: fix empty netname context on secondary channels")
Reported-by: default avatarJulian Sikorski <belegdol@gmail.com>
Tested-by: default avatarJulian Sikorski <belegdol+github@gmail.com>
Reviewed-by: default avatarShyam Prasad N <sprasad@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 2883f4b5

fs/cifs/smb2pdu.c

+7 −6
Original line number Diff line number Diff line
@@ -571,10 +571,6 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, 
	*total_len += ctxt_len;

	pneg_ctxt += ctxt_len;



	build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);

	*total_len += sizeof(struct smb2_posix_neg_context);

	pneg_ctxt += sizeof(struct smb2_posix_neg_context);



	/*

	 * secondary channels don't have the hostname field populated

	 * use the hostname field in the primary channel instead
@@ -586,9 +582,14 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, 
					      hostname);

		*total_len += ctxt_len;

		pneg_ctxt += ctxt_len;

		neg_context_count = 4;

	} else /* second channels do not have a hostname */

		neg_context_count = 3;

	} else

		neg_context_count = 2;



	build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);

	*total_len += sizeof(struct smb2_posix_neg_context);

	pneg_ctxt += sizeof(struct smb2_posix_neg_context);

	neg_context_count++;



	if (server->compress_algorithm) {

		build_compression_ctxt((struct smb2_compression_capabilities_context *)