Starting with 5.18.8 (and 5.19-rc4) 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 round up to 8 byte
lengths 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: 73130a7b1ac9 ("smb3: fix empty netname context on secondary channels")
See attached fix to cifs.ko
--
Thanks,
Steve
From a8d8532e4c335f0a31dd213abe4e31682f34647c Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Tue, 12 Jul 2022 00:11:42 -0500
Subject: [PATCH] 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
contexts (negotiate contexts typically round up to 8 byte
lengths 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: 73130a7b1ac9 ("smb3: fix empty netname context on secondary channels")
Reported-by: Julian Sikorski <belegdol@xxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 12b4dddaedb0..c705de32e225 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -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 *)
--
2.34.1
