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authorSteve French <stfrench@microsoft.com>2022-07-12 00:11:42 -0500
committerSteve French <stfrench@microsoft.com>2022-07-13 19:59:47 -0500
commit32f319183c439b239294cb2d70ada3564c4c7c39 (patch)
tree1f245440fa1ac47a2be016c5d5b73f3fd8ba7e74
parent2883f4b5a0e1ac9472c7e3ae9bbdb4ea5a2117c6 (diff)
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: 73130a7b1ac9 ("smb3: fix empty netname context on secondary channels") Reported-by: Julian Sikorski <belegdol@gmail.com> Tested-by: Julian Sikorski <belegdol+github@gmail.com> Reviewed-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/cifs/smb2pdu.c13
1 files 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 *)