Hi Greg,
Please find the backported version of the patch for the 5.4-stable tree in attachments.
Best regards,
Pavel Shilovsky
-----Original Message-----
From: gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx>
Sent: Monday, December 28, 2020 1:35 AM
To: Steven French <Steven.French@xxxxxxxxxxxxx>; Pavel Shilovskiy <pshilov@xxxxxxxxxxxxx>; Shyam Prasad <Shyam.Prasad@xxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Subject: [EXTERNAL] FAILED: patch "[PATCH] SMB3.1.1: do not log warning message if server doesn't" failed to apply to 5.4-stable tree
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7955f105afb6034af344038d663bc98809483cdd Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Wed, 9 Dec 2020 22:19:00 -0600
Subject: [PATCH] SMB3.1.1: do not log warning message if server doesn't populate salt
In the negotiate protocol preauth context, the server is not required to populate the salt (although it is done by most servers) so do not warn on mount.
We retain the checks (warn) that the preauth context is the minimum size and that the salt does not exceed DataLength of the SMB response.
Although we use the defaults in the case that the preauth context response is invalid, these checks may be useful in the future as servers add support for additional mechanisms.
CC: Stable <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index acb72705062d..fc06c762fbbf 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -427,8 +427,8 @@ build_preauth_ctxt(struct smb2_preauth_neg_context *pneg_ctxt)
pneg_ctxt->ContextType = SMB2_PREAUTH_INTEGRITY_CAPABILITIES;
pneg_ctxt->DataLength = cpu_to_le16(38);
pneg_ctxt->HashAlgorithmCount = cpu_to_le16(1);
- pneg_ctxt->SaltLength = cpu_to_le16(SMB311_SALT_SIZE);
- get_random_bytes(pneg_ctxt->Salt, SMB311_SALT_SIZE);
+ pneg_ctxt->SaltLength = cpu_to_le16(SMB311_LINUX_CLIENT_SALT_SIZE);
+ get_random_bytes(pneg_ctxt->Salt, SMB311_LINUX_CLIENT_SALT_SIZE);
pneg_ctxt->HashAlgorithms = SMB2_PREAUTH_INTEGRITY_SHA512; }
@@ -566,6 +566,9 @@ static void decode_preauth_context(struct smb2_preauth_neg_context *ctxt)
if (len < MIN_PREAUTH_CTXT_DATA_LEN) {
pr_warn_once("server sent bad preauth context\n");
return;
+ } else if (len < MIN_PREAUTH_CTXT_DATA_LEN + le16_to_cpu(ctxt->SaltLength)) {
+ pr_warn_once("server sent invalid SaltLength\n");
+ return;
}
if (le16_to_cpu(ctxt->HashAlgorithmCount) != 1)
pr_warn_once("Invalid SMB3 hash algorithm count\n"); diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index fa57b03ca98c..204a622b89ed 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -333,12 +333,20 @@ struct smb2_neg_context {
/* Followed by array of data */
} __packed;
-#define SMB311_SALT_SIZE 32
+#define SMB311_LINUX_CLIENT_SALT_SIZE 32
/* Hash Algorithm Types */
#define SMB2_PREAUTH_INTEGRITY_SHA512 cpu_to_le16(0x0001)
#define SMB2_PREAUTH_HASH_SIZE 64
-#define MIN_PREAUTH_CTXT_DATA_LEN (SMB311_SALT_SIZE + 6)
+/*
+ * SaltLength that the server send can be zero, so the only three
+required
+ * fields (all __le16) end up six bytes total, so the minimum context
+data len
+ * in the response is six bytes which accounts for
+ *
+ * HashAlgorithmCount, SaltLength, and 1 HashAlgorithm.
+ */
+#define MIN_PREAUTH_CTXT_DATA_LEN 6
+
struct smb2_preauth_neg_context {
__le16 ContextType; /* 1 */
__le16 DataLength;
@@ -346,7 +354,7 @@ struct smb2_preauth_neg_context {
__le16 HashAlgorithmCount; /* 1 */
__le16 SaltLength;
__le16 HashAlgorithms; /* HashAlgorithms[0] since only one defined */
- __u8 Salt[SMB311_SALT_SIZE];
+ __u8 Salt[SMB311_LINUX_CLIENT_SALT_SIZE];
} __packed;
/* Encryption Algorithms Ciphers */
Attachment:
0001-SMB3.1.1-do-not-log-warning-message-if-server-doesn-.patch
Description: 0001-SMB3.1.1-do-not-log-warning-message-if-server-doesn-.patch
