This is a note to let you know that I've just added the patch titled
ksmbd: avoid out of bounds access in decode_preauth_ctxt()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ksmbd-avoid-out-of-bounds-access-in-decode_preauth_ctxt.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e7067a446264a7514fa1cfaa4052cdb6803bc6a2 Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@xxxxxxx>
Date: Thu, 13 Apr 2023 23:49:57 +0900
Subject: ksmbd: avoid out of bounds access in decode_preauth_ctxt()
From: David Disseldorp <ddiss@xxxxxxx>
commit e7067a446264a7514fa1cfaa4052cdb6803bc6a2 upstream.
Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within
the SMB request boundary; deassemble_neg_contexts() only checks that the
eight byte smb2_neg_context header + (client controlled) DataLength are
within the packet boundary, which is insufficient.
Checking for sizeof(struct smb2_preauth_neg_context) is overkill given
that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt.
Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
Acked-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ksmbd/smb2pdu.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -880,17 +880,21 @@ static void assemble_neg_contexts(struct
}
static __le32 decode_preauth_ctxt(struct ksmbd_conn *conn,
- struct smb2_preauth_neg_context *pneg_ctxt)
+ struct smb2_preauth_neg_context *pneg_ctxt,
+ int len_of_ctxts)
{
- __le32 err = STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP;
+ /*
+ * sizeof(smb2_preauth_neg_context) assumes SMB311_SALT_SIZE Salt,
+ * which may not be present. Only check for used HashAlgorithms[1].
+ */
+ if (len_of_ctxts < MIN_PREAUTH_CTXT_DATA_LEN)
+ return STATUS_INVALID_PARAMETER;
- if (pneg_ctxt->HashAlgorithms == SMB2_PREAUTH_INTEGRITY_SHA512) {
- conn->preauth_info->Preauth_HashId =
- SMB2_PREAUTH_INTEGRITY_SHA512;
- err = STATUS_SUCCESS;
- }
+ if (pneg_ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512)
+ return STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP;
- return err;
+ conn->preauth_info->Preauth_HashId = SMB2_PREAUTH_INTEGRITY_SHA512;
+ return STATUS_SUCCESS;
}
static void decode_encrypt_ctxt(struct ksmbd_conn *conn,
@@ -1018,7 +1022,8 @@ static __le32 deassemble_neg_contexts(st
break;
status = decode_preauth_ctxt(conn,
- (struct smb2_preauth_neg_context *)pctx);
+ (struct smb2_preauth_neg_context *)pctx,
+ len_of_ctxts);
if (status != STATUS_SUCCESS)
break;
} else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES) {
Patches currently in stable-queue which might be from ddiss@xxxxxxx are
queue-5.15/ksmbd-avoid-out-of-bounds-access-in-decode_preauth_ctxt.patch
