From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9804A3B8959; Tue, 10 Mar 2026 19:53:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172381; cv=none; b=qqM8ODf1w9l+blLmFi8x8Rphj6j31A6DrEmwul0aoa7uaSyHx9xx3NbVo7fDjaazWKjXXmpaSoX9dncfvmj8UwyZEenckjhqJLp7rkYWgVDTIfmlsVQrLb69zs4TxgekYDWXlzKIvdvccMLHXR1VYiis0/h8Noma+7onUv/eNKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172381; c=relaxed/simple; bh=kN/Vk85gyOzB9l+V19qIFjeAt0h9A4wogUE0W0Vedxo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IzAP2BA/edMJsYdn7E4cc8lfJRCHHHUIqsTuwzHyfXStZAjeWVMsaVvznJ0N1EhjC0wctADAu8D2TdcD5ClTpti4gihRa/f3dl3VnWsuKn23dwnszwlmUtPXtz0ftdMZGPW7NyExlMFI6S8jWncj47L834Dx3mEDtQTP8jr0NoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EcLHkQXG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EcLHkQXG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3485C2BC87; Tue, 10 Mar 2026 19:53:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773172381; bh=kN/Vk85gyOzB9l+V19qIFjeAt0h9A4wogUE0W0Vedxo=; h=From:To:Cc:Subject:Date:From; b=EcLHkQXGN1Q7dVL+q+zJJ2xH9UCjawRXffJNQ6GZ4CHtIOczRKbmmL2TwPr5Eh+zs 2Q/vPcrIVhT3ASSIGI55BC8jsY9g5UNizxG0zNV+14Sx056k5RMV3LIwXC6EuO6Mu2 UuvlKjxpjCUxPtaQRbts5a7bOMt+aOJ/ZfPHlS2RTRDTk90KeG0Qf6BWM5OuHLXHGo UWmumdGquktlMqvBaR4tkawYd/Mz1E1rsWEgXWnG0CY5aM5dXcmZX5QT92CPPq3YXW hT3XZUHcYFnfditYPl1IC/+5Tg41SkGrGauKyDOO/R/QRc7STBsx295Jhf0S+pcQsx jk0y6dDwlzG2Q== From: Eric Biggers To: stable@vger.kernel.org Cc: linux-crypto@vger.kernel.org, linux-cifs@vger.kernel.org, Eric Biggers , Namjae Jeon , Steve French Subject: [PATCH 5.15] ksmbd: Compare MACs in constant time Date: Tue, 10 Mar 2026 12:52:59 -0700 Message-ID: <20260310195259.70949-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit commit c5794709bc9105935dbedef8b9cf9c06f2b559fa upstream. To prevent timing attacks, MAC comparisons need to be constant-time. Replace the memcmp() with the correct function, crypto_memneq(). Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Acked-by: Namjae Jeon Signed-off-by: Steve French --- fs/ksmbd/auth.c | 4 +++- fs/ksmbd/smb2pdu.c | 5 +++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/ksmbd/auth.c b/fs/ksmbd/auth.c index 647692ca78a28..7a06139274172 100644 --- a/fs/ksmbd/auth.c +++ b/fs/ksmbd/auth.c @@ -11,10 +11,11 @@ #include #include #include #include #include +#include #include #include #include "auth.h" #include "glob.h" @@ -279,11 +280,12 @@ int ksmbd_auth_ntlmv2(struct ksmbd_conn *conn, struct ksmbd_session *sess, if (rc) { ksmbd_debug(AUTH, "Could not generate sess key\n"); goto out; } - if (memcmp(ntlmv2->ntlmv2_hash, ntlmv2_rsp, CIFS_HMAC_MD5_HASH_SIZE) != 0) + if (crypto_memneq(ntlmv2->ntlmv2_hash, ntlmv2_rsp, + CIFS_HMAC_MD5_HASH_SIZE)) rc = -EINVAL; out: if (ctx) ksmbd_release_crypto_ctx(ctx); kfree(construct); diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index b5ff4c855f9cb..829329abca664 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -2,10 +2,11 @@ /* * Copyright (C) 2016 Namjae Jeon * Copyright (C) 2018 Samsung Electronics Co., Ltd. */ +#include #include #include #include #include #include @@ -8396,11 +8397,11 @@ int smb2_check_sign_req(struct ksmbd_work *work) if (ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, 1, signature)) return 0; - if (memcmp(signature, signature_req, SMB2_SIGNATURE_SIZE)) { + if (crypto_memneq(signature, signature_req, SMB2_SIGNATURE_SIZE)) { pr_err("bad smb2 signature\n"); return 0; } return 1; @@ -8484,11 +8485,11 @@ int smb3_check_sign_req(struct ksmbd_work *work) iov[0].iov_len = len; if (ksmbd_sign_smb3_pdu(conn, signing_key, iov, 1, signature)) return 0; - if (memcmp(signature, signature_req, SMB2_SIGNATURE_SIZE)) { + if (crypto_memneq(signature, signature_req, SMB2_SIGNATURE_SIZE)) { pr_err("bad smb2 signature\n"); return 0; } return 1; base-commit: 91d48252ad4b17577cf8cc8d3e1353402e4da8f1 -- 2.53.0