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 B93B93C060A; Tue, 10 Mar 2026 19:52:56 +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=1773172376; cv=none; b=OAx8jn5aCDa+GAoTCEHPYa+PgJVISofeN56FWBAQuBLpg7sUpJRQp//9B63sNMi4xZbyy24CS2KXCNUy591CVpwgf65yh/sHt9Cio2eEb6hH0dRqmflUqyavQYjqpmsuO7DkGOJDPEzuCV3vzBI3S+npRMP+fa/fbVhCYQnruvM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172376; c=relaxed/simple; bh=khME16d+H0DEAV2zpYTok5ib8wH/YwlxS/FiTIEAWD4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ESETRYNE+u3jp8fCusTc3zB7cK24QRPfWvDV+RJrpTBUrzucbkFLHKKCsKHG+2q4F9mEXxzy/pCqCG+8mTtomr28JnccowjA6bVSI8zqw1W6mwZ9/BXFW+3Bwu3mZRBo4pTyf8yJviYHBprrUHK9xbOXgAatfoJIiFmrqSjQo6g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=l0QFzv0v; 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="l0QFzv0v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D41ADC2BC87; Tue, 10 Mar 2026 19:52:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773172376; bh=khME16d+H0DEAV2zpYTok5ib8wH/YwlxS/FiTIEAWD4=; h=From:To:Cc:Subject:Date:From; b=l0QFzv0vuKpEcGmP2WR5dfqTMnhuMkwa7B7ix5D47tY1eQ7YekU1ZzCZTaImIGbD8 xWLENRKOt+LZ0xx4tX5Wv9WI4/gJLIxOkFh1HQG3CIVRbpaRyKy0rxpA+iBaRR2vXl L8g8rnQ71n94AYeH+fYjJ+0QLxgZ0LSlhDVYR/Looco8PF26uNhZUoQeZyJBhJ8LaZ QO1Jqcz1aZf/QKIh1+BOE5sn/Uu98KZPUV+7Jlz9k7vYJaGE0igaiLZMSmr/WKGR8L 8mzNp5TMayDRosyeNfYfYVN7esFnRM/gadqU16kJzqWpsuWjnmlyuFl3axxX+Varbm ZkhM5wv6ldHkw== 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 6.6] ksmbd: Compare MACs in constant time Date: Tue, 10 Mar 2026 12:52:53 -0700 Message-ID: <20260310195253.70903-1-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/smb/server/Kconfig | 1 + fs/smb/server/auth.c | 4 +++- fs/smb/server/smb2pdu.c | 5 +++-- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/smb/server/Kconfig b/fs/smb/server/Kconfig index cabe6a843c6a0..da0187e76cf1c 100644 --- a/fs/smb/server/Kconfig +++ b/fs/smb/server/Kconfig @@ -9,10 +9,11 @@ config SMB_SERVER select CRYPTO select CRYPTO_MD5 select CRYPTO_HMAC select CRYPTO_ECB select CRYPTO_LIB_DES + select CRYPTO_LIB_UTILS select CRYPTO_SHA256 select CRYPTO_CMAC select CRYPTO_SHA512 select CRYPTO_AEAD2 select CRYPTO_CCM diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index f4b20b80af062..a2dfb981ce666 100644 --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -11,10 +11,11 @@ #include #include #include #include #include +#include #include #include #include "auth.h" #include "glob.h" @@ -281,11 +282,12 @@ 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/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index da4d914c87ad2..6a128a3be61e7 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -2,10 +2,11 @@ /* * Copyright (C) 2016 Namjae Jeon * Copyright (C) 2018 Samsung Electronics Co., Ltd. */ +#include #include #include #include #include #include @@ -8802,11 +8803,11 @@ 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; @@ -8890,11 +8891,11 @@ 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: 4fc00fe35d46b4fc8dac2eb543a0e3d44bb15f47 -- 2.53.0