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 7108A3B0AD8; Mon, 23 Mar 2026 14:40:31 +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=1774276831; cv=none; b=FNRCttfLB0I2TdpJ60eVa0QE3AvqKyic+CVwZ0jhgZtFk6UGBUggJOBPl12RCfG60DFU8SUQkyS6yuSYZjCsEAKTvem21vK71mDChwYHSFUTNldyXRWk3lyN+5cL+hSQCh3CmRwjWMhXymwHN4S5S+ZFEakWDG+oBl01Mf4+vHA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774276831; c=relaxed/simple; bh=i7Fv4+W8vbcjiJuI6nYRty8fhG0Aw97mGW1BQPGG1Yo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I06EXLWnHPWNyNcu40c1rb/g5VdODOquxRWrt0VLXAhv14/WXkKP5GyFiNvAcHl7RHLNCNRND29Cnz0HFP1m5/8d93k/EkhIjkY6/gFgkD2ZPZgYcs+ROcpj9wyALYQUAgpGTY+o0tlF2iac1+wgSl//r//4HeCs972T8EpacGk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cM+kgzWQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cM+kgzWQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0D74C2BCB3; Mon, 23 Mar 2026 14:40:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774276831; bh=i7Fv4+W8vbcjiJuI6nYRty8fhG0Aw97mGW1BQPGG1Yo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cM+kgzWQQfbUrk93ClAVJMdYARgpgDKGdJTzGMk1G/QlxTJFepVhG/1xg8HkJdm6H A6fKrLb8PNxsSBBiZ6msQb0wWOw6PnRGWhO1TNcPq+1/1euUC/SRfIYxgZ/EbkWPGA TDu2Emlg1/dpE1pSasgCTxiqE7+FkzLsSIAkzgxU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Biggers , Namjae Jeon , Steve French Subject: [PATCH 6.12 220/460] ksmbd: Compare MACs in constant time Date: Mon, 23 Mar 2026 14:43:36 +0100 Message-ID: <20260323134531.903906082@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134526.647552166@linuxfoundation.org> References: <20260323134526.647552166@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers 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 Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/Kconfig | 1 + fs/smb/server/auth.c | 4 +++- fs/smb/server/smb2pdu.c | 5 +++-- 3 files changed, 7 insertions(+), 3 deletions(-) --- a/fs/smb/server/Kconfig +++ b/fs/smb/server/Kconfig @@ -11,6 +11,7 @@ config SMB_SERVER select CRYPTO_HMAC select CRYPTO_ECB select CRYPTO_LIB_DES + select CRYPTO_LIB_UTILS select CRYPTO_SHA256 select CRYPTO_CMAC select CRYPTO_SHA512 --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -283,7 +284,8 @@ int ksmbd_auth_ntlmv2(struct ksmbd_conn 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) --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -4,6 +4,7 @@ * Copyright (C) 2018 Samsung Electronics Co., Ltd. */ +#include #include #include #include @@ -8825,7 +8826,7 @@ int smb2_check_sign_req(struct ksmbd_wor 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; } @@ -8913,7 +8914,7 @@ int smb3_check_sign_req(struct ksmbd_wor 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; }