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 D2546363C74; Tue, 17 Mar 2026 17:28:35 +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=1773768515; cv=none; b=Tia+nTicq3sHeHY+p7gR7BIci0+aiSivZ1FU1CRrOgjwQi/ZlX2n5y+1hq9Re1dUlBt7Y840B13qv122EhHIuXKuSpSrVsjxDOexoHymtHQn4SIAa60OEqV/jV11l2RaxwSjefnGs4YX90v+QYUd+S6XCXaWvhg0aNBnDvrFc08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773768515; c=relaxed/simple; bh=z6UPk7aehkFuSe60LsnkSfyaaGXzslRawfuAlc7HkHw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FbVpoCu5lVqK2GZNT6ymhz+zdCyVfCFORqUDmUrbOVlrln8O3fFdZDaJtLAY5m93cXJbBRk70PLBisvjrpNhs9o1MK7brBVBHgC3nS7p9LLI6brAutY8cbjy30xtuX0Ajae20qMy5ifxtvgkUAJcjmL6tJC8I2RiTs9A2w4O3Ng= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0pi3/6bQ; 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="0pi3/6bQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40091C4CEF7; Tue, 17 Mar 2026 17:28:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773768515; bh=z6UPk7aehkFuSe60LsnkSfyaaGXzslRawfuAlc7HkHw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0pi3/6bQIvrD6KTaf+2iRYJQF7b2vdTyp9mhRw+AydGbCPZVgKXLWXpK7atzpdBQp rNLQORmXGkXwqFKnAG6XHCIX4R7hnjUNpFT7txiqhoHwk8GlvBLMkVM9Q3rqHM4NTe 2WW9qLS1P17Rq2URY4V2hc3k2AZ0XWh/8q7hmXFw= 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 6.18 328/333] ksmbd: Compare MACs in constant time Date: Tue, 17 Mar 2026 17:35:57 +0100 Message-ID: <20260317163011.569832299@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260317162959.345812316@linuxfoundation.org> References: <20260317162959.345812316@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 6.18-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 @@ -13,6 +13,7 @@ config SMB_SERVER select CRYPTO_LIB_ARC4 select CRYPTO_LIB_DES select CRYPTO_LIB_SHA256 + 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 @@ -8881,7 +8882,7 @@ 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; } @@ -8969,7 +8970,7 @@ 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; }