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 5725E3B38A1; Tue, 10 Mar 2026 19:52:59 +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=1773172379; cv=none; b=Egwqt2EBF3aN9p+aKfwa4VQlTgECWeKmkDX+mZlj9YYWZ+G3IOzuckVx+EkQnaLWV351UsIpMsjtuMlBLWLO4+gc+QN1CPLq8Qk+pNvkurtZbpkWTFd83RGku/tLXtgbH2J3/DSV7R/Cbp/9yWbllH7zXYee7C2BurRXEtIlcFc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172379; c=relaxed/simple; bh=4qdRfUtne0l7LP0Cb7GPiynsQvcOqzkMXf3BODgdwPU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Wo2kkRdNppyj3U2lOeJX8HQKAKm6MjxzK59EdK3n+37mBphx1CxeRceyq2uOuxzx+359i+agvTIEUiQt5X+CKCfG1cgzVldtLphqZK3NGj6cmX13ibm9pno27oA4Vx5fILw6r+fWOnGzzrsw6uo09wuUD2mRmWeNpXsTDFUnwAg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sXRgF9eD; 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="sXRgF9eD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EF3BC19423; Tue, 10 Mar 2026 19:52:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773172378; bh=4qdRfUtne0l7LP0Cb7GPiynsQvcOqzkMXf3BODgdwPU=; h=From:To:Cc:Subject:Date:From; b=sXRgF9eDoiGMkhOhzFmZ42eSO2X8XvDNgAvpWVt7OuDPxoVp6uGpzTf3V5FboMmms P2uSett33hTgomOZPVvXgO1joKDP7tNPHFxOz+qU/02X//aPLUuGAk6lhYWeQFAEwa bKbirlPD6nsNg1DVJE7nFxBofpAORtt4rXlCjfB0bLaNzJ9JksrCgTH4M8R+Vg2hH6 HKzfyEPzeZL6hVwTLoJLtlOgRGV4Kzsdl0FRlRf6q8nS4/usgjL6E+ua0y/nXJgb2U mAq/Sobjv0awnTfJmB9NYRmLjm1ebfQe7ueiQ+TQoxky/SxSAzRaC8nv6Gp7334vI5 BVXQer6VB/XSg== 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 6.1] ksmbd: Compare MACs in constant time Date: Tue, 10 Mar 2026 12:52:56 -0700 Message-ID: <20260310195256.70926-1-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/auth.c | 4 +++- fs/smb/server/smb2pdu.c | 5 +++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index f8a192cc82f24..4c3384bbbb492 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" @@ -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/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 2b16bd4882499..641618a9e6e8b 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 @@ -8428,11 +8429,11 @@ 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; @@ -8516,11 +8517,11 @@ 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: f2ddafa93a259310ca47507153b7811ec54ab7fd -- 2.53.0