From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 387A24499AA for ; Wed, 12 Aug 2026 13:02:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786539737; cv=none; b=HJqjRwwKWgd4onmlN6HvQC7Llr+vHKlQTgheenW7cp33N2XFyAry6nLwG/V4GQ4JBubj2Cn9My2aoo91SRtmmlGVtF3S6PdvMBPDxULlhDr2mVyzWNF6FkYscXXgPuP3mr3CnbzUxcf2yaidaK9JupVCVWxjCLqIa2SqoCUMaGQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786539737; c=relaxed/simple; bh=Ak8TRsQm8sEv91HLZDJ2c4Tbi82najZMuf991Ee04eo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nNA26dMlkpGBVv3doDgFm7qmLCtMEpEP2n1qvPrTljC2L+0mODlSedt1MctBUR3pWm0Cx66+xegaESQ2jvq5C5BjiEIupINM5DNHYD81CiCoEvZqM5EMCY8Wps8uoLSjodZ3hBdrs+I+gRdhN4TOgJ8Cc4urH+oVMl1NIbJgd2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=O+yl16H5; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="O+yl16H5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1786539735; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C4G9wA9sxztkPp9GXgL2r4jkSKN5/Us6P6aBbvPhsk8=; b=O+yl16H5LjLXUXeWN2kA/GuLIexeMxLd8rMnHDVXvdyb8wD+Kg9a9SqArHqPRAYiemTTlC ostVKbN1m5cQ+rfuzQ8ub1rnoX5MJaU3Onr2LZ+cefWvNqS7S1Os86KzcuPM+4+Oqsbafk Bm7qnAG+AV9ZyDscMnA1bunsPiI0KkE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-522-8ZbhZGt2PBKLUKZOKg6AKQ-1; Wed, 12 Aug 2026 09:02:11 -0400 X-MC-Unique: 8ZbhZGt2PBKLUKZOKg6AKQ-1 X-Mimecast-MFC-AGG-ID: 8ZbhZGt2PBKLUKZOKg6AKQ_1786539729 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8CC3618007FD; Wed, 12 Aug 2026 13:02:09 +0000 (UTC) Received: from thuth-p1g4.redhat.corp (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E17E1195DF91; Wed, 12 Aug 2026 13:02:06 +0000 (UTC) From: Thomas Huth To: Steve French Cc: Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/5] smb: client: Clear sensitive stack data in smb1encrypt.c Date: Wed, 12 Aug 2026 15:01:51 +0200 Message-ID: <20260812130152.2861834-5-thuth@redhat.com> In-Reply-To: <20260812130152.2861834-1-thuth@redhat.com> References: <20260812130152.2861834-1-thuth@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 From: Thomas Huth Make sure to not leak signature data via the stack, clear it with memzero_explicit() before leaving the function. To avoid that we have to introduce "goto"-cleanup here, we re-arrange the code a little bit (and drop the commented cifs_dump_mem debug code that looks like a leftover from very early days). Signed-off-by: Thomas Huth --- fs/smb/client/smb1encrypt.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/smb/client/smb1encrypt.c b/fs/smb/client/smb1encrypt.c index bf10fdeeedcab..c9eb68f04e7b0 100644 --- a/fs/smb/client/smb1encrypt.c +++ b/fs/smb/client/smb1encrypt.c @@ -81,6 +81,7 @@ int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server, else memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8); + memzero_explicit(smb_signature, sizeof(smb_signature)); return rc; } @@ -126,15 +127,13 @@ int cifs_verify_signature(struct smb_rqst *rqst, rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be); cifs_server_unlock(server); - if (rc) - return rc; - -/* cifs_dump_mem("what we think it should be: ", - what_we_think_sig_should_be, 16); */ - - if (crypto_memneq(server_response_sig, what_we_think_sig_should_be, 8)) - return -EACCES; - else - return 0; + if (!rc) { + if (crypto_memneq(server_response_sig, + what_we_think_sig_should_be, 8)) + rc = -EACCES; + } + memzero_explicit(what_we_think_sig_should_be, + sizeof(what_we_think_sig_should_be)); + return rc; } -- 2.55.0