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 CD99030DD11 for ; Fri, 6 Mar 2026 02:05:59 +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=1772762762; cv=none; b=bq7vbixkZ/2qnedB7M2nMKPn1OnwxKr0UJo3qOIriOy0KrvO9LnRNM8JfuH9klL/FDVRyapGDy1DTh9PlC2uYXHK5qb3yT7bOg7zbzC661dJ+j+nZedQ9EI/Kwb5+ReLzeauzA3dHwHX0FvP49mucoXNQMMwcuFQ4ryjT5sJSGU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772762762; c=relaxed/simple; bh=nsKQ37saL2v30eJ8dxlprdP8ilkf6sMcjRw0O5R9hfA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j2WasUjq2b5tzEg4HolvU/JVZsCm6S/STS2okNRpqjeKMALNiBG2mpIWVhMclSYr7uM5SUryreFgh0YQv8gmt4sAMnMD6GLj1OqTbtB5LYEDGjYgc80IqRl/rmdI7+eu4hkYjzud2ivDMiiUq7U373nH9l0PGDvHlZPXR1m4VlY= 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=ddWvLvvT; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=rpWk4H4G; 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="ddWvLvvT"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="rpWk4H4G" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772762758; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ku+fyGp/YTBjGS772gug0NvDgqgMuQqPxeBeDkG1f5g=; b=ddWvLvvTOx0OZMK4I1h4IsF2+Qgx7Vd/ad0vkBefNBqlLHsy6MePG+u3iZIdoKd/bpPFF4 Shnn2D0/aF0NOz32TqZUlLJph0dGa2X8r0m7hy9KkvmcAIeNYw5I0dQDZtnI/kE4cGpxoK pwZE9IrhcXgNVRkm83DJWiiT9dhuupU= Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-144-g8YlpsO_N1yCV94zJevp5Q-1; Thu, 05 Mar 2026 21:05:57 -0500 X-MC-Unique: g8YlpsO_N1yCV94zJevp5Q-1 X-Mimecast-MFC-AGG-ID: g8YlpsO_N1yCV94zJevp5Q_1772762756 Received: by mail-pl1-f198.google.com with SMTP id d9443c01a7336-2ae4e20a414so261959835ad.3 for ; Thu, 05 Mar 2026 18:05:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1772762756; x=1773367556; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=ku+fyGp/YTBjGS772gug0NvDgqgMuQqPxeBeDkG1f5g=; b=rpWk4H4GVnpOwGVAp8xCJCjti+A7b/rQgUg+/af1ZjTJkbK97cFvjx12WpTHhEspWE sWaLjuJQG2l8EX2LnRL3Mc1gJfFCLB74xgK3hNqCy8Y3IAycx31cR5KtFWgKs/SCeFPu OiqAugixENrckV9vx+RVjL4O5VAfN1wdMFZ96YLqXWiM5U5IW73Sa/Jb04b0jNbTMF4s dCX72Qbrl1x0EGKqCjK0+5aBfQRkaaxpRv/SOUxI5tRmlVId7lpknVRGGTr2miIURruZ hZBIFqIyuo1ENjc56EA/nFB4viMdIdwmVC0Z/gP0C0NZXjK7Z8c3pKJaFTqKTLRlQ7fM +KQg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772762756; x=1773367556; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ku+fyGp/YTBjGS772gug0NvDgqgMuQqPxeBeDkG1f5g=; b=Y6P+GA14oM85bvj501ONWTYnSxWQ12sxssxMYNp430WY0j4Ab0EGErb6Yf4xApI3u/ fP9bjiES54SXAVYfXpwLROmhxXRS5BzM0sNnvDvo1hcwv7BPzELwyzDwov6u/zo196/F +/N0ZOyNcs4siPNrJxzryOW+mop0WF4ig2+7Dpn97/rEn4FomQgqnrU5iHcu7Mw41MWs 8BIxrSA8cuGs70X+qTFxBTgV73XKROiNIAuoW7a7GndUYqisqxuxMYiAJvGc79MzAC8v chc4JGjXBjlL8NHuZVUenld5kYjXoMD0opZqSST3y58sqkqyalUvoaILlD87ZPbIoUg0 5fxg== X-Forwarded-Encrypted: i=1; AJvYcCUKj1JQX4gl4+aKeG/ZmYdd7nYxt1C4n8bSdTBbvafxpq37uUpmQlrX9oSO11n4uyFAX8Evdps=@vger.kernel.org X-Gm-Message-State: AOJu0YxV1oiRe76Iy/1POEHO1+1rAuJerjr1HOsOBkXIRlqZ7kJ9nVHV ftprb8DL83OrC6cCRsRjsjaBHbRdc5H7llqnNygfPkET0uYKrJtcciM0RCIt59nrZnmjnZbMA+l egkMW2ZJOTp2cwVFHIJ63TdEHS6fSj5i3ygqxK0EGMjz+1k/AV47wWTXoLA== X-Gm-Gg: ATEYQzxq7ubwG0sThWswKuMOEzlA90HQEsP7GXDVEZOTqwprBN7AJx18UBNR0eWTpaF hCz5Mebtwu+G0Mbs+4mRAbInS8IivDpUjfCm9WZzHW+9jzFV/c57LvYR8p0CKWhN8C4oDhRvZcv baRoaDAlM/e0dHgP/QmYqic4OKrV6fhDsO6wkpuuK8K3vYyB5z/+gawgsWUUxH+AHlcqWig5lOV Luk/8aRky9S30MYAQzQ7lsLIS+ik+6Hvgp0Fg2KVKZjd5aI+iprGM0oLHsPRmSRVlEF1ZY0mELj +K/P03oGVl5NFbk8vooBhXwBIEBahOTUiR5pYXs7UJBbRQU1kul3gsxnJZem418s/dh8HoTFkSK T1lrvEvT4chli X-Received: by 2002:a17:903:19e5:b0:2ae:61bb:425c with SMTP id d9443c01a7336-2ae8242cfa9mr6322975ad.35.1772762756408; Thu, 05 Mar 2026 18:05:56 -0800 (PST) X-Received: by 2002:a17:903:19e5:b0:2ae:61bb:425c with SMTP id d9443c01a7336-2ae8242cfa9mr6322775ad.35.1772762755920; Thu, 05 Mar 2026 18:05:55 -0800 (PST) Received: from localhost ([209.132.188.88]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ae83f77350sm517165ad.51.2026.03.05.18.05.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Mar 2026 18:05:55 -0800 (PST) Date: Fri, 6 Mar 2026 10:00:12 +0800 From: Coiby Xu To: Baoquan He Cc: Thorsten Blum , Andrew Morton , Vivek Goyal , Dave Young , stable@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] crash_dump: Don't log dm-crypt key bytes in read_key_from_user_keying Message-ID: References: <20260227230008.858641-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Mon, Mar 02, 2026 at 11:48:22AM +0800, Baoquan He wrote: >On 02/28/26 at 12:00am, Thorsten Blum wrote: >> When debug logging is enabled, read_key_from_user_keying() logs the >> first 8 bytes of the key payload and partially exposes the dm-crypt key. >> Stop logging any key bytes. >> >> Fixes: 479e58549b0f ("crash_dump: store dm crypt keys in kdump reserved memory") >> Cc: stable@vger.kernel.org >> Signed-off-by: Thorsten Blum >> --- >> kernel/crash_dump_dm_crypt.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c >> index 27a144920562..5ce958d069dd 100644 >> --- a/kernel/crash_dump_dm_crypt.c >> +++ b/kernel/crash_dump_dm_crypt.c >> @@ -168,8 +168,8 @@ static int read_key_from_user_keying(struct dm_crypt_key *dm_key) >> >> memcpy(dm_key->data, ukp->data, ukp->datalen); >> dm_key->key_size = ukp->datalen; >> - kexec_dprintk("Get dm crypt key (size=%u) %s: %8ph\n", dm_key->key_size, >> - dm_key->key_desc, dm_key->data); >> + kexec_dprintk("Get dm crypt key (size=%u) %s\n", dm_key->key_size, > >Make sense to me. > >The kexec_dprintk() is only for debug printing. We can remove above line >or change it to pr_debug() if security is worried. > >Coiby, what do you think? I think we can assume a key can be reliably read thus no need to print the first 8 bytes to check it. So this patch looks good to me. And thanks to Thorsten for suggesting multiple improvements on kernel/crash_dump_dm_crypt.c! > >Thanks >Baoquan > -- Best regards, Coiby