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 02D87231845 for ; Thu, 12 Jun 2025 11:18:49 +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=1749727131; cv=none; b=Ioj0lhJt1HfPvVoU9K5eDSBv1X8zb7wcgoD4a7+qvbzp2LNeZTCMxGizI0n23ePVhqvE/f3tR1yaLenLwbVEflGCz0GTTUks7clwN3tdX1BehNJ8ytJ+Rsp8nOsMdnZoXL2kIYc9uqORhTnHRWyFCP5XSArSiL4/7bIPhEeCEJI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749727131; c=relaxed/simple; bh=3JjbhQubAgFcC97e/UoQ9hKiqpfIzqZGcS7aEKOfAmE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bvkwFyLTJC/FVeJNul7DuMklgAx27VciaaR9rd8+ClPEoQDk4RfwPzLF1Z6FP76QzQhJTYRU4u2RttFBtTNCXzUT5/+deiD90xR9JKEwy/vd1NlOsRFEz4x7vmLRFTgM8WTCd23YCEZsmYEme/WefJwib8EBGbpunU2L8c1P8FA= 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=MEDJOBfZ; 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="MEDJOBfZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749727129; 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=7T84xXSWCXYbJ0BcRNBZS+rZcumc2YBPF5dRlJgvCIQ=; b=MEDJOBfZyG25IE+p9qjIS59GgUzgByWRoPy1D1fgNpNO+cP59QYEtDZVechHJB5DQFMpM8 re8e7LLCz0IdrByETtoZ6SXPVrVPdtB4M1bGonoOpg1aW0VnibXHgLzJ/YvrNyHNkFdv7D TYfoE5asgSGvnCzDQdtgli5Pe43m4Y8= 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-592-oLHAgfETPii7mcF4IS4JBw-1; Thu, 12 Jun 2025 07:18:45 -0400 X-MC-Unique: oLHAgfETPii7mcF4IS4JBw-1 X-Mimecast-MFC-AGG-ID: oLHAgfETPii7mcF4IS4JBw_1749727124 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 C725E1800292; Thu, 12 Jun 2025 11:18:43 +0000 (UTC) Received: from localhost (unknown [10.72.112.181]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 34D00180045C; Thu, 12 Jun 2025 11:18:41 +0000 (UTC) Date: Thu, 12 Jun 2025 19:18:37 +0800 From: Baoquan He To: Mimi Zohar Cc: linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, coxu@redhat.com, piliu@redhat.com, pmenzel@molgen.mpg.de, chenste@linux.microsoft.com Subject: Re: [PATCH v2] ima: add a knob ima= to make IMA be able to be disabled Message-ID: References: <20250611082535.127759-1-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On 06/12/25 at 06:59am, Mimi Zohar wrote: > Hi Baoquan, > > As discussed > https://lore.kernel.org/linux-integrity/aC6ezNcUZ%2FulKgpv@MiWiFi-R3L-srv/ the > Subject line should indicate disabling IMA is limited to kdump. Oops, my bad, I forgot this one. > > On Wed, 2025-06-11 at 16:25 +0800, Baoquan He wrote: > > Kdump kernel doesn't need IMA functionality, and enabling IMA will cost > > extra memory. It would be very helpful to allow IMA to be disabled for > > kdump kernel. > > > > Hence add a knob ima=on|off here to allow turning IMA off in kdump > > kernel if needed. > > > > Note that this IMA disabling is only limited to kdump kernel, please don't > > abuse it in other kernel and thus serious consequences are caused. > > Remove the word 'only', here, and in other places. Sure, will udpate in all relevant places. Thanks. > > > > > Signed-off-by: Baoquan He > > --- > > v1->v2: > > - Improve patch log and doc description; > > - Make slight adjustment in code; > > These are all made according to Mimi's great suggestions. > > > > .../admin-guide/kernel-parameters.txt | 5 ++++ > > security/integrity/ima/ima_main.c | 26 +++++++++++++++++++ > > 2 files changed, 31 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index b3d62f4c370a..1de67b9c20b4 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2214,6 +2214,11 @@ > > different crypto accelerators. This option can be used > > to achieve best performance for particular HW. > > > > + ima= [IMA] Enable or disable IMA > > + Format: { "off" | "on" } > > + Default: "on" > > + Note that this is only limited to kdump kernel. > > Remove the word 'only' -> Note that disabling IMA is limited to kdump kernel. > > > + > > indirect_target_selection= [X86,Intel] Mitigation control for Indirect > > Target Selection(ITS) bug in Intel CPUs. Updated > > microcode is also required for a fix in IBPB. > > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > > index f99ab1a3b0f0..c38f3881d72f 100644 > > --- a/security/integrity/ima/ima_main.c > > +++ b/security/integrity/ima/ima_main.c > > @@ -27,6 +27,7 @@ > > #include > > #include > > #include > > +#include > > > > #include "ima.h" > > > > @@ -38,11 +39,30 @@ int ima_appraise; > > > > int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1; > > static int hash_setup_done; > > +static int ima_disabled __ro_after_init; > > > > static struct notifier_block ima_lsm_policy_notifier = { > > .notifier_call = ima_lsm_policy_change, > > }; > > > > +static int __init ima_setup(char *str) > > +{ > > + if (!is_kdump_kernel()) { > > + pr_info("Warning: ima setup option only permitted in kdump"); > > + return 1; > > + } > > + > > + if (strncmp(str, "off", 3) == 0) > > + ima_disabled = 1; > > + else if (strncmp(str, "on", 2) == 0) > > + ima_disabled = 0; > > + else > > + pr_err("Invalid ima setup option: \"%s\" , please specify ima=on|off.", str); > > + > > + return 1; > > +} > > +__setup("ima=", ima_setup); > > + > > static int __init hash_setup(char *str) > > { > > struct ima_template_desc *template_desc = ima_template_desc_current(); > > @@ -1186,6 +1206,12 @@ static int __init init_ima(void) > > { > > int error; > > > > + /*Note that turning IMA off is only limited to kdump kernel.*/ > > Remove the word "only" -> Note that turning IMA off is intentionally limited to > kdump kernel." > > > + if (ima_disabled && is_kdump_kernel()) { > > + pr_info("IMA functionality is disabled"); > > + return 0; > > + } > > + > > ima_appraise_parse_cmdline(); > > ima_init_template_list(); > > hash_setup(CONFIG_IMA_DEFAULT_HASH); > > Mimi >