From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 965F224EF7F for ; Wed, 19 Mar 2025 08:09:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742371777; cv=none; b=JAJ09xf4Ymxri5XdLXzqh0zKVEWD0Y+swqjZfkjVBU7W3Hy4dW6b2Gj0CQP7llUpuxLBSnzEwl9UdH946YKTm5fitgQDM0LBnMTpM+kfL5+LMJI1qG/5yuInMUEl3WOFynrRPUUJDHr5A7uN+1hkHKNrFlDhymz1YzzuHsc/Vk4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742371777; c=relaxed/simple; bh=/RyUaNE0UU+t49cR7Ub3ihRvxXSjG6lxTyyoBfxdah0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Dw4EYS/zS6KeRjuYhNAZt3SNme7+T4WeI22M9dvqSrxZAJ+XZDSxyAeIyO1Aw1Obu4AeanLB9DVX2+hD/CQtY1da7FEwMePfh7vB7Ths0QjFR0uPjYVbHVdPFCCwvxOZVbW4G3u3WjGZiNmKrSrUYsZQM1MWAeaKyYJQO2ty6Mk= 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=VLQF/fvY; arc=none smtp.client-ip=170.10.129.124 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="VLQF/fvY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742371774; 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=da3J5jJT52UU43EbiSqWzdE0F7xr9cBU/xSV0I+jpPU=; b=VLQF/fvYaux5BczpCrL0JJszRKeNHWZDXPg0BvTjgzS0Wzvve8ytJaOCX5ejuthzLslg6J REx7NCRltBvpMK2Qa2zr9F54S3CieodaVCBJ+4dVyGaiJD0Y8+u1sx8uNKpGK20ioey54s 6q1re+52hCMnsn7Lc6hZoOuFyCY0w/w= 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-133-dp3Ycc5PM42ogmmscQGWIA-1; Wed, 19 Mar 2025 04:09:30 -0400 X-MC-Unique: dp3Ycc5PM42ogmmscQGWIA-1 X-Mimecast-MFC-AGG-ID: dp3Ycc5PM42ogmmscQGWIA_1742371767 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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 2AB01180025A; Wed, 19 Mar 2025 08:09:27 +0000 (UTC) Received: from localhost (unknown [10.72.112.30]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 34FA31955BE1; Wed, 19 Mar 2025 08:09:23 +0000 (UTC) Date: Wed, 19 Mar 2025 16:09:19 +0800 From: Baoquan He To: steven chen Cc: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@hansenpartnership.com, vgoyal@redhat.com, dyoung@redhat.com Subject: Re: [PATCH v10 2/8] ima: define and call ima_alloc_kexec_file_buf() Message-ID: References: <20250318010448.954-1-chenste@linux.microsoft.com> <20250318010448.954-3-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@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: <20250318010448.954-3-chenste@linux.microsoft.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On 03/17/25 at 06:04pm, steven chen wrote: > Carrying the IMA measurement list across kexec requires allocating a > buffer and copying the measurement records. Separate allocating the > buffer and copying the measurement records into separate functions in > order to allocate the buffer at kexec 'load' and copy the measurements > at kexec 'execute'. > > This patch includes the following changes: > - Refactor ima_dump_measurement_list() to move the memory allocation > to a separate function ima_alloc_kexec_file_buf() which allocates > buffer of size 'kexec_segment_size' at kexec 'load'. > - Make the local variable ima_kexec_file in ima_dump_measurement_list() > a local static to the file, so that it can be accessed from > ima_alloc_kexec_file_buf(). > - Make necessary changes to the function ima_add_kexec_buffer() to call > the above two functions. We may not need above details about code change because it's not so difficult to get them from patch. > > Signed-off-by: Tushar Sugandhi > Signed-off-by: steven chen > --- > security/integrity/ima/ima_kexec.c | 67 +++++++++++++++++++++++++----- > 1 file changed, 56 insertions(+), 11 deletions(-) > > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index 8567619889d1..45170e283272 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -15,6 +15,48 @@ > #include "ima.h" > > #ifdef CONFIG_IMA_KEXEC > +static struct seq_file ima_kexec_file; > + > +static void ima_reset_kexec_file(struct seq_file *sf) > +{ > + sf->buf = NULL; > + sf->size = 0; > + sf->read_pos = 0; > + sf->count = 0; > +} > + > +static void ima_free_kexec_file_buf(struct seq_file *sf) > +{ > + vfree(sf->buf); > + ima_reset_kexec_file(sf); > +} > + > +static int ima_alloc_kexec_file_buf(size_t segment_size) > +{ > + /* > + * kexec 'load' may be called multiple times. > + * Free and realloc the buffer only if the segment_size is > + * changed from the previous kexec 'load' call. > + */ > + if (ima_kexec_file.buf && ima_kexec_file.size == segment_size) > + goto out; > + > + ima_free_kexec_file_buf(&ima_kexec_file); > + > + /* segment size can't change between kexec load and execute */ > + ima_kexec_file.buf = vmalloc(segment_size); > + if (!ima_kexec_file.buf) > + return -ENOMEM; > + > + ima_kexec_file.size = segment_size; > + > +out: > + ima_kexec_file.read_pos = 0; > + ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ > + > + return 0; > +} > + > /* > * Copy the measurement list to the allocated memory > * compare the size of IMA measurement list with the size of the allocated memory > @@ -26,23 +68,16 @@ > static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, > unsigned long segment_size) > { > - struct seq_file ima_kexec_file; > struct ima_queue_entry *qe; > struct ima_kexec_hdr khdr; > int ret = 0; > > /* segment size can't change between kexec load and execute */ > - ima_kexec_file.buf = vmalloc(segment_size); > if (!ima_kexec_file.buf) { > - ret = -ENOMEM; > - goto out; > + pr_err("Kexec file buf not allocated\n"); > + return -EINVAL; > } > > - ima_kexec_file.file = NULL; > - ima_kexec_file.size = segment_size; > - ima_kexec_file.read_pos = 0; > - ima_kexec_file.count = sizeof(khdr); /* reserved space */ > - > memset(&khdr, 0, sizeof(khdr)); > khdr.version = 1; > /* This is an append-only list, no need to hold the RCU read lock */ > @@ -79,8 +114,6 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, > *buffer_size = ima_kexec_file.count; > *buffer = ima_kexec_file.buf; > out: > - if (ret == -EINVAL) > - vfree(ima_kexec_file.buf); > return ret; > } > > @@ -119,6 +152,12 @@ void ima_add_kexec_buffer(struct kimage *image) > return; > } > > + ret = ima_alloc_kexec_file_buf(kexec_segment_size); > + if (ret < 0) { > + pr_err("Not enough memory for the kexec measurement buffer.\n"); > + return; > + } > + > ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, > kexec_segment_size); > if (!kexec_buffer) { > @@ -140,6 +179,12 @@ void ima_add_kexec_buffer(struct kimage *image) > image->ima_buffer_size = kexec_segment_size; > image->ima_buffer = kexec_buffer; > > + /* > + * kexec owns kexec_buffer after kexec_add_buffer() is called > + * and it will vfree() that buffer. > + */ > + ima_reset_kexec_file(&ima_kexec_file); I can't see why we need call ima_reset_kexec_file() here. If we need reuse the buffer, we will reset the needed fields at the end of ima_alloc_kexec_file_buf(). Not sure if I miss anything. static int ima_alloc_kexec_file_buf(size_t segment_size) { ...... out: ima_kexec_file.read_pos = 0; ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ return 0; }