Linux-mm Archive on lore.kernel.org
 help / color / Atom feed
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@amacapital.net>,
	David Howells <dhowells@redhat.com>
Cc: Kees Cook <keescook@chromium.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Kai Huang <kai.huang@linux.intel.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	linux-mm@kvack.org, kvm@vger.kernel.org,
	keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH, RFC 30/62] keys/mktme: Set up a percpu_ref_count for MKTME keys
Date: Wed,  8 May 2019 17:43:50 +0300
Message-ID: <20190508144422.13171-31-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20190508144422.13171-1-kirill.shutemov@linux.intel.com>

From: Alison Schofield <alison.schofield@intel.com>

The MKTME key service needs to keep usage counts on the encryption
keys in order to know when it is safe to free a key for reuse.

percpu_ref_count applies well here because the key service will
take the initial reference and typically hold that reference while
the intermediary references are get/put. The intermediaries in this
case are the encrypted VMA's.

Align the percpu_ref_init and percpu_ref_kill with the key service
instantiate and destroy methods respectively.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 security/keys/mktme_keys.c | 40 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/security/keys/mktme_keys.c b/security/keys/mktme_keys.c
index f70533b1a7fd..496b5c1b7461 100644
--- a/security/keys/mktme_keys.c
+++ b/security/keys/mktme_keys.c
@@ -8,6 +8,7 @@
 #include <linux/key-type.h>
 #include <linux/mm.h>
 #include <linux/parser.h>
+#include <linux/percpu-refcount.h>
 #include <linux/random.h>
 #include <linux/string.h>
 #include <asm/intel_pconfig.h>
@@ -80,6 +81,26 @@ int mktme_keyid_from_key(struct key *key)
 	return 0;
 }
 
+struct percpu_ref *encrypt_count;
+void mktme_percpu_ref_release(struct percpu_ref *ref)
+{
+	unsigned long flags;
+	int keyid;
+
+	for (keyid = 1; keyid <= mktme_nr_keyids; keyid++) {
+		if (&encrypt_count[keyid] == ref)
+			break;
+	}
+	if (&encrypt_count[keyid] != ref) {
+		pr_debug("%s: invalid ref counter\n", __func__);
+		return;
+	}
+	percpu_ref_exit(ref);
+	spin_lock_irqsave(&mktme_map_lock, flags);
+	mktme_release_keyid(keyid);
+	spin_unlock_irqrestore(&mktme_map_lock, flags);
+}
+
 enum mktme_opt_id {
 	OPT_ERROR,
 	OPT_TYPE,
@@ -225,7 +246,10 @@ static int mktme_program_keyid(int keyid, struct mktme_payload *payload)
 /* Key Service Method called when a Userspace Key is garbage collected. */
 static void mktme_destroy_key(struct key *key)
 {
-	mktme_release_keyid(mktme_keyid_from_key(key));
+	int keyid = mktme_keyid_from_key(key);
+
+	mktme_map->key[keyid] = (void *)-1;
+	percpu_ref_kill(&encrypt_count[keyid]);
 }
 
 /* Key Service Method to create a new key. Payload is preparsed. */
@@ -241,9 +265,15 @@ int mktme_instantiate_key(struct key *key, struct key_preparsed_payload *prep)
 	if (!keyid)
 		return -ENOKEY;
 
+	if (percpu_ref_init(&encrypt_count[keyid], mktme_percpu_ref_release,
+			    0, GFP_KERNEL))
+		goto err_out;
+
 	if (!mktme_program_keyid(keyid, payload))
 		return MKTME_PROG_SUCCESS;
 
+	percpu_ref_exit(&encrypt_count[keyid]);
+err_out:
 	spin_lock_irqsave(&mktme_lock, flags);
 	mktme_release_keyid(keyid);
 	spin_unlock_irqrestore(&mktme_lock, flags);
@@ -447,10 +477,18 @@ static int __init init_mktme(void)
 	/* Initialize first programming targets */
 	mktme_update_pconfig_targets();
 
+	/* Reference counters to protect in use KeyIDs */
+	encrypt_count = kvcalloc(mktme_nr_keyids + 1, sizeof(encrypt_count[0]),
+				 GFP_KERNEL);
+	if (!encrypt_count)
+		goto free_targets;
+
 	ret = register_key_type(&key_type_mktme);
 	if (!ret)
 		return ret;			/* SUCCESS */
 
+	kvfree(encrypt_count);
+free_targets:
 	free_cpumask_var(mktme_leadcpus);
 	bitmap_free(mktme_target_map);
 free_cache:
-- 
2.20.1


  parent reply index

Thread overview: 153+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 14:43 [PATCH, RFC 00/62] Intel MKTME enabling Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 01/62] mm: Do no merge VMAs with different encryption KeyIDs Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 02/62] mm: Add helpers to setup zero page mappings Kirill A. Shutemov
2019-05-29  7:21   ` Mike Rapoport
2019-05-08 14:43 ` [PATCH, RFC 03/62] mm/ksm: Do not merge pages with different KeyIDs Kirill A. Shutemov
2019-05-10 18:07   ` Dave Hansen
2019-05-13 14:27     ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 04/62] mm/page_alloc: Unify alloc_hugepage_vma() Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 05/62] mm/page_alloc: Handle allocation for encrypted memory Kirill A. Shutemov
2019-05-29  7:21   ` Mike Rapoport
2019-05-29 12:47     ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 06/62] mm/khugepaged: Handle encrypted pages Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 07/62] x86/mm: Mask out KeyID bits from page table entry pfn Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 08/62] x86/mm: Introduce variables to store number, shift and mask of KeyIDs Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 09/62] x86/mm: Preserve KeyID on pte_modify() and pgprot_modify() Kirill A. Shutemov
2019-06-14  9:15   ` Peter Zijlstra
2019-06-14 13:03     ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 10/62] x86/mm: Detect MKTME early Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 11/62] x86/mm: Add a helper to retrieve KeyID for a page Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 12/62] x86/mm: Add a helper to retrieve KeyID for a VMA Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 13/62] x86/mm: Add hooks to allocate and free encrypted pages Kirill A. Shutemov
2019-06-14  9:34   ` Peter Zijlstra
2019-06-14 11:04     ` Peter Zijlstra
2019-06-14 13:28       ` Kirill A. Shutemov
2019-06-14 13:43         ` Peter Zijlstra
2019-06-14 22:41           ` Kirill A. Shutemov
2019-06-17  9:25             ` Peter Zijlstra
2019-06-14 13:14     ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 14/62] x86/mm: Map zero pages into encrypted mappings correctly Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 15/62] x86/mm: Rename CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 16/62] x86/mm: Allow to disable MKTME after enumeration Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 17/62] x86/mm: Calculate direct mapping size Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 18/62] x86/mm: Implement syncing per-KeyID direct mappings Kirill A. Shutemov
2019-06-14  9:51   ` Peter Zijlstra
2019-06-14 22:43     ` Kirill A. Shutemov
2019-06-17  9:27       ` Peter Zijlstra
2019-06-17 14:43         ` Kirill A. Shutemov
2019-06-17 14:51           ` Peter Zijlstra
2019-06-17 15:17             ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 19/62] x86/mm: Handle encrypted memory in page_to_virt() and __pa() Kirill A. Shutemov
2019-06-14 11:10   ` Peter Zijlstra
2019-05-08 14:43 ` [PATCH, RFC 20/62] mm/page_ext: Export lookup_page_ext() symbol Kirill A. Shutemov
2019-06-14 11:12   ` Peter Zijlstra
2019-06-14 22:44     ` Kirill A. Shutemov
2019-06-17  9:30       ` Peter Zijlstra
2019-06-17 11:01         ` Kai Huang
2019-06-17 11:13           ` Huang, Kai
2019-05-08 14:43 ` [PATCH, RFC 21/62] mm/rmap: Clear vma->anon_vma on unlink_anon_vmas() Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 22/62] x86/pconfig: Set a valid encryption algorithm for all MKTME commands Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 23/62] keys/mktme: Introduce a Kernel Key Service for MKTME Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 24/62] keys/mktme: Preparse the MKTME key payload Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 25/62] keys/mktme: Instantiate and destroy MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 26/62] keys/mktme: Move the MKTME payload into a cache aligned structure Kirill A. Shutemov
2019-06-14 11:35   ` Peter Zijlstra
2019-06-14 17:10     ` Alison Schofield
2019-05-08 14:43 ` [PATCH, RFC 27/62] keys/mktme: Strengthen the entropy of CPU generated MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 28/62] keys/mktme: Set up PCONFIG programming targets for " Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 29/62] keys/mktme: Program MKTME keys into the platform hardware Kirill A. Shutemov
2019-05-08 14:43 ` Kirill A. Shutemov [this message]
2019-05-08 14:43 ` [PATCH, RFC 31/62] keys/mktme: Require CAP_SYS_RESOURCE capability for MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 32/62] keys/mktme: Store MKTME payloads if cmdline parameter allows Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 33/62] acpi: Remove __init from acpi table parsing functions Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 34/62] acpi/hmat: Determine existence of an ACPI HMAT Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 35/62] keys/mktme: Require ACPI HMAT to register the MKTME Key Service Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 36/62] acpi/hmat: Evaluate topology presented in ACPI HMAT for MKTME Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 37/62] keys/mktme: Do not allow key creation in unsafe topologies Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 38/62] keys/mktme: Support CPU hotplug for MKTME key service Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 39/62] keys/mktme: Find new PCONFIG targets during memory hotplug Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 40/62] keys/mktme: Program new PCONFIG targets with MKTME keys Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 41/62] keys/mktme: Support memory hotplug for " Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 42/62] mm: Generalize the mprotect implementation to support extensions Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 43/62] syscall/x86: Wire up a system call for MKTME encryption keys Kirill A. Shutemov
2019-05-29  7:21   ` Mike Rapoport
2019-05-29 18:12     ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 44/62] x86/mm: Set KeyIDs in encrypted VMAs for MKTME Kirill A. Shutemov
2019-06-14 11:44   ` Peter Zijlstra
2019-06-14 17:33     ` Alison Schofield
2019-06-14 18:26       ` Dave Hansen
2019-06-14 18:46         ` Alison Schofield
2019-06-14 19:11           ` Dave Hansen
2019-06-17  9:10             ` Peter Zijlstra
2019-05-08 14:44 ` [PATCH, RFC 45/62] mm: Add the encrypt_mprotect() system call " Kirill A. Shutemov
2019-06-14 11:47   ` Peter Zijlstra
2019-06-14 17:35     ` Alison Schofield
2019-06-14 11:51   ` Peter Zijlstra
2019-06-15  0:32     ` Alison Schofield
2019-06-17  9:08       ` Peter Zijlstra
2019-06-17 15:07   ` Andy Lutomirski
2019-06-17 15:28     ` Dave Hansen
2019-06-17 15:46       ` Andy Lutomirski
2019-06-17 18:27         ` Dave Hansen
2019-06-17 19:12           ` Andy Lutomirski
2019-06-17 21:36             ` Dave Hansen
2019-06-18  0:48               ` Kai Huang
2019-06-18  1:50                 ` Andy Lutomirski
2019-06-18  2:11                   ` Kai Huang
2019-06-18  4:24                     ` Andy Lutomirski
2019-06-18 14:19                   ` Dave Hansen
2019-06-18  0:05             ` Kai Huang
2019-06-18  0:15               ` Andy Lutomirski
2019-06-18  1:35                 ` Kai Huang
2019-06-18  1:43                   ` Andy Lutomirski
2019-06-18  2:23                     ` Kai Huang
2019-06-18  9:12                       ` Peter Zijlstra
2019-06-18 14:09                         ` Dave Hansen
2019-06-18 16:15                           ` Kirill A. Shutemov
2019-06-18 16:22                             ` Dave Hansen
2019-06-18 16:36                               ` Andy Lutomirski
2019-06-18 16:48                                 ` Dave Hansen
2019-06-18 14:13                 ` Dave Hansen
2019-06-17 23:59           ` Kai Huang
2019-06-18  1:34             ` Lendacky, Thomas
2019-06-18  1:40               ` Andy Lutomirski
2019-06-18  2:02                 ` Lendacky, Thomas
2019-06-18  4:19                 ` Andy Lutomirski
2019-05-08 14:44 ` [PATCH, RFC 46/62] x86/mm: Keep reference counts on encrypted VMAs " Kirill A. Shutemov
2019-06-14 11:54   ` Peter Zijlstra
2019-06-14 18:39     ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 47/62] mm: Restrict MKTME memory encryption to anonymous VMAs Kirill A. Shutemov
2019-06-14 11:55   ` Peter Zijlstra
2019-06-15  0:07     ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 48/62] selftests/x86/mktme: Test the MKTME APIs Kirill A. Shutemov
2019-05-08 17:09   ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 49/62] mm, x86: export several MKTME variables Kirill A. Shutemov
2019-06-14 11:56   ` Peter Zijlstra
2019-06-17  3:14     ` Kai Huang
2019-06-17  7:46       ` Peter Zijlstra
2019-06-17  8:39         ` Kai Huang
2019-06-17 11:25           ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 50/62] kvm, x86, mmu: setup MKTME keyID to spte for given PFN Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 51/62] iommu/vt-d: Support MKTME in DMA remapping Kirill A. Shutemov
2019-06-14 12:04   ` Peter Zijlstra
2019-05-08 14:44 ` [PATCH, RFC 52/62] x86/mm: introduce common code for mem encryption Kirill A. Shutemov
2019-05-08 16:58   ` Christoph Hellwig
2019-05-08 20:52     ` Jacob Pan
2019-05-08 21:21       ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 53/62] x86/mm: Use common code for DMA memory encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 54/62] x86/mm: Disable MKTME on incompatible platform configurations Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 55/62] x86/mm: Disable MKTME if not all system memory supports encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 56/62] x86: Introduce CONFIG_X86_INTEL_MKTME Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 57/62] x86/mktme: Overview of Multi-Key Total Memory Encryption Kirill A. Shutemov
2019-05-29  7:21   ` Mike Rapoport
2019-05-29 18:13     ` Alison Schofield
2019-07-14 18:16   ` Randy Dunlap
2019-07-15  9:02     ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 58/62] x86/mktme: Document the MKTME provided security mitigations Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 59/62] x86/mktme: Document the MKTME kernel configuration requirements Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 60/62] x86/mktme: Document the MKTME Key Service API Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 61/62] x86/mktme: Document the MKTME API for anonymous memory encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 62/62] x86/mktme: Demonstration program using the MKTME APIs Kirill A. Shutemov
2019-05-29  7:30 ` [PATCH, RFC 00/62] Intel MKTME enabling Mike Rapoport
2019-05-29 18:20   ` Alison Schofield
2019-06-14 12:15 ` Peter Zijlstra

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190508144422.13171-31-kirill.shutemov@linux.intel.com \
    --to=kirill.shutemov@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=alison.schofield@intel.com \
    --cc=bp@alien8.de \
    --cc=dave.hansen@intel.com \
    --cc=dhowells@redhat.com \
    --cc=hpa@zytor.com \
    --cc=jacob.jun.pan@linux.intel.com \
    --cc=kai.huang@linux.intel.com \
    --cc=keescook@chromium.org \
    --cc=keyrings@vger.kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=luto@amacapital.net \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org linux-mm@archiver.kernel.org
	public-inbox-index linux-mm


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/ public-inbox