From patchwork Tue Dec 4 07:39:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alison Schofield X-Patchwork-Id: 10711189 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A377B13BF for ; Tue, 4 Dec 2018 07:37:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8C5E82A46B for ; Tue, 4 Dec 2018 07:37:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7FD302A582; Tue, 4 Dec 2018 07:37:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D79A72A46B for ; Tue, 4 Dec 2018 07:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726020AbeLDHhZ (ORCPT ); Tue, 4 Dec 2018 02:37:25 -0500 Received: from mga12.intel.com ([192.55.52.136]:55172 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725983AbeLDHhY (ORCPT ); Tue, 4 Dec 2018 02:37:24 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Dec 2018 23:37:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,313,1539673200"; d="scan'208";a="126888419" Received: from alison-desk.jf.intel.com (HELO alison-desk) ([10.54.74.53]) by fmsmga001.fm.intel.com with ESMTP; 03 Dec 2018 23:37:23 -0800 From: Alison Schofield To: dhowells@redhat.com, tglx@linutronix.de Cc: jmorris@namei.org, mingo@redhat.com, hpa@zytor.com, bp@alien8.de, luto@kernel.org, peterz@infradead.org, kirill.shutemov@linux.intel.com, dave.hansen@intel.com, kai.huang@intel.com, jun.nakajima@intel.com, dan.j.williams@intel.com, jarkko.sakkinen@intel.com, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: [RFC v2 06/13] mm: Add the encrypt_mprotect() system call Date: Mon, 3 Dec 2018 23:39:53 -0800 Message-Id: <0c5d9e96c75445ced3b22d9359a8cb3fa2b6f8ad.1543903910.git.alison.schofield@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Implement memory encryption with a new system call that is an extension of the legacy mprotect() system call. In encrypt_mprotect the caller must pass a handle to a previously allocated and programmed encryption key. Validate the key and store the keyid bits in the vm_page_prot for each VMA in the protection range. Signed-off-by: Alison Schofield Signed-off-by: Kirill A. Shutemov --- fs/exec.c | 4 ++-- include/linux/key.h | 2 ++ include/linux/mm.h | 3 ++- mm/mprotect.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++------ 4 files changed, 62 insertions(+), 10 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index fc281b738a98..a0946b23e2c5 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -752,8 +752,8 @@ int setup_arg_pages(struct linux_binprm *bprm, vm_flags |= mm->def_flags; vm_flags |= VM_STACK_INCOMPLETE_SETUP; - ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, - vm_flags); + ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, vm_flags, + -1); if (ret) goto out_unlock; BUG_ON(prev != vma); diff --git a/include/linux/key.h b/include/linux/key.h index e58ee10f6e58..fb8a7d5f6149 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -346,6 +346,8 @@ static inline key_serial_t key_serial(const struct key *key) extern void key_set_timeout(struct key *, unsigned); +extern key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, + key_perm_t perm); /* * The permissions required on a key that we're looking up. */ diff --git a/include/linux/mm.h b/include/linux/mm.h index e2d87e92ca74..09182d78e7b7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1607,7 +1607,8 @@ extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long int dirty_accountable, int prot_numa); extern int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, - unsigned long end, unsigned long newflags); + unsigned long end, unsigned long newflags, + int newkeyid); /* * doesn't attempt to fault and will return short. diff --git a/mm/mprotect.c b/mm/mprotect.c index b57075e278fb..ad8127dc9aac 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -346,7 +347,8 @@ static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, - unsigned long start, unsigned long end, unsigned long newflags) + unsigned long start, unsigned long end, unsigned long newflags, + int newkeyid) { struct mm_struct *mm = vma->vm_mm; unsigned long oldflags = vma->vm_flags; @@ -356,7 +358,14 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, int error; int dirty_accountable = 0; - if (newflags == oldflags) { + /* + * Flags match and Keyids match or we have NO_KEY. + * This _fixup is usually called from do_mprotect_ext() except + * for one special case: caller fs/exec.c/setup_arg_pages() + * In that case, newkeyid is passed as -1 (NO_KEY). + */ + if (newflags == oldflags && + (newkeyid == vma_keyid(vma) || newkeyid == NO_KEY)) { *pprev = vma; return 0; } @@ -422,6 +431,8 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, } success: + if (newkeyid != NO_KEY) + mprotect_set_encrypt(vma, newkeyid, start, end); /* * vm_flags and vm_page_prot are protected by the mmap_sem * held in write mode. @@ -453,10 +464,15 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, } /* - * When pkey==NO_KEY we get legacy mprotect behavior here. + * do_mprotect_ext() supports the legacy mprotect behavior plus extensions + * for Protection Keys and Memory Encryption Keys. These extensions are + * mutually exclusive and the behavior is: + * (pkey==NO_KEY && keyid==NO_KEY) ==> legacy mprotect + * (pkey is valid) ==> legacy mprotect plus Protection Key extensions + * (keyid is valid) ==> legacy mprotect plus Encryption Key extensions */ static int do_mprotect_ext(unsigned long start, size_t len, - unsigned long prot, int pkey) + unsigned long prot, int pkey, int keyid) { unsigned long nstart, end, tmp, reqprot; struct vm_area_struct *vma, *prev; @@ -554,7 +570,8 @@ static int do_mprotect_ext(unsigned long start, size_t len, tmp = vma->vm_end; if (tmp > end) tmp = end; - error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); + error = mprotect_fixup(vma, &prev, nstart, tmp, newflags, + keyid); if (error) goto out; nstart = tmp; @@ -579,7 +596,7 @@ static int do_mprotect_ext(unsigned long start, size_t len, SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, unsigned long, prot) { - return do_mprotect_ext(start, len, prot, NO_KEY); + return do_mprotect_ext(start, len, prot, NO_KEY, NO_KEY); } #ifdef CONFIG_ARCH_HAS_PKEYS @@ -587,7 +604,7 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, unsigned long, prot, int, pkey) { - return do_mprotect_ext(start, len, prot, pkey); + return do_mprotect_ext(start, len, prot, pkey, NO_KEY); } SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) @@ -636,3 +653,35 @@ SYSCALL_DEFINE1(pkey_free, int, pkey) } #endif /* CONFIG_ARCH_HAS_PKEYS */ + +#ifdef CONFIG_X86_INTEL_MKTME + +SYSCALL_DEFINE4(encrypt_mprotect, unsigned long, start, size_t, len, + unsigned long, prot, key_serial_t, serial) +{ + key_ref_t key_ref; + struct key *key; + int ret, keyid; + + if (!PAGE_ALIGNED(len)) + return -EINVAL; + + key_ref = lookup_user_key(serial, 0, KEY_NEED_VIEW); + if (IS_ERR(key_ref)) + return PTR_ERR(key_ref); + + key = key_ref_to_ptr(key_ref); + mktme_map_lock(); + keyid = mktme_map_keyid_from_key(key); + if (!keyid) { + mktme_map_unlock(); + key_ref_put(key_ref); + return -EINVAL; + } + ret = do_mprotect_ext(start, len, prot, NO_KEY, keyid); + mktme_map_unlock(); + key_ref_put(key_ref); + return ret; +} + +#endif /* CONFIG_X86_INTEL_MKTME */