[RFC,v2,12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows

Message ID	c2668d6d260bff3c88440ad097eb1445ea005860.1543903910.git.alison.schofield@intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> From: Alison Schofield <alison.schofield@intel.com> 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 12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows Date: Mon, 3 Dec 2018 23:39:59 -0800 Message-Id: <c2668d6d260bff3c88440ad097eb1445ea005860.1543903910.git.alison.schofield@intel.com> In-Reply-To: <cover.1543903910.git.alison.schofield@intel.com> References: <cover.1543903910.git.alison.schofield@intel.com> In-Reply-To: <cover.1543903910.git.alison.schofield@intel.com> References: <cover.1543903910.git.alison.schofield@intel.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk
Series	Multi-Key Total Memory Encryption API (MKTME) \| expand [RFC,v2,00/13] Multi-Key Total Memory Encryption API (MKTME) [RFC,v2,01/13] x86/mktme: Document the MKTME APIs [RFC,v2,02/13] mm: Generalize the mprotect implementation to support extensions [RFC,v2,03/13] syscall/x86: Wire up a new system call for memory encryption keys [RFC,v2,04/13] x86/mm: Add helper functions for MKTME memory encryption keys [RFC,v2,05/13] x86/mm: Set KeyIDs in encrypted VMAs [RFC,v2,07/13] x86/mm: Add helpers for reference counting encrypted VMAs [RFC,v2,08/13] mm: Use reference counting for encrypted VMAs [RFC,v2,09/13] mm: Restrict memory encryption to anonymous VMA's [RFC,v2,10/13] keys/mktme: Add the MKTME Key Service type for memory encryption [RFC,v2,11/13] keys/mktme: Program memory encryption keys on a system wide basis [RFC,v2,12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows [RFC,v2,13/13] keys/mktme: Support CPU Hotplug for MKTME keys

diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst index b8d0bc07ed0a..1b62b86d0666 100644 --- a/Documentation/admin-guide/kernel-parameters.rst +++ b/Documentation/admin-guide/kernel-parameters.rst @@ -120,6 +120,7 @@ parameter is applicable:: Documentation/m68k/kernel-options.txt. MDA MDA console support is enabled. MIPS MIPS architecture is enabled. + MKTME Multi-Key Total Memory Encryption is enabled. MOUSE Appropriate mouse support is enabled. MSI Message Signaled Interrupts (PCI). MTD MTD (Memory Technology Device) support is enabled. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 81d1d5a74728..c777dbf0f75c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2497,6 +2497,17 @@ in the "bleeding edge" mini2440 support kernel at http://repo.or.cz/w/linux-2.6/mini2440.git + mktme_savekeys [X86, MKTME] When CONFIG_X86_INTEL_MKTME is set + this parameter allows the kernel to save the user + specified MKTME key payload. Saving this payload + means that the MKTME Key Service can always allows + the addition of new physical packages. If the + mktme_savekeys parameter is not present, users key + data will not be saved, and new physical packages + may only be added to the system if no user type + MKTME keys are in use. + See Documentation/x86/mktme.rst + mminit_loglevel= [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this parameter allows control of the logging verbosity for diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c index 55d34beb9b81..f96f4f2884e8 100644 --- a/arch/x86/mm/mktme.c +++ b/arch/x86/mm/mktme.c @@ -99,10 +99,12 @@ void mktme_map_set_keyid(int keyid, void *key) mktme_map->mapped_keyids++; } +extern unsigned long *mktme_bitmap_user_type; void mktme_map_free_keyid(int keyid) { mktme_map->key[keyid] = 0; mktme_map->mapped_keyids--; + clear_bit(keyid, mktme_bitmap_user_type); } int mktme_map_keyid_from_key(void *key) diff --git a/security/keys/mktme_keys.c b/security/keys/mktme_keys.c index 7f113146acf2..e9c7d306cba1 100644 --- a/security/keys/mktme_keys.c +++ b/security/keys/mktme_keys.c @@ -23,6 +23,11 @@ struct kmem_cache *mktme_prog_cache; /* Hardware programming cache */ cpumask_var_t mktme_leadcpus; /* one cpu per pkg to program keys */ +/* Kernel command line parameter allows saving of users key payload. */ +static bool mktme_savekeys; +/* Track the existence of user type keys to make package hotplug decisions. */ +unsigned long *mktme_bitmap_user_type; + static const char * const mktme_program_err[] = { "KeyID was successfully programmed", /* 0 */ "Invalid KeyID programming command", /* 1 */ @@ -54,6 +59,9 @@ struct mktme_payload { u8 tweak_key[MKTME_AES_XTS_SIZE]; }; +/* Store keys in this vault if cmdline parameter mktme_savekeys allows */ +struct mktme_payload *mktme_vault; + /* Key Service Method called when Key is garbage collected. */ static void mktme_destroy_key(struct key *key) { @@ -121,6 +129,23 @@ static int mktme_program_keyid(int keyid, struct mktme_payload *payload) return ret; } +static void mktme_load_vault(int keyid, struct mktme_payload *payload) +{ + /* + * Always save the control fields to program hotplugged + * packages with RANDOM, CLEAR, or NO_ENCRYPT type keys. + */ + mktme_vault[keyid].keyid_ctrl = payload->keyid_ctrl; + + /* Only save data and tweak keys if allowed */ + if (mktme_savekeys) { + memcpy(mktme_vault[keyid].data_key, payload->data_key, + MKTME_AES_XTS_SIZE); + memcpy(mktme_vault[keyid].tweak_key, payload->tweak_key, + MKTME_AES_XTS_SIZE); + } +} + /* Key Service Method to update an existing key. */ static int mktme_update_key(struct key *key, struct key_preparsed_payload *prep) @@ -144,11 +169,23 @@ static int mktme_update_key(struct key *key, keyid, ref_count); return -EBUSY; } + + /* Forget if key was user type. */ + clear_bit(keyid, mktme_bitmap_user_type); + ret = mktme_program_keyid(keyid, payload); if (ret != MKTME_PROG_SUCCESS) { pr_debug("%s: %s\n", __func__, mktme_program_err[ret]); ret = -ENOKEY; + goto out; } + + mktme_load_vault(keyid, payload); + + /* Remember if this key is user type. */ + if ((payload->keyid_ctrl & 0xff) == MKTME_KEYID_SET_KEY_DIRECT) + set_bit(keyid, mktme_bitmap_user_type); +out: mktme_map_unlock(); return ret; } @@ -171,6 +208,13 @@ int mktme_instantiate_key(struct key *key, struct key_preparsed_payload *prep) ret = -ENOKEY; goto out; } + + mktme_load_vault(keyid, payload); + + /* Remember if key is user type. */ + if ((payload->keyid_ctrl & 0xff) == MKTME_KEYID_SET_KEY_DIRECT) + set_bit(keyid, mktme_bitmap_user_type); + mktme_map_set_keyid(keyid, key); key_get_encrypt_ref(keyid); out: @@ -380,10 +424,23 @@ static int __init init_mktme(void) if (mktme_build_leadcpus_mask() < 0) goto free_array; + mktme_bitmap_user_type = bitmap_zalloc(mktme_nr_keyids, GFP_KERNEL); + if (!mktme_bitmap_user_type) + goto free_mask; + + mktme_vault = kzalloc(sizeof(mktme_vault[0]) * (mktme_nr_keyids + 1), + GFP_KERNEL); + if (!mktme_vault) + goto free_bitmap; + ret = register_key_type(&key_type_mktme); if (!ret) return ret; /* SUCCESS */ + kfree(mktme_vault); +free_bitmap: + bitmap_free(mktme_bitmap_user_type); +free_mask: free_cpumask_var(mktme_leadcpus); free_array: mktme_free_encrypt_array(); @@ -396,3 +453,11 @@ static int __init init_mktme(void) } late_initcall(init_mktme); + +static int mktme_enable_savekeys(char *__unused) +{ + mktme_savekeys = true; + return 1; +} +__setup("mktme_savekeys", mktme_enable_savekeys); +

[RFC,v2,12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows

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