/* General persistent per-UID keyrings register * * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public Licence * as published by the Free Software Foundation; either version * 2 of the Licence, or (at your option) any later version. */ #include #include "internal.h" unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */ /* * Create the persistent keyring register for the current user namespace. * * Called with the namespace's sem locked for writing. */ static int key_create_persistent_register(struct user_namespace *ns) { struct key *reg = keyring_alloc(".persistent_register", KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ), KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); if (IS_ERR(reg)) return PTR_ERR(reg); ns->persistent_keyring_register = reg; return 0; } /* * Create the persistent keyring for the specified user. * * Called with the namespace's sem locked for writing. */ static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid, struct keyring_index_key *index_key) { struct key *persistent; key_ref_t reg_ref, persistent_ref; if (!ns->persistent_keyring_register) { long err = key_create_persistent_register(ns); if (err < 0) return ERR_PTR(err); } else { reg_ref = make_key_ref(ns->persistent_keyring_register, true); persistent_ref = find_key_to_update(reg_ref, index_key); if (persistent_ref) return persistent_ref; } persistent = keyring_alloc(index_key->description, uid, INVALID_GID, current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ), KEY_ALLOC_NOT_IN_QUOTA, NULL, ns->persistent_keyring_register); if (IS_ERR(persistent)) return ERR_CAST(persistent); return make_key_ref(persistent, true); } /* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */ static long key_get_persistent(struct user_namespace *ns, kuid_t uid, key_ref_t dest_ref) { struct keyring_index_key index_key; struct key *persistent; key_ref_t reg_ref, persistent_ref; char buf[32]; long ret; /* Look in the register if it exists */ index_key.type = &key_type_keyring; index_key.description = buf; index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid)); if (ns->persistent_keyring_register) { reg_ref = make_key_ref(ns->persistent_keyring_register, true); down_read(&ns->persistent_keyring_register_sem); persistent_ref = find_key_to_update(reg_ref, &index_key); up_read(&ns->persistent_keyring_register_sem); if (persistent_ref) goto found; } /* It wasn't in the register, so we'll need to create it. We might * also need to create the register. */ down_write(&ns->persistent_keyring_register_sem); persistent_ref = key_create_persistent(ns, uid, &index_key); up_write(&ns->persistent_keyring_register_sem); if (!IS_ERR(persistent_ref)) goto found; return PTR_ERR(persistent_ref); found: ret = key_task_permission(persistent_ref, current_cred(), KEY_NEED_LINK); if (ret == 0) { persistent = key_ref_to_ptr(persistent_ref); ret = key_link(key_ref_to_ptr(dest_ref), persistent); if (ret == 0) { key_set_timeout(persistent, persistent_keyring_expiry); ret = persistent->serial; } } key_ref_put(persistent_ref); return ret; } /* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */ long keyctl_get_persistent(uid_t _uid, key_serial_t destid) { struct user_namespace *ns = current_user_ns(); key_ref_t dest_ref; kuid_t uid; long ret; /* -1 indicates the current user */ if (_uid == (uid_t)-1) { uid = current_uid(); } else { uid = make_kuid(ns, _uid); if (!uid_valid(uid)) return -EINVAL; /* You can only see your own persistent cache if you're not * sufficiently privileged. */ if (!uid_eq(uid, current_uid()) && !uid_eq(uid, current_euid()) && !ns_capable(ns, CAP_SETUID)) return -EPERM; } /* There must be a destination keyring */ dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(dest_ref)) return PTR_ERR(dest_ref); if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) { ret = -ENOTDIR; goto out_put_dest; } ret = key_get_persistent(ns, uid, dest_ref); out_put_dest: key_ref_put(dest_ref); return ret; } td class='ctrl'>mode:
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /tools/perf/tests/backward-ring-buffer.c
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/perf/tests/backward-ring-buffer.c')