diff options
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/Makefile | 1 | ||||
| -rw-r--r-- | security/keys/compat.c | 3 | ||||
| -rw-r--r-- | security/keys/gc.c | 218 | ||||
| -rw-r--r-- | security/keys/internal.h | 10 | ||||
| -rw-r--r-- | security/keys/key.c | 24 | ||||
| -rw-r--r-- | security/keys/keyctl.c | 162 | ||||
| -rw-r--r-- | security/keys/keyring.c | 99 | ||||
| -rw-r--r-- | security/keys/proc.c | 93 | ||||
| -rw-r--r-- | security/keys/process_keys.c | 69 | ||||
| -rw-r--r-- | security/keys/sysctl.c | 28 |
10 files changed, 638 insertions, 69 deletions
diff --git a/security/keys/Makefile b/security/keys/Makefile index 747a464943af..74d5447d7df7 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -3,6 +3,7 @@ # obj-y := \ + gc.o \ key.o \ keyring.o \ keyctl.o \ diff --git a/security/keys/compat.c b/security/keys/compat.c index c766c68a63bc..792c0a611a6d 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -82,6 +82,9 @@ asmlinkage long compat_sys_keyctl(u32 option, case KEYCTL_GET_SECURITY: return keyctl_get_security(arg2, compat_ptr(arg3), arg4); + case KEYCTL_SESSION_TO_PARENT: + return keyctl_session_to_parent(); + default: return -EOPNOTSUPP; } diff --git a/security/keys/gc.c b/security/keys/gc.c new file mode 100644 index 000000000000..485fc6233c38 --- /dev/null +++ b/security/keys/gc.c @@ -0,0 +1,218 @@ +/* Key garbage collector + * + * Copyright (C) 2009 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 <linux/module.h> +#include <keys/keyring-type.h> +#include "internal.h" + +/* + * Delay between key revocation/expiry in seconds + */ +unsigned key_gc_delay = 5 * 60; + +/* + * Reaper + */ +static void key_gc_timer_func(unsigned long); +static void key_garbage_collector(struct work_struct *); +static DEFINE_TIMER(key_gc_timer, key_gc_timer_func, 0, 0); +static DECLARE_WORK(key_gc_work, key_garbage_collector); +static key_serial_t key_gc_cursor; /* the last key the gc considered */ +static bool key_gc_again; +static unsigned long key_gc_executing; +static time_t key_gc_next_run = LONG_MAX; +static time_t key_gc_new_timer; + +/* + * Schedule a garbage collection run + * - precision isn't particularly important + */ +void key_schedule_gc(time_t gc_at) +{ + unsigned long expires; + time_t now = current_kernel_time().tv_sec; + + kenter("%ld", gc_at - now); + + if (gc_at <= now) { + schedule_work(&key_gc_work); + } else if (gc_at < key_gc_next_run) { + expires = jiffies + (gc_at - now) * HZ; + mod_timer(&key_gc_timer, expires); + } +} + +/* + * The garbage collector timer kicked off + */ +static void key_gc_timer_func(unsigned long data) +{ + kenter(""); + key_gc_next_run = LONG_MAX; + schedule_work(&key_gc_work); +} + +/* + * Garbage collect pointers from a keyring + * - return true if we altered the keyring + */ +static bool key_gc_keyring(struct key *keyring, time_t limit) + __releases(key_serial_lock) +{ + struct keyring_list *klist; + struct key *key; + int loop; + + kenter("%x", key_serial(keyring)); + + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) + goto dont_gc; + + /* scan the keyring looking for dead keys */ + klist = rcu_dereference(keyring->payload.subscriptions); + if (!klist) + goto dont_gc; + + for (loop = klist->nkeys - 1; loop >= 0; loop--) { + key = klist->keys[loop]; + if (test_bit(KEY_FLAG_DEAD, &key->flags) || + (key->expiry > 0 && key->expiry <= limit)) + goto do_gc; + } + +dont_gc: + kleave(" = false"); + return false; + +do_gc: + key_gc_cursor = keyring->serial; + key_get(keyring); + spin_unlock(&key_serial_lock); + keyring_gc(keyring, limit); + key_put(keyring); + kleave(" = true"); + return true; +} + +/* + * Garbage collector for keys + * - this involves scanning the keyrings for dead, expired and revoked keys + * that have overstayed their welcome + */ +static void key_garbage_collector(struct work_struct *work) +{ + struct rb_node *rb; + key_serial_t cursor; + struct key *key, *xkey; + time_t new_timer = LONG_MAX, limit, now; + + now = current_kernel_time().tv_sec; + kenter("[%x,%ld]", key_gc_cursor, key_gc_new_timer - now); + + if (test_and_set_bit(0, &key_gc_executing)) { + key_schedule_gc(current_kernel_time().tv_sec + 1); + kleave(" [busy; deferring]"); + return; + } + + limit = now; + if (limit > key_gc_delay) + limit -= key_gc_delay; + else + limit = key_gc_delay; + + spin_lock(&key_serial_lock); + + if (unlikely(RB_EMPTY_ROOT(&key_serial_tree))) { + spin_unlock(&key_serial_lock); + clear_bit(0, &key_gc_executing); + return; + } + + cursor = key_gc_cursor; + if (cursor < 0) + cursor = 0; + if (cursor > 0) + new_timer = key_gc_new_timer; + else + key_gc_again = false; + + /* find the first key above the cursor */ + key = NULL; + rb = key_serial_tree.rb_node; + while (rb) { + xkey = rb_entry(rb, struct key, serial_node); + if (cursor < xkey->serial) { + key = xkey; + rb = rb->rb_left; + } else if (cursor > xkey->serial) { + rb = rb->rb_right; + } else { + rb = rb_next(rb); + if (!rb) + goto reached_the_end; + key = rb_entry(rb, struct key, serial_node); + break; + } + } + + if (!key) + goto reached_the_end; + + /* trawl through the keys looking for keyrings */ + for (;;) { + if (key->expiry > now && key->expiry < new_timer) { + kdebug("will expire %x in %ld", + key_serial(key), key->expiry - now); + new_timer = key->expiry; + } + + if (key->type == &key_type_keyring && + key_gc_keyring(key, limit)) + /* the gc had to release our lock so that the keyring + * could be modified, so we have to get it again */ + goto gc_released_our_lock; + + rb = rb_next(&key->serial_node); + if (!rb) + goto reached_the_end; + key = rb_entry(rb, struct key, serial_node); + } + +gc_released_our_lock: + kdebug("gc_released_our_lock"); + key_gc_new_timer = new_timer; + key_gc_again = true; + clear_bit(0, &key_gc_executing); + schedule_work(&key_gc_work); + kleave(" [continue]"); + return; + + /* when we reach the end of the run, we set the timer for the next one */ +reached_the_end: + kdebug("reached_the_end"); + spin_unlock(&key_serial_lock); + key_gc_new_timer = new_timer; + key_gc_cursor = 0; + clear_bit(0, &key_gc_executing); + + if (key_gc_again) { + /* there may have been a key that expired whilst we were + * scanning, so if we discarded any links we should do another + * scan */ + new_timer = now + 1; + key_schedule_gc(new_timer); + } else if (new_timer < LONG_MAX) { + new_timer += key_gc_delay; + key_schedule_gc(new_timer); + } + kleave(" [end]"); +} diff --git a/security/keys/internal.h b/security/keys/internal.h index 9fb679c66b8a..24ba0307b7ad 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -124,11 +124,18 @@ extern struct key *request_key_and_link(struct key_type *type, struct key *dest_keyring, unsigned long flags); -extern key_ref_t lookup_user_key(key_serial_t id, int create, int partial, +extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, key_perm_t perm); +#define KEY_LOOKUP_CREATE 0x01 +#define KEY_LOOKUP_PARTIAL 0x02 +#define KEY_LOOKUP_FOR_UNLINK 0x04 extern long join_session_keyring(const char *name); +extern unsigned key_gc_delay; +extern void keyring_gc(struct key *keyring, time_t limit); +extern void key_schedule_gc(time_t expiry_at); + /* * check to see whether permission is granted to use a key in the desired way */ @@ -194,6 +201,7 @@ extern long keyctl_set_timeout(key_serial_t, unsigned); extern long keyctl_assume_authority(key_serial_t); extern long keyctl_get_security(key_serial_t keyid, char __user *buffer, size_t buflen); +extern long keyctl_session_to_parent(void); /* * debugging key validation diff --git a/security/keys/key.c b/security/keys/key.c index 4a1297d1ada4..e50d264c9ad1 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -500,6 +500,7 @@ int key_negate_and_link(struct key *key, set_bit(KEY_FLAG_INSTANTIATED, &key->flags); now = current_kernel_time(); key->expiry = now.tv_sec + timeout; + key_schedule_gc(key->expiry + key_gc_delay); if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) awaken = 1; @@ -642,10 +643,8 @@ struct key *key_lookup(key_serial_t id) goto error; found: - /* pretend it doesn't exist if it's dead */ - if (atomic_read(&key->usage) == 0 || - test_bit(KEY_FLAG_DEAD, &key->flags) || - key->type == &key_type_dead) + /* pretend it doesn't exist if it is awaiting deletion */ + if (atomic_read(&key->usage) == 0) goto not_found; /* this races with key_put(), but that doesn't matter since key_put() @@ -890,6 +889,9 @@ EXPORT_SYMBOL(key_update); */ void key_revoke(struct key *key) { + struct timespec now; + time_t time; + key_check(key); /* make sure no one's trying to change or use the key when we mark it @@ -902,6 +904,14 @@ void key_revoke(struct key *key) key->type->revoke) key->type->revoke(key); + /* set the death time to no more than the expiry time */ + now = current_kernel_time(); + time = now.tv_sec; + if (key->revoked_at == 0 || key->revoked_at > time) { + key->revoked_at = time; + key_schedule_gc(key->revoked_at + key_gc_delay); + } + up_write(&key->sem); } /* end key_revoke() */ @@ -958,8 +968,10 @@ void unregister_key_type(struct key_type *ktype) for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { key = rb_entry(_n, struct key, serial_node); - if (key->type == ktype) + if (key->type == ktype) { key->type = &key_type_dead; + set_bit(KEY_FLAG_DEAD, &key->flags); + } } spin_unlock(&key_serial_lock); @@ -984,6 +996,8 @@ void unregister_key_type(struct key_type *ktype) spin_unlock(&key_serial_lock); up_write(&key_types_sem); + key_schedule_gc(0); + } /* end unregister_key_type() */ EXPORT_SYMBOL(unregister_key_type); diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 7f09fb897d2b..2fb28efc5326 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -103,7 +103,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, } /* find the target keyring (which must be writable) */ - keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error3; @@ -185,7 +185,8 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, /* get the destination keyring if specified */ dest_ref = NULL; if (destringid) { - dest_ref = lookup_user_key(destringid, 1, 0, KEY_WRITE); + dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, + KEY_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; @@ -233,9 +234,11 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, long keyctl_get_keyring_ID(key_serial_t id, int create) { key_ref_t key_ref; + unsigned long lflags; long ret; - key_ref = lookup_user_key(id, create, 0, KEY_SEARCH); + lflags = create ? KEY_LOOKUP_CREATE : 0; + key_ref = lookup_user_key(id, lflags, KEY_SEARCH); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -309,7 +312,7 @@ long keyctl_update_key(key_serial_t id, } /* find the target key (which must be writable) */ - key_ref = lookup_user_key(id, 0, 0, KEY_WRITE); + key_ref = lookup_user_key(id, 0, KEY_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; @@ -337,10 +340,16 @@ long keyctl_revoke_key(key_serial_t id) key_ref_t key_ref; long ret; - key_ref = lookup_user_key(id, 0, 0, KEY_WRITE); + key_ref = lookup_user_key(id, 0, KEY_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); - goto error; + if (ret != -EACCES) + goto error; + key_ref = lookup_user_key(id, 0, KEY_SETATTR); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } } key_revoke(key_ref_to_ptr(key_ref)); @@ -363,7 +372,7 @@ long keyctl_keyring_clear(key_serial_t ringid) key_ref_t keyring_ref; long ret; - keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; @@ -389,13 +398,13 @@ long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) key_ref_t keyring_ref, key_ref; long ret; - keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } - key_ref = lookup_user_key(id, 1, 0, KEY_LINK); + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; @@ -423,13 +432,13 @@ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) key_ref_t keyring_ref, key_ref; long ret; - keyring_ref = lookup_user_key(ringid, 0, 0, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } - key_ref = lookup_user_key(id, 0, 0, 0); + key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; @@ -465,7 +474,7 @@ long keyctl_describe_key(key_serial_t keyid, char *tmpbuf; long ret; - key_ref = lookup_user_key(keyid, 0, 1, KEY_VIEW); + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); if (IS_ERR(key_ref)) { /* viewing a key under construction is permitted if we have the * authorisation token handy */ @@ -474,7 +483,8 @@ long keyctl_describe_key(key_serial_t keyid, if (!IS_ERR(instkey)) { key_put(instkey); key_ref = lookup_user_key(keyid, - 0, 1, 0); + KEY_LOOKUP_PARTIAL, + 0); if (!IS_ERR(key_ref)) goto okay; } @@ -558,7 +568,7 @@ long keyctl_keyring_search(key_serial_t ringid, } /* get the keyring at which to begin the search */ - keyring_ref = lookup_user_key(ringid, 0, 0, KEY_SEARCH); + keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error2; @@ -567,7 +577,8 @@ long keyctl_keyring_search(key_serial_t ringid, /* get the destination keyring if specified */ dest_ref = NULL; if (destringid) { - dest_ref = lookup_user_key(destringid, 1, 0, KEY_WRITE); + dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, + KEY_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; @@ -637,7 +648,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) long ret; /* find the key first */ - key_ref = lookup_user_key(keyid, 0, 0, 0); + key_ref = lookup_user_key(keyid, 0, 0); if (IS_ERR(key_ref)) { ret = -ENOKEY; goto error; @@ -700,7 +711,8 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) if (uid == (uid_t) -1 && gid == (gid_t) -1) goto error; - key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR); + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -805,7 +817,8 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) goto error; - key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR); + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -847,7 +860,7 @@ static long get_instantiation_keyring(key_serial_t ringid, /* if a specific keyring is nominated by ID, then use that */ if (ringid > 0) { - dkref = lookup_user_key(ringid, 1, 0, KEY_WRITE); + dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); if (IS_ERR(dkref)) return PTR_ERR(dkref); *_dest_keyring = key_ref_to_ptr(dkref); @@ -1083,7 +1096,8 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout) time_t expiry; long ret; - key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR); + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -1101,6 +1115,7 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout) } key->expiry = expiry; + key_schedule_gc(key->expiry + key_gc_delay); up_write(&key->sem); key_put(key); @@ -1170,7 +1185,7 @@ long keyctl_get_security(key_serial_t keyid, char *context; long ret; - key_ref = lookup_user_key(keyid, 0, 1, KEY_VIEW); + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); if (IS_ERR(key_ref)) { if (PTR_ERR(key_ref) != -EACCES) return PTR_ERR(key_ref); @@ -1182,7 +1197,7 @@ long keyctl_get_security(key_serial_t keyid, return PTR_ERR(key_ref); key_put(instkey); - key_ref = lookup_user_key(keyid, 0, 1, 0); + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0); if (IS_ERR(key_ref)) return PTR_ERR(key_ref); } @@ -1213,6 +1228,106 @@ long keyctl_get_security(key_serial_t keyid, return ret; } +/* + * attempt to install the calling process's session keyring on the process's + * parent process + * - the keyring must exist and must grant us LINK permission + * - implements keyctl(KEYCTL_SESSION_TO_PARENT) + */ +long keyctl_session_to_parent(void) +{ + struct task_struct *me, *parent; + const struct cred *mycred, *pcred; + struct cred *cred, *oldcred; + key_ref_t keyring_r; + int ret; + + keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK); + if (IS_ERR(keyring_r)) + return PTR_ERR(keyring_r); + + /* our parent is going to need a new cred struct, a new tgcred struct + * and new security data, so we allocate them here to prevent ENOMEM in + * our parent */ + ret = -ENOMEM; + cred = cred_alloc_blank(); + if (!cred) + goto error_keyring; + + cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r); + keyring_r = NULL; + + me = current; + write_lock_irq(&tasklist_lock); + + parent = me->real_parent; + ret = -EPERM; + + /* the parent mustn't be init and mustn't be a kernel thread */ + if (parent->pid <= 1 || !parent->mm) + goto not_permitted; + + /* the parent must be single threaded */ + if (atomic_read(&parent->signal->count) != 1) + goto not_permitted; + + /* the parent and the child must have different session keyrings or + * there's no point */ + mycred = current_cred(); + pcred = __task_cred(parent); + if (mycred == pcred || + mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) + goto already_same; + + /* the parent must have the same effective ownership and mustn't be + * SUID/SGID */ + if (pcred-> uid != mycred->euid || + pcred->euid != mycred->euid || + pcred->suid != mycred->euid || + pcred-> gid != mycred->egid || + pcred->egid != mycred->egid || + pcred->sgid != mycred->egid) + goto not_permitted; + + /* the keyrings must have the same UID */ + if (pcred ->tgcred->session_keyring->uid != mycred->euid || + mycred->tgcred->session_keyring->uid != mycred->euid) + goto not_permitted; + + /* the LSM must permit the replacement of the parent's keyring with the + * keyring from this process */ + ret = security_key_session_to_parent(mycred, pcred, + key_ref_to_ptr(keyring_r)); + if (ret < 0) + goto not_permitted; + + /* if there's an already pending keyring replacement, then we replace + * that */ + oldcred = parent->replacement_session_keyring; + + /* the replacement session keyring is applied just prior to userspace + * restarting */ + parent->replacement_session_keyring = cred; + cred = NULL; + set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME); + + write_unlock_irq(&tasklist_lock); + if (oldcred) + put_cred(oldcred); + return 0; + +already_same: + ret = 0; +not_permitted: + write_unlock_irq(&tasklist_lock); + put_cred(cred); + return ret; + +error_keyring: + key_ref_put(keyring_r); + return ret; +} + /*****************************************************************************/ /* * the key control system call @@ -1298,6 +1413,9 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, (char __user *) arg3, (size_t) arg4); + case KEYCTL_SESSION_TO_PARENT: + return keyctl_session_to_parent(); + default: return -EOPNOTSUPP; } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 3dba81c2eba3..8ec02746ca99 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1000,3 +1000,102 @@ static void keyring_revoke(struct key *keyring) } } /* end keyring_revoke() */ + +/* + * Determine whether a key is dead + */ +static bool key_is_dead(struct key *key, time_t limit) +{ + return test_bit(KEY_FLAG_DEAD, &key->flags) || + (key->expiry > 0 && key->expiry <= limit); +} + +/* + * Collect garbage from the contents of a keyring + */ +void keyring_gc(struct key *keyring, time_t limit) +{ + struct keyring_list *klist, *new; + struct key *key; + int loop, keep, max; + + kenter("{%x,%s}", key_serial(keyring), keyring->description); + + down_write(&keyring->sem); + + klist = keyring->payload.subscriptions; + if (!klist) + goto no_klist; + + /* work out how many subscriptions we're keeping */ + keep = 0; + for (loop = klist->nkeys - 1; loop >= 0; loop--) + if (!key_is_dead(klist->keys[loop], limit)) + keep++; + + if (keep == klist->nkeys) + goto just_return; + + /* allocate a new keyring payload */ + max = roundup(keep, 4); + new = kmalloc(sizeof(struct keyring_list) + max * sizeof(struct key *), + GFP_KERNEL); + if (!new) + goto nomem; + new->maxkeys = max; + new->nkeys = 0; + new->delkey = 0; + + /* install the live keys + * - must take care as expired keys may be updated back to life + */ + keep = 0; + for (loop = klist->nkeys - 1; loop >= 0; loop--) { + key = klist->keys[loop]; + if (!key_is_dead(key, limit)) { + if (keep >= max) + goto discard_new; + new->keys[keep++] = key_get(key); + } + } + new->nkeys = keep; + + /* adjust the quota */ + key_payload_reserve(keyring, + sizeof(struct keyring_list) + + KEYQUOTA_LINK_BYTES * keep); + + if (keep == 0) { + rcu_assign_pointer(keyring->payload.subscriptions, NULL); + kfree(new); + } else { + rcu_assign_pointer(keyring->payload.subscriptions, new); + } + + up_write(&keyring->sem); + + call_rcu(&klist->rcu, keyring_clear_rcu_disposal); + kleave(" [yes]"); + return; + +discard_new: + new->nkeys = keep; + keyring_clear_rcu_disposal(&new->rcu); + up_write(&keyring->sem); + kleave(" [discard]"); + return; + +just_return: + up_write(&keyring->sem); + kleave(" [no dead]"); + return; + +no_klist: + up_write(&keyring->sem); + kleave(" [no_klist]"); + return; + +nomem: + up_write(&keyring->sem); + kleave(" [oom]"); +} diff --git a/security/keys/proc.c b/security/keys/proc.c index 769f9bdfd2b3..9d01021ca0c8 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -91,59 +91,94 @@ __initcall(key_proc_init); */ #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS -static struct rb_node *__key_serial_next(struct rb_node *n) +static struct rb_node *key_serial_next(struct rb_node *n) { + struct user_namespace *user_ns = current_user_ns(); + + n = rb_next(n); while (n) { struct key *key = rb_entry(n, struct key, serial_node); - if (key->user->user_ns == current_user_ns()) + if (key->user->user_ns == user_ns) break; n = rb_next(n); } return n; } -static struct rb_node *key_serial_next(struct rb_node *n) +static int proc_keys_open(struct inode *inode, struct file *file) { - return __key_serial_next(rb_next(n)); + return seq_open(file, &proc_keys_ops); } -static struct rb_node *key_serial_first(struct rb_root *r) +static struct key *find_ge_key(key_serial_t id) { - struct rb_node *n = rb_first(r); - return __key_serial_next(n); -} + struct user_namespace *user_ns = current_user_ns(); + struct rb_node *n = key_serial_tree.rb_node; + struct key *minkey = NULL; -static int proc_keys_open(struct inode *inode, struct file *file) -{ - return seq_open(file, &proc_keys_ops); + while (n) { + struct key *key = rb_entry(n, struct key, serial_node); + if (id < key->serial) { + if (!minkey || minkey->serial > key->serial) + minkey = key; + n = n->rb_left; + } else if (id > key->serial) { + n = n->rb_right; + } else { + minkey = key; + break; + } + key = NULL; + } + if (!minkey) + return NULL; + + for (;;) { + if (minkey->user->user_ns == user_ns) + return minkey; + n = rb_next(&minkey->serial_node); + if (!n) + return NULL; + minkey = rb_entry(n, struct key, serial_node); + } } static void *proc_keys_start(struct seq_file *p, loff_t *_pos) + __acquires(key_serial_lock) { - struct rb_node *_p; - loff_t pos = *_pos; + key_serial_t pos = *_pos; + struct key *key; spin_lock(&key_serial_lock); - _p = key_serial_first(&key_serial_tree); - while (pos > 0 && _p) { - pos--; - _p = key_serial_next(_p); - } - - return _p; + if (*_pos > INT_MAX) + return NULL; + key = find_ge_key(pos); + if (!key) + return NULL; + *_pos = key->serial; + return &key->serial_node; +} +static inline key_serial_t key_node_serial(struct rb_node *n) +{ + struct key *key = rb_entry(n, struct key, serial_node); + return key->serial; } static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos) { - (*_pos)++; - return key_serial_next((struct rb_node *) v); + struct rb_node *n; + n = key_serial_next(v); + if (n) + *_pos = key_node_serial(n); + return n; } static void proc_keys_stop(struct seq_file *p, void *v) + __releases(key_serial_lock) { spin_unlock(&key_serial_lock); } @@ -174,11 +209,9 @@ static int proc_keys_show(struct seq_file *m, void *v) /* come up with a suitable timeout value */ if (key->expiry == 0) { memcpy(xbuf, "perm", 5); - } - else if (now.tv_sec >= key->expiry) { + } else if (now.tv_sec >= key->expiry) { memcpy(xbuf, "expd", 5); - } - else { + } else { timo = key->expiry - now.tv_sec; if (timo < 60) @@ -218,9 +251,7 @@ static int proc_keys_show(struct seq_file *m, void *v) seq_putc(m, '\n'); rcu_read_unlock(); - return 0; - } #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */ @@ -246,6 +277,7 @@ static struct rb_node *key_user_first(struct rb_root *r) struct rb_node *n = rb_first(r); return __key_user_next(n); } + /*****************************************************************************/ /* * implement "/proc/key-users" to provides a list of the key users @@ -253,10 +285,10 @@ static struct rb_node *key_user_first(struct rb_root *r) static int proc_key_users_open(struct inode *inode, struct file *file) { return seq_open(file, &proc_key_users_ops); - } static void *proc_key_users_start(struct seq_file *p, loff_t *_pos) + __acquires(key_user_lock) { struct rb_node *_p; loff_t pos = *_pos; @@ -270,17 +302,16 @@ static void *proc_key_users_start(struct seq_file *p, loff_t *_pos) } return _p; - } static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos) { (*_pos)++; return key_user_next((struct rb_node *) v); - } static void proc_key_users_stop(struct seq_file *p, void *v) + __releases(key_user_lock) { spin_unlock(&key_user_lock); } diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 276d27882ce8..5c23afb31ece 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -17,6 +17,7 @@ #include <linux/fs.h> #include <linux/err.h> #include <linux/mutex.h> +#include <linux/security.h> #include <linux/user_namespace.h> #include <asm/uaccess.h> #include "internal.h" @@ -487,7 +488,7 @@ static int lookup_user_key_possessed(const struct key *key, const void *target) * - don't create special keyrings unless so requested * - partially constructed keys aren't found unless requested */ -key_ref_t lookup_user_key(key_serial_t id, int create, int partial, +key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, key_perm_t perm) { struct request_key_auth *rka; @@ -503,7 +504,7 @@ try_again: switch (id) { case KEY_SPEC_THREAD_KEYRING: if (!cred->thread_keyring) { - if (!create) + if (!(lflags & KEY_LOOKUP_CREATE)) goto error; ret = install_thread_keyring(); @@ -521,7 +522,7 @@ try_again: case KEY_SPEC_PROCESS_KEYRING: if (!cred->tgcred->process_keyring) { - if (!create) + if (!(lflags & KEY_LOOKUP_CREATE)) goto error; ret = install_process_keyring(); @@ -642,7 +643,14 @@ try_again: break; } - if (!partial) { + /* unlink does not use the nominated key in any way, so can skip all + * the permission checks as it is only concerned with the keyring */ + if (lflags & KEY_LOOKUP_FOR_UNLINK) { + ret = 0; + goto error; + } + + if (!(lflags & KEY_LOOKUP_PARTIAL)) { ret = wait_for_key_construction(key, true); switch (ret) { case -ERESTARTSYS: @@ -660,7 +668,8 @@ try_again: } ret = -EIO; - if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) + if (!(lflags & KEY_LOOKUP_PARTIAL) && + !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) goto invalid_key; /* check the permissions */ @@ -702,7 +711,7 @@ long join_session_keyring(const char *name) /* only permit this if there's a single thread in the thread group - * this avoids us having to adjust the creds on all threads and risking * ENOMEM */ - if (!is_single_threaded(current)) + if (!current_is_single_threaded()) return -EMLINK; new = prepare_creds(); @@ -760,3 +769,51 @@ error: abort_creds(new); return ret; } + +/* + * Replace a process's session keyring when that process resumes userspace on + * behalf of one of its children + */ +void key_replace_session_keyring(void) +{ + const struct cred *old; + struct cred *new; + + if (!current->replacement_session_keyring) + return; + + write_lock_irq(&tasklist_lock); + new = current->replacement_session_keyring; + current->replacement_session_keyring = NULL; + write_unlock_irq(&tasklist_lock); + + if (!new) + return; + + old = current_cred(); + new-> uid = old-> uid; + new-> euid = old-> euid; + new-> suid = old-> suid; + new->fsuid = old->fsuid; + new-> gid = old-> gid; + new-> egid = old-> egid; + new-> sgid = old-> sgid; + new->fsgid = old->fsgid; + new->user = get_uid(old->user); + new->group_info = get_group_info(old->group_info); + + new->securebits = old->securebits; + new->cap_inheritable = old->cap_inheritable; + new->cap_permitted = old->cap_permitted; + new->cap_effective = old->cap_effective; + new->cap_bset = old->cap_bset; + + new->jit_keyring = old->jit_keyring; + new->thread_keyring = key_get(old->thread_keyring); + new->tgcred->tgid = old->tgcred->tgid; + new->tgcred->process_keyring = key_get(old->tgcred->process_keyring); + + security_transfer_creds(new, old); + + commit_creds(new); +} diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c index b611d493c2d8..5e05dc09e2db 100644 --- a/security/keys/sysctl.c +++ b/security/keys/sysctl.c @@ -13,6 +13,8 @@ #include <linux/sysctl.h> #include "internal.h" +static const int zero, one = 1, max = INT_MAX; + ctl_table key_sysctls[] = { { .ctl_name = CTL_UNNUMBERED, @@ -20,7 +22,9 @@ ctl_table key_sysctls[] = { .data = &key_quota_maxkeys, .maxlen = sizeof(unsigned), .mode = 0644, - .proc_handler = &proc_dointvec, + .proc_handler = &proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, }, { .ctl_name = CTL_UNNUMBERED, @@ -28,7 +32,9 @@ ctl_table key_sysctls[] = { .data = &key_quota_maxbytes, .maxlen = sizeof(unsigned), .mode = 0644, - .proc_handler = &proc_dointvec, + .proc_handler = &proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, }, { .ctl_name = CTL_UNNUMBERED, @@ -36,7 +42,9 @@ ctl_table key_sysctls[] = { .data = &key_quota_root_maxkeys, .maxlen = sizeof(unsigned), .mode = 0644, - .proc_handler = &proc_dointvec, + .proc_handler = &proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, }, { .ctl_name = CTL_UNNUMBERED, @@ -44,7 +52,19 @@ ctl_table key_sysctls[] = { .data = &key_quota_root_maxbytes, .maxlen = sizeof(unsigned), .mode = 0644, - .proc_handler = &proc_dointvec, + .proc_handler = &proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, + }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "gc_delay", + .data = &key_gc_delay, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .extra1 = (void *) &zero, + .extra2 = (void *) &max, }, { .ctl_name = 0 } }; |