From 9578e327b2b4935a25d49e3891b8fcca9b6c10c6 Mon Sep 17 00:00:00 2001 From: Luis Henriques Date: Tue, 30 Jan 2024 10:13:44 +0000 Subject: keys: update key quotas in key_put() Delaying key quotas update when key's refcount reaches 0 in key_put() has been causing some issues in fscrypt testing, specifically in fstest generic/581. This commit fixes this test flakiness by dealing with the quotas immediately, and leaving all the other clean-ups to the key garbage collector. This is done by moving the updates to the qnkeys and qnbytes fields in struct key_user from key_gc_unused_keys() into key_put(). Unfortunately, this also means that we need to switch to the irq-version of the spinlock that protects these fields and use spin_lock_{irqsave,irqrestore} in all the code that touches these fields. Signed-off-by: Luis Henriques Reviewed-by: Jarkko Sakkinen Acked-by: David Howells Signed-off-by: Jarkko Sakkinen --- security/keys/gc.c | 8 -------- security/keys/key.c | 32 ++++++++++++++++++++++---------- security/keys/keyctl.c | 11 ++++++----- 3 files changed, 28 insertions(+), 23 deletions(-) (limited to 'security') diff --git a/security/keys/gc.c b/security/keys/gc.c index eaddaceda14e..7d687b0962b1 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -155,14 +155,6 @@ static noinline void key_gc_unused_keys(struct list_head *keys) security_key_free(key); - /* deal with the user's key tracking and quota */ - if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { - spin_lock(&key->user->lock); - key->user->qnkeys--; - key->user->qnbytes -= key->quotalen; - spin_unlock(&key->user->lock); - } - atomic_dec(&key->user->nkeys); if (state != KEY_IS_UNINSTANTIATED) atomic_dec(&key->user->nikeys); diff --git a/security/keys/key.c b/security/keys/key.c index 560790038329..2a9a769e795e 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -230,6 +230,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, struct key *key; size_t desclen, quotalen; int ret; + unsigned long irqflags; key = ERR_PTR(-EINVAL); if (!desc || !*desc) @@ -259,7 +260,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxbytes : key_quota_maxbytes; - spin_lock(&user->lock); + spin_lock_irqsave(&user->lock, irqflags); if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { if (user->qnkeys + 1 > maxkeys || user->qnbytes + quotalen > maxbytes || @@ -269,7 +270,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, user->qnkeys++; user->qnbytes += quotalen; - spin_unlock(&user->lock); + spin_unlock_irqrestore(&user->lock, irqflags); } /* allocate and initialise the key and its description */ @@ -327,10 +328,10 @@ security_error: kfree(key->description); kmem_cache_free(key_jar, key); if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { - spin_lock(&user->lock); + spin_lock_irqsave(&user->lock, irqflags); user->qnkeys--; user->qnbytes -= quotalen; - spin_unlock(&user->lock); + spin_unlock_irqrestore(&user->lock, irqflags); } key_user_put(user); key = ERR_PTR(ret); @@ -340,10 +341,10 @@ no_memory_3: kmem_cache_free(key_jar, key); no_memory_2: if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { - spin_lock(&user->lock); + spin_lock_irqsave(&user->lock, irqflags); user->qnkeys--; user->qnbytes -= quotalen; - spin_unlock(&user->lock); + spin_unlock_irqrestore(&user->lock, irqflags); } key_user_put(user); no_memory_1: @@ -351,7 +352,7 @@ no_memory_1: goto error; no_quota: - spin_unlock(&user->lock); + spin_unlock_irqrestore(&user->lock, irqflags); key_user_put(user); key = ERR_PTR(-EDQUOT); goto error; @@ -380,8 +381,9 @@ int key_payload_reserve(struct key *key, size_t datalen) if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ? key_quota_root_maxbytes : key_quota_maxbytes; + unsigned long flags; - spin_lock(&key->user->lock); + spin_lock_irqsave(&key->user->lock, flags); if (delta > 0 && (key->user->qnbytes + delta > maxbytes || @@ -392,7 +394,7 @@ int key_payload_reserve(struct key *key, size_t datalen) key->user->qnbytes += delta; key->quotalen += delta; } - spin_unlock(&key->user->lock); + spin_unlock_irqrestore(&key->user->lock, flags); } /* change the recorded data length if that didn't generate an error */ @@ -645,8 +647,18 @@ void key_put(struct key *key) if (key) { key_check(key); - if (refcount_dec_and_test(&key->usage)) + if (refcount_dec_and_test(&key->usage)) { + unsigned long flags; + + /* deal with the user's key tracking and quota */ + if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { + spin_lock_irqsave(&key->user->lock, flags); + key->user->qnkeys--; + key->user->qnbytes -= key->quotalen; + spin_unlock_irqrestore(&key->user->lock, flags); + } schedule_work(&key_gc_work); + } } } EXPORT_SYMBOL(key_put); diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 10ba439968f7..4bc3e9398ee3 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -954,6 +954,7 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) long ret; kuid_t uid; kgid_t gid; + unsigned long flags; uid = make_kuid(current_user_ns(), user); gid = make_kgid(current_user_ns(), group); @@ -1010,7 +1011,7 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxbytes : key_quota_maxbytes; - spin_lock(&newowner->lock); + spin_lock_irqsave(&newowner->lock, flags); if (newowner->qnkeys + 1 > maxkeys || newowner->qnbytes + key->quotalen > maxbytes || newowner->qnbytes + key->quotalen < @@ -1019,12 +1020,12 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) newowner->qnkeys++; newowner->qnbytes += key->quotalen; - spin_unlock(&newowner->lock); + spin_unlock_irqrestore(&newowner->lock, flags); - spin_lock(&key->user->lock); + spin_lock_irqsave(&key->user->lock, flags); key->user->qnkeys--; key->user->qnbytes -= key->quotalen; - spin_unlock(&key->user->lock); + spin_unlock_irqrestore(&key->user->lock, flags); } atomic_dec(&key->user->nkeys); @@ -1056,7 +1057,7 @@ error: return ret; quota_overrun: - spin_unlock(&newowner->lock); + spin_unlock_irqrestore(&newowner->lock, flags); zapowner = newowner; ret = -EDQUOT; goto error_put; -- cgit v1.2.3-70-g09d2