From: ebiggers3@gmail.com (Eric Biggers)
To: linux-security-module@vger.kernel.org
Subject: [PATCH v2 1/6] KEYS: fix race between updating and finding negative key
Date: Tue, 26 Sep 2017 13:39:09 -0700 [thread overview]
Message-ID: <20170926203909.GA126069@gmail.com> (raw)
In-Reply-To: <20170926201105.126166-2-ebiggers3@gmail.com>
On Tue, Sep 26, 2017 at 01:11:00PM -0700, Eric Biggers wrote:
> +static void mark_key_instantiated(struct key *key, unsigned int reject_error)
> +{
> + unsigned long old, new;
> +
> + do {
> + old = READ_ONCE(key->flags);
> + new = (old & ~(KEY_FLAG_NEGATIVE |
> + KEY_FLAGS_REJECT_ERROR_MASK)) |
> + KEY_FLAG_INSTANTIATED |
> + (reject_error ? KEY_FLAG_NEGATIVE : 0) |
> + (reject_error << KEY_FLAGS_REJECT_ERROR_SHIFT);
> + } while (cmpxchg_release(&key->flags, old, new) != old);
> +}
Sorry, I realized I screwed this up --- the flags like KEY_FLAG_NEGATIVE need to
be (1 << KEY_FLAG_NEGATIVE). I'll send another version which will be better
tested...
Eric
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next prev parent reply other threads:[~2017-09-26 20:39 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-26 20:10 [PATCH v2 0/6] KEYS: fix atomicity issues with key flags Eric Biggers
2017-09-26 20:11 ` [PATCH v2 1/6] KEYS: fix race between updating and finding negative key Eric Biggers
2017-09-26 20:39 ` Eric Biggers [this message]
2017-09-26 20:11 ` [PATCH v2 2/6] KEYS: load key flags atomically in key_is_instantiated() Eric Biggers
2017-09-26 20:11 ` [PATCH v2 3/6] KEYS: load key flags and expiry time atomically in key_validate() Eric Biggers
2017-09-26 20:11 ` [PATCH v2 4/6] KEYS: load key flags and expiry time atomically in keyring_search_iterator() Eric Biggers
2017-09-26 20:11 ` [PATCH v2 5/6] KEYS: load key flags and expiry time atomically in proc_keys_show() Eric Biggers
2017-09-26 20:11 ` [PATCH v2 6/6] KEYS: remove KEY_FLAG_NEGATIVE Eric Biggers
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