KEYS: The request_key() syscall should link an existing key to the dest keyring
in [Kernel]
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From: David Howells on 27 Apr 2010 06:20 Andrew Morton <akpm(a)linux-foundation.org> wrote: > I don't think I understand that description. Are you saying that the > patch switches things from the first example output into the second case? request_key() system call is meant to recursively search all your keyrings for the key you desire, and, optionally, if it doesn't exist, call out to userspace to create one for you. If request_key() finds or creates a key, it should, optionally, create a link to that key from the destination keyring specified. Therefore, if, after a successful call to request_key() with a desination keyring specified, you see the destination keyring empty, the code didn't work correctly. If you see the found key in the keyring, then it did - which is what the patch is required for. > Is the fix needed in -stable? Yes. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: David Howells on 28 Apr 2010 11:00 Vegard Nossum <vegard.nossum(a)gmail.com> wrote: > 1. Is it correct to return -EINPROGRESS in this case? Yes - it prevents construct_key_and_link() from going on to call construct_key(). The key in question is returned in *_key. However, I don't think I handle other errors coming back from construct_alloc_key() correctly. > 2. (Why) Shouldn't the return value of __key_link() be checked? It should. In fact, I should probably precheck and preallocate the keyring to make sure I don't get errors after allocating the new key. > 3. In __key_link(), shouldn't rcu_dereference() be used when accessing > keyring->payload.subscriptions? No. We have to hold a write lock on the keyring semaphore if we're going to call __key_link() to add something to it. We should, however, call rcu_dereference_protected(). You should find a patch for this in your inbox. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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