Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KEYS: Invert FINAL_PUT bit
Invert the FINAL_PUT bit so that test_bit_acquire and clear_bit_unlock
can be used instead of smp_mb.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
authored by
Herbert Xu
and committed by
Linus Torvalds
488ef356
aef17cb3
+6
-5
+1
-1
include/linux/key.h
+1
-1
include/linux/key.h
···
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#define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */
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#define KEY_FLAG_KEEP 8 /* set if key should not be removed */
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#define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */
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-
#define KEY_FLAG_FINAL_PUT 10 /* set if final put has happened on key */
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+
#define KEY_FLAG_USER_ALIVE 10 /* set if final put has not happened on key yet */
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/* the key type and key description string
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* - the desc is used to match a key against search criteria
+2
-2
security/keys/gc.c
+2
-2
security/keys/gc.c
···
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key = rb_entry(cursor, struct key, serial_node);
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cursor = rb_next(cursor);
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-
if (test_bit(KEY_FLAG_FINAL_PUT, &key->flags)) {
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-
smp_mb(); /* Clobber key->user after FINAL_PUT seen. */
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+
if (!test_bit_acquire(KEY_FLAG_USER_ALIVE, &key->flags)) {
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+
/* Clobber key->user after final put seen. */
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goto found_unreferenced_key;
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}
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+3
-2
security/keys/key.c
+3
-2
security/keys/key.c
···
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key->restrict_link = restrict_link;
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key->last_used_at = ktime_get_real_seconds();
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+
key->flags |= 1 << KEY_FLAG_USER_ALIVE;
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
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key->flags |= 1 << KEY_FLAG_IN_QUOTA;
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if (flags & KEY_ALLOC_BUILT_IN)
···
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key->user->qnbytes -= key->quotalen;
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spin_unlock_irqrestore(&key->user->lock, flags);
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}
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-
smp_mb(); /* key->user before FINAL_PUT set. */
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-
set_bit(KEY_FLAG_FINAL_PUT, &key->flags);
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+
/* Mark key as safe for GC after key->user done. */
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+
clear_bit_unlock(KEY_FLAG_USER_ALIVE, &key->flags);
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schedule_work(&key_gc_work);
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664
}
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665
}