52 lines
1.8 KiB
Diff
52 lines
1.8 KiB
Diff
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From 7707055082a7005ad94ba81e5240644db8c0324a
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From: David Howells <dhowells@redhat.com>
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Date: Tue Jan 26 16:28:17 2016 +0000
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Subject: [PATCH] KEYS: Only apply KEY_FLAG_KEEP to a key if a parent keyring has it set
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KEY_FLAG_KEEP should only be applied to a key if the keyring it is being
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linked into has KEY_FLAG_KEEP set.
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To this end, partially revert the following patch:
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commit 1d6d167c2efcfe9539d9cffb1a1be9c92e39c2c0
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Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
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Date: Thu Jan 7 07:46:36 2016 -0500
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KEYS: refcount bug fix
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to undo the change that made it unconditional (Mimi got it right the first
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time).
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Without undoing this change, it becomes impossible to delete, revoke or
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invalidate keys added to keyrings through __key_instantiate_and_link()
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where the keyring has itself been linked to. To test this, run the
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following command sequence:
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keyctl newring foo @s
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keyctl add user a a %:foo
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keyctl unlink %user:a %:foo
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keyctl clear %:foo
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With the commit mentioned above the third and fourth commands fail with
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EPERM when they should succeed.
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Reported-by: Stephen Gallager <sgallagh@redhat.com>
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Signed-off-by: David Howells <dhowells@redhat.com>
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cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
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cc: keyrings@vger.kernel.org
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cc: stable@vger.kernel.org
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diff --git a/security/keys/key.c b/security/keys/key.c
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index 07a87311055c..09ef276c4bdc 100644
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--- a/security/keys/key.c
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+++ b/security/keys/key.c
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@@ -430,7 +430,8 @@ static int __key_instantiate_and_link(struct key *key,
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/* and link it into the destination keyring */
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if (keyring) {
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- set_bit(KEY_FLAG_KEEP, &key->flags);
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+ if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
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+ set_bit(KEY_FLAG_KEEP, &key->flags);
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__key_link(key, _edit);
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}
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