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authorDavid Howells <dhowells@redhat.com>2013-12-02 11:24:19 +0000
committerDavid Howells <dhowells@redhat.com>2013-12-02 11:24:19 +0000
commit9c5e45df215b4788f7a41c983ce862d08a083c2d (patch)
tree8cc80b01bfd2501b21e84688f4d34bb9516a17da /security
parent23fd78d76415729b338ff1802a0066b4a62f7fb8 (diff)
KEYS: Fix searching of nested keyrings
If a keyring contains more than 16 keyrings (the capacity of a single node in the associative array) then those keyrings are split over multiple nodes arranged as a tree. If search_nested_keyrings() is called to search the keyring then it will attempt to manually walk over just the 0 branch of the associative array tree where all the keyring links are stored. This works provided the key is found before the algorithm steps from one node containing keyrings to a child node or if there are sufficiently few keyring links that the keyrings are all in one node. However, if the algorithm does need to step from a node to a child node, it doesn't change the node pointer unless a shortcut also gets transited. This means that the algorithm will keep scanning the same node over and over again without terminating and without returning. To fix this, move the internal-pointer-to-node translation from inside the shortcut transit handler so that it applies it to node arrival as well. This can be tested by: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done for ((i=17; i<=20; i++)); do keyctl search $r user a$i; done The searches should all complete successfully (or with an error for 17-20), but instead one or more of them will hang. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Stephen Gallagher <sgallagh@redhat.com>
Diffstat (limited to 'security')
-rw-r--r--security/keys/keyring.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 3dd8445cd489..d46cbc5e335e 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -690,8 +690,8 @@ descend_to_node:
smp_read_barrier_depends();
ptr = ACCESS_ONCE(shortcut->next_node);
BUG_ON(!assoc_array_ptr_is_node(ptr));
- node = assoc_array_ptr_to_node(ptr);
}
+ node = assoc_array_ptr_to_node(ptr);
begin_node:
kdebug("begin_node");

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