linux/security
David Howells 9c5e45df21 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>
2013-12-02 11:24:19 +00:00
..
apparmor Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-11-21 19:46:00 -08:00
integrity ima: store address of template_fmt_copy in a pointer before calling strsep 2013-11-30 13:09:53 +11:00
keys KEYS: Fix searching of nested keyrings 2013-12-02 11:24:19 +00:00
selinux Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-11-21 19:46:00 -08:00
smack Smack: Ptrace access check mode 2013-10-28 10:23:36 -07:00
tomoyo Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
yama yama: Better permission check for ptraceme 2013-03-26 13:17:58 -07:00
capability.c Merge branch 'master' of git://git.infradead.org/users/pcmoore/selinux into ra-next 2013-10-22 22:26:41 +11:00
commoncap.c capabilities: allow nice if we are privileged 2013-08-30 23:44:09 -07:00
device_cgroup.c device_cgroup: remove can_attach 2013-10-24 06:56:56 -04:00
inode.c securityfs: fix object creation races 2012-01-10 10:20:35 -05:00
Kconfig KEYS: Move the key config into security/keys/Kconfig 2012-05-11 10:56:56 +01:00
lsm_audit.c Merge git://git.infradead.org/users/eparis/audit 2013-11-21 19:18:14 -08:00
Makefile security: remove erroneous comment about capabilities.o link ordering 2013-09-24 11:26:28 +10:00
min_addr.c mmap_min_addr check CAP_SYS_RAWIO only for write 2010-04-23 08:56:31 +10:00
security.c Merge branch 'master' of git://git.infradead.org/users/pcmoore/selinux into ra-next 2013-10-22 22:26:41 +11:00