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path: root/security/keys/big_key.c
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2014-09-16KEYS: Remove key_type::match in favour of overriding default by match_preparseDavid Howells
A previous patch added a ->match_preparse() method to the key type. This is allowed to override the function called by the iteration algorithm. Therefore, we can just set a default that simply checks for an exact match of the key description with the original criterion data and allow match_preparse to override it as needed. The key_type::match op is then redundant and can be removed, as can the user_match() function. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-09-16KEYS: Remove key_type::def_lookup_typeDavid Howells
Remove key_type::def_lookup_type as it's no longer used. The information now defaults to KEYRING_SEARCH_LOOKUP_DIRECT but may be overridden by type->match_preparse(). Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-07-22KEYS: big_key: Use key preparsingDavid Howells
Make use of key preparsing in the big key type so that quota size determination can take place prior to keyring locking when a key is being added. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com>
2013-12-02security: shmem: implement kernel private shmem inodesEric Paris
We have a problem where the big_key key storage implementation uses a shmem backed inode to hold the key contents. Because of this detail of implementation LSM checks are being done between processes trying to read the keys and the tmpfs backed inode. The LSM checks are already being handled on the key interface level and should not be enforced at the inode level (since the inode is an implementation detail, not a part of the security model) This patch implements a new function shmem_kernel_file_setup() which returns the equivalent to shmem_file_setup() only the underlying inode has S_PRIVATE set. This means that all LSM checks for the inode in question are skipped. It should only be used for kernel internal operations where the inode is not exposed to userspace without proper LSM checking. It is possible that some other users of shmem_file_setup() should use the new interface, but this has not been explored. Reproducing this bug is a little bit difficult. The steps I used on Fedora are: (1) Turn off selinux enforcing: setenforce 0 (2) Create a huge key k=`dd if=/dev/zero bs=8192 count=1 | keyctl padd big_key test-key @s` (3) Access the key in another context: runcon system_u:system_r:httpd_t:s0-s0:c0.c1023 keyctl print $k >/dev/null (4) Examine the audit logs: ausearch -m AVC -i --subject httpd_t | audit2allow If the last command's output includes a line that looks like: allow httpd_t user_tmpfs_t:file { open read }; There was an inode check between httpd and the tmpfs filesystem. With this patch no such denial will be seen. (NOTE! you should clear your audit log if you have tested for this previously) (Please return you box to enforcing) Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Hugh Dickins <hughd@google.com> cc: linux-mm@kvack.org
2013-11-13KEYS: Fix error handling in big_key instantiationDavid Howells
In the big_key_instantiate() function we return 0 if kernel_write() returns us an error rather than returning an error. This can potentially lead to dentry_open() giving a BUG when called from big_key_read() with an unset tmpfile path. ------------[ cut here ]------------ kernel BUG at fs/open.c:798! ... RIP: 0010:[<ffffffff8119bbd1>] dentry_open+0xd1/0xe0 ... Call Trace: [<ffffffff812350c5>] big_key_read+0x55/0x100 [<ffffffff81231084>] keyctl_read_key+0xb4/0xe0 [<ffffffff81231e58>] SyS_keyctl+0xf8/0x1d0 [<ffffffff815bb799>] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Stephen Gallagher <sgallagh@redhat.com>
2013-10-30KEYS: fix error return code in big_key_instantiate()Wei Yongjun
Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: Implement a big key type that can save to tmpfsDavid Howells
Implement a big key type that can save its contents to tmpfs and thus swapspace when memory is tight. This is useful for Kerberos ticket caches. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Simo Sorce <simo@redhat.com>