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| author | David Howells <dhowells@redhat.com> | 2012-01-18 19:31:45 +0400 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2012-01-19 07:38:51 +0400 |
| commit | 700920eb5ba4de5417b446c9a8bb008df2b973e0 (patch) | |
| tree | 8e2caa32a5cdcd47347ff84bc3e95915d000f537 /Documentation | |
| parent | 53999bf34d55981328f8ba9def558d3e104d6e36 (diff) | |
| download | linux-700920eb5ba4de5417b446c9a8bb008df2b973e0.tar.xz | |
KEYS: Allow special keyrings to be cleared
The kernel contains some special internal keyrings, for instance the DNS
resolver keyring :
2a93faf1 I----- 1 perm 1f030000 0 0 keyring .dns_resolver: empty
It would occasionally be useful to allow the contents of such keyrings to be
flushed by root (cache invalidation).
Allow a flag to be set on a keyring to mark that someone possessing the
sysadmin capability can clear the keyring, even without normal write access to
the keyring.
Set this flag on the special keyrings created by the DNS resolver, the NFS
identity mapper and the CIFS identity mapper.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/dns_resolver.txt | 4 | ||||
| -rw-r--r-- | Documentation/security/keys.txt | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/networking/dns_resolver.txt b/Documentation/networking/dns_resolver.txt index 7f531ad83285..d86adcdae420 100644 --- a/Documentation/networking/dns_resolver.txt +++ b/Documentation/networking/dns_resolver.txt @@ -102,6 +102,10 @@ implemented in the module can be called after doing: If _expiry is non-NULL, the expiry time (TTL) of the result will be returned also. +The kernel maintains an internal keyring in which it caches looked up keys. +This can be cleared by any process that has the CAP_SYS_ADMIN capability by +the use of KEYCTL_KEYRING_CLEAR on the keyring ID. + =============================== READING DNS KEYS FROM USERSPACE diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 4d75931d2d79..713ec232c562 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -554,6 +554,10 @@ The keyctl syscall functions are: process must have write permission on the keyring, and it must be a keyring (or else error ENOTDIR will result). + This function can also be used to clear special kernel keyrings if they + are appropriately marked if the user has CAP_SYS_ADMIN capability. The + DNS resolver cache keyring is an example of this. + (*) Link a key into a keyring: |