When a key description argument is imported into the kernel from userspace, as happens in add_key(), request_key(), KEYCTL_JOIN_SESSION_KEYRING, KEYCTL_SEARCH, the description is copied into a buffer up to PAGE_SIZE in size. PAGE_SIZE, however, is a variable quantity, depending on the arch. Fix this at 4096 instead (ie. 4095 plus a NUL termination) and define a constant (KEY_MAX_DESC_SIZE) to this end. When reading the description back with KEYCTL_DESCRIBE, a PAGE_SIZE internal buffer is allocated into which the information and description will be rendered. This means that the description will get truncated if an extremely long description it has to be crammed into the buffer with the stringified information. There is no particular need to copy the description into the buffer, so just copy it directly to userspace in a separate operation. Reported-by: Christian Kastner <debian@kvr.at> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Christian Kastner <debian@kvr.at>
Reinstate the generation of EPERM for a key type name beginning with a '.' in a userspace call. Types whose name begins with a '.' are internal only. The test was removed by: commit a4e3b8d79a5c6d40f4a9703abf7fe3abcc6c3b8d Author: Mimi Zohar <zohar@linux.vnet.ibm.com> Date: Thu May 22 14:02:23 2014 -0400 Subject: KEYS: special dot prefixed keyring name bug fix I think we want to keep the restriction on type name so that userspace can't add keys of a special internal type. Note that removal of the test causes several of the tests in the keyutils testsuite to fail. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Special kernel keys, such as those used to hold DNS results for AFS, CIFS and NFS and those used to hold idmapper results for NFS, used to be 'invalidateable' with key_revoke(). However, since the default permissions for keys were reduced: Commit: 96b5c8fea6c0861621051290d705ec2e971963f1 KEYS: Reduce initial permissions on keys it has become impossible to do this. Add a key flag (KEY_FLAG_ROOT_CAN_INVAL) that will permit a key to be invalidated by root. This should not be used for system keyrings as the garbage collector will try and remove any invalidate key. For system keyrings, KEY_FLAG_ROOT_CAN_CLEAR can be used instead. After this, from userspace, keyctl_invalidate() and "keyctl invalidate" can be used by any possessor of CAP_SYS_ADMIN (typically root) to invalidate DNS and idmapper keys. Invalidated keys are immediately garbage collected and will be immediately rerequested if needed again. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Steve Dickson <steved@redhat.com>
Dot prefixed keyring names are supposed to be reserved for the kernel, but add_key() calls key_get_type_from_user(), which incorrectly verifies the 'type' field, not the 'description' field. This patch verifies the 'description' field isn't dot prefixed, when creating a new keyring, and removes the dot prefix test in key_get_type_from_user(). Changelog v6: - whitespace and other cleanup Changelog v5: - Only prevent userspace from creating a dot prefixed keyring, not regular keys - Dmitry Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: David Howells <dhowells@redhat.com>
Move the flags representing required permission to linux/key.h as the perm
parameter of security_key_permission() is in terms of them - and not the
permissions mask flags used in key->perm.
Whilst we're at it:
(1) Rename them to be KEY_NEED_xxx rather than KEY_xxx to avoid collisions
with symbols in uapi/linux/input.h.
(2) Don't use key_perm_t for a mask of required permissions, but rather limit
it to the permissions mask attached to the key and arguments related
directly to that.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Add support for per-user_namespace registers of persistent per-UID kerberos caches held within the kernel. This allows the kerberos cache to be retained beyond the life of all a user's processes so that the user's cron jobs can work. The kerberos cache is envisioned as a keyring/key tree looking something like: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 big_key - A ccache blob \___ tkt12345 big_key - Another ccache blob Or possibly: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 keyring - A ccache \___ krbtgt/REDHAT.COM@REDHAT.COM big_key \___ http/REDHAT.COM@REDHAT.COM user \___ afs/REDHAT.COM@REDHAT.COM user \___ nfs/REDHAT.COM@REDHAT.COM user \___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key \___ http/KERNEL.ORG@KERNEL.ORG big_key What goes into a particular Kerberos cache is entirely up to userspace. Kernel support is limited to giving you the Kerberos cache keyring that you want. The user asks for their Kerberos cache by: krb_cache = keyctl_get_krbcache(uid, dest_keyring); The uid is -1 or the user's own UID for the user's own cache or the uid of some other user's cache (requires CAP_SETUID). This permits rpc.gssd or whatever to mess with the cache. The cache returned is a keyring named "_krb.<uid>" that the possessor can read, search, clear, invalidate, unlink from and add links to. Active LSMs get a chance to rule on whether the caller is permitted to make a link. Each uid's cache keyring is created when it first accessed and is given a timeout that is extended each time this function is called so that the keyring goes away after a while. The timeout is configurable by sysctl but defaults to three days. Each user_namespace struct gets a lazily-created keyring that serves as the register. The cache keyrings are added to it. This means that standard key search and garbage collection facilities are available. The user_namespace struct's register goes away when it does and anything left in it is then automatically gc'd. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Simo Sorce <simo@redhat.com> cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com>
Faster kernel compiles by way of fewer unnecessary includes. [akpm@linux-foundation.org: fix fallout] [akpm@linux-foundation.org: fix build] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull security subsystem updates from James Morris: "A quiet cycle for the security subsystem with just a few maintenance updates." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: Smack: create a sysfs mount point for smackfs Smack: use select not depends in Kconfig Yama: remove locking from delete path Yama: add RCU to drop read locking drivers/char/tpm: remove tasklet and cleanup KEYS: Use keyring_alloc() to create special keyrings KEYS: Reduce initial permissions on keys KEYS: Make the session and process keyrings per-thread seccomp: Make syscall skipping and nr changes more consistent key: Fix resource leak keys: Fix unreachable code KEYS: Add payload preparsing opportunity prior to key instantiate or update
Pull module signing support from Rusty Russell: "module signing is the highlight, but it's an all-over David Howells frenzy..." Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG. * 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits) X.509: Fix indefinite length element skip error handling X.509: Convert some printk calls to pr_devel asymmetric keys: fix printk format warning MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking MODSIGN: Make mrproper should remove generated files. MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs MODSIGN: Use the same digest for the autogen key sig as for the module sig MODSIGN: Sign modules during the build process MODSIGN: Provide a script for generating a key ID from an X.509 cert MODSIGN: Implement module signature checking MODSIGN: Provide module signing public keys to the kernel MODSIGN: Automatically generate module signing keys if missing MODSIGN: Provide Kconfig options MODSIGN: Provide gitignore and make clean rules for extra files MODSIGN: Add FIPS policy module: signature checking hook X.509: Add a crypto key parser for binary (DER) X.509 certificates MPILIB: Provide a function to read raw data into an MPI X.509: Add an ASN.1 decoder X.509: Add simple ASN.1 grammar compiler ...