aboutsummaryrefslogtreecommitdiff
path: root/include/linux/netlink.h
AgeCommit message (Collapse)Author
2007-02-12[PATCH] eCryptfs: Public key transport mechanismMichael Halcrow
This is the transport code for public key functionality in eCryptfs. It manages encryption/decryption request queues with a transport mechanism. Currently, netlink is the only implemented transport. Each inode has a unique File Encryption Key (FEK). Under passphrase, a File Encryption Key Encryption Key (FEKEK) is generated from a salt/passphrase combo on mount. This FEKEK encrypts each FEK and writes it into the header of each file using the packet format specified in RFC 2440. This is all symmetric key encryption, so it can all be done via the kernel crypto API. These new patches introduce public key encryption of the FEK. There is no asymmetric key encryption support in the kernel crypto API, so eCryptfs pushes the FEK encryption and decryption out to a userspace daemon. After considering our requirements and determining the complexity of using various transport mechanisms, we settled on netlink for this communication. eCryptfs stores authentication tokens into the kernel keyring. These tokens correlate with individual keys. For passphrase mode of operation, the authentication token contains the symmetric FEKEK. For public key, the authentication token contains a PKI type and an opaque data blob managed by individual PKI modules in userspace. Each user who opens a file under an eCryptfs partition mounted in public key mode must be running a daemon. That daemon has the user's credentials and has access to all of the keys to which the user should have access. The daemon, when started, initializes the pluggable PKI modules available on the system and registers itself with the eCryptfs kernel module. Userspace utilities register public key authentication tokens into the user session keyring. These authentication tokens correlate key signatures with PKI modules and PKI blobs. The PKI blobs contain PKI-specific information necessary for the PKI module to carry out asymmetric key encryption and decryption. When the eCryptfs module parses the header of an existing file and finds a Tag 1 (Public Key) packet (see RFC 2440), it reads in the public key identifier (signature). The asymmetrically encrypted FEK is in the Tag 1 packet; eCryptfs puts together a decrypt request packet containing the signature and the encrypted FEK, then it passes it to the daemon registered for the current->euid via a netlink unicast to the PID of the daemon, which was registered at the time the daemon was started by the user. The daemon actually just makes calls to libecryptfs, which implements request packet parsing and manages PKI modules. libecryptfs grabs the public key authentication token for the given signature from the user session keyring. This auth tok tells libecryptfs which PKI module should receive the request. libecryptfs then makes a decrypt() call to the PKI module, and it passes along the PKI block from the auth tok. The PKI uses the blob to figure out how it should decrypt the data passed to it; it performs the decryption and passes the decrypted data back to libecryptfs. libecryptfs then puts together a reply packet with the decrypted FEK and passes that back to the eCryptfs module. The eCryptfs module manages these request callouts to userspace code via message context structs. The module maintains an array of message context structs and places the elements of the array on two lists: a free and an allocated list. When eCryptfs wants to make a request, it moves a msg ctx from the free list to the allocated list, sets its state to pending, and fires off the message to the user's registered daemon. When eCryptfs receives a netlink message (via the callback), it correlates the msg ctx struct in the alloc list with the data in the message itself. The msg->index contains the offset of the array of msg ctx structs. It verifies that the registered daemon PID is the same as the PID of the process that sent the message. It also validates a sequence number between the received packet and the msg ctx. Then, it copies the contents of the message (the reply packet) into the msg ctx struct, sets the state in the msg ctx to done, and wakes up the process that was sleeping while waiting for the reply. The sleeping process was whatever was performing the sys_open(). This process originally called ecryptfs_send_message(); it is now in ecryptfs_wait_for_response(). When it wakes up and sees that the msg ctx state was set to done, it returns a pointer to the message contents (the reply packet) and returns. If all went well, this packet contains the decrypted FEK, which is then copied into the crypt_stat struct, and life continues as normal. The case for creation of a new file is very similar, only instead of a decrypt request, eCryptfs sends out an encrypt request. > - We have a great clod of key mangement code in-kernel. Why is that > not suitable (or growable) for public key management? eCryptfs uses Howells' keyring to store persistent key data and PKI state information. It defers public key cryptographic transformations to userspace code. The userspace data manipulation request really is orthogonal to key management in and of itself. What eCryptfs basically needs is a secure way to communicate with a particular daemon for a particular task doing a syscall, based on the UID. Nothing running under another UID should be able to access that channel of communication. > - Is it appropriate that new infrastructure for public key > management be private to a particular fs? The messaging.c file contains a lot of code that, perhaps, could be extracted into a separate kernel service. In essence, this would be a sort of request/reply mechanism that would involve a userspace daemon. I am not aware of anything that does quite what eCryptfs does, so I was not aware of any existing tools to do just what we wanted. > What happens if one of these daemons exits without sending a quit > message? There is a stale uid<->pid association in the hash table for that user. When the user registers a new daemon, eCryptfs cleans up the old association and generates a new one. See ecryptfs_process_helo(). > - _why_ does it use netlink? Netlink provides the transport mechanism that would minimize the complexity of the implementation, given that we can have multiple daemons (one per user). I explored the possibility of using relayfs, but that would involve having to introduce control channels and a protocol for creating and tearing down channels for the daemons. We do not have to worry about any of that with netlink. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-02[NETLINK]: Remove unused dst_pid field in netlink_skb_parmsThomas Graf
The destination PID is passed directly to netlink_unicast() respectively netlink_multicast(). Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02[NETLINK]: Do precise netlink message allocations where possibleThomas Graf
Account for the netlink message header size directly in nlmsg_new() instead of relying on the caller calculate it correctly. Replaces error handling of message construction functions when constructing notifications with bug traps since a failure implies a bug in calculating the size of the skb. Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Paul Moore <paul.moore@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-02[SCSI] SCSI and FC Transport: add netlink support for posting of transport ↵James Smart
events This patch formally adds support for the posting of FC events via netlink. It is a followup to the original RFC at: http://marc.theaimsgroup.com/?l=linux-scsi&m=114530667923464&w=2 and the initial posting at: http://marc.theaimsgroup.com/?l=linux-scsi&m=115507374832500&w=2 The patch has been updated to optimize the send path, per the discussions in the initial posting. Per discussions at the Storage Summit and at OLS, we are to use netlink for async events from transports. Also per discussions, to avoid a netlink protocol per transport, I've create a single NETLINK_SCSITRANSPORT protocol, which can then be used by all transports. This patch: - Creates new files scsi_netlink.c and scsi_netlink.h, which contains the single and shared definitions for the SCSI Transport. It is tied into the base SCSI subsystem intialization. Contains a single interface routine, scsi_send_transport_event(), for a transport to send an event (via multicast to a protocol specific group). - Creates a new scsi_netlink_fc.h file, which contains the FC netlink event messages - Adds 3 new routines to the fc transport: fc_get_event_number() - to get a FC event # fc_host_post_event() - to send a simple FC event (32 bits of data) fc_host_post_vendor_event() - to send a Vendor unique event, with arbitrary amounts of data. Note: the separation of event number allows for a LLD to send a standard event, followed by vendor-specific data for the event. Note: This patch assumes 2 prior fc transport patches have been installed: http://marc.theaimsgroup.com/?l=linux-scsi&m=115555807316329&w=2 http://marc.theaimsgroup.com/?l=linux-scsi&m=115581614930261&w=2 Sorry - next time I'll do something like making these individual patches of the same posting when I know they'll be posted closely together. Signed-off-by: James Smart <James.Smart@emulex.com> Tidy up configuration not to make SCSI always select NET Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-06-22[PATCH] w1: netlink: Mark netlink group 1 as unused.Evgeniy Polyakov
netlink_w1 was moved to connector. Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-05-01[PATCH] Reworked patch for labels on user space messagesSteve Grubb
The below patch should be applied after the inode and ipc sid patches. This patch is a reworking of Tim's patch that has been updated to match the inode and ipc patches since its similar. [updated: > Stephen Smalley also wanted to change a variable from isec to tsec in the > user sid patch. ] Signed-off-by: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-20[NETLINK]: Add netlink_has_listeners for avoiding unneccessary event message ↵Patrick McHardy
generation Keep a bitmask of multicast groups with subscribed listeners to let netlink users check for listeners before generating multicast messages. Queries don't perform any locking, which may result in false positives, it is guaranteed however that any new subscriptions are visible before bind() or setsockopt() return. Signed-off-by: Patrick McHardy <kaber@trash.net> ACKed-by: Jamal Hadi Salim<hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-09[NETLINK]: Fix a severe bugAlexey Kuznetsov
netlink overrun was broken while improvement of netlink. Destination socket is used in the place where it was meant to be source socket, so that now overrun is never sent to user netlink sockets, when it should be, and it even can be set on kernel socket, which results in complete deadlock of rtnetlink. Suggested fix is to restore status quo passing source socket as additional argument to netlink_attachskb(). A little explanation: overrun is set on a socket, when it failed to receive some message and sender of this messages does not or even have no way to handle this error. This happens in two cases: 1. when kernel sends something. Kernel never retransmits and cannot wait for buffer space. 2. when user sends a broadcast and the message was not delivered to some recipients. Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[NETLINK]: Type-safe netlink messages/attributes interfaceThomas Graf
Introduces a new type-safe interface for netlink message and attributes handling. The interface is fully binary compatible with the old interface towards userspace. Besides type safety, this interface features attribute validation capabilities, simplified message contstruction, and documentation. The resulting netlink code should be smaller, less error prone and easier to understand. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-08[PATCH] gfp flags annotations - part 1Al Viro
- added typedef unsigned int __nocast gfp_t; - replaced __nocast uses for gfp flags with gfp_t - it gives exactly the same warnings as far as sparse is concerned, doesn't change generated code (from gcc point of view we replaced unsigned int with typedef) and documents what's going on far better. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-14[NETLINK]: Reserve a slot for NETLINK_GENERIC.David S. Miller
As requested by Jamal. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-11[NET]: Add netlink connector.Evgeniy Polyakov
Kernel connector - new userspace <-> kernel space easy to use communication module which implements easy to use bidirectional message bus using netlink as it's backend. Connector was created to eliminate complex skb handling both in send and receive message bus direction. Connector driver adds possibility to connect various agents using as one of it's backends netlink based network. One must register callback and identifier. When driver receives special netlink message with appropriate identifier, appropriate callback will be called. From the userspace point of view it's quite straightforward: socket(); bind(); send(); recv(); But if kernelspace want to use full power of such connections, driver writer must create special sockets, must know about struct sk_buff handling... Connector allows any kernelspace agents to use netlink based networking for inter-process communication in a significantly easier way: int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *)); void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask); struct cb_id { __u32 idx; __u32 val; }; idx and val are unique identifiers which must be registered in connector.h for in-kernel usage. void (*callback) (void *) - is a callback function which will be called when message with above idx.val will be received by connector core. Using connector completely hides low-level transport layer from it's users. Connector uses new netlink ability to have many groups in one socket. [ Incorporating many cleanups and fixes by myself and Andrew Morton -DaveM ] Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Fix sparse warningsArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Add "groups" argument to netlink_kernel_createPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Add set/getsockopt options to support more than 32 groupsPatrick McHardy
NETLINK_ADD_MEMBERSHIP/NETLINK_DROP_MEMBERSHIP are used to join/leave groups, NETLINK_PKTINFO is used to enable nl_pktinfo control messages for received packets to get the extended destination group number. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Use group numbers instead of bitmasks internallyPatrick McHardy
Using the group number allows increasing the number of groups without beeing limited by the size of the bitmask. It introduces one limitation for netlink users: messages can't be broadcasted to multiple groups anymore, however this feature was never used inside the kernel. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Remove unused groups member from struct netlink_skb_parmsPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[TCPDIAG]: Just rename everything to inet_diagArnaldo Carvalho de Melo
Next changeset will rename tcp_diag.[ch] to inet_diag.[ch]. I'm taking this longer route so as to easy review, making clear the changes made all along the way. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29[NETLINK]: Add properly module refcounting for kernel netlink sockets.Harald Welte
- Remove bogus code for compiling netlink as module - Add module refcounting support for modules implementing a netlink protocol - Add support for autoloading modules that implement a netlink protocol as soon as someone opens a socket for that protocol Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-08[NETLINK]: Allocate and kill some netlink numbers.David S. Miller
NETLINK_ARPD is unused, allocate it to the Open-iSCSI folks. NETLINK_ROUTE6 and NETLINK_TAPBASE are no longer used, delete them. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-24[W1]: Do not use NFLOG netlink number.David S. Miller
Use the reserved by never used NETLINK_SKIP value instead. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-11[NETLINK]: Reserve NETLINK_NETFILTER.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-28[NETLINK]: Clear padding in netlink messagesPatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-21[NETLINK]: netlink_callback structure needs 5 args not 4Alexey Kuznetsov
net/ipv4/tcp_diag.c uses up to ->args[4] Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-20[NETLINK]: fib_lookup() via netlinkRobert Olsson
Below is a more generic patch to do fib_lookup via netlink. For others we should say that we discussed this as a way to verify route selection. It's also possible there are others uses for this. In short the fist half of struct fib_result_nl is filled in by caller and netlink call fills in the other half and returns it. In case anyone is interested there is a corresponding user app to compare the full routing table this was used to test implementation of the LC-trie. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-18[NETLINK]: Introduce NLMSG_NEW macro to better handle netlink flagsThomas Graf
Introduces a new macro NLMSG_NEW which extends NLMSG_PUT but takes a flags argument. NLMSG_PUT stays there for compatibility but now calls NLMSG_NEW with flags == 0. NLMSG_PUT_ANSWER is renamed to NLMSG_NEW_ANSWER which now also takes a flags argument. Also converts the users of NLMSG_PUT_ANSWER to use NLMSG_NEW_ANSWER and fixes the two direct users of __nlmsg_put to either provide the flags or use NLMSG_NEW(_ANSWER). Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-18[NETLINK]: New message building macrosThomas Graf
NLMSG_PUT_ANSWER(skb, nlcb, type, length) Start a new netlink message as answer to a request, returns the message header. NLMSG_END(skb, nlh) End a netlink message, fixes total message length, returns skb->len. NLMSG_CANCEL(skb, nlh) Cancel the building process and trim whole message from skb again, returns -1. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-29Add audit uid to netlink credentialsSerge Hallyn
Most audit control messages are sent over netlink.In order to properly log the identity of the sender of audit control messages, we would like to add the loginuid to the netlink_creds structure, as per the attached patch. Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!