kernel/linux.git/net/rxrpc/security.c, branch v6.12.80

rxrpc: Fix incoming call setup race

2023-01-07T09:30:26+00:00

An incoming call can race with rxrpc socket destruction, leading to a leaked call. This may result in an oops when the call timer eventually expires: BUG: kernel NULL pointer dereference, address: 0000000000000874 RIP: 0010:_raw_spin_lock_irqsave+0x2a/0x50 Call Trace: try_to_wake_up+0x59/0x550 ? __local_bh_enable_ip+0x37/0x80 ? rxrpc_poke_call+0x52/0x110 [rxrpc] ? rxrpc_poke_call+0x110/0x110 [rxrpc] ? rxrpc_poke_call+0x110/0x110 [rxrpc] call_timer_fn+0x24/0x120 with a warning in the kernel log looking something like: rxrpc: Call 00000000ba5e571a still in use (1,SvAwtACK,1061d,0)! incurred during rmmod of rxrpc. The 1061d is the call flags: RECVMSG_READ_ALL, RX_HEARD, BEGAN_RX_TIMER, RX_LAST, EXPOSED, IS_SERVICE, RELEASED but no DISCONNECTED flag (0x800), so it's an incoming (service) call and it's still connected. The race appears to be that: (1) rxrpc_new_incoming_call() consults the service struct, checks sk_state and allocates a call - then pauses, possibly for an interrupt. (2) rxrpc_release_sock() sets RXRPC_CLOSE, nulls the service pointer, discards the prealloc and releases all calls attached to the socket. (3) rxrpc_new_incoming_call() resumes, launching the new call, including its timer and attaching it to the socket. Fix this by read-locking local->services_lock to access the AF_RXRPC socket providing the service rather than RCU in rxrpc_new_incoming_call(). There's no real need to use RCU here as local->services_lock is only write-locked by the socket side in two places: when binding and when shutting down. Fixes: 5e6ef4f1017c ("rxrpc: Make the I/O thread take over the call and local processor work") Reported-by: Marc Dionne Signed-off-by: David Howells cc: linux-afs@lists.infradead.org

rxrpc: Move client call connection to the I/O thread

2023-01-06T09:43:33+00:00

Move the connection setup of client calls to the I/O thread so that a whole load of locking and barrierage can be eliminated. This necessitates the app thread waiting for connection to complete before it can begin encrypting data. This also completes the fix for a race that exists between call connection and call disconnection whereby the data transmission code adds the call to the peer error distribution list after the call has been disconnected (say by the rxrpc socket getting closed). The fix is to complete the process of moving call connection, data transmission and call disconnection into the I/O thread and thus forcibly serialising them. Note that the issue may predate the overhaul to an I/O thread model that were included in the merge window for v6.2, but the timing is very much changed by the change given below. Fixes: cf37b5987508 ("rxrpc: Move DATA transmission into call processor work item") Reported-by: syzbot+c22650d2844392afdcfd@syzkaller.appspotmail.com Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org

rxrpc: Tidy up abort generation infrastructure

2023-01-06T09:43:32+00:00

Tidy up the abort generation infrastructure in the following ways: (1) Create an enum and string mapping table to list the reasons an abort might be generated in tracing. (2) Replace the 3-char string with the values from (1) in the places that use that to log the abort source. This gets rid of a memcpy() in the tracepoint. (3) Subsume the rxrpc_rx_eproto tracepoint with the rxrpc_abort tracepoint and use values from (1) to indicate the trace reason. (4) Always make a call to an abort function at the point of the abort rather than stashing the values into variables and using goto to get to a place where it reported. The C optimiser will collapse the calls together as appropriate. The abort functions return a value that can be returned directly if appropriate. Note that this extends into afs also at the points where that generates an abort. To aid with this, the afs sources need to #define RXRPC_TRACE_ONLY_DEFINE_ENUMS before including the rxrpc tracing header because they don't have access to the rxrpc internal structures that some of the tracepoints make use of. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org

rxrpc: Fix security setting propagation

2022-12-19T09:51:31+00:00

Fix the propagation of the security settings from sendmsg to the rxrpc_call struct. Fixes: f3441d4125fc ("rxrpc: Copy client call parameters into rxrpc_call earlier") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller

rxrpc: Copy client call parameters into rxrpc_call earlier

2022-12-01T13:36:41+00:00

Copy client call parameters into rxrpc_call earlier so that that can be used to convey them to the connection code - which can then be offloaded to the I/O thread. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org

rxrpc: Drop rxrpc_conn_parameters from rxrpc_connection and rxrpc_bundle

2022-12-01T13:36:38+00:00

Remove the rxrpc_conn_parameters struct from the rxrpc_connection and rxrpc_bundle structs and emplace the members directly. These are going to get filled in from the rxrpc_call struct in future. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org

rxrpc: Hand server key parsing off to the security class

2020-11-23T18:09:29+00:00

Hand responsibility for parsing a server key off to the security class. We can determine which class from the description. This is necessary as rxgk server keys have different lookup requirements and different content requirements (dependent on crypto type) to those of rxkad server keys. Signed-off-by: David Howells

rxrpc: Don't retain the server key in the connection

2020-11-23T18:09:29+00:00

Don't retain a pointer to the server key in the connection, but rather get it on demand when the server has to deal with a response packet. This is necessary to implement RxGK (GSSAPI-mediated transport class), where we can't know which key we'll need until we've challenged the client and got back the response. This also means that we don't need to do a key search in the accept path in softirq mode. Also, whilst we're at it, allow the security class to ask for a kvno and encoding-type variant of a server key as RxGK needs different keys for different encoding types. Keys of this type have an extra bit in the description: ":::" Signed-off-by: David Howells

rxrpc: Support keys with multiple authentication tokens

2020-11-23T18:09:29+00:00

rxrpc-type keys can have multiple tokens attached for different security classes. Currently, rxrpc always picks the first one, whether or not the security class it indicates is supported. Add preliminary support for choosing which security class will be used (this will need to be directed from a higher layer) and go through the tokens to find one that's supported. Signed-off-by: David Howells

rxrpc: Fix missing security check on incoming calls

2019-12-20T16:21:32+00:00

Fix rxrpc_new_incoming_call() to check that we have a suitable service key available for the combination of service ID and security class of a new incoming call - and to reject calls for which we don't. This causes an assertion like the following to appear: rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false kernel BUG at net/rxrpc/call_object.c:456! Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than RXRPC_CALL_COMPLETE (12). Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Reported-by: Marc Dionne Signed-off-by: David Howells