linux-dev/net/rxrpc/recvmsg.c, branch linus/master

rxrpc: Fix decision on when to generate an IDLE ACK

2022-05-22T20:30:53Z

Fix the decision on when to generate an IDLE ACK by keeping a count of the number of packets we've received, but not yet soft-ACK'd, and the number of packets we've processed, but not yet hard-ACK'd, rather than trying to keep track of which DATA sequence numbers correspond to those points. We then generate an ACK when either counter exceeds 2. The counters are both cleared when we transcribe the information into any sort of ACK packet for transmission. IDLE and DELAY ACKs are skipped if both counters are 0 (ie. no change). Fixes: 805b21b929e2 ("rxrpc: Send an ACK after every few DATA packets we receive") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller

afs: Don't truncate iter during data fetch

2021-04-23T09:17:26Z

Don't truncate the iterator to correspond to the actual data size when fetching the data from the server - rather, pass the length we want to read to rxrpc. This will allow the clear-after-read code in future to simply clear the remaining iterator capacity rather than having to reinitialise the iterator. Signed-off-by: David Howells Tested-By: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/158861249201.340223.13035445866976590375.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465825061.1377938.14403904452300909320.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588531418.3465195.10712005940763063144.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118148567.1232039.13380313332292947956.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161044610.2537118.17908520793806837792.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340407907.1303470.6501394859511712746.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539551721.286939.14655713136572200716.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653807790.2770958.14034599989374173734.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789090823.6155.15673999934535049102.stgit@warthog.procyon.org.uk/ # v6

net: rxrpc: convert comma to semicolon

2020-12-10T00:23:07Z

Replace a comma between expression statements by a semicolon. Signed-off-by: Zheng Yongjun Reviewed-by: David Howells Signed-off-by: David S. Miller

rxrpc: Fix accept on a connection that need securing

2020-10-05T15:35:57Z

When a new incoming call arrives at an userspace rxrpc socket on a new connection that has a security class set, the code currently pushes it onto the accept queue to hold a ref on it for the socket. This doesn't work, however, as recvmsg() pops it off, notices that it's in the SERVER_SECURING state and discards the ref. This means that the call runs out of refs too early and the kernel oopses. By contrast, a kernel rxrpc socket manually pre-charges the incoming call pool with calls that already have user call IDs assigned, so they are ref'd by the call tree on the socket. Change the mode of operation for userspace rxrpc server sockets to work like this too. Although this is a UAPI change, server sockets aren't currently functional. Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Signed-off-by: David Howells

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59Z

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

rxrpc: Fix race between recvmsg and sendmsg on immediate call failure

2020-07-30T23:50:20Z

There's a race between rxrpc_sendmsg setting up a call, but then failing to send anything on it due to an error, and recvmsg() seeing the call completion occur and trying to return the state to the user. An assertion fails in rxrpc_recvmsg() because the call has already been released from the socket and is about to be released again as recvmsg deals with it. (The recvmsg_q queue on the socket holds a ref, so there's no problem with use-after-free.) We also have to be careful not to end up reporting an error twice, in such a way that both returns indicate to userspace that the user ID supplied with the call is no longer in use - which could cause the client to malfunction if it recycles the user ID fast enough. Fix this by the following means: (1) When sendmsg() creates a call after the point that the call has been successfully added to the socket, don't return any errors through sendmsg(), but rather complete the call and let recvmsg() retrieve them. Make sendmsg() return 0 at this point. Further calls to sendmsg() for that call will fail with ESHUTDOWN. Note that at this point, we haven't send any packets yet, so the server doesn't yet know about the call. (2) If sendmsg() returns an error when it was expected to create a new call, it means that the user ID wasn't used. (3) Mark the call disconnected before marking it completed to prevent an oops in rxrpc_release_call(). (4) recvmsg() will then retrieve the error and set MSG_EOR to indicate that the user ID is no longer known by the kernel. An oops like the following is produced: kernel BUG at net/rxrpc/recvmsg.c:605! ... RIP: 0010:rxrpc_recvmsg+0x256/0x5ae ... Call Trace: ? __init_waitqueue_head+0x2f/0x2f ____sys_recvmsg+0x8a/0x148 ? import_iovec+0x69/0x9c ? copy_msghdr_from_user+0x5c/0x86 ___sys_recvmsg+0x72/0xaa ? __fget_files+0x22/0x57 ? __fget_light+0x46/0x51 ? fdget+0x9/0x1b do_recvmmsg+0x15e/0x232 ? _raw_spin_unlock+0xa/0xb ? vtime_delta+0xf/0x25 __x64_sys_recvmmsg+0x2c/0x2f do_syscall_64+0x4c/0x78 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 357f5ef64628 ("rxrpc: Call rxrpc_release_call() on error in rxrpc_new_client_call()") Reported-by: syzbot+b54969381df354936d96@syzkaller.appspotmail.com Signed-off-by: David Howells Reviewed-by: Marc Dionne Signed-off-by: David S. Miller

rxrpc: Fix sendmsg() returning EPIPE due to recvmsg() returning ENODATA

2020-07-21T00:47:10Z

rxrpc_sendmsg() returns EPIPE if there's an outstanding error, such as if rxrpc_recvmsg() indicating ENODATA if there's nothing for it to read. Change rxrpc_recvmsg() to return EAGAIN instead if there's nothing to read as this particular error doesn't get stored in ->sk_err by the networking core. Also change rxrpc_sendmsg() so that it doesn't fail with delayed receive errors (there's no way for it to report which call, if any, the error was caused by). Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells Signed-off-by: David S. Miller

rxrpc: Fix missing notification

2020-06-05T12:36:35Z

Under some circumstances, rxrpc will fail a transmit a packet through the underlying UDP socket (ie. UDP sendmsg returns an error). This may result in a call getting stuck. In the instance being seen, where AFS tries to send a probe to the Volume Location server, tracepoints show the UDP Tx failure (in this case returing error 99 EADDRNOTAVAIL) and then nothing more: afs_make_vl_call: c=0000015d VL.GetCapabilities rxrpc_call: c=0000015d NWc u=1 sp=rxrpc_kernel_begin_call+0x106/0x170 [rxrpc] a=00000000dd89ee8a rxrpc_call: c=0000015d Gus u=2 sp=rxrpc_new_client_call+0x14f/0x580 [rxrpc] a=00000000e20e4b08 rxrpc_call: c=0000015d SEE u=2 sp=rxrpc_activate_one_channel+0x7b/0x1c0 [rxrpc] a=00000000e20e4b08 rxrpc_call: c=0000015d CON u=2 sp=rxrpc_kernel_begin_call+0x106/0x170 [rxrpc] a=00000000e20e4b08 rxrpc_tx_fail: c=0000015d r=1 ret=-99 CallDataNofrag The problem is that if the initial packet fails and the retransmission timer hasn't been started, the call is set to completed and an error is returned from rxrpc_send_data_packet() to rxrpc_queue_packet(). Though rxrpc_instant_resend() is called, this does nothing because the call is marked completed. So rxrpc_notify_socket() isn't called and the error is passed back up to rxrpc_send_data(), rxrpc_kernel_send_data() and thence to afs_make_call() and afs_vl_get_capabilities() where it is simply ignored because it is assumed that the result of a probe will be collected asynchronously. Fileserver probing is similarly affected via afs_fs_get_capabilities(). Fix this by always issuing a notification in __rxrpc_set_call_completion() if it shifts a call to the completed state, even if an error is also returned to the caller through the function return value. Also put in a little bit of optimisation to avoid taking the call state_lock and disabling softirqs if the call is already in the completed state and remove some now redundant rxrpc_notify_socket() calls. Fixes: f5c17aaeb2ae ("rxrpc: Calls should only have one terminal state") Reported-by: Gerry Seidman Signed-off-by: David Howells Reviewed-by: Marc Dionne

rxrpc: Move the call completion handling out of line

2020-06-05T12:36:35Z

Move the handling of call completion out of line so that the next patch can add more code in that area. Signed-off-by: David Howells Reviewed-by: Marc Dionne

rxrpc: Fix handling of last subpacket of jumbo packet

2019-10-31T19:23:09Z

When rxrpc_recvmsg_data() sets the return value to 1 because it's drained all the data for the last packet, it checks the last-packet flag on the whole packet - but this is wrong, since the last-packet flag is only set on the final subpacket of the last jumbo packet. This means that a call that receives its last packet in a jumbo packet won't complete properly. Fix this by having rxrpc_locate_data() determine the last-packet state of the subpacket it's looking at and passing that back to the caller rather than having the caller look in the packet header. The caller then needs to cache this in the rxrpc_call struct as rxrpc_locate_data() isn't then called again for this packet. Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Fixes: e2de6c404898 ("rxrpc: Use info in skbuff instead of reparsing a jumbo packet") Signed-off-by: David Howells Signed-off-by: David S. Miller