kernel/fs/lockd/clntproc.c, branch linux-5.1.y

Merge tag 'nfs-for-4.21-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

2019-01-03T00:35:23Z

Pull NFS client updates from Anna Schumaker: "Stable bugfixes: - xprtrdma: Yet another double DMA-unmap # v4.20 Features: - Allow some /proc/sys/sunrpc entries without CONFIG_SUNRPC_DEBUG - Per-xprt rdma receive workqueues - Drop support for FMR memory registration - Make port= mount option optional for RDMA mounts Other bugfixes and cleanups: - Remove unused nfs4_xdev_fs_type declaration - Fix comments for behavior that has changed - Remove generic RPC credentials by switching to 'struct cred' - Fix crossing mountpoints with different auth flavors - Various xprtrdma fixes from testing and auditing the close code - Fixes for disconnect issues when using xprtrdma with krb5 - Clean up and improve xprtrdma trace points - Fix NFS v4.2 async copy reboot recovery" * tag 'nfs-for-4.21-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (63 commits) sunrpc: convert to DEFINE_SHOW_ATTRIBUTE sunrpc: Add xprt after nfs4_test_session_trunk() sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS sunrpc: handle ENOMEM in rpcb_getport_async NFS: remove unnecessary test for IS_ERR(cred) xprtrdma: Prevent leak of rpcrdma_rep objects NFSv4.2 fix async copy reboot recovery xprtrdma: Don't leak freed MRs xprtrdma: Add documenting comment for rpcrdma_buffer_destroy xprtrdma: Replace outdated comment for rpcrdma_ep_post xprtrdma: Update comments in frwr_op_send SUNRPC: Fix some kernel doc complaints SUNRPC: Simplify defining common RPC trace events NFS: Fix NFSv4 symbolic trace point output xprtrdma: Trace mapping, alloc, and dereg failures xprtrdma: Add trace points for calls to transport switch methods xprtrdma: Relocate the xprtrdma_mr_map trace points xprtrdma: Clean up of xprtrdma chunk trace points xprtrdma: Remove unused fields from rpcrdma_ia xprtrdma: Cull dprintk() call sites ...

NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.

2018-12-19T18:52:46Z

SUNRPC has two sorts of credentials, both of which appear as "struct rpc_cred". There are "generic credentials" which are supplied by clients such as NFS and passed in 'struct rpc_message' to indicate which user should be used to authorize the request, and there are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS which describe the credential to be sent over the wires. This patch replaces all the generic credentials by 'struct cred' pointers - the credential structure used throughout Linux. For machine credentials, there is a special 'struct cred *' pointer which is statically allocated and recognized where needed as having a special meaning. A look-up of a low-level cred will map this to a machine credential. Signed-off-by: NeilBrown Acked-by: J. Bruce Fields Signed-off-by: Anna Schumaker

lockd: Show pid of lockd for remote locks

2018-12-14T17:52:16Z

Commit 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific l_pid for remote locks") specified that the l_pid returned for F_GETLK on a local file that has a remote lock should be the pid of the lock manager process. That commit, while updating other filesystems, failed to update lockd, such that locks created by lockd had their fl_pid set to that of the remote process holding the lock. Fix that here to be the pid of lockd. Also, fix the client case so that the returned lock pid is negative, which indicates a remote lock on a remote file. Fixes: 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific...") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Coddington Signed-off-by: J. Bruce Fields

nfsd: fix leaked file lock with nfs exported overlayfs

2018-08-09T20:11:21Z

nfsd and lockd call vfs_lock_file() to lock/unlock the inode returned by locks_inode(file). Many places in nfsd/lockd code use the inode returned by file_inode(file) for lock manipulation. With Overlayfs, file_inode() (the underlying inode) is not the same object as locks_inode() (the overlay inode). This can result in "Leaked POSIX lock" messages and eventually to a kernel crash as reported by Eddie Horng: https://marc.info/?l=linux-unionfs&m=153086643202072&w=2 Fix all the call sites in nfsd/lockd that should use locks_inode(). This is a correctness bug that manifested when overlayfs gained NFS export support in v4.16. Reported-by: Eddie Horng Tested-by: Eddie Horng Cc: Jeff Layton Fixes: 8383f1748829 ("ovl: wire up NFS export operations") Cc: stable@vger.kernel.org Signed-off-by: Amir Goldstein Signed-off-by: J. Bruce Fields

lockd: convert nlm_rqst.a_count from atomic_t to refcount_t

2018-01-15T04:06:30Z

atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable nlm_rqst.a_count is used as pure reference counter. Convert it to refcount_t and fix up the operations. **Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the nlm_rqst.a_count it might make a difference in following places: - nlmclnt_release_call() and nlmsvc_release_call(): decrement in refcount_dec_and_test() only provides RELEASE ordering and control dependency on success vs. fully ordered atomic counterpart Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: Trond Myklebust

lockd: convert nlm_lockowner.count from atomic_t to refcount_t

2018-01-15T04:06:29Z

atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable nlm_lockowner.count is used as pure reference counter. Convert it to refcount_t and fix up the operations. **Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the nlm_lockowner.count it might make a difference in following places: - nlm_put_lockowner(): decrement in refcount_dec_and_lock() only provides RELEASE ordering, control dependency on success and holds a spin lock on success vs. fully ordered atomic counterpart. No changes in spin lock guarantees. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: Trond Myklebust

lockd: Introduce nlmclnt_operations

2017-04-21T14:45:01Z

NFS would enjoy the ability to modify the behavior of the NLM client's unlock RPC task in order to delay the transmission of the unlock until IO that was submitted under that lock has completed. This ability can ensure that the NLM client will always complete the transmission of an unlock even if the waiting caller has been interrupted with fatal signal. For this purpose, a pointer to a struct nlmclnt_operations can be assigned in a nfs_module's nfs_rpc_ops that will install those nlmclnt_operations on the nlm_host. The struct nlmclnt_operations defines three callback operations that will be used in a following patch: nlmclnt_alloc_call - used to call back after a successful allocation of a struct nlm_rqst in nlmclnt_proc(). nlmclnt_unlock_prepare - used to call back during NLM unlock's rpc_call_prepare. The NLM client defers calling rpc_call_start() until this callback returns false. nlmclnt_release_call - used to call back when the NLM client's struct nlm_rqst is freed. Signed-off-by: Benjamin Coddington Reviewed-by: Jeff Layton Signed-off-by: Trond Myklebust

Move locks API users to locks_lock_inode_wait()

2015-10-22T18:57:36Z

Instead of having users check for FL_POSIX or FL_FLOCK to call the correct locks API function, use the check within locks_lock_inode_wait(). This allows for some later cleanup. Signed-off-by: Benjamin Coddington Signed-off-by: Jeff Layton

LOCKD: Don't call utsname()->nodename from nlmclnt_setlockargs

2013-08-05T19:03:46Z

Firstly, nlmclnt_setlockargs can be called from a reclaimer thread, in which case we're in entirely the wrong namespace. Secondly, commit 8aac62706adaaf0fab02c4327761561c8bda9448 (move exit_task_namespaces() outside of exit_notify()) now means that exit_task_work() is called after exit_task_namespaces(), which triggers an Oops when we're freeing up the locks. Fix this by ensuring that we initialise the nlm_host's rpc_client at mount time, so that the cl_nodename field is initialised to the value of utsname()->nodename that the net namespace uses. Then replace the lockd callers of utsname()->nodename. Signed-off-by: Trond Myklebust Cc: Toralf Förster Cc: Oleg Nesterov Cc: Nix Cc: Jeff Layton Cc: stable@vger.kernel.org # 3.10.x

LOCKD: Ensure that nlmclnt_block resets block->b_status after a server reboot

2013-04-21T22:08:42Z

After a server reboot, the reclaimer thread will recover all the existing locks. For locks that are blocked, however, it will change the value of block->b_status to nlm_lck_denied_grace_period in order to signal that they need to wake up and resend the original blocking lock request. Due to a bug, however, the block->b_status never gets reset after the blocked locks have been woken up, and so the process goes into an infinite loop of resends until the blocked lock is satisfied. Reported-by: Marc Eshel Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org