blaster4385/linux-IllusionX/fs/nfsd, branch v6.12.10

nfsd: restore callback functionality for NFSv4.0

2025-01-02T09:34:11Z

[ Upstream commit 7917f01a286ce01e9c085e24468421f596ee1a0c ] A recent patch inadvertently broke callbacks for NFSv4.0. In the 4.0 case we do not expect a session to be found but still need to call setup_callback_client() which will not try to dereference it. This patch moves the check for failure to find a session into the 4.1+ branch of setup_callback_client() Fixes: 1e02c641c3a4 ("NFSD: Prevent NULL dereference in nfsd4_process_cb_update()") Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

nfsd: Revert "nfsd: release svc_expkey/svc_export with rcu_work"

2025-01-02T09:34:11Z

[ Upstream commit 69d803c40edeaf94089fbc8751c9b746cdc35044 ] This reverts commit f8c989a0c89a75d30f899a7cabdc14d72522bb8d. Before this commit, svc_export_put or expkey_put will call path_put with sync mode. After this commit, path_put will be called with async mode. And this can lead the unexpected results show as follow. mkfs.xfs -f /dev/sda echo "/ *(rw,no_root_squash,fsid=0)" > /etc/exports echo "/mnt *(rw,no_root_squash,fsid=1)" >> /etc/exports exportfs -ra service nfs-server start mount -t nfs -o vers=4.0 127.0.0.1:/mnt /mnt1 mount /dev/sda /mnt/sda touch /mnt1/sda/file exportfs -r umount /mnt/sda # failed unexcepted The touch will finally call nfsd_cross_mnt, add refcount to mount, and then add cache_head. Before this commit, exportfs -r will call cache_flush to cleanup all cache_head, and path_put in svc_export_put/expkey_put will be finished with sync mode. So, the latter umount will always success. However, after this commit, path_put will be called with async mode, the latter umount may failed, and if we add some delay, umount will success too. Personally I think this bug and should be fixed. We first revert before bugfix patch, and then fix the original bug with a different way. Fixes: f8c989a0c89a ("nfsd: release svc_expkey/svc_export with rcu_work") Signed-off-by: Yang Erkun Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

nfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur

2024-12-09T09:41:09Z

commit 98100e88dd8865999dc6379a3356cd799795fe7b upstream. The action force umount(umount -f) will attempt to kill all rpc_task even umount operation may ultimately fail if some files remain open. Consequently, if an action attempts to open a file, it can potentially send two rpc_task to nfs server. NFS CLIENT thread1 thread2 open("file") ... nfs4_do_open _nfs4_do_open _nfs4_open_and_get_state _nfs4_proc_open nfs4_run_open_task /* rpc_task1 */ rpc_run_task rpc_wait_for_completion_task umount -f nfs_umount_begin rpc_killall_tasks rpc_signal_task rpc_task1 been wakeup and return -512 _nfs4_do_open // while loop ... nfs4_run_open_task /* rpc_task2 */ rpc_run_task rpc_wait_for_completion_task While processing an open request, nfsd will first attempt to find or allocate an nfs4_openowner. If it finds an nfs4_openowner that is not marked as NFS4_OO_CONFIRMED, this nfs4_openowner will released. Since two rpc_task can attempt to open the same file simultaneously from the client to server, and because two instances of nfsd can run concurrently, this situation can lead to lots of memory leak. Additionally, when we echo 0 to /proc/fs/nfsd/threads, warning will be triggered. NFS SERVER nfsd1 nfsd2 echo 0 > /proc/fs/nfsd/threads nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // alloc oo1, stateid1 nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // find oo1, without NFS4_OO_CONFIRMED release_openowner unhash_openowner_locked list_del_init(&oo->oo_perclient) // cannot find this oo // from client, LEAK!!! alloc_stateowner // alloc oo2 nfsd4_process_open2 init_open_stateid // associate oo1 // with stateid1, stateid1 LEAK!!! nfs4_get_vfs_file // alloc nfsd_file1 and nfsd_file_mark1 // all LEAK!!! nfsd4_process_open2 ... write_threads ... nfsd_destroy_serv nfsd_shutdown_net nfs4_state_shutdown_net nfs4_state_destroy_net destroy_client __destroy_client // won't find oo1!!! nfsd_shutdown_generic nfsd_file_cache_shutdown kmem_cache_destroy for nfsd_file_slab and nfsd_file_mark_slab // bark since nfsd_file1 // and nfsd_file_mark1 // still alive ======================================================================= BUG nfsd_file (Not tainted): Objects remaining in nfsd_file on __kmem_cache_shutdown() ----------------------------------------------------------------------- Slab 0xffd4000004438a80 objects=34 used=1 fp=0xff11000110e2ad28 flags=0x17ffffc0000240(workingset|head|node=0|zone=2|lastcpupid=0x1fffff) CPU: 4 UID: 0 PID: 757 Comm: sh Not tainted 6.12.0-rc6+ #19 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: dump_stack_lvl+0x53/0x70 slab_err+0xb0/0xf0 __kmem_cache_shutdown+0x15c/0x310 kmem_cache_destroy+0x66/0x160 nfsd_file_cache_shutdown+0xac/0x210 [nfsd] nfsd_destroy_serv+0x251/0x2a0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1ae/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Disabling lock debugging due to kernel taint Object 0xff11000110e2ac38 @offset=3128 Allocated in nfsd_file_do_acquire+0x20f/0xa30 [nfsd] age=1635 cpu=3 pid=800 nfsd_file_do_acquire+0x20f/0xa30 [nfsd] nfsd_file_acquire_opened+0x5f/0x90 [nfsd] nfs4_get_vfs_file+0x4c9/0x570 [nfsd] nfsd4_process_open2+0x713/0x1070 [nfsd] nfsd4_open+0x74b/0x8b0 [nfsd] nfsd4_proc_compound+0x70b/0xc20 [nfsd] nfsd_dispatch+0x1b4/0x3a0 [nfsd] svc_process_common+0x5b8/0xc50 [sunrpc] svc_process+0x2ab/0x3b0 [sunrpc] svc_handle_xprt+0x681/0xa20 [sunrpc] nfsd+0x183/0x220 [nfsd] kthread+0x199/0x1e0 ret_from_fork+0x31/0x60 ret_from_fork_asm+0x1a/0x30 Add nfs4_openowner_unhashed to help found unhashed nfs4_openowner, and break nfsd4_open process to fix this problem. Cc: stable@vger.kernel.org # v5.4+ Reviewed-by: Jeff Layton Signed-off-by: Yang Erkun Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: make sure exp active before svc_export_show

2024-12-09T09:41:09Z

commit be8f982c369c965faffa198b46060f8853e0f1f0 upstream. The function `e_show` was called with protection from RCU. This only ensures that `exp` will not be freed. Therefore, the reference count for `exp` can drop to zero, which will trigger a refcount use-after-free warning when `exp_get` is called. To resolve this issue, use `cache_get_rcu` to ensure that `exp` remains active. ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 3 PID: 819 at lib/refcount.c:25 refcount_warn_saturate+0xb1/0x120 CPU: 3 UID: 0 PID: 819 Comm: cat Not tainted 6.12.0-rc3+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcount_warn_saturate+0xb1/0x120 ... Call Trace: e_show+0x20b/0x230 [nfsd] seq_read_iter+0x589/0x770 seq_read+0x1e5/0x270 vfs_read+0x125/0x530 ksys_read+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: bf18f163e89c ("NFSD: Using exp_get for export getting") Cc: stable@vger.kernel.org # 4.20+ Signed-off-by: Yang Erkun Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

NFSD: Prevent a potential integer overflow

2024-12-05T13:03:02Z

commit 7f33b92e5b18e904a481e6e208486da43e4dc841 upstream. If the tag length is >= U32_MAX - 3 then the "length + 4" addition can result in an integer overflow. Address this by splitting the decoding into several steps so that decode_cb_compound4res() does not have to perform arithmetic on the unsafe length value. Reported-by: Dan Carpenter Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfs_common: must not hold RCU while calling nfsd_file_put_local

2024-12-05T13:02:27Z

[ Upstream commit c840b8e1f039e90f97ca55525667eb961422f86c ] Move holding the RCU from nfs_to_nfsd_file_put_local to nfs_to_nfsd_net_put. It is the call to nfs_to->nfsd_serv_put that requires the RCU anyway (the puts for nfsd_file and netns were combined to avoid an extra indirect reference but that micro-optimization isn't possible now). This fixes xfstests generic/013 and it triggering: "Voluntary context switch within RCU read-side critical section!" [ 143.545738] Call Trace: [ 143.546206] [ 143.546625] ? show_regs+0x6d/0x80 [ 143.547267] ? __warn+0x91/0x140 [ 143.547951] ? rcu_note_context_switch+0x496/0x5d0 [ 143.548856] ? report_bug+0x193/0x1a0 [ 143.549557] ? handle_bug+0x63/0xa0 [ 143.550214] ? exc_invalid_op+0x1d/0x80 [ 143.550938] ? asm_exc_invalid_op+0x1f/0x30 [ 143.551736] ? rcu_note_context_switch+0x496/0x5d0 [ 143.552634] ? wakeup_preempt+0x62/0x70 [ 143.553358] __schedule+0xaa/0x1380 [ 143.554025] ? _raw_spin_unlock_irqrestore+0x12/0x40 [ 143.554958] ? try_to_wake_up+0x1fe/0x6b0 [ 143.555715] ? wake_up_process+0x19/0x20 [ 143.556452] schedule+0x2e/0x120 [ 143.557066] schedule_preempt_disabled+0x19/0x30 [ 143.557933] rwsem_down_read_slowpath+0x24d/0x4a0 [ 143.558818] ? xfs_efi_item_format+0x50/0xc0 [xfs] [ 143.559894] down_read+0x4e/0xb0 [ 143.560519] xlog_cil_commit+0x1b2/0xbc0 [xfs] [ 143.561460] ? _raw_spin_unlock+0x12/0x30 [ 143.562212] ? xfs_inode_item_precommit+0xc7/0x220 [xfs] [ 143.563309] ? xfs_trans_run_precommits+0x69/0xd0 [xfs] [ 143.564394] __xfs_trans_commit+0xb5/0x330 [xfs] [ 143.565367] xfs_trans_roll+0x48/0xc0 [xfs] [ 143.566262] xfs_defer_trans_roll+0x57/0x100 [xfs] [ 143.567278] xfs_defer_finish_noroll+0x27a/0x490 [xfs] [ 143.568342] xfs_defer_finish+0x1a/0x80 [xfs] [ 143.569267] xfs_bunmapi_range+0x4d/0xb0 [xfs] [ 143.570208] xfs_itruncate_extents_flags+0x13d/0x230 [xfs] [ 143.571353] xfs_free_eofblocks+0x12e/0x190 [xfs] [ 143.572359] xfs_file_release+0x12d/0x140 [xfs] [ 143.573324] __fput+0xe8/0x2d0 [ 143.573922] __fput_sync+0x1d/0x30 [ 143.574574] nfsd_filp_close+0x33/0x60 [nfsd] [ 143.575430] nfsd_file_free+0x96/0x150 [nfsd] [ 143.576274] nfsd_file_put+0xf7/0x1a0 [nfsd] [ 143.577104] nfsd_file_put_local+0x18/0x30 [nfsd] [ 143.578070] nfs_close_local_fh+0x101/0x110 [nfs_localio] [ 143.579079] __put_nfs_open_context+0xc9/0x180 [nfs] [ 143.580031] nfs_file_clear_open_context+0x4a/0x60 [nfs] [ 143.581038] nfs_file_release+0x3e/0x60 [nfs] [ 143.581879] __fput+0xe8/0x2d0 [ 143.582464] __fput_sync+0x1d/0x30 [ 143.583108] __x64_sys_close+0x41/0x80 [ 143.583823] x64_sys_call+0x189a/0x20d0 [ 143.584552] do_syscall_64+0x64/0x170 [ 143.585240] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 143.586185] RIP: 0033:0x7f3c5153efd7 Fixes: 65f2a5c36635 ("nfs_common: fix race in NFS calls to nfsd_file_put_local() and nfsd_serv_put()") Signed-off-by: Mike Snitzer Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFSD: Fix nfsd4_shutdown_copy()

2024-12-05T13:02:26Z

[ Upstream commit 62a8642ba00aa8ceb0a02ade942f5ec52e877c95 ] nfsd4_shutdown_copy() is just this: while ((copy = nfsd4_get_copy(clp)) != NULL) nfsd4_stop_copy(copy); nfsd4_get_copy() bumps @copy's reference count, preventing nfsd4_stop_copy() from releasing @copy. A while loop like this usually works by removing the first element of the list, but neither nfsd4_get_copy() nor nfsd4_stop_copy() alters the async_copies list. Best I can tell, then, is that nfsd4_shutdown_copy() continues to loop until other threads manage to remove all the items from this list. The spinning loop blocks shutdown until these items are gone. Possibly the reason we haven't seen this issue in the field is because client_has_state() prevents __destroy_client() from calling nfsd4_shutdown_copy() if there are any items on this list. In a subsequent patch I plan to remove that restriction. Fixes: e0639dc5805a ("NFSD introduce async copy feature") Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

nfsd: release svc_expkey/svc_export with rcu_work

2024-12-05T13:02:26Z

[ Upstream commit f8c989a0c89a75d30f899a7cabdc14d72522bb8d ] The last reference for `cache_head` can be reduced to zero in `c_show` and `e_show`(using `rcu_read_lock` and `rcu_read_unlock`). Consequently, `svc_export_put` and `expkey_put` will be invoked, leading to two issues: 1. The `svc_export_put` will directly free ex_uuid. However, `e_show`/`c_show` will access `ex_uuid` after `cache_put`, which can trigger a use-after-free issue, shown below. ================================================================== BUG: KASAN: slab-use-after-free in svc_export_show+0x362/0x430 [nfsd] Read of size 1 at addr ff11000010fdc120 by task cat/870 CPU: 1 UID: 0 PID: 870 Comm: cat Not tainted 6.12.0-rc3+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: dump_stack_lvl+0x53/0x70 print_address_description.constprop.0+0x2c/0x3a0 print_report+0xb9/0x280 kasan_report+0xae/0xe0 svc_export_show+0x362/0x430 [nfsd] c_show+0x161/0x390 [sunrpc] seq_read_iter+0x589/0x770 seq_read+0x1e5/0x270 proc_reg_read+0xe1/0x140 vfs_read+0x125/0x530 ksys_read+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Allocated by task 830: kasan_save_stack+0x20/0x40 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 __kmalloc_node_track_caller_noprof+0x1bc/0x400 kmemdup_noprof+0x22/0x50 svc_export_parse+0x8a9/0xb80 [nfsd] cache_do_downcall+0x71/0xa0 [sunrpc] cache_write_procfs+0x8e/0xd0 [sunrpc] proc_reg_write+0xe1/0x140 vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 868: kasan_save_stack+0x20/0x40 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x37/0x50 kfree+0xf3/0x3e0 svc_export_put+0x87/0xb0 [nfsd] cache_purge+0x17f/0x1f0 [sunrpc] nfsd_destroy_serv+0x226/0x2d0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e 2. We cannot sleep while using `rcu_read_lock`/`rcu_read_unlock`. However, `svc_export_put`/`expkey_put` will call path_put, which subsequently triggers a sleeping operation due to the following `dput`. ============================= WARNING: suspicious RCU usage 5.10.0-dirty #141 Not tainted ----------------------------- ... Call Trace: dump_stack+0x9a/0xd0 ___might_sleep+0x231/0x240 dput+0x39/0x600 path_put+0x1b/0x30 svc_export_put+0x17/0x80 e_show+0x1c9/0x200 seq_read_iter+0x63f/0x7c0 seq_read+0x226/0x2d0 vfs_read+0x113/0x2c0 ksys_read+0xc9/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1 Fix these issues by using `rcu_work` to help release `svc_expkey`/`svc_export`. This approach allows for an asynchronous context to invoke `path_put` and also facilitates the freeing of `uuid/exp/key` after an RCU grace period. Fixes: 9ceddd9da134 ("knfsd: Allow lockless lookups of the exports") Signed-off-by: Yang Erkun Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFSD: Cap the number of bytes copied by nfs4_reset_recoverydir()

2024-12-05T13:02:26Z

[ Upstream commit f64ea4af43161bb86ffc77e6aeb5bcf5c3229df0 ] It's only current caller already length-checks the string, but let's be safe. Fixes: 0964a3d3f1aa ("[PATCH] knfsd: nfsd4 reboot dirname fix") Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

NFSD: Prevent NULL dereference in nfsd4_process_cb_update()

2024-12-05T13:02:26Z

[ Upstream commit 1e02c641c3a43c88cecc08402000418e15578d38 ] @ses is initialized to NULL. If __nfsd4_find_backchannel() finds no available backchannel session, setup_callback_client() will try to dereference @ses and segfault. Fixes: dcbeaa68dbbd ("nfsd4: allow backchannel recovery") Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin