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2025-05-02virtiofs: add filesystem context source name checkXiangsheng Hou1-0/+3
commit a94fd938df2b1628da66b498aa0eeb89593bc7a2 upstream. In certain scenarios, for example, during fuzz testing, the source name may be NULL, which could lead to a kernel panic. Therefore, an extra check for the source name should be added. Fixes: a62a8ef9d97d ("virtio-fs: add virtiofs filesystem") Cc: <stable@vger.kernel.org> # all LTS kernels Signed-off-by: Xiangsheng Hou <xiangsheng.hou@mediatek.com> Link: https://lore.kernel.org/20250407115111.25535-1-xiangsheng.hou@mediatek.com Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-10fuse: don't truncate cached, mutated symlinkMiklos Szeredi1-1/+1
[ Upstream commit b4c173dfbb6c78568578ff18f9e8822d7bd0e31b ] Fuse allows the value of a symlink to change and this property is exploited by some filesystems (e.g. CVMFS). It has been observed, that sometimes after changing the symlink contents, the value is truncated to the old size. This is caused by fuse_getattr() racing with fuse_reverse_inval_inode(). fuse_reverse_inval_inode() updates the fuse_inode's attr_version, which results in fuse_change_attributes() exiting before updating the cached attributes This is okay, as the cached attributes remain invalid and the next call to fuse_change_attributes() will likely update the inode with the correct values. The reason this causes problems is that cached symlinks will be returned through page_get_link(), which truncates the symlink to inode->i_size. This is correct for filesystems that don't mutate symlinks, but in this case it causes bad behavior. The solution is to just remove this truncation. This can cause a regression in a filesystem that relies on supplying a symlink larger than the file size, but this is unlikely. If that happens we'd need to make this behavior conditional. Reported-by: Laura Promberger <laura.promberger@cern.ch> Tested-by: Sam Lewis <samclewis@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20250220100258.793363-1-mszeredi@redhat.com Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12fuse: use unsigned type for getxattr/listxattr size truncationJann Horn1-2/+2
commit b18915248a15eae7d901262f108d6ff0ffb4ffc1 upstream. The existing code uses min_t(ssize_t, outarg.size, XATTR_LIST_MAX) when parsing the FUSE daemon's response to a zero-length getxattr/listxattr request. On 32-bit kernels, where ssize_t and outarg.size are the same size, this is wrong: The min_t() will pass through any size values that are negative when interpreted as signed. fuse_listxattr() will then return this userspace-supplied negative value, which callers will treat as an error value. This kind of bug pattern can lead to fairly bad security bugs because of how error codes are used in the Linux kernel. If a caller were to convert the numeric error into an error pointer, like so: struct foo *func(...) { int len = fuse_getxattr(..., NULL, 0); if (len < 0) return ERR_PTR(len); ... } then it would end up returning this userspace-supplied negative value cast to a pointer - but the caller of this function wouldn't recognize it as an error pointer (IS_ERR_VALUE() only detects values in the narrow range in which legitimate errno values are), and so it would just be treated as a kernel pointer. I think there is at least one theoretical codepath where this could happen, but that path would involve virtio-fs with submounts plus some weird SELinux configuration, so I think it's probably not a concern in practice. Cc: stable@vger.kernel.org # v4.9 Fixes: 63401ccdb2ca ("fuse: limit xattr returned size") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-12fuse: update stats for pages in dropped aux writeback listJoanne Koong1-1/+7
commit f7790d67785302b3116bbbfda62a5a44524601a3 upstream. In the case where the aux writeback list is dropped (e.g. the pages have been truncated or the connection is broken), the stats for its pages and backing device info need to be updated as well. Fixes: e2653bd53a98 ("fuse: fix leaked aux requests") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Cc: <stable@vger.kernel.org> # v5.1 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-04virtiofs: forbid newlines in tagsStefan Hajnoczi1-0/+10
[ Upstream commit 40488cc16f7ea0d193a4e248f0d809c25cc377db ] Newlines in virtiofs tags are awkward for users and potential vectors for string injection attacks. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-04fuse: Initialize beyond-EOF page contents before setting uptodateJann Horn1-2/+4
commit 3c0da3d163eb32f1f91891efaade027fa9b245b9 upstream. fuse_notify_store(), unlike fuse_do_readpage(), does not enable page zeroing (because it can be used to change partial page contents). So fuse_notify_store() must be more careful to fully initialize page contents (including parts of the page that are beyond end-of-file) before marking the page uptodate. The current code can leave beyond-EOF page contents uninitialized, which makes these uninitialized page contents visible to userspace via mmap(). This is an information leak, but only affects systems which do not enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the corresponding kernel command line parameter). Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2574 Cc: stable@kernel.org Fixes: a1d75f258230 ("fuse: add store request") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-19fuse: verify {g,u}id mount options correctlyEric Sandeen1-4/+20
[ Upstream commit 525bd65aa759ec320af1dc06e114ed69733e9e23 ] As was done in 0200679fc795 ("tmpfs: verify {g,u}id mount options correctly") we need to validate that the requested uid and/or gid is representable in the filesystem's idmapping. Cribbing from the above commit log, The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, fuse has been doing the correct thing. But since fuse is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock. Fixes: c30da2e981a7 ("fuse: convert to use the new mount API") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Eric Sandeen <sandeen@redhat.com> Link: https://lore.kernel.org/r/8f07d45d-c806-484d-a2e3-7a2199df1cd2@redhat.com Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-19fuse: name fs_context consistentlyMiklos Szeredi3-41/+41
[ Upstream commit 84c215075b5723ab946708a6c74c26bd3c51114c ] Naming convention under fs/fuse/: struct fuse_conn *fc; struct fs_context *fsc; Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Stable-dep-of: 525bd65aa759 ("fuse: verify {g,u}id mount options correctly") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13fuse: don't unhash rootMiklos Szeredi2-3/+5
[ Upstream commit b1fe686a765e6c0d71811d825b5a1585a202b777 ] The root inode is assumed to be always hashed. Do not unhash the root inode even if it is marked BAD. Fixes: 5d069dbe8aaf ("fuse: fix bad inode") Cc: <stable@vger.kernel.org> # v5.11 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13fuse: fix root lookup with nonzero generationMiklos Szeredi1-0/+4
[ Upstream commit 68ca1b49e430f6534d0774a94147a823e3b8b26e ] The root inode has a fixed nodeid and generation (1, 0). Prior to the commit 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") generation number on lookup was ignored. After this commit lookup with the wrong generation number resulted in the inode being unhashed. This is correct for non-root inodes, but replacing the root inode is wrong and results in weird behavior. Fix by reverting to the old behavior if ignoring the generation for the root inode, but issuing a warning in dmesg. Reported-by: Antonio SJ Musumeci <trapexit@spawn.link> Closes: https://lore.kernel.org/all/CAOQ4uxhek5ytdN8Yz2tNEOg5ea4NkBb4nk0FGPjPk_9nz-VG3g@mail.gmail.com/ Fixes: 15db16837a35 ("fuse: fix illegal access to inode with reused nodeid") Cc: <stable@vger.kernel.org> # v5.14 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-20fuse: dax: set fc->dax to NULL in fuse_dax_conn_free()Hangyu Hua1-0/+1
commit 7f8ed28d1401320bcb02dda81b3c23ab2dc5a6d8 upstream. fuse_dax_conn_free() will be called when fuse_fill_super_common() fails after fuse_dax_conn_alloc(). Then deactivate_locked_super() in virtio_fs_get_tree() will call virtio_kill_sb() to release the discarded superblock. This will call fuse_dax_conn_free() again in fuse_conn_put(), resulting in a possible double free. Fixes: 1dd539577c42 ("virtiofs: add a mount option to enable dax") Signed-off-by: Hangyu Hua <hbh25y@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Cc: <stable@vger.kernel.org> # v5.10 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-09-19fuse: nlookup missing decrement in fuse_direntplus_linkruanmeisi1-1/+9
commit b8bd342d50cbf606666488488f9fea374aceb2d5 upstream. During our debugging of glusterfs, we found an Assertion failed error: inode_lookup >= nlookup, which was caused by the nlookup value in the kernel being greater than that in the FUSE file system. The issue was introduced by fuse_direntplus_link, where in the function, fuse_iget increments nlookup, and if d_splice_alias returns failure, fuse_direntplus_link returns failure without decrementing nlookup https://github.com/gluster/glusterfs/pull/4081 Signed-off-by: ruanmeisi <ruan.meisi@zte.com.cn> Fixes: 0b05b18381ee ("fuse: implement NFS-like readdirplus support") Cc: <stable@vger.kernel.org> # v3.9 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27fuse: revalidate: don't invalidate if interruptedMiklos Szeredi1-1/+1
commit a9d1c4c6df0e568207907c04aed9e7beb1294c42 upstream. If the LOOKUP request triggered from fuse_dentry_revalidate() is interrupted, then the dentry will be invalidated, possibly resulting in submounts being unmounted. Reported-by: Xu Rongbo <xurongbo@baidu.com> Closes: https://lore.kernel.org/all/CAJfpegswN_CJJ6C3RZiaK6rpFmNyWmXfaEpnQUJ42KCwNF5tWw@mail.gmail.com/ Fixes: 9e6268db496a ("[PATCH] FUSE - read-write operations") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26fuse: fix deadlock between atomic O_TRUNC and page invalidationMiklos Szeredi2-12/+22
commit 2fdbb8dd01556e1501132b5ad3826e8f71e24a8b upstream. fuse_finish_open() will be called with FUSE_NOWRITE set in case of atomic O_TRUNC open(), so commit 76224355db75 ("fuse: truncate pagecache on atomic_o_trunc") replaced invalidate_inode_pages2() by truncate_pagecache() in such a case to avoid the A-A deadlock. However, we found another A-B-B-A deadlock related to the case above, which will cause the xfstests generic/464 testcase hung in our virtio-fs test environment. For example, consider two processes concurrently open one same file, one with O_TRUNC and another without O_TRUNC. The deadlock case is described below, if open(O_TRUNC) is already set_nowrite(acquired A), and is trying to lock a page (acquiring B), open() could have held the page lock (acquired B), and waiting on the page writeback (acquiring A). This would lead to deadlocks. open(O_TRUNC) ---------------------------------------------------------------- fuse_open_common inode_lock [C acquire] fuse_set_nowrite [A acquire] fuse_finish_open truncate_pagecache lock_page [B acquire] truncate_inode_page unlock_page [B release] fuse_release_nowrite [A release] inode_unlock [C release] ---------------------------------------------------------------- open() ---------------------------------------------------------------- fuse_open_common fuse_finish_open invalidate_inode_pages2 lock_page [B acquire] fuse_launder_page fuse_wait_on_page_writeback [A acquire & release] unlock_page [B release] ---------------------------------------------------------------- Besides this case, all calls of invalidate_inode_pages2() and invalidate_inode_pages2_range() in fuse code also can deadlock with open(O_TRUNC). Fix by moving the truncate_pagecache() call outside the nowrite protected region. The nowrite protection is only for delayed writeback (writeback_cache) case, where inode lock does not protect against truncation racing with writes on the server. Write syscalls racing with page cache truncation still get the inode lock protection. This patch also changes the order of filemap_invalidate_lock() vs. fuse_set_nowrite() in fuse_open_common(). This new order matches the order found in fuse_file_fallocate() and fuse_do_setattr(). Reported-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com> Tested-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com> Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26fuse: always revalidate rename target dentryJiachen Zhang1-1/+1
commit ccc031e26afe60d2a5a3d93dabd9c978210825fb upstream. The previous commit df8629af2934 ("fuse: always revalidate if exclusive create") ensures that the dentries are revalidated on O_EXCL creates. This commit complements it by also performing revalidation for rename target dentries. Otherwise, a rename target file that only exists in kernel dentry cache but not in the filesystem will result in EEXIST if RENAME_NOREPLACE flag is used. Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com> Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26fuse: fix attr version comparison in fuse_read_update_size()Miklos Szeredi1-1/+1
commit 484ce65715b06aead8c4901f01ca32c5a240bc71 upstream. A READ request returning a short count is taken as indication of EOF, and the cached file size is modified accordingly. Fix the attribute version checking to allow for changes to fc->attr_version on other inodes. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26fuse: check s_root when destroying sbMiklos Szeredi2-2/+2
commit d534d31d6a45d71de61db22090b4820afb68fddc upstream. Checking "fm" works because currently sb->s_fs_info is cleared on error paths; however, sb->s_root is what generic_shutdown_super() checks to determine whether the sb was fully initialized or not. This change will allow cleanup of sb setup error paths. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26virtiofs: split requests that exceed virtqueue sizeConnor Kuehl3-3/+22
commit a7f0d7aab0b4f3f0780b1f77356e2fe7202ac0cb upstream. If an incoming FUSE request can't fit on the virtqueue, the request is placed onto a workqueue so a worker can try to resubmit it later where there will (hopefully) be space for it next time. This is fine for requests that aren't larger than a virtqueue's maximum capacity. However, if a request's size exceeds the maximum capacity of the virtqueue (even if the virtqueue is empty), it will be doomed to a life of being placed on the workqueue, removed, discovered it won't fit, and placed on the workqueue yet again. Furthermore, from section 2.6.5.3.1 (Driver Requirements: Indirect Descriptors) of the virtio spec: "A driver MUST NOT create a descriptor chain longer than the Queue Size of the device." To fix this, limit the number of pages FUSE will use for an overall request. This way, each request can realistically fit on the virtqueue when it is decomposed into a scattergather list and avoid violating section 2.6.5.3.1 of the virtio spec. Signed-off-by: Connor Kuehl <ckuehl@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26virtiofs: clean up error handling in virtio_fs_get_tree()Miklos Szeredi1-13/+12
commit 833c5a42e28beeefa1f9bd476a63fe8050c1e8ca upstream. Avoid duplicating error cleanup. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Yang Bo <yb203166@antfin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-19fuse: always revalidate if exclusive createMiklos Szeredi1-1/+1
commit df8629af293493757beccac2d3168fe5a315636e upstream. Failure to do so may result in EEXIST even if the file only exists in the cache and not in the filesystem. The atomic nature of O_EXCL mandates that the cached state should be ignored and existence verified anew. Reported-by: Ken Schalk <kschalk@nvidia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Wu Bo <bo.wu@vivo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-02fuse: lock inode unconditionally in fuse_fallocate()Miklos Szeredi1-20/+16
commit 44361e8cf9ddb23f17bdcc40ca944abf32e83e79 upstream. file_modified() must be called with inode lock held. fuse_fallocate() didn't lock the inode in case of just FALLOC_KEEP_SIZE flags value, which resulted in a kernel Warning in notify_change(). Lock the inode unconditionally, like all other fallocate implementations do. Reported-by: Pengfei Xu <pengfei.xu@intel.com> Reported-and-tested-by: syzbot+462da39f0667b357c4b6@syzkaller.appspotmail.com Fixes: 4a6f278d4827 ("fuse: add file_modified() to fallocate") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-16fuse: fix readdir cache raceMiklos Szeredi1-1/+9
[ Upstream commit 9fa248c65bdbf5af0a2f74dd38575acfc8dfd2bf ] There's a race in fuse's readdir cache that can result in an uninitilized page being read. The page lock is supposed to prevent this from happening but in the following case it doesn't: Two fuse_add_dirent_to_cache() start out and get the same parameters (size=0,offset=0). One of them wins the race to create and lock the page, after which it fills in data, sets rdc.size and unlocks the page. In the meantime the page gets evicted from the cache before the other instance gets to run. That one also creates the page, but finds the size to be mismatched, bails out and leaves the uninitialized page in the cache. Fix by marking a filled page uptodate and ignoring non-uptodate pages. Reported-by: Frank Sorenson <fsorenso@redhat.com> Fixes: 5d7bc7e8680c ("fuse: allow using readdir cache") Cc: <stable@vger.kernel.org> # v4.20 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-10fuse: add file_modified() to fallocateMiklos Szeredi1-0/+4
commit 4a6f278d4827b59ba26ceae0ff4529ee826aa258 upstream. Add missing file_modified() call to fuse_file_fallocate(). Without this fallocate on fuse failed to clear privileges. Fixes: 05ba1f082300 ("fuse: add FALLOCATE operation") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-21fuse: Remove the control interface for virtio-fsXie Yongji1-2/+2
[ Upstream commit c64797809a64c73497082aa05e401a062ec1af34 ] The commit 15c8e72e88e0 ("fuse: allow skipping control interface and forced unmount") tries to remove the control interface for virtio-fs since it does not support aborting requests which are being processed. But it doesn't work now. This patch fixes it by skipping creating the control interface if fuse_conn->no_control is set. Fixes: 15c8e72e88e0 ("fuse: allow skipping control interface and forced unmount") Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-21fuse: limit nsecMiklos Szeredi1-0/+6
commit 47912eaa061a6a81e4aa790591a1874c650733c0 upstream. Limit nanoseconds to 0..999999999. Fixes: d8a5ba45457e ("[PATCH] FUSE - core") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16fuse: fix pipe buffer lifetime for direct_ioMiklos Szeredi3-1/+13
commit 0c4bcfdecb1ac0967619ee7ff44871d93c08c909 upstream. In FOPEN_DIRECT_IO mode, fuse_file_write_iter() calls fuse_direct_write_iter(), which normally calls fuse_direct_io(), which then imports the write buffer with fuse_get_user_pages(), which uses iov_iter_get_pages() to grab references to userspace pages instead of actually copying memory. On the filesystem device side, these pages can then either be read to userspace (via fuse_dev_read()), or splice()d over into a pipe using fuse_dev_splice_read() as pipe buffers with &nosteal_pipe_buf_ops. This is wrong because after fuse_dev_do_read() unlocks the FUSE request, the userspace filesystem can mark the request as completed, causing write() to return. At that point, the userspace filesystem should no longer have access to the pipe buffer. Fix by copying pages coming from the user address space to new pipe buffers. Reported-by: Jann Horn <jannh@google.com> Fixes: c3021629a0d8 ("fuse: support splice() reading from fuse device") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-27fuse: Pass correct lend value to filemap_write_and_wait_range()Xie Yongji1-1/+1
commit e388164ea385f04666c4633f5dc4f951fca71890 upstream. The acceptable maximum value of lend parameter in filemap_write_and_wait_range() is LLONG_MAX rather than -1. And there is also some logic depending on LLONG_MAX check in write_cache_pages(). So let's pass LLONG_MAX to filemap_write_and_wait_range() in fuse_writeback_range() instead. Fixes: 59bda8ecee2f ("fuse: flush extending writes") Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Cc: <stable@vger.kernel.org> # v5.15 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-22fuse: annotate lock in fuse_reverse_inval_entry()Miklos Szeredi1-1/+1
commit bda9a71980e083699a0360963c0135657b73f47a upstream. Add missing inode lock annotatation; found by syzbot. Reported-and-tested-by: syzbot+9f747458f5990eaa8d43@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-17fuse: make sure reclaim doesn't write the inodeMiklos Szeredi4-0/+27
commit 5c791fe1e2a4f401f819065ea4fc0450849f1818 upstream. In writeback cache mode mtime/ctime updates are cached, and flushed to the server using the ->write_inode() callback. Closing the file will result in a dirty inode being immediately written, but in other cases the inode can remain dirty after all references are dropped. This result in the inode being written back from reclaim, which can deadlock on a regular allocation while the request is being served. The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because serving a request involves unrelated userspace process(es). Instead do the same as for dirty pages: make sure the inode is written before the last reference is gone. - fallocate(2)/copy_file_range(2): these call file_update_time() or file_modified(), so flush the inode before returning from the call - unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so flush the ctime directly from this helper Reported-by: chenguanyou <chenguanyou@xiaomi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: Ed Tsai <ed.tsai@mediatek.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01fuse: release pipe buf after last useMiklos Szeredi1-5/+5
commit 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 upstream. Checking buf->flags should be done before the pipe_buf_release() is called on the pipe buffer, since releasing the buffer might modify the flags. This is exactly what page_cache_pipe_buf_release() does, and which results in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was trying to fix. Reported-by: Justin Forbes <jmforbes@linuxtx.org> Fixes: 712a951025c0 ("fuse: fix page stealing") Cc: <stable@vger.kernel.org> # v2.6.35 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-18fuse: fix page stealingMiklos Szeredi1-2/+12
commit 712a951025c0667ff00b25afc360f74e639dfabe upstream. It is possible to trigger a crash by splicing anon pipe bufs to the fuse device. The reason for this is that anon_pipe_buf_release() will reuse buf->page if the refcount is 1, but that page might have already been stolen and its flags modified (e.g. PG_lru added). This happens in the unlikely case of fuse_dev_splice_write() getting around to calling pipe_buf_release() after a page has been stolen, added to the page cache and removed from the page cache. Fix by calling pipe_buf_release() right after the page was inserted into the page cache. In this case the page has an elevated refcount so any release function will know that the page isn't reusable. Reported-by: Frank Dinoff <fdinoff@google.com> Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/ Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device") Cc: <stable@vger.kernel.org> # v2.6.35 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22fuse: fix use after free in fuse_read_interrupt()Miklos Szeredi1-2/+2
[ Upstream commit e1e71c168813564be0f6ea3d6740a059ca42d177 ] There is a potential race between fuse_read_interrupt() and fuse_request_end(). TASK1 in fuse_read_interrupt(): delete req->intr_entry (while holding fiq->lock) TASK2 in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock wake up TASK3 TASK3 request is freed TASK1 in fuse_read_interrupt(): dereference req->in.h.unique ***BAM*** Fix by always grabbing fiq->lock if the request was ever interrupted (FR_INTERRUPTED set) thereby serializing with concurrent fuse_read_interrupt() calls. FR_INTERRUPTED is set before the request is queued on fiq->interrupts. Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not cleared in this case. Reported-by: lijiazi <lijiazi@xiaomi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15fuse: flush extending writesMiklos Szeredi1-1/+1
commit 59bda8ecee2ffc6a602b7bf2b9e43ca669cdbdcd upstream. Callers of fuse_writeback_range() assume that the file is ready for modification by the server in the supplied byte range after the call returns. If there's a write that extends the file beyond the end of the supplied range, then the file needs to be extended to at least the end of the range, but currently that's not done. There are at least two cases where this can cause problems: - copy_file_range() will return short count if the file is not extended up to end of the source range. - FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE will not extend the file, hence the region may not be fully allocated. Fix by flushing writes from the start of the range up to the end of the file. This could be optimized if the writes are non-extending, etc, but it's probably not worth the trouble. Fixes: a2bc92362941 ("fuse: fix copy_file_range() in the writeback case") Fixes: 6b1bdb56b17c ("fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)") Cc: <stable@vger.kernel.org> # v5.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-15fuse: truncate pagecache on atomic_o_truncMiklos Szeredi1-2/+5
commit 76224355db7570cbe6b6f75c8929a1558828dd55 upstream. fuse_finish_open() will be called with FUSE_NOWRITE in case of atomic O_TRUNC. This can deadlock with fuse_wait_on_page_writeback() in fuse_launder_page() triggered by invalidate_inode_pages2(). Fix by replacing invalidate_inode_pages2() in fuse_finish_open() with a truncate_pagecache() call. This makes sense regardless of FOPEN_KEEP_CACHE or fc->writeback cache, so do it unconditionally. Reported-by: Xie Yongji <xieyongji@bytedance.com> Reported-and-tested-by: syzbot+bea44a5189836d956894@syzkaller.appspotmail.com Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-08fuse: fix illegal access to inode with reused nodeidAmir Goldstein4-5/+15
commit 15db16837a35d8007cb8563358787412213db25e upstream. Server responds to LOOKUP and other ops (READDIRPLUS/CREATE/MKNOD/...) with ourarg containing nodeid and generation. If a fuse inode is found in inode cache with the same nodeid but different generation, the existing fuse inode should be unhashed and marked "bad" and a new inode with the new generation should be hashed instead. This can happen, for example, with passhrough fuse filesystem that returns the real filesystem ino/generation on lookup and where real inode numbers can get recycled due to real files being unlinked not via the fuse passthrough filesystem. With current code, this situation will not be detected and an old fuse dentry that used to point to an older generation real inode, can be used to access a completely new inode, which should be accessed only via the new dentry. Note that because the FORGET message carries the nodeid w/o generation, the server should wait to get FORGET counts for the nlookup counts of the old and reused inodes combined, before it can free the resources associated to that nodeid. Stable backport notes: * This is not a regression. The bug has been in fuse forever, but only a certain class of low level fuse filesystems can trigger this bug * Because there is no way to check if this fix is applied in runtime, libfuse test_examples.py tests this fix with hardcoded check for kernel version >= 5.14 * After backport to stable kernel(s), the libfuse test can be updated to also check minimal stable kernel version(s) * Depends on "fuse: fix bad inode" which is already applied to stable kernels v5.4.y and v5.10.y * Required backporting helper inode_wrong_type() Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxi8DymG=JO_sAU+wS8akFdzh+PuXwW3Ebgahd2Nwnh7zA@mail.gmail.com/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-08new helper: inode_wrong_type()Al Viro3-5/+5
commit 6e3e2c4362e41a2f18e3f7a5ad81bd2f49a47b85 upstream. inode_wrong_type(inode, mode) returns true if setting inode->i_mode to given value would've changed the inode type. We have enough of those checks open-coded to make a helper worthwhile. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: reject internal errnoMiklos Szeredi1-1/+1
commit 49221cf86d18bb66fe95d3338cb33bd4b9880ca5 upstream. Don't allow userspace to report errors that could be kernel-internal. Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Fixes: 334f485df85a ("[PATCH] FUSE - device functions") Cc: <stable@vger.kernel.org> # v2.6.14 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: check connected before queueing on fpq->ioMiklos Szeredi1-0/+9
commit 80ef08670d4c28a06a3de954bd350368780bcfef upstream. A request could end up on the fpq->io list after fuse_abort_conn() has reset fpq->connected and aborted requests on that list: Thread-1 Thread-2 ======== ======== ->fuse_simple_request() ->shutdown ->__fuse_request_send() ->queue_request() ->fuse_abort_conn() ->fuse_dev_do_read() ->acquire(fpq->lock) ->wait_for(fpq->lock) ->set err to all req's in fpq->io ->release(fpq->lock) ->acquire(fpq->lock) ->add req to fpq->io After the userspace copy is done the request will be ended, but req->out.h.error will remain uninitialized. Also the copy might block despite being already aborted. Fix both issues by not allowing the request to be queued on the fpq->io list after fuse_abort_conn() has processed this list. Reported-by: Pradeep P V K <pragalla@codeaurora.org> Fixes: fd22d62ed0c3 ("fuse: no fc->lock for iqueue parts") Cc: <stable@vger.kernel.org> # v4.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: ignore PG_workingset after stealingMiklos Szeredi1-0/+1
commit b89ecd60d38ec042d63bdb376c722a16f92bcb88 upstream. Fix the "fuse: trying to steal weird page" warning. Description from Johannes Weiner: "Think of it as similar to PG_active. It's just another usage/heat indicator of file and anon pages on the reclaim LRU that, unlike PG_active, persists across deactivation and even reclaim (we store it in the page cache / swapper cache tree until the page refaults). So if fuse accepts pages that can legally have PG_active set, PG_workingset is fine too." Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com> Fixes: 1899ad18c607 ("mm: workingset: tell cache transitions from workingset thrashing") Cc: <stable@vger.kernel.org> # v4.20 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: Fix infinite loop in sget_fc()Greg Kurz1-0/+11
commit e4a9ccdd1c03b3dc58214874399d24331ea0a3ab upstream. We don't set the SB_BORN flag on submounts. This is wrong as these superblocks are then considered as partially constructed or dying in the rest of the code and can break some assumptions. One such case is when you have a virtiofs filesystem with submounts and you try to mount it again : virtio_fs_get_tree() tries to obtain a superblock with sget_fc(). The logic in sget_fc() is to loop until it has either found an existing matching superblock with SB_BORN set or to create a brand new one. It is assumed that a superblock without SB_BORN is transient and the loop is restarted. Forgetting to set SB_BORN on submounts hence causes sget_fc() to retry forever. Setting SB_BORN requires special care, i.e. a write barrier for super_cache_count() which can check SB_BORN without taking any lock. We should call vfs_get_tree() to deal with that but this requires to have a proper ->get_tree() implementation for submounts, which is a bigger piece of work. Go for a simple bug fix in the meatime. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: Fix crash if superblock of submount gets killed earlyGreg Kurz1-4/+4
commit e3a43f2a95393000778f8f302d48795add2fc4a8 upstream. As soon as fuse_dentry_automount() does up_write(&sb->s_umount), the superblock can theoretically be killed. If this happens before the submount was added to the &fc->mounts list, fuse_mount_remove() later crashes in list_del_init() because it assumes the submount to be already there. Add the submount before dropping sb->s_umount to fix the inconsistency. It is okay to nest fc->killsb under sb->s_umount, we already do this on the ->kill_sb() path. Signed-off-by: Greg Kurz <groug@kaod.org> Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14fuse: Fix crash in fuse_dentry_automount() error pathGreg Kurz1-1/+5
commit d92d88f0568e97c437eeb79d9c9609bd8277406f upstream. If fuse_fill_super_submount() returns an error, the error path triggers a crash: [ 26.206673] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] [ 26.226362] RIP: 0010:__list_del_entry_valid+0x25/0x90 [...] [ 26.247938] Call Trace: [ 26.248300] fuse_mount_remove+0x2c/0x70 [fuse] [ 26.248892] virtio_kill_sb+0x22/0x160 [virtiofs] [ 26.249487] deactivate_locked_super+0x36/0xa0 [ 26.250077] fuse_dentry_automount+0x178/0x1a0 [fuse] The crash happens because fuse_mount_remove() assumes that the FUSE mount was already added to list under the FUSE connection, but this only done after fuse_fill_super_submount() has returned success. This means that until fuse_fill_super_submount() has returned success, the FUSE mount isn't actually owned by the superblock. We should thus reclaim ownership by clearing sb->s_fs_info, which will skip the call to fuse_mount_remove(), and perform rollback, like virtio_fs_get_tree() already does for the root sb. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-19cuse: prevent cloneMiklos Szeredi1-0/+2
[ Upstream commit 8217673d07256b22881127bf50dce874d0e51653 ] For cloned connections cuse_channel_release() will be called more than once, resulting in use after free. Prevent device cloning for CUSE, which does not make sense at this point, and highly unlikely to be used in real life. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-19virtiofs: fix usernsMiklos Szeredi1-2/+1
[ Upstream commit 0a7419c68a45d2d066b996be5087aa2d07ce80eb ] get_user_ns() is done twice (once in virtio_fs_get_tree() and once in fuse_conn_init()), resulting in a reference leak. Also looks better to use fsc->user_ns (which *should* be the current_user_ns() at this point). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-19fuse: invalidate attrs when page writeback completesVivek Goyal1-0/+9
[ Upstream commit 3466958beb31a8e9d3a1441a34228ed088b84f3e ] In fuse when a direct/write-through write happens we invalidate attrs because that might have updated mtime/ctime on server and cached mtime/ctime will be stale. What about page writeback path. Looks like we don't invalidate attrs there. To be consistent, invalidate attrs in writeback path as well. Only exception is when writeback_cache is enabled. In that case we strust local mtime/ctime and there is no need to invalidate attrs. Recently users started experiencing failure of xfstests generic/080, geneirc/215 and generic/614 on virtiofs. This happened only newer "stat" utility and not older one. This patch fixes the issue. So what's the root cause of the issue. Here is detailed explanation. generic/080 test does mmap write to a file, closes the file and then checks if mtime has been updated or not. When file is closed, it leads to flushing of dirty pages (and that should update mtime/ctime on server). But we did not explicitly invalidate attrs after writeback finished. Still generic/080 passed so far and reason being that we invalidated atime in fuse_readpages_end(). This is called in fuse_readahead() path and always seems to trigger before mmaped write. So after mmaped write when lstat() is called, it sees that atleast one of the fields being asked for is invalid (atime) and that results in generating GETATTR to server and mtime/ctime also get updated and test passes. But newer /usr/bin/stat seems to have moved to using statx() syscall now (instead of using lstat()). And statx() allows it to query only ctime or mtime (and not rest of the basic stat fields). That means when querying for mtime, fuse_update_get_attr() sees that mtime is not invalid (only atime is invalid). So it does not generate a new GETATTR and fill stat with cached mtime/ctime. And that means updated mtime is not seen by xfstest and tests start failing. Invalidating attrs after writeback completion should solve this problem in a generic manner. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-11fuse: fix write deadlockVivek Goyal2-12/+30
commit 4f06dd92b5d0a6f8eec6a34b8d6ef3e1f4ac1e10 upstream. There are two modes for write(2) and friends in fuse: a) write through (update page cache, send sync WRITE request to userspace) b) buffered write (update page cache, async writeout later) The write through method kept all the page cache pages locked that were used for the request. Keeping more than one page locked is deadlock prone and Qian Cai demonstrated this with trinity fuzzing. The reason for keeping the pages locked is that concurrent mapped reads shouldn't try to pull possibly stale data into the page cache. For full page writes, the easy way to fix this is to make the cached page be the authoritative source by marking the pa