kernel/git/stable/linux-stable.git/fs/fuse, branch linux-4.19.y

fuse: use unsigned type for getxattr/listxattr size truncation

2024-09-12T09:02:51+00:00

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 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: Initialize beyond-EOF page contents before setting uptodate

2024-09-04T11:12:58+00:00

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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fuse: don't unhash root

2024-04-13T10:50:05+00:00

[ 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: # v5.11 Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: nlookup missing decrement in fuse_direntplus_link

2024-01-15T17:23:43+00:00

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 Fixes: 0b05b18381ee ("fuse: implement NFS-like readdirplus support") Cc: # v3.9 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: revalidate: don't invalidate if interrupted

2023-08-11T09:45:24+00:00

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 Closes: https://lore.kernel.org/all/CAJfpegswN_CJJ6C3RZiaK6rpFmNyWmXfaEpnQUJ42KCwNF5tWw@mail.gmail.com/ Fixes: 9e6268db496a ("[PATCH] FUSE - read-write operations") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

treewide: Remove uninitialized_var() usage

2023-08-11T09:45:01+00:00

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream. Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var$([^$]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe # IB Acked-by: Kalle Valo # wireless drivers Reviewed-by: Chao Yu # erofs Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

fuse: limit nsec

2022-08-25T09:14:55+00:00

commit 47912eaa061a6a81e4aa790591a1874c650733c0 upstream. Limit nanoseconds to 0..999999999. Fixes: d8a5ba45457e ("[PATCH] FUSE - core") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: fix pipe buffer lifetime for direct_io

2022-04-15T12:14:37+00:00

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 Fixes: c3021629a0d8 ("fuse: support splice() reading from fuse device") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Zach O'Keefe Signed-off-by: Greg Kroah-Hartman

fuse: fix live lock in fuse_iget()

2022-01-27T08:04:34+00:00

commit 775c5033a0d164622d9d10dd0f0a5531639ed3ed upstream. Commit 5d069dbe8aaf ("fuse: fix bad inode") replaced make_bad_inode() in fuse_iget() with a private implementation fuse_make_bad(). The private implementation fails to remove the bad inode from inode cache, so the retry loop with iget5_locked() finds the same bad inode and marks it bad forever. kmsg snip: [ ] rcu: INFO: rcu_sched self-detected stall on CPU ... [ ] ? bit_wait_io+0x50/0x50 [ ] ? fuse_init_file_inode+0x70/0x70 [ ] ? find_inode.isra.32+0x60/0xb0 [ ] ? fuse_init_file_inode+0x70/0x70 [ ] ilookup5_nowait+0x65/0x90 [ ] ? fuse_init_file_inode+0x70/0x70 [ ] ilookup5.part.36+0x2e/0x80 [ ] ? fuse_init_file_inode+0x70/0x70 [ ] ? fuse_inode_eq+0x20/0x20 [ ] iget5_locked+0x21/0x80 [ ] ? fuse_inode_eq+0x20/0x20 [ ] fuse_iget+0x96/0x1b0 Fixes: 5d069dbe8aaf ("fuse: fix bad inode") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

fuse: fix bad inode

2022-01-27T08:04:34+00:00

commit 5d069dbe8aaf2a197142558b6fb2978189ba3454 upstream. Jan Kara's analysis of the syzbot report (edited): The reproducer opens a directory on FUSE filesystem, it then attaches dnotify mark to the open directory. After that a fuse_do_getattr() call finds that attributes returned by the server are inconsistent, and calls make_bad_inode() which, among other things does: inode->i_mode = S_IFREG; This then confuses dnotify which doesn't tear down its structures properly and eventually crashes. Avoid calling make_bad_inode() on a live inode: switch to a private flag on the fuse inode. Also add the test to ops which the bad_inode_ops would have caught. This bug goes back to the initial merge of fuse in 2.6.14... Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi Tested-by: Jan Kara Cc: [bwh: Backported to 4.19: - Drop changes in fuse_dir_fsync(), fuse_readahead(), fuse_evict_inode() - In fuse_get_link(), return ERR_PTR(-EIO) for bad inodes - Convert some additional calls to is_bad_inode() - Adjust filename, context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman