kernel/linux.git/fs/exfat, branch v6.19.11

exfat: fix remount failure in different process environments

2025-12-03T01:00:17+00:00

The kernel test robot reported that the exFAT remount operation failed. The reason for the failure was that the process's umask is different between mount and remount, causing fs_fmask and fs_dmask are changed. Potentially, both gid and uid may also be changed. Therefore, when initializing fs_context for remount, inherit these mount options from the options used during mount. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202511251637.81670f5c-lkp@intel.com Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: fix divide-by-zero in exfat_allocate_bitmap

2025-12-03T01:00:16+00:00

The variable max_ra_count can be 0 in exfat_allocate_bitmap(), which causes a divide-by-zero error in the subsequent modulo operation (i % max_ra_count), leading to a system crash. When max_ra_count is 0, it means that readahead is not used. This patch load the bitmap without readahead. Fixes: 9fd688678dd8 ("exfat: optimize allocation bitmap loading time") Reported-by: Jiaming Zhang Signed-off-by: Namjae Jeon

exfat: validate the cluster bitmap bits of directory

2025-12-03T01:00:16+00:00

Syzbot created this issue by testing an image that did not have the root cluster bitmap bit marked. After accessing a file through the root directory via exfat_lookup, when creating a file again with mkdir, the root cluster bit can be allocated for direcotry, which can cause the root cluster to be zeroed out and the same entry can be allocated in the same cluster. This patch improved this issue by adding exfat_test_bitmap to validate the cluster bits of the root directory and directory. And the first cluster bit of the root directory should never be unset except when storage is corrupted. This bit is set to allow operations after mount. Reported-by: syzbot+5216036fc59c43d1ee02@syzkaller.appspotmail.com Tested-by: syzbot+5216036fc59c43d1ee02@syzkaller.appspotmail.com Reviewed-by: Sungjong Seo Reviewed-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: zero out post-EOF page cache on file extension

2025-12-03T01:00:16+00:00

xfstests generic/363 was failing due to unzeroed post-EOF page cache that allowed mmap writes beyond EOF to become visible after file extension. For example, in following xfs_io sequence, 0x22 should not be written to the file but would become visible after the extension: xfs_io -f -t -c "pwrite -S 0x11 0 8" \ -c "mmap 0 4096" \ -c "mwrite -S 0x22 32 32" \ -c "munmap" \ -c "pwrite -S 0x33 512 32" \ $testfile This violates the expected behavior where writes beyond EOF via mmap should not persist after the file is extended. Instead, the extended region should contain zeros. Fix this by using truncate_pagecache() to truncate the page cache after the current EOF when extending the file. Signed-off-by: Yuezhang Mo Signed-off-by: Namjae Jeon

exfat: fix refcount leak in exfat_find

2025-12-03T01:00:16+00:00

Fix refcount leaks in `exfat_find` related to `exfat_get_dentry_set`. Function `exfat_get_dentry_set` would increase the reference counter of `es->bh` on success. Therefore, `exfat_put_dentry_set` must be called after `exfat_get_dentry_set` to ensure refcount consistency. This patch relocate two checks to avoid possible leaks. Fixes: 82ebecdc74ff ("exfat: fix improper check of dentry.stream.valid_size") Fixes: 13940cef9549 ("exfat: add a check for invalid data size") Signed-off-by: Shuhao Fu Reviewed-by: Yuezhang Mo Signed-off-by: Namjae Jeon

Merge tag 'vfs-6.18-rc7.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

2025-11-17T17:11:27+00:00

Pull vfs fixes from Christian Brauner: - Fix unitialized variable in statmount_string() - Fix hostfs mounting when passing host root during boot - Fix dynamic lookup to fail on cell lookup failure - Fix missing file type when reading bfs inodes from disk - Enforce checking of sb_min_blocksize() calls and update all callers accordingly - Restore write access before closing files opened by open_exec() in binfmt_misc - Always freeze efivarfs during suspend/hibernate cycles - Fix statmount()'s and listmount()'s grab_requested_mnt_ns() helper to actually allow mount namespace file descriptor in addition to mount namespace ids - Fix tmpfs remount when noswap is specified - Switch Landlock to iput_not_last() to remove false-positives from might_sleep() annotations in iput() - Remove dead node_to_mnt_ns() code - Ensure that per-queue kobjects are successfully created * tag 'vfs-6.18-rc7.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: landlock: fix splats from iput() after it started calling might_sleep() fs: add iput_not_last() shmem: fix tmpfs reconfiguration (remount) when noswap is set fs/namespace: correctly handle errors returned by grab_requested_mnt_ns power: always freeze efivarfs binfmt_misc: restore write access before closing files opened by open_exec() block: add __must_check attribute to sb_min_blocksize() virtio-fs: fix incorrect check for fsvq->kobj xfs: check the return value of sb_min_blocksize() in xfs_fs_fill_super isofs: check the return value of sb_min_blocksize() in isofs_fill_super exfat: check return value of sb_min_blocksize in exfat_read_boot_sector vfat: fix missing sb_min_blocksize() return value checks mnt: Remove dead code which might prevent from building bfs: Reconstruct file type when loading from disk afs: Fix dynamic lookup to fail on cell lookup failure hostfs: Fix only passing host root in boot stage with new mount fs: Fix uninitialized 'offp' in statmount_string()

exfat: check return value of sb_min_blocksize in exfat_read_boot_sector

2025-11-05T13:00:16+00:00

sb_min_blocksize() may return 0. Check its return value to avoid accessing the filesystem super block when sb->s_blocksize is 0. Cc: stable@vger.kernel.org # v6.15 Fixes: 719c1e1829166d ("exfat: add super block operations") Reviewed-by: Christoph Hellwig Signed-off-by: Yongpeng Yang Link: https://patch.msgid.link/20251104125009.2111925-3-yangyongpeng.storage@gmail.com Signed-off-by: Christian Brauner

exfat: fix out-of-bounds in exfat_nls_to_ucs2()

2025-10-15T08:53:20+00:00

Since the len argument value passed to exfat_ioctl_set_volume_label() from exfat_nls_to_utf16() is passed 1 too large, an out-of-bounds read occurs when dereferencing p_cstring in exfat_nls_to_ucs2() later. And because of the NLS_NAME_OVERLEN macro, another error occurs when creating a file with a period at the end using utf8 and other iocharsets. So to avoid this, you should remove the code that uses NLS_NAME_OVERLEN macro and make the len argument value be the length of the label string, but with a maximum length of FSLABEL_MAX - 1. Reported-by: syzbot+98cc76a76de46b3714d4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=98cc76a76de46b3714d4 Fixes: d01579d590f7 ("exfat: Add support for FS_IOC_{GET,SET}FSLABEL") Suggested-by: Pali Rohár Signed-off-by: Jeongjun Park Signed-off-by: Namjae Jeon

exfat: fix improper check of dentry.stream.valid_size

2025-10-15T05:37:21+00:00

We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability. Co-developed-by: Seunghun Han Signed-off-by: Seunghun Han Co-developed-by: Jihoon Kwon Signed-off-by: Jihoon Kwon Signed-off-by: Jaehun Gou Signed-off-by: Namjae Jeon

Merge tag 'exfat-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

2025-10-03T21:02:53+00:00

Pull exfat updates from Namjae Jeon: - Add support for FS_IOC_{GET,SET}FSLABEL ioctl - Two small clean-up patches - Optimizes allocation bitmap loading time on large partitions with small cluster sizes - Allow changes for discard, zero_size_dir, and errors options via remount - Validate that the clusters used for the allocation bitmap are correctly marked as in-use during mount, preventing potential data corruption from reallocating the bitmap's own space - Uses ratelimit to avoid too many error prints on I/O error path * tag 'exfat-for-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat: exfat: Add support for FS_IOC_{GET,SET}FSLABEL exfat: combine iocharset and utf8 option setup exfat: support modifying mount options via remount exfat: optimize allocation bitmap loading time exfat: Remove unnecessary parentheses exfat: drop redundant conversion to bool exfat: validate cluster allocation bits of the allocation bitmap exfat: limit log print for IO error