kernel/linux.git/fs/exfat, branch v6.12.97

exfat: preserve benign secondary entries during rename and move

2026-07-24T14:11:54+00:00

[ Upstream commit 942296784b2a9439651750c42f540bf2579b330f ] Commit 8258ef28001a ("exfat: handle unreconized benign secondary entries") added cluster freeing for benign secondary entries inside exfat_remove_entries(). However, exfat_remove_entries() is also called from the rename and move paths (exfat_rename_file and exfat_move_file), where the old entry set is being relocated rather than deleted. This causes benign secondary entries such as vendor extension entries to be silently destroyed on rename or cross-directory move, violating the exFAT spec requirement (section 8.2) that implementations preserve unrecognized benign secondary entries. Fix this by adding a free_benign parameter to exfat_remove_entries() so callers can suppress cluster freeing during relocation, and extending exfat_init_ext_entry() to copy trailing benign secondary entries from the old entry set into the new one internally. Also clean up the error paths to delete newly allocated entries on failure. Fixes: 8258ef28001a ("exfat: handle unreconized benign secondary entries") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-fsdevel/CAG7tbBV--waov7XVu2FHQEc6paR92dufS=em9DW5Kzsrpu3iQg@mail.gmail.com/ Signed-off-by: Rochan Avlur Reviewed-by: Yuezhang Mo Signed-off-by: Namjae Jeon Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: fix incorrect directory checksum after rename to shorter name

2026-07-24T14:11:54+00:00

[ Upstream commit ff37797badd831797b8a27830fe5046d7e23fdc3 ] When renaming a file in-place to a shorter name, exfat_remove_entries marks excess entries as DELETED, but es->num_entries is not updated accordingly. As a result, exfat_update_dir_chksum iterates over the deleted entries and computes an incorrect checksum. This does not lead to persistent corruption because mark_inode_dirty() is called afterward, and __exfat_write_inode later recomputes the checksum using the correct num_entries value. Fix by setting es->num_entries = num_entries in exfat_init_ext_entry. Signed-off-by: Chi Zhiling Reviewed-by: Sungjong Seo Reviewed-by: Yuezhang Mo Signed-off-by: Namjae Jeon Stable-dep-of: 942296784b2a ("exfat: preserve benign secondary entries during rename and move") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: move exfat_chain_set() out of __exfat_resolve_path()

2026-07-24T14:11:54+00:00

[ Upstream commit 0891c7313d87a1b6baf7162bc2f0d755ce70383f ] __exfat_resolve_path() mixes two functions. The first one is to resolve and check if the path is valid. The second one is to output the cluster assigned to the directory. The second one is only needed when need to traverse the directory entries, and calling exfat_chain_set() so early causes p_dir to be passed as an argument multiple times, increasing the complexity of the code. This commit moves the call to exfat_chain_set() before traversing directory entries. Signed-off-by: Yuezhang Mo Reviewed-by: Aoyama Wataru Reviewed-by: Daniel Palmer Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Stable-dep-of: 942296784b2a ("exfat: preserve benign secondary entries during rename and move") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: add exfat_get_dentry_set_by_ei() helper

2026-07-24T14:11:54+00:00

[ Upstream commit ac844e91364a03c35838fd488437605fbe56f8c3 ] This helper gets the directory entry set of the file for the exfat inode which has been created. It's used to remove all the instances of the pattern it replaces making the code cleaner, it's also a preparation for changing ->dir to record the cluster where the directory entry set is located and changing ->entry to record the index of the directory entry within the cluster. Signed-off-by: Yuezhang Mo Reviewed-by: Aoyama Wataru Reviewed-by: Daniel Palmer Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Stable-dep-of: 942296784b2a ("exfat: preserve benign secondary entries during rename and move") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: rename argument name for exfat_move_file and exfat_rename_file

2026-07-24T14:11:53+00:00

[ Upstream commit 06a2b0b3b490a6103376652c01c3ac6e8e22e654 ] In this exfat implementation, the relationship between inode and ei is ei=EXFAT_I(inode). However, in the arguments of exfat_move_file() and exfat_rename_file(), argument 'inode' indicates the parent directory, but argument 'ei' indicates the target file to be renamed. They do not have the above relationship, which is not friendly to code readers. So this commit renames 'inode' to 'parent_inode', making the argument name match its role. Signed-off-by: Yuezhang Mo Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Stable-dep-of: 942296784b2a ("exfat: preserve benign secondary entries during rename and move") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: remove unnecessary read entry in __exfat_rename()

2026-07-24T14:11:53+00:00

[ Upstream commit 30ef0e0d7ff5b6dceda19d18a85d9d72a4909784 ] To determine whether it is a directory, there is no need to read its directory entry, just use S_ISDIR(inode->i_mode). Signed-off-by: Yuezhang Mo Reviewed-by: Aoyama Wataru Reviewed-by: Daniel Palmer Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon Stable-dep-of: 942296784b2a ("exfat: preserve benign secondary entries during rename and move") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

exfat: bound uniname advance in exfat_find_dir_entry()

2026-07-18T14:52:14+00:00

commit 3a1230e7b043c62737b05a3e9275ca83a43ad20a upstream. In exfat_find_dir_entry(), each TYPE_EXTEND (file name) entry advances the output pointer by a fixed amount while the loop guard only tracks the accumulated name length: if (++order == 2) uniname = p_uniname->name; else uniname += EXFAT_FILE_NAME_LEN; len = exfat_extract_uni_name(ep, entry_uniname); name_len += len; unichar = *(uniname+len); *(uniname+len) = 0x0; uniname grows by EXFAT_FILE_NAME_LEN (15) per name entry, but name_len grows only by the actual extracted length, which is shorter when a name fragment contains an early NUL. The only guard is `name_len >= MAX_NAME_LENGTH`, so a crafted directory with many short name fragments lets uniname run far past the p_uniname->name[MAX_NAME_LENGTH + 3] buffer while name_len stays small, causing an out-of-bounds read and write at *(uniname+len). The sibling extractor exfat_get_uniname_from_ext_entry() already stops on a short fragment (the lockstep `len != EXFAT_FILE_NAME_LEN` guard added in commit d42334578eba ("exfat: check if filename entries exceeds max filename length")); exfat_find_dir_entry() never got the equivalent. Track the per-entry write offset as a count and reject a fragment once the offset, or the offset plus the extracted length, would exceed MAX_NAME_LENGTH, before forming the output pointer. Fixes: ca06197382bd ("exfat: add directory operations") Cc: stable@vger.kernel.org Suggested-by: Namjae Jeon Signed-off-by: Bryam Vargas Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman

exfat: fix potential use-after-free in exfat_find_dir_entry()

2026-07-04T11:43:34+00:00

commit 3f5f8ee9917cc2b9076ac533492d8a200edcabb8 upstream. In exfat_find_dir_entry(), the buffer_head obtained from exfat_get_dentry() is released with brelse(bh) before the fall-through TYPE_EXTEND branch reads the directory entry through ep (which points into bh->b_data): brelse(bh); if (entry_type == TYPE_EXTEND) { ... len = exfat_extract_uni_name(ep, entry_uniname); ... } After brelse() drops our reference, nothing guarantees that the underlying page backing bh->b_data remains valid for the subsequent exfat_extract_uni_name() read. This is the same pattern fixed in commit fc961522ddbd ("exfat: Fix potential use after free in exfat_load_upcase_table()"). Move brelse(bh) so it runs after ep is no longer dereferenced on each branch. Confirmed on QEMU x86_64 with CONFIG_KASAN=y + CONFIG_DEBUG_PAGEALLOC=y + CONFIG_PAGE_POISONING=y on linux-next, using a crafted exFAT image (long filename with same-hash collisions forcing the TYPE_EXTEND path). With a debug-only invalidate_bdev() inserted between brelse(bh) and the ep read to make the stale-deref window deterministic, the unpatched kernel faults: BUG: KASAN: use-after-free in exfat_find_dir_entry+0x133b/0x15a0 BUG: unable to handle page fault for address: ffff88801a5fa0c2 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI RIP: 0010:exfat_find_dir_entry+0x1188/0x15a0 With this patch applied, the same instrumented harness completes cleanly under the same sanitizer stack. I have not reproduced a crash on an uninstrumented kernel under ordinary reclaim; the instrumented A/B establishes the lifetime violation and that the patch closes it, not an unaided triggerability claim. Fixes: ca06197382bd ("exfat: add directory operations") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman

exfat: fix refcount leak in exfat_find

2026-01-30T09:28:48+00:00

[ Upstream commit 9aee8de970f18c2aaaa348e3de86c38e2d956c1d ] 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 Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Greg Kroah-Hartman

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

2026-01-08T09:14:11+00:00

[ Upstream commit 4e163c39dd4e70fcdce948b8774d96e0482b4a11 ] 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 Signed-off-by: Sasha Levin