kernel/linux.git/fs/ext4/dir.c, branch v6.19.11

ext4: support large block size in ext4_readdir()

2025-11-29T03:35:26+00:00

In ext4_readdir(), page_cache_sync_readahead() is used to readahead mapped physical blocks. With LBS support, this can lead to a negative right shift. To fix this, the page index is now calculated by first converting the physical block number (pblk) to a file position (pos) before converting it to a page index. Also, the correct number of pages to readahead is now passed. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi Reviewed-by: Jan Kara Reviewed-by: Pankaj Raghav Reviewed-by: Ojaswin Mujoo Message-ID: <20251121090654.631996-9-libaokun@huaweicloud.com> Signed-off-by: Theodore Ts'o

ext4: fix OOB read when checking dotdot dir

2025-03-21T05:33:11+00:00

Mounting a corrupted filesystem with directory which contains '.' dir entry with rec_len == block size results in out-of-bounds read (later on, when the corrupted directory is removed). ext4_empty_dir() assumes every ext4 directory contains at least '.' and '..' as directory entries in the first data block. It first loads the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry() and then uses its rec_len member to compute the location of '..' dir entry (in ext4_next_entry). It assumes the '..' dir entry fits into the same data block. If the rec_len of '.' is precisely one block (4KB), it slips through the sanity checks (it is considered the last directory entry in the data block) and leaves "struct ext4_dir_entry_2 *de" point exactly past the memory slot allocated to the data block. The following call to ext4_check_dir_entry() on new value of de then dereferences this pointer which results in out-of-bounds mem access. Fix this by extending __ext4_check_dir_entry() to check for '.' dir entries that reach the end of data block. Make sure to ignore the phony dir entries for checksum (by checking name_len for non-zero). Note: This is reported by KASAN as use-after-free in case another structure was recently freed from the slot past the bound, but it is really an OOB read. This issue was found by syzkaller tool. Call Trace: [ 38.594108] BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x67e/0x710 [ 38.594649] Read of size 2 at addr ffff88802b41a004 by task syz-executor/5375 [ 38.595158] [ 38.595288] CPU: 0 UID: 0 PID: 5375 Comm: syz-executor Not tainted 6.14.0-rc7 #1 [ 38.595298] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 38.595304] Call Trace: [ 38.595308] [ 38.595311] dump_stack_lvl+0xa7/0xd0 [ 38.595325] print_address_description.constprop.0+0x2c/0x3f0 [ 38.595339] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595349] print_report+0xaa/0x250 [ 38.595359] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595368] ? kasan_addr_to_slab+0x9/0x90 [ 38.595378] kasan_report+0xab/0xe0 [ 38.595389] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595400] __ext4_check_dir_entry+0x67e/0x710 [ 38.595410] ext4_empty_dir+0x465/0x990 [ 38.595421] ? __pfx_ext4_empty_dir+0x10/0x10 [ 38.595432] ext4_rmdir.part.0+0x29a/0xd10 [ 38.595441] ? __dquot_initialize+0x2a7/0xbf0 [ 38.595455] ? __pfx_ext4_rmdir.part.0+0x10/0x10 [ 38.595464] ? __pfx___dquot_initialize+0x10/0x10 [ 38.595478] ? down_write+0xdb/0x140 [ 38.595487] ? __pfx_down_write+0x10/0x10 [ 38.595497] ext4_rmdir+0xee/0x140 [ 38.595506] vfs_rmdir+0x209/0x670 [ 38.595517] ? lookup_one_qstr_excl+0x3b/0x190 [ 38.595529] do_rmdir+0x363/0x3c0 [ 38.595537] ? __pfx_do_rmdir+0x10/0x10 [ 38.595544] ? strncpy_from_user+0x1ff/0x2e0 [ 38.595561] __x64_sys_unlinkat+0xf0/0x130 [ 38.595570] do_syscall_64+0x5b/0x180 [ 38.595583] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: ac27a0ec112a0 ("[PATCH] ext4: initial copy of files from ext3") Signed-off-by: Jakub Acs Cc: Theodore Ts'o Cc: Andreas Dilger Cc: linux-ext4@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Mahmoud Adam Cc: stable@vger.kernel.org Cc: security@kernel.org Link: https://patch.msgid.link/b3ae36a6794c4a01944c7d70b403db5b@amazon.de Signed-off-by: Theodore Ts'o

ext4: remove redundant function ext4_has_metadata_csum

2025-03-17T15:19:41+00:00

Since commit f2b4fa19647e ("ext4: switch to using the crc32c library"), ext4_has_metadata_csum() is just an alias for ext4_has_feature_metadata_csum(). ext4_has_feature_metadata_csum() is generated by EXT4_FEATURE_RO_COMPAT_FUNCS and uses the regular naming convention for checking a single ext4 feature. Therefore, remove ext4_has_metadata_csum() and update all its callers to use ext4_has_feature_metadata_csum() directly. Signed-off-by: Eric Biggers Reviewed-by: Darrick J. Wong Link: https://patch.msgid.link/20250207031335.42637-1-ebiggers@kernel.org Signed-off-by: Theodore Ts'o

ext4: use struct_size() to improve ext4_htree_store_dirent()

2024-11-13T17:56:48+00:00

Inline and use struct_size() to calculate the number of bytes to allocate for new_fn and remove the local variable len. Reviewed-by: Jan Kara Signed-off-by: Thorsten Blum Link: https://patch.msgid.link/20241105103353.11590-2-thorsten.blum@linux.dev Signed-off-by: Theodore Ts'o

ext4: annotate struct fname with __counted_by()

2024-11-13T17:56:48+00:00

Add the __counted_by compiler attribute to the flexible array member name to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Reviewed-by: Jan Kara Signed-off-by: Thorsten Blum Link: https://patch.msgid.link/20241105101813.10864-2-thorsten.blum@linux.dev Signed-off-by: Theodore Ts'o

Merge tag 'ext4_for_linus-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2024-09-21T02:26:45+00:00

Pull ext4 updates from Ted Ts'o: "Lots of cleanups and bug fixes this cycle, primarily in the block allocation, extent management, fast commit, and journalling" * tag 'ext4_for_linus-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (93 commits) ext4: convert EXT4_B2C(sbi->s_stripe) users to EXT4_NUM_B2C ext4: check stripe size compatibility on remount as well ext4: fix i_data_sem unlock order in ext4_ind_migrate() ext4: remove the special buffer dirty handling in do_journal_get_write_access ext4: fix a potential assertion failure due to improperly dirtied buffer ext4: hoist ext4_block_write_begin and replace the __block_write_begin ext4: persist the new uptodate buffers in ext4_journalled_zero_new_buffers ext4: dax: keep orphan list before truncate overflow allocated blocks ext4: fix error message when rejecting the default hash ext4: save unnecessary indentation in ext4_ext_create_new_leaf() ext4: make some fast commit functions reuse extents path ext4: refactor ext4_swap_extents() to reuse extents path ext4: get rid of ppath in convert_initialized_extent() ext4: get rid of ppath in ext4_ext_handle_unwritten_extents() ext4: get rid of ppath in ext4_ext_convert_to_initialized() ext4: get rid of ppath in ext4_convert_unwritten_extents_endio() ext4: get rid of ppath in ext4_split_convert_extents() ext4: get rid of ppath in ext4_split_extent() ext4: get rid of ppath in ext4_force_split_extent_at() ext4: get rid of ppath in ext4_split_extent_at() ...

ext4: store cookie in private data

2024-09-09T09:58:08+00:00

Store the cookie to detect concurrent seeks on directories in file->private_data. Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-11-6d3e4816aa7b@kernel.org Acked-by: Theodore Ts'o Reviewed-by: Jan Kara Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner

ext4: correct encrypted dentry name hash when not casefolded

2024-08-27T01:20:25+00:00

EXT4_DIRENT_HASH and EXT4_DIRENT_MINOR_HASH will access struct ext4_dir_entry_hash followed ext4_dir_entry. But there is no ext4_dir_entry_hash followed when inode is encrypted and not casefolded Signed-off-by: yao.ly Link: https://patch.msgid.link/1719816219-128287-1-git-send-email-yao.ly@linux.alibaba.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

use ->bd_mapping instead of ->bd_inode->i_mapping

2024-05-03T06:36:51+00:00

Just the low-hanging fruit... Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20240411145346.2516848-2-viro@zeniv.linux.org.uk Signed-off-by: Christian Brauner

ext4: fix spelling errors in comments

2022-05-11T19:19:06+00:00

'functoin' and 'entres' should be 'function' and 'entries' respectively Signed-off-by: Chin Yik Ming Link: https://lore.kernel.org/r/20220402090744.8918-1-yikming2222@gmail.com Signed-off-by: Theodore Ts'o