linux-stable.git/fs/nilfs2, branch linux-6.10.y

nilfs2: fix potential oob read in nilfs_btree_check_delete()

2024-10-04T14:32:58+00:00

[ Upstream commit f9c96351aa6718b42a9f42eaf7adce0356bdb5e8 ]

The function nilfs_btree_check_delete(), which checks whether degeneration
to direct mapping occurs before deleting a b-tree entry, causes memory
access outside the block buffer when retrieving the maximum key if the
root node has no entries.

This does not usually happen because b-tree mappings with 0 child nodes
are never created by mkfs.nilfs2 or nilfs2 itself.  However, it can happen
if the b-tree root node read from a device is configured that way, so fix
this potential issue by adding a check for that case.

Link: https://lkml.kernel.org/r/20240904081401.16682-4-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi 
Cc: Lizhi Xu 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

nilfs2: determine empty node blocks as corrupted

2024-10-04T14:32:58+00:00

[ Upstream commit 111b812d3662f3a1b831d19208f83aa711583fe6 ]

Due to the nature of b-trees, nilfs2 itself and admin tools such as
mkfs.nilfs2 will never create an intermediate b-tree node block with 0
child nodes, nor will they delete (key, pointer)-entries that would result
in such a state.  However, it is possible that a b-tree node block is
corrupted on the backing device and is read with 0 child nodes.

Because operation is not guaranteed if the number of child nodes is 0 for
intermediate node blocks other than the root node, modify
nilfs_btree_node_broken(), which performs sanity checks when reading a
b-tree node block, so that such cases will be judged as metadata
corruption.

Link: https://lkml.kernel.org/r/20240904081401.16682-3-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi 
Cc: Lizhi Xu 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

nilfs2: fix potential null-ptr-deref in nilfs_btree_insert()

2024-10-04T14:32:58+00:00

[ Upstream commit 9403001ad65ae4f4c5de368bdda3a0636b51d51a ]

Patch series "nilfs2: fix potential issues with empty b-tree nodes".

This series addresses three potential issues with empty b-tree nodes that
can occur with corrupted filesystem images, including one recently
discovered by syzbot.

This patch (of 3):

If a b-tree is broken on the device, and the b-tree height is greater than
2 (the level of the root node is greater than 1) even if the number of
child nodes of the b-tree root is 0, a NULL pointer dereference occurs in
nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert().

This is because, when the number of child nodes of the b-tree root is 0,
nilfs_btree_do_lookup() does not set the block buffer head in any of
path[x].bp_bh, leaving it as the initial value of NULL, but if the level
of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(),
which accesses the buffer memory of path[x].bp_bh, is called.

Fix this issue by adding a check to nilfs_btree_root_broken(), which
performs sanity checks when reading the root node from the device, to
detect this inconsistency.

Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause
early on.

Link: https://lkml.kernel.org/r/20240904081401.16682-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240902084101.138971-1-lizhi.xu@windriver.com
Link: https://lkml.kernel.org/r/20240904081401.16682-2-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi 
Reported-by: syzbot+9bff4c7b992038a7409f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9bff4c7b992038a7409f
Cc: Lizhi Xu 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

nilfs2: fix state management in error path of log writing function

2024-09-12T09:12:48+00:00

commit 6576dd6695f2afca3f4954029ac4a64f82ba60ab upstream.

After commit a694291a6211 ("nilfs2: separate wait function from
nilfs_segctor_write") was applied, the log writing function
nilfs_segctor_do_construct() was able to issue I/O requests continuously
even if user data blocks were split into multiple logs across segments,
but two potential flaws were introduced in its error handling.

First, if nilfs_segctor_begin_construction() fails while creating the
second or subsequent logs, the log writing function returns without
calling nilfs_segctor_abort_construction(), so the writeback flag set on
pages/folios will remain uncleared.  This causes page cache operations to
hang waiting for the writeback flag.  For example,
truncate_inode_pages_final(), which is called via nilfs_evict_inode() when
an inode is evicted from memory, will hang.

Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared.
As a result, if the next log write involves checkpoint creation, that's
fine, but if a partial log write is performed that does not, inodes with
NILFS_I_COLLECTED set are erroneously removed from the "sc_dirty_files"
list, and their data and b-tree blocks may not be written to the device,
corrupting the block mapping.

Fix these issues by uniformly calling nilfs_segctor_abort_construction()
on failure of each step in the loop in nilfs_segctor_do_construct(),
having it clean up logs and segment usages according to progress, and
correcting the conditions for calling nilfs_redirty_inodes() to ensure
that the NILFS_I_COLLECTED flag is cleared.

Link: https://lkml.kernel.org/r/20240814101119.4070-1-konishi.ryusuke@gmail.com
Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write")
Signed-off-by: Ryusuke Konishi 
Tested-by: Ryusuke Konishi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

nilfs2: protect references to superblock parameters exposed in sysfs

2024-09-12T09:12:48+00:00

commit 683408258917541bdb294cd717c210a04381931e upstream.

The superblock buffers of nilfs2 can not only be overwritten at runtime
for modifications/repairs, but they are also regularly swapped, replaced
during resizing, and even abandoned when degrading to one side due to
backing device issues.  So, accessing them requires mutual exclusion using
the reader/writer semaphore "nilfs->ns_sem".

Some sysfs attribute show methods read this superblock buffer without the
necessary mutual exclusion, which can cause problems with pointer
dereferencing and memory access, so fix it.

Link: https://lkml.kernel.org/r/20240811100320.9913-1-konishi.ryusuke@gmail.com
Fixes: da7141fb78db ("nilfs2: add /sys/fs/nilfs2/ group")
Signed-off-by: Ryusuke Konishi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

nilfs2: fix missing cleanup on rollforward recovery error

2024-09-12T09:12:48+00:00

commit 5787fcaab9eb5930f5378d6a1dd03d916d146622 upstream.

In an error injection test of a routine for mount-time recovery, KASAN
found a use-after-free bug.

It turned out that if data recovery was performed using partial logs
created by dsync writes, but an error occurred before starting the log
writer to create a recovered checkpoint, the inodes whose data had been
recovered were left in the ns_dirty_files list of the nilfs object and
were not freed.

Fix this issue by cleaning up inodes that have read the recovery data if
the recovery routine fails midway before the log writer starts.

Link: https://lkml.kernel.org/r/20240810065242.3701-1-konishi.ryusuke@gmail.com
Fixes: 0f3e1c7f23f8 ("nilfs2: recovery functions")
Signed-off-by: Ryusuke Konishi 
Tested-by: Ryusuke Konishi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

nilfs2: handle inconsistent state in nilfs_btnode_create_block()

2024-08-03T07:00:47+00:00

commit 4811f7af6090e8f5a398fbdd766f903ef6c0d787 upstream.

Syzbot reported that a buffer state inconsistency was detected in
nilfs_btnode_create_block(), triggering a kernel bug.

It is not appropriate to treat this inconsistency as a bug; it can occur
if the argument block address (the buffer index of the newly created
block) is a virtual block number and has been reallocated due to
corruption of the bitmap used to manage its allocation state.

So, modify nilfs_btnode_create_block() and its callers to treat it as a
possible filesystem error, rather than triggering a kernel bug.

Link: https://lkml.kernel.org/r/20240725052007.4562-1-konishi.ryusuke@gmail.com
Fixes: a60be987d45d ("nilfs2: B-tree node cache")
Signed-off-by: Ryusuke Konishi 
Reported-by: syzbot+89cc4f2324ed37988b60@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=89cc4f2324ed37988b60
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

nilfs2: avoid undefined behavior in nilfs_cnt32_ge macro

2024-08-03T07:00:25+00:00

[ Upstream commit 0f3819e8c483771a59cf9d3190cd68a7a990083c ]

According to the C standard 3.4.3p3, the result of signed integer overflow
is undefined.  The macro nilfs_cnt32_ge(), which compares two sequence
numbers, uses signed integer subtraction that can overflow, and therefore
the result of the calculation may differ from what is expected due to
undefined behavior in different environments.

Similar to an earlier change to the jiffies-related comparison macros in
commit 5a581b367b5d ("jiffies: Avoid undefined behavior from signed
overflow"), avoid this potential issue by changing the definition of the
macro to perform the subtraction as unsigned integers, then cast the
result to a signed integer for comparison.

Link: https://lkml.kernel.org/r/20130727225828.GA11864@linux.vnet.ibm.com
Link: https://lkml.kernel.org/r/20240702183512.6390-1-konishi.ryusuke@gmail.com
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

nilfs2: fix kernel bug on rename operation of broken directory

2024-07-04T05:40:38+00:00

Syzbot reported that in rename directory operation on broken directory on
nilfs2, __block_write_begin_int() called to prepare block write may fail
BUG_ON check for access exceeding the folio/page size.

This is because nilfs_dotdot(), which gets parent directory reference
entry ("..") of the directory to be moved or renamed, does not check
consistency enough, and may return location exceeding folio/page size for
broken directories.

Fix this issue by checking required directory entries ("." and "..") in
the first chunk of the directory in nilfs_dotdot().

Link: https://lkml.kernel.org/r/20240628165107.9006-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi 
Reported-by: syzbot+d3abed1ad3d367fa2627@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d3abed1ad3d367fa2627
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi 
Cc: 
Signed-off-by: Andrew Morton

nilfs2: fix incorrect inode allocation from reserved inodes

2024-07-03T19:29:25+00:00

If the bitmap block that manages the inode allocation status is corrupted,
nilfs_ifile_create_inode() may allocate a new inode from the reserved
inode area where it should not be allocated.

Previous fix commit d325dc6eb763 ("nilfs2: fix use-after-free bug of
struct nilfs_root"), fixed the problem that reserved inodes with inode
numbers less than NILFS_USER_INO (=11) were incorrectly reallocated due to
bitmap corruption, but since the start number of non-reserved inodes is
read from the super block and may change, in which case inode allocation
may occur from the extended reserved inode area.

If that happens, access to that inode will cause an IO error, causing the
file system to degrade to an error state.

Fix this potential issue by adding a wraparound option to the common
metadata object allocation routine and by modifying
nilfs_ifile_create_inode() to disable the option so that it only allocates
inodes with inode numbers greater than or equal to the inode number read
in "nilfs->ns_first_ino", regardless of the bitmap status of reserved
inodes.

Link: https://lkml.kernel.org/r/20240623051135.4180-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi 
Cc: Hillf Danton 
Cc: Jan Kara 
Cc: Matthew Wilcox (Oracle) 
Cc: 
Signed-off-by: Andrew Morton