kernel/linux.git/fs/ext4/xattr.c, branch linux-6.0.y

ext4: allocate extended attribute value in vmalloc area

2023-01-07T10:16:05+00:00

commit cc12a6f25e07ed05d5825a1664b67a970842b2ca upstream. Now, extended attribute value maximum length is 64K. The memory requested here does not need continuous physical addresses, so it is appropriate to use kvmalloc to request memory. At the same time, it can also cope with the situation that the extended attribute will become longer in the future. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20221208023233.1231330-3-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix inode leak in ext4_xattr_inode_create() on an error path

2023-01-07T10:16:05+00:00

commit e4db04f7d3dbbe16680e0ded27ea2a65b10f766a upstream. There is issue as follows when do setxattr with inject fault: [localhost]# fsck.ext4 -fn /dev/sda e2fsck 1.46.6-rc1 (12-Sep-2022) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Unattached zero-length inode 15. Clear? no Unattached inode 15 Connect to /lost+found? no Pass 5: Checking group summary information /dev/sda: ********** WARNING: Filesystem still has errors ********** /dev/sda: 15/655360 files (0.0% non-contiguous), 66755/2621440 blocks This occurs in 'ext4_xattr_inode_create()'. If 'ext4_mark_inode_dirty()' fails, dropping i_nlink of the inode is needed. Or will lead to inode leak. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20221208023233.1231330-5-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix deadlock due to mbcache entry corruption

2023-01-07T10:16:04+00:00

commit a44e84a9b7764c72896f7241a0ec9ac7e7ef38dd upstream. When manipulating xattr blocks, we can deadlock infinitely looping inside ext4_xattr_block_set() where we constantly keep finding xattr block for reuse in mbcache but we are unable to reuse it because its reference count is too big. This happens because cache entry for the xattr block is marked as reusable (e_reusable set) although its reference count is too big. When this inconsistency happens, this inconsistent state is kept indefinitely and so ext4_xattr_block_set() keeps retrying indefinitely. The inconsistent state is caused by non-atomic update of e_reusable bit. e_reusable is part of a bitfield and e_reusable update can race with update of e_referenced bit in the same bitfield resulting in loss of one of the updates. Fix the problem by using atomic bitops instead. This bug has been around for many years, but it became *much* easier to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr blocks"). Cc: stable@vger.kernel.org Fixes: 6048c64b2609 ("mbcache: add reusable flag to cache entries") Fixes: 65f8b80053a1 ("ext4: fix race when reusing xattr blocks") Reported-and-tested-by: Jeremi Piotrowski Reported-by: Thilo Fromm Link: https://lore.kernel.org/r/c77bf00f-4618-7149-56f1-b8d1664b9d07@linux.microsoft.com/ Signed-off-by: Jan Kara Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20221123193950.16758-1-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: avoid BUG_ON when creating xattrs

2023-01-07T10:16:04+00:00

commit b40ebaf63851b3a401b0dc9263843538f64f5ce6 upstream. Commit fb0a387dcdcd ("ext4: limit block allocations for indirect-block files to < 2^32") added code to try to allocate xattr block with 32-bit block number for indirect block based files on the grounds that these files cannot use larger block numbers. It also added BUG_ON when allocated block could not fit into 32 bits. This is however bogus reasoning because xattr block is stored in inode->i_file_acl and inode->i_file_acl_hi and as such even indirect block based files can happily use full 48 bits for xattr block number. The proper handling seems to be there basically since 64-bit block number support was added. So remove the bogus limitation and BUG_ON. Cc: Eric Sandeen Fixes: fb0a387dcdcd ("ext4: limit block allocations for indirect-block files to < 2^32") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20221121130929.32031-1-jack@suse.cz Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix i_version handling in ext4

2022-10-21T10:37:50+00:00

commit a642c2c0827f5604a93f9fa1e5701eecdce4ae22 upstream. ext4 currently updates the i_version counter when the atime is updated during a read. This is less than ideal as it can cause unnecessary cache invalidations with NFSv4 and unnecessary remeasurements for IMA. The increment in ext4_mark_iloc_dirty is also problematic since it can corrupt the i_version counter for ea_inodes. We aren't bumping the file times in ext4_mark_iloc_dirty, so changing the i_version there seems wrong, and is the cause of both problems. Remove that callsite and add increments to the setattr, setxattr and ioctl codepaths, at the same times that we update the ctime. The i_version bump that already happens during timestamp updates should take care of the rest. In ext4_move_extents, increment the i_version on both inodes, and also add in missing ctime updates. [ Some minor updates since we've already enabled the i_version counter unconditionally already via another patch series. -- TYT ] Cc: stable@kernel.org Cc: Lukas Czerner Reviewed-by: Jan Kara Reviewed-by: Christian Brauner (Microsoft) Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20220908172448.208585-3-jlayton@kernel.org Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix race when reusing xattr blocks

2022-08-03T03:56:25+00:00

When ext4_xattr_block_set() decides to remove xattr block the following race can happen: CPU1 CPU2 ext4_xattr_block_set() ext4_xattr_release_block() new_bh = ext4_xattr_block_cache_find() lock_buffer(bh); ref = le32_to_cpu(BHDR(bh)->h_refcount); if (ref == 1) { ... mb_cache_entry_delete(); unlock_buffer(bh); ext4_free_blocks(); ... ext4_forget(..., bh, ...); jbd2_journal_revoke(..., bh); ext4_journal_get_write_access(..., new_bh, ...) do_get_write_access() jbd2_journal_cancel_revoke(..., new_bh); Later the code in ext4_xattr_block_set() finds out the block got freed and cancels reusal of the block but the revoke stays canceled and so in case of block reuse and journal replay the filesystem can get corrupted. If the race works out slightly differently, we can also hit assertions in the jbd2 code. Fix the problem by making sure that once matching mbcache entry is found, code dropping the last xattr block reference (or trying to modify xattr block in place) waits until the mbcache entry reference is dropped. This way code trying to reuse xattr block is protected from someone trying to drop the last reference to xattr block. Reported-and-tested-by: Ritesh Harjani CC: stable@vger.kernel.org Fixes: 82939d7999df ("ext4: convert to mbcache2") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220712105436.32204-5-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: unindent codeblock in ext4_xattr_block_set()

2022-08-03T03:56:25+00:00

Remove unnecessary else (and thus indentation level) from a code block in ext4_xattr_block_set(). It will also make following code changes easier. No functional changes. CC: stable@vger.kernel.org Fixes: 82939d7999df ("ext4: convert to mbcache2") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220712105436.32204-4-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: remove EA inode entry from mbcache on inode eviction

2022-08-03T03:56:25+00:00

Currently we remove EA inode from mbcache as soon as its xattr refcount drops to zero. However there can be pending attempts to reuse the inode and thus refcount handling code has to handle the situation when refcount increases from zero anyway. So save some work and just keep EA inode in mbcache until it is getting evicted. At that moment we are sure following iget() of EA inode will fail anyway (or wait for eviction to finish and load things from the disk again) and so removing mbcache entry at that moment is fine and simplifies the code a bit. CC: stable@vger.kernel.org Fixes: 82939d7999df ("ext4: convert to mbcache2") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220712105436.32204-3-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: fix use-after-free in ext4_xattr_set_entry

2022-08-03T03:52:34+00:00

Hulk Robot reported a issue: ================================================================== BUG: KASAN: use-after-free in ext4_xattr_set_entry+0x18ab/0x3500 Write of size 4105 at addr ffff8881675ef5f4 by task syz-executor.0/7092 CPU: 1 PID: 7092 Comm: syz-executor.0 Not tainted 4.19.90-dirty #17 Call Trace: [...] memcpy+0x34/0x50 mm/kasan/kasan.c:303 ext4_xattr_set_entry+0x18ab/0x3500 fs/ext4/xattr.c:1747 ext4_xattr_ibody_inline_set+0x86/0x2a0 fs/ext4/xattr.c:2205 ext4_xattr_set_handle+0x940/0x1300 fs/ext4/xattr.c:2386 ext4_xattr_set+0x1da/0x300 fs/ext4/xattr.c:2498 __vfs_setxattr+0x112/0x170 fs/xattr.c:149 __vfs_setxattr_noperm+0x11b/0x2a0 fs/xattr.c:180 __vfs_setxattr_locked+0x17b/0x250 fs/xattr.c:238 vfs_setxattr+0xed/0x270 fs/xattr.c:255 setxattr+0x235/0x330 fs/xattr.c:520 path_setxattr+0x176/0x190 fs/xattr.c:539 __do_sys_lsetxattr fs/xattr.c:561 [inline] __se_sys_lsetxattr fs/xattr.c:557 [inline] __x64_sys_lsetxattr+0xc2/0x160 fs/xattr.c:557 do_syscall_64+0xdf/0x530 arch/x86/entry/common.c:298 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x459fe9 RSP: 002b:00007fa5e54b4c08 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 000000000051bf60 RCX: 0000000000459fe9 RDX: 00000000200003c0 RSI: 0000000020000180 RDI: 0000000020000140 RBP: 000000000051bf60 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000001009 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc73c93fc0 R14: 000000000051bf60 R15: 00007fa5e54b4d80 [...] ================================================================== Above issue may happen as follows: ------------------------------------- ext4_xattr_set ext4_xattr_set_handle ext4_xattr_ibody_find >> s->end < s->base >> no EXT4_STATE_XATTR >> xattr_check_inode is not executed ext4_xattr_ibody_set ext4_xattr_set_entry >> size_t min_offs = s->end - s->base >> UAF in memcpy we can easily reproduce this problem with the following commands: mkfs.ext4 -F /dev/sda mount -o debug_want_extra_isize=128 /dev/sda /mnt touch /mnt/file setfattr -n user.cat -v `seq -s z 4096|tr -d '[:digit:]'` /mnt/file In ext4_xattr_ibody_find, we have the following assignment logic: header = IHDR(inode, raw_inode) = raw_inode + EXT4_GOOD_OLD_INODE_SIZE + i_extra_isize is->s.base = IFIRST(header) = header + sizeof(struct ext4_xattr_ibody_header) is->s.end = raw_inode + s_inode_size In ext4_xattr_set_entry min_offs = s->end - s->base = s_inode_size - EXT4_GOOD_OLD_INODE_SIZE - i_extra_isize - sizeof(struct ext4_xattr_ibody_header) last = s->first free = min_offs - ((void *)last - s->base) - sizeof(__u32) = s_inode_size - EXT4_GOOD_OLD_INODE_SIZE - i_extra_isize - sizeof(struct ext4_xattr_ibody_header) - sizeof(__u32) In the calculation formula, all values except s_inode_size and i_extra_size are fixed values. When i_extra_size is the maximum value s_inode_size - EXT4_GOOD_OLD_INODE_SIZE, min_offs is -4 and free is -8. The value overflows. As a result, the preceding issue is triggered when memcpy is executed. Therefore, when finding xattr or setting xattr, check whether there is space for storing xattr in the inode to resolve this issue. Cc: stable@kernel.org Reported-by: Hulk Robot Signed-off-by: Baokun Li Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220616021358.2504451-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o

ext4: use kmemdup() to replace kmalloc + memcpy

2022-06-18T23:35:43+00:00

Replace kmalloc + memcpy with kmemdup() Signed-off-by: Shuqi Zhang Reviewed-by: Ritesh Harjani Link: https://lore.kernel.org/r/20220525030120.803330-1-zhangshuqi3@huawei.com Signed-off-by: Theodore Ts'o