kernel/linux.git/fs/ext4/xattr.c, branch v6.1

ext4: fix i_version handling in ext4

2022-10-01T03:46:52+00:00

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

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

ext4: fast commit may not fallback for ineligible commit

2022-02-03T15:56:39+00:00

For the follow scenario: 1. jbd start commit transaction n 2. task A get new handle for transaction n+1 3. task A do some ineligible actions and mark FC_INELIGIBLE 4. jbd complete transaction n and clean FC_INELIGIBLE 5. task A call fsync In this case fast commit will not fallback to full commit and transaction n+1 also not handled by jbd. Make ext4_fc_mark_ineligible() also record transaction tid for latest ineligible case, when call ext4_fc_cleanup() check current transaction tid, if small than latest ineligible tid do not clear the EXT4_MF_FC_INELIGIBLE. Reported-by: kernel test robot Reported-by: Dan Carpenter Reported-by: Ritesh Harjani Suggested-by: Harshad Shirwadkar Signed-off-by: Xin Yin Link: https://lore.kernel.org/r/20220117093655.35160-2-yinxin.x@bytedance.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

ext4: Support for checksumming from journal triggers

2021-08-31T03:36:50+00:00

JBD2 layer support triggers which are called when journaling layer moves buffer to a certain state. We can use the frozen trigger, which gets called when buffer data is frozen and about to be written out to the journal, to compute block checksums for some buffer types (similarly as does ocfs2). This avoids unnecessary repeated recomputation of the checksum (at the cost of larger window where memory corruption won't be caught by checksumming) and is even necessary when there are unsynchronized updaters of the checksummed data. So add superblock and journal trigger type arguments to ext4_journal_get_write_access() and ext4_journal_get_create_access() so that frozen triggers can be set accordingly. Also add inode argument to ext4_walk_page_buffers() and all the callbacks used with that function for the same purpose. This patch is mostly only a change of prototype of the above mentioned functions and a few small helpers. Real checksumming will come later. Reviewed-by: Theodore Ts'o Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20210816095713.16537-1-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: remove duplicate definition of ext4_xattr_ibody_inline_set()

2021-06-24T14:09:39+00:00

ext4_xattr_ibody_inline_set() & ext4_xattr_ibody_set() have the exact same definition. Hence remove ext4_xattr_ibody_inline_set() and all its call references. Convert the callers of it to call ext4_xattr_ibody_set() instead. [ Modified to preserve ext4_xattr_ibody_set() and remove ext4_xattr_ibody_inline_set() instead. -- TYT ] Signed-off-by: Ritesh Harjani Link: https://lore.kernel.org/r/fd566b799bbbbe9b668eb5eecde5b5e319e3694f.1622685482.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o

ext4: fix various seppling typos

2021-04-10T03:14:59+00:00

Signed-off-by: Bhaskar Chowdhury Link: https://lore.kernel.org/r/cover.1616840203.git.unixbhaskar@gmail.com Signed-off-by: Theodore Ts'o