kernel/git/stable/linux.git/fs/ext4, branch linux-5.18.y

ext4: fix race when reusing xattr blocks

2022-08-17T12:42:32+00:00

[ Upstream commit 65f8b80053a1b2fd602daa6814e62d6fa90e5e9b ] 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 Signed-off-by: Sasha Levin

ext4: unindent codeblock in ext4_xattr_block_set()

2022-08-17T12:42:32+00:00

[ Upstream commit fd48e9acdf26d0cbd80051de07d4a735d05d29b2 ] 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 Signed-off-by: Sasha Levin

ext4: use kmemdup() to replace kmalloc + memcpy

2022-08-17T12:42:32+00:00

[ Upstream commit 4efd9f0d120c55b08852ee5605dbb02a77089a5d ] 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 Signed-off-by: Sasha Levin

ext4: remove EA inode entry from mbcache on inode eviction

2022-08-17T12:42:32+00:00

[ Upstream commit 6bc0d63dad7f9f54d381925ee855b402f652fa39 ] 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 Signed-off-by: Sasha Levin

ext4: make sure ext4_append() always allocates new block

2022-08-17T12:42:31+00:00

[ Upstream commit b8a04fe77ef1360fbf73c80fddbdfeaa9407ed1b ] ext4_append() must always allocate a new block, otherwise we run the risk of overwriting existing directory block corrupting the directory tree in the process resulting in all manner of problems later on. Add a sanity check to see if the logical block is already allocated and error out if it is. Cc: stable@kernel.org Signed-off-by: Lukas Czerner Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20220704142721.157985-2-lczerner@redhat.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: check if directory block is within i_size

2022-08-17T12:42:31+00:00

[ Upstream commit 65f8ea4cd57dbd46ea13b41dc8bac03176b04233 ] Currently ext4 directory handling code implicitly assumes that the directory blocks are always within the i_size. In fact ext4_append() will attempt to allocate next directory block based solely on i_size and the i_size is then appropriately increased after a successful allocation. However, for this to work it requires i_size to be correct. If, for any reason, the directory inode i_size is corrupted in a way that the directory tree refers to a valid directory block past i_size, we could end up corrupting parts of the directory tree structure by overwriting already used directory blocks when modifying the directory. Fix it by catching the corruption early in __ext4_read_dirblock(). Addresses Red-Hat-Bugzilla: #2070205 CVE: CVE-2022-1184 Signed-off-by: Lukas Czerner Cc: stable@vger.kernel.org Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20220704142721.157985-1-lczerner@redhat.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix warning in ext4_iomap_begin as race between bmap and write

2022-08-17T12:42:31+00:00

[ Upstream commit 51ae846cff568c8c29921b1b28eb2dfbcd4ac12d ] We got issue as follows: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 9310 at fs/ext4/inode.c:3441 ext4_iomap_begin+0x182/0x5d0 RIP: 0010:ext4_iomap_begin+0x182/0x5d0 RSP: 0018:ffff88812460fa08 EFLAGS: 00010293 RAX: ffff88811f168000 RBX: 0000000000000000 RCX: ffffffff97793c12 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: ffff88812c669160 R08: ffff88811f168000 R09: ffffed10258cd20f R10: ffff88812c669077 R11: ffffed10258cd20e R12: 0000000000000001 R13: 00000000000000a4 R14: 000000000000000c R15: ffff88812c6691ee FS: 00007fd0d6ff3740(0000) GS:ffff8883af180000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0d6dda290 CR3: 0000000104a62000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: iomap_apply+0x119/0x570 iomap_bmap+0x124/0x150 ext4_bmap+0x14f/0x250 bmap+0x55/0x80 do_vfs_ioctl+0x952/0xbd0 __x64_sys_ioctl+0xc6/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Above issue may happen as follows: bmap write bmap ext4_bmap iomap_bmap ext4_iomap_begin ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin ext4_da_write_inline_data_begin ext4_prepare_inline_data ext4_create_inline_data ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA); if (WARN_ON_ONCE(ext4_has_inline_data(inode))) ->trigger bug_on To solved above issue hold inode lock in ext4_bamp. Signed-off-by: Ye Bin Link: https://lore.kernel.org/r/20220617013935.397596-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Sasha Levin

ext4: correct the misjudgment in ext4_iget_extra_inode

2022-08-17T12:42:31+00:00

[ Upstream commit fd7e672ea98b95b9d4c9dae316639f03c16a749d ] Use the EXT4_INODE_HAS_XATTR_SPACE macro to more accurately determine whether the inode have xattr space. Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220616021358.2504451-5-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: correct max_inline_xattr_value_size computing

2022-08-17T12:42:31+00:00

[ Upstream commit c9fd167d57133c5b748d16913c4eabc55e531c73 ] If the ext4 inode does not have xattr space, 0 is returned in the get_max_inline_xattr_value_size function. Otherwise, the function returns a negative value when the inode does not contain EXT4_STATE_XATTR. Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220616021358.2504451-4-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix use-after-free in ext4_xattr_set_entry

2022-08-17T12:42:31+00:00

[ Upstream commit 67d7d8ad99beccd9fe92d585b87f1760dc9018e3 ] 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 Signed-off-by: Sasha Levin