kernel/git/stable/linux-stable.git/fs/ext4, branch linux-4.19.y

ext4: fix FS_IOC_GETFSMAP handling

2024-12-05T09:59:38+00:00

commit 4a622e4d477bb12ad5ed4abbc7ad1365de1fa347 upstream. The original implementation ext4's FS_IOC_GETFSMAP handling only worked when the range of queried blocks included at least one free (unallocated) block range. This is because how the metadata blocks were emitted was as a side effect of ext4_mballoc_query_range() calling ext4_getfsmap_datadev_helper(), and that function was only called when a free block range was identified. As a result, this caused generic/365 to fail. Fix this by creating a new function ext4_getfsmap_meta_helper() which gets called so that blocks before the first free block range in a block group can get properly reported. Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: supress data-race warnings in ext4_free_inodes_{count,set}()

2024-12-05T09:59:38+00:00

commit 902cc179c931a033cd7f4242353aa2733bf8524c upstream. find_group_other() and find_group_orlov() read *_lo, *_hi with ext4_free_inodes_count without additional locking. This can cause data-race warning, but since the lock is held for most writes and free inodes value is generally not a problem even if it is incorrect, it is more appropriate to use READ_ONCE()/WRITE_ONCE() than to add locking. ================================================================== BUG: KCSAN: data-race in ext4_free_inodes_count / ext4_free_inodes_set write to 0xffff88810404300e of 2 bytes by task 6254 on cpu 1: ext4_free_inodes_set+0x1f/0x80 fs/ext4/super.c:405 __ext4_new_inode+0x15ca/0x2200 fs/ext4/ialloc.c:1216 ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391 vfs_symlink+0xca/0x1d0 fs/namei.c:4615 do_symlinkat+0xe3/0x340 fs/namei.c:4641 __do_sys_symlinkat fs/namei.c:4657 [inline] __se_sys_symlinkat fs/namei.c:4654 [inline] __x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654 x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e read to 0xffff88810404300e of 2 bytes by task 6257 on cpu 0: ext4_free_inodes_count+0x1c/0x80 fs/ext4/super.c:349 find_group_other fs/ext4/ialloc.c:594 [inline] __ext4_new_inode+0x6ec/0x2200 fs/ext4/ialloc.c:1017 ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391 vfs_symlink+0xca/0x1d0 fs/namei.c:4615 do_symlinkat+0xe3/0x340 fs/namei.c:4641 __do_sys_symlinkat fs/namei.c:4657 [inline] __se_sys_symlinkat fs/namei.c:4654 [inline] __x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654 x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e Cc: stable@vger.kernel.org Signed-off-by: Jeongjun Park Reviewed-by: Andreas Dilger Link: https://patch.msgid.link/20241003125337.47283-1-aha310510@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: nested locking for xattr inode

2024-11-08T15:19:16+00:00

[ Upstream commit d1bc560e9a9c78d0b2314692847fc8661e0aeb99 ] Add nested locking with I_MUTEX_XATTR subclass to avoid lockdep warning while handling xattr inode on file open syscall at ext4_xattr_inode_iget. Backtrace EXT4-fs (loop0): Ignoring removed oldalloc option ====================================================== WARNING: possible circular locking dependency detected 5.10.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor543/2794 is trying to acquire lock: ffff8880215e1a48 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:782 [inline] ffff8880215e1a48 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425 but task is already holding lock: ffff8880215e3278 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x136d/0x19c0 fs/ext4/inode.c:5559 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ei->i_data_sem/3){++++}-{3:3}: lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566 down_write+0x93/0x180 kernel/locking/rwsem.c:1564 ext4_update_i_disksize fs/ext4/ext4.h:3267 [inline] ext4_xattr_inode_write fs/ext4/xattr.c:1390 [inline] ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1538 [inline] ext4_xattr_set_entry+0x331a/0x3d80 fs/ext4/xattr.c:1662 ext4_xattr_ibody_set+0x124/0x390 fs/ext4/xattr.c:2228 ext4_xattr_set_handle+0xc27/0x14e0 fs/ext4/xattr.c:2385 ext4_xattr_set+0x219/0x390 fs/ext4/xattr.c:2498 ext4_xattr_user_set+0xc9/0xf0 fs/ext4/xattr_user.c:40 __vfs_setxattr+0x404/0x450 fs/xattr.c:177 __vfs_setxattr_noperm+0x11d/0x4f0 fs/xattr.c:208 __vfs_setxattr_locked+0x1f9/0x210 fs/xattr.c:266 vfs_setxattr+0x112/0x2c0 fs/xattr.c:283 setxattr+0x1db/0x3e0 fs/xattr.c:548 path_setxattr+0x15a/0x240 fs/xattr.c:567 __do_sys_setxattr fs/xattr.c:582 [inline] __se_sys_setxattr fs/xattr.c:578 [inline] __x64_sys_setxattr+0xc5/0xe0 fs/xattr.c:578 do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62 entry_SYSCALL_64_after_hwframe+0x61/0xcb -> #0 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain+0x1695/0x58f0 kernel/locking/lockdep.c:3729 __lock_acquire+0x12fd/0x20d0 kernel/locking/lockdep.c:4955 lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566 down_write+0x93/0x180 kernel/locking/rwsem.c:1564 inode_lock include/linux/fs.h:782 [inline] ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425 ext4_xattr_inode_get+0x138/0x410 fs/ext4/xattr.c:485 ext4_xattr_move_to_block fs/ext4/xattr.c:2580 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2682 [inline] ext4_expand_extra_isize_ea+0xe70/0x1bb0 fs/ext4/xattr.c:2774 __ext4_expand_extra_isize+0x304/0x3f0 fs/ext4/inode.c:5898 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline] __ext4_mark_inode_dirty+0x591/0x810 fs/ext4/inode.c:6018 ext4_setattr+0x1400/0x19c0 fs/ext4/inode.c:5562 notify_change+0xbb6/0xe60 fs/attr.c:435 do_truncate+0x1de/0x2c0 fs/open.c:64 handle_truncate fs/namei.c:2970 [inline] do_open fs/namei.c:3311 [inline] path_openat+0x29f3/0x3290 fs/namei.c:3425 do_filp_open+0x20b/0x450 fs/namei.c:3452 do_sys_openat2+0x124/0x460 fs/open.c:1207 do_sys_open fs/open.c:1223 [inline] __do_sys_open fs/open.c:1231 [inline] __se_sys_open fs/open.c:1227 [inline] __x64_sys_open+0x221/0x270 fs/open.c:1227 do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62 entry_SYSCALL_64_after_hwframe+0x61/0xcb other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_data_sem/3); lock(&ea_inode->i_rwsem#7/1); lock(&ei->i_data_sem/3); lock(&ea_inode->i_rwsem#7/1); *** DEADLOCK *** 5 locks held by syz-executor543/2794: #0: ffff888026fbc448 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x4a/0x2a0 fs/namespace.c:365 #1: ffff8880215e3488 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:782 [inline] #1: ffff8880215e3488 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: do_truncate+0x1cf/0x2c0 fs/open.c:62 #2: ffff8880215e3310 (&ei->i_mmap_sem){++++}-{3:3}, at: ext4_setattr+0xec4/0x19c0 fs/ext4/inode.c:5519 #3: ffff8880215e3278 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x136d/0x19c0 fs/ext4/inode.c:5559 #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline] #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5938 [inline] #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4fb/0x810 fs/ext4/inode.c:6018 stack backtrace: CPU: 1 PID: 2794 Comm: syz-executor543 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x177/0x211 lib/dump_stack.c:118 print_circular_bug+0x146/0x1b0 kernel/locking/lockdep.c:2002 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2123 check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain+0x1695/0x58f0 kernel/locking/lockdep.c:3729 __lock_acquire+0x12fd/0x20d0 kernel/locking/lockdep.c:4955 lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566 down_write+0x93/0x180 kernel/locking/rwsem.c:1564 inode_lock include/linux/fs.h:782 [inline] ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425 ext4_xattr_inode_get+0x138/0x410 fs/ext4/xattr.c:485 ext4_xattr_move_to_block fs/ext4/xattr.c:2580 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2682 [inline] ext4_expand_extra_isize_ea+0xe70/0x1bb0 fs/ext4/xattr.c:2774 __ext4_expand_extra_isize+0x304/0x3f0 fs/ext4/inode.c:5898 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline] __ext4_mark_inode_dirty+0x591/0x810 fs/ext4/inode.c:6018 ext4_setattr+0x1400/0x19c0 fs/ext4/inode.c:5562 notify_change+0xbb6/0xe60 fs/attr.c:435 do_truncate+0x1de/0x2c0 fs/open.c:64 handle_truncate fs/namei.c:2970 [inline] do_open fs/namei.c:3311 [inline] path_openat+0x29f3/0x3290 fs/namei.c:3425 do_filp_open+0x20b/0x450 fs/namei.c:3452 do_sys_openat2+0x124/0x460 fs/open.c:1207 do_sys_open fs/open.c:1223 [inline] __do_sys_open fs/open.c:1231 [inline] __se_sys_open fs/open.c:1227 [inline] __x64_sys_open+0x221/0x270 fs/open.c:1227 do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f0cde4ea229 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd81d1c978 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0030656c69662f30 RCX: 00007f0cde4ea229 RDX: 0000000000000089 RSI: 00000000000a0a00 RDI: 00000000200001c0 RBP: 2f30656c69662f2e R08: 0000000000208000 R09: 0000000000208000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd81d1c9c0 R13: 00007ffd81d1ca00 R14: 0000000000080000 R15: 0000000000000003 EXT4-fs error (device loop0): ext4_expand_extra_isize_ea:2730: inode #13: comm syz-executor543: corrupted in-inode xattr Signed-off-by: Wojciech Gładysz Link: https://patch.msgid.link/20240801143827.19135-1-wojciech.gladysz@infogain.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix inode tree inconsistency caused by ENOMEM

2024-11-08T15:19:16+00:00

commit 3f5424790d4377839093b68c12b130077a4e4510 upstream. If ENOMEM fails when the extent is splitting, we need to restore the length of the split extent. In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will it alloc memory and change the shape of the extent tree,even if an ENOMEM is returned at this time, the extent tree is still self-consistent, Just restore the split extent lens in the function ext4_split_extent_at. ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf 1)ext4_ext_split ext4_find_extent 2)ext4_ext_grow_indepth ext4_find_extent Signed-off-by: zhanchengbin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230103022812.130603-1-zhanchengbin1@huawei.com Signed-off-by: Theodore Ts'o Cc: Baokun Li Signed-off-by: Greg Kroah-Hartman

ext4: update orig_path in ext4_find_extent()

2024-11-08T15:19:15+00:00

[ Upstream commit 5b4b2dcace35f618fe361a87bae6f0d13af31bc1 ] In ext4_find_extent(), if the path is not big enough, we free it and set *orig_path to NULL. But after reallocating and successfully initializing the path, we don't update *orig_path, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example: ext4_split_extent path = *ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); *orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(*ppath = NULL) path = *ppath; ex = path[depth].p_ext; // NULL pointer dereference! ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Call Trace: ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ================================================================== Therefore, *orig_path is updated when the extent lookup succeeds, so that the caller can safely use path or *ppath. Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240822023545.1994557-6-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix slab-use-after-free in ext4_split_extent_at()

2024-11-08T15:19:15+00:00

[ Upstream commit c26ab35702f8cd0cdc78f96aa5856bfb77be798f ] We hit the following use-after-free: ================================================================== BUG: KASAN: slab-use-after-free in ext4_split_extent_at+0xba8/0xcc0 Read of size 2 at addr ffff88810548ed08 by task kworker/u20:0/40 CPU: 0 PID: 40 Comm: kworker/u20:0 Not tainted 6.9.0-dirty #724 Call Trace: kasan_report+0x93/0xc0 ext4_split_extent_at+0xba8/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Allocated by task 40: __kmalloc_noprof+0x1ac/0x480 ext4_find_extent+0xf3b/0x1e70 ext4_ext_map_blocks+0x188/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Freed by task 40: kfree+0xf1/0x2b0 ext4_find_extent+0xa71/0x1e70 ext4_ext_insert_extent+0xa22/0x3260 ext4_split_extent_at+0x3ef/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ================================================================== The flow of issue triggering is as follows: ext4_split_extent_at path = *ppath ext4_ext_insert_extent(ppath) ext4_ext_create_new_leaf(ppath) ext4_find_extent(orig_path) path = *orig_path read_extent_tree_block // return -ENOMEM or -EIO ext4_free_ext_path(path) kfree(path) *orig_path = NULL a. If err is -ENOMEM: ext4_ext_dirty(path + path->p_depth) // path use-after-free !!! b. If err is -EIO and we have EXT_DEBUG defined: ext4_ext_show_leaf(path) eh = path[depth].p_hdr // path also use-after-free !!! So when trying to zeroout or fix the extent length, call ext4_find_extent() to update the path. In addition we use *ppath directly as an ext4_ext_show_leaf() input to avoid possible use-after-free when EXT_DEBUG is defined, and to avoid unnecessary path updates. Fixes: dfe5080939ea ("ext4: drop EXT4_EX_NOFREE_ON_ERR from rest of extents handling code") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-4-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: avoid ext4_error()'s caused by ENOMEM in the truncate path

2024-11-08T15:19:15+00:00

[ Upstream commit 73c384c0cdaa8ea9ca9ef2d0cff6a25930f1648e ] We can't fail in the truncate path without requiring an fsck. Add work around for this by using a combination of retry loops and the __GFP_NOFAIL flag. From: Theodore Ts'o Signed-off-by: Theodore Ts'o Signed-off-by: Anna Pendleton Reviewed-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20200507175028.15061-1-pendleton@google.com Signed-off-by: Theodore Ts'o Stable-dep-of: c26ab35702f8 ("ext4: fix slab-use-after-free in ext4_split_extent_at()") Signed-off-by: Sasha Levin

ext4: fix incorrect tid assumption in ext4_wait_for_tail_page_commit()

2024-11-08T15:19:14+00:00

commit dd589b0f1445e1ea1085b98edca6e4d5dedb98d0 upstream. Function ext4_wait_for_tail_page_commit() assumes that '0' is not a valid value for transaction IDs, which is incorrect. Don't assume that and invoke jbd2_log_wait_commit() if the journal had a committing transaction instead. Signed-off-by: Luis Henriques (SUSE) Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240724161119.13448-2-luis.henriques@linux.dev Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix double brelse() the buffer of the extents path

2024-11-08T15:19:14+00:00

commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: aovid use-after-free in ext4_ext_insert_extent()

2024-11-08T15:19:14+00:00

commit a164f3a432aae62ca23d03e6d926b122ee5b860d upstream. As Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is reallocated in ext4_ext_create_new_leaf(), we'll use the stale path and cause UAF. Below is a sample trace with dummy values: ext4_ext_insert_extent path = *ppath = 2000 ext4_ext_create_new_leaf(ppath) ext4_find_extent(ppath) path = *ppath = 2000 if (depth > path[0].p_maxdepth) kfree(path = 2000); *ppath = path = NULL; path = kcalloc() = 3000 *ppath = 3000; return path; /* here path is still 2000, UAF! */ eh = path[depth].p_hdr ================================================================== BUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330 Read of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179 CPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866 Call Trace: ext4_ext_insert_extent+0x26d4/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 [...] Allocated by task 179: ext4_find_extent+0x81c/0x1f70 ext4_ext_map_blocks+0x146/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] Freed by task 179: kfree+0xcb/0x240 ext4_find_extent+0x7c0/0x1f70 ext4_ext_insert_extent+0xa26/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] ================================================================== So use *ppath to update the path to avoid the above problem. Reported-by: Ojaswin Mujoo Closes: https://lore.kernel.org/r/ZqyL6rmtwl6N4MWR@li-bb2b2a4c-3307-11b2-a85c-8fa5c3a69313.ibm.com Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240822023545.1994557-7-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman