[5.10,76/86] ext4: fix use-after-free in ext4_search_dir

From: Ye Bin <yebin10@huawei.com>

From: Ye Bin <yebin10@huawei.com>

commit c186f0887fe7061a35cebef024550ec33ef8fbd8 upstream.

We got issue as follows:
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
==================================================================
BUG: KASAN: use-after-free in ext4_search_dir fs/ext4/namei.c:1394 [inline]
BUG: KASAN: use-after-free in search_dirblock fs/ext4/namei.c:1199 [inline]
BUG: KASAN: use-after-free in __ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
Read of size 1 at addr ffff8881317c3005 by task syz-executor117/2331

CPU: 1 PID: 2331 Comm: syz-executor117 Not tainted 5.10.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:83 [inline]
 dump_stack+0x144/0x187 lib/dump_stack.c:124
 print_address_description+0x7d/0x630 mm/kasan/report.c:387
 __kasan_report+0x132/0x190 mm/kasan/report.c:547
 kasan_report+0x47/0x60 mm/kasan/report.c:564
 ext4_search_dir fs/ext4/namei.c:1394 [inline]
 search_dirblock fs/ext4/namei.c:1199 [inline]
 __ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
 ext4_lookup_entry fs/ext4/namei.c:1622 [inline]
 ext4_lookup+0xb8/0x3a0 fs/ext4/namei.c:1690
 __lookup_hash+0xc5/0x190 fs/namei.c:1451
 do_rmdir+0x19e/0x310 fs/namei.c:3760
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x445e59
Code: 4d c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 1b c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff2277fac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000400280 RCX: 0000000000445e59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000002
R10: 00007fff2277f990 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:0000000048cd3304 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1317c3
flags: 0x200000000000000()
raw: 0200000000000000 ffffea0004526588 ffffea0004528088 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881317c2f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881317c2f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881317c3000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8881317c3080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881317c3100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

ext4_search_dir:
  ...
  de = (struct ext4_dir_entry_2 *)search_buf;
  dlimit = search_buf + buf_size;
  while ((char *) de < dlimit) {
  ...
    if ((char *) de + de->name_len <= dlimit &&
	 ext4_match(dir, fname, de)) {
	    ...
    }
  ...
    de_len = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize);
    if (de_len <= 0)
      return -1;
    offset += de_len;
    de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
  }

Assume:
de=0xffff8881317c2fff
dlimit=0x0xffff8881317c3000

If read 'de->name_len' which address is 0xffff8881317c3005, obviously is
out of range, then will trigger use-after-free.
To solve this issue, 'dlimit' must reserve 8 bytes, as we will read
'de->name_len' to judge if '(char *) de + de->name_len' out of range.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220324064816.1209985-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/ext4/ext4.h  |    4 ++++
 fs/ext4/namei.c |    4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

Message ID	20220426081743.403331226@linuxfoundation.org
State	New
Headers	show Return-Path: <stable-owner@kernel.org> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org, Ye Bin <yebin10@huawei.com>, Jan Kara <jack@suse.cz>, Theodore Tso <tytso@mit.edu>, stable@kernel.org Subject: [PATCH 5.10 76/86] ext4: fix use-after-free in ext4_search_dir Date: Tue, 26 Apr 2022 10:21:44 +0200 Message-Id: <20220426081743.403331226@linuxfoundation.org> In-Reply-To: <20220426081741.202366502@linuxfoundation.org> References: <20220426081741.202366502@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	None \| expand [5.10,02/86] mm: page_alloc: fix building error on -Werror=array-compare [5.10,03/86] tracing: Dump stacktrace trigger to the corresponding instance [5.10,04/86] perf tools: Fix segfault accessing sample_id xyarray [5.10,05/86] gfs2: assign rgrp glock before compute_bitstructs [5.10,06/86] net/sched: cls_u32: fix netns refcount changes in u32_change() [5.10,07/86] ALSA: usb-audio: Clear MIDI port active flag after draining [5.10,08/86] ALSA: hda/realtek: Add quirk for Clevo NP70PNP [5.10,09/86] dm: fix mempool NULL pointer race when completing IO [5.10,10/86] ASoC: atmel: Remove system clock tree configuration for at91sam9g20ek [5.10,11/86] ASoC: msm8916-wcd-digital: Check failure for devm_snd_soc_register_component [5.10,12/86] ASoC: codecs: wcd934x: do not switch off SIDO Buck when codec is in use [5.10,13/86] dmaengine: imx-sdma: Fix error checking in sdma_event_remap [5.10,14/86] dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources [5.10,15/86] spi: spi-mtk-nor: initialize spi controller after resume [5.10,16/86] esp: limit skb_page_frag_refill use to a single page [5.10,17/86] igc: Fix infinite loop in release_swfw_sync [5.10,18/86] igc: Fix BUG: scheduling while atomic [5.10,19/86] rxrpc: Restore removed timer deletion [5.10,20/86] net/smc: Fix sock leak when release after smc_shutdown() [5.10,21/86] net/packet: fix packet_sock xmit return value checking [5.10,22/86] ip6_gre: Avoid updating tunnel->tun_hlen in __gre6_xmit() [5.10,23/86] ip6_gre: Fix skb_under_panic in __gre6_xmit() [5.10,24/86] net/sched: cls_u32: fix possible leak in u32_init_knode() [5.10,25/86] l3mdev: l3mdev_master_upper_ifindex_by_index_rcu should be using netdev_master_upper... [5.10,26/86] ipv6: make ip6_rt_gc_expire an atomic_t [5.10,27/86] netlink: reset network and mac headers in netlink_dump() [5.10,28/86] net: stmmac: Use readl_poll_timeout_atomic() in atomic state [5.10,29/86] dmaengine: idxd: add RO check for wq max_batch_size write [5.10,30/86] dmaengine: idxd: add RO check for wq max_transfer_size write [5.10,31/86] selftests: mlxsw: vxlan_flooding: Prevent flooding of unwanted packets [5.10,32/86] arm64/mm: Remove [PUD\|PMD]_TABLE_BIT from [pud\|pmd]_bad() [5.10,33/86] arm64: mm: fix p?d_leaf() [5.10,34/86] ARM: vexpress/spc: Avoid negative array index when !SMP [5.10,35/86] reset: tegra-bpmp: Restore Handle errors in BPMP response [5.10,36/86] platform/x86: samsung-laptop: Fix an unsigned comparison which can never be negative [5.10,37/86] ALSA: usb-audio: Fix undefined behavior due to shift overflowing the constant [5.10,38/86] arm64: dts: imx: Fix imx8*-var-som touchscreen property sizes [5.10,39/86] vxlan: fix error return code in vxlan_fdb_append [5.10,40/86] cifs: Check the IOCB_DIRECT flag, not O_DIRECT [5.10,41/86] net: atlantic: Avoid out-of-bounds indexing [5.10,42/86] mt76: Fix undefined behavior due to shift overflowing the constant [5.10,43/86] brcmfmac: sdio: Fix undefined behavior due to shift overflowing the constant [5.10,44/86] dpaa_eth: Fix missing of_node_put in dpaa_get_ts_info() [5.10,45/86] drm/msm/mdp5: check the return of kzalloc() [5.10,46/86] net: macb: Restart tx only if queue pointer is lagging [5.10,47/86] scsi: qedi: Fix failed disconnect handling [5.10,48/86] stat: fix inconsistency between struct stat and struct compat_stat [5.10,49/86] nvme: add a quirk to disable namespace identifiers [5.10,50/86] nvme-pci: disable namespace identifiers for Qemu controllers [5.10,51/86] EDAC/synopsys: Read the error count from the correct register [5.10,52/86] mm, hugetlb: allow for "high" userspace addresses [5.10,53/86] oom_kill.c: futex: delay the OOM reaper to allow time for proper futex cleanup [5.10,54/86] mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() [5.10,55/86] ata: pata_marvell: Check the bmdma_addr beforing reading [5.10,56/86] dma: at_xdmac: fix a missing check on list iterator [5.10,57/86] net: atlantic: invert deep par in pm functions, preventing null derefs [5.10,58/86] xtensa: patch_text: Fixup last cpu should be master [5.10,59/86] xtensa: fix a7 clobbering in coprocessor context load/store [5.10,60/86] openvswitch: fix OOB access in reserve_sfa_size() [5.10,61/86] gpio: Request interrupts after IRQ is initialized [5.10,62/86] ASoC: soc-dapm: fix two incorrect uses of list iterator [5.10,63/86] e1000e: Fix possible overflow in LTR decoding [5.10,64/86] ARC: entry: fix syscall_trace_exit argument [5.10,65/86] arm_pmu: Validate single/group leader events [5.10,66/86] sched/pelt: Fix attach_entity_load_avg() corner case [5.10,67/86] perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled [5.10,68/86] drm/panel/raspberrypi-touchscreen: Avoid NULL deref if not initialised [5.10,69/86] drm/panel/raspberrypi-touchscreen: Initialise the bridge in prepare [5.10,70/86] KVM: PPC: Fix TCE handling for VFIO [5.10,71/86] drm/vc4: Use pm_runtime_resume_and_get to fix pm_runtime_get_sync() usage [5.10,72/86] powerpc/perf: Fix power9 event alternatives [5.10,73/86] perf report: Set PERF_SAMPLE_DATA_SRC bit for Arm SPE event [5.10,74/86] ext4: fix fallocate to use file_modified to update permissions consistently [5.10,75/86] ext4: fix symlink file size not match to file content [5.10,76/86] ext4: fix use-after-free in ext4_search_dir [5.10,77/86] ext4: limit length to bitmap_maxbytes - blocksize in punch_hole [5.10,78/86] ext4, doc: fix incorrect h_reserved size [5.10,79/86] ext4: fix overhead calculation to account for the reserved gdt blocks [5.10,80/86] ext4: force overhead calculation if the s_overhead_cluster makes no sense [5.10,81/86] can: isotp: stop timeout monitoring when no first frame was sent [5.10,82/86] jbd2: fix a potential race while discarding reserved buffers after an abort [5.10,83/86] spi: atmel-quadspi: Fix the buswidth adjustment between spi-mem and controller [5.10,84/86] staging: ion: Prevent incorrect reference counting behavour [5.10,85/86] block/compat_ioctl: fix range check in BLKGETSIZE [5.10,86/86] Revert "net: micrel: fix KS8851_MLL Kconfig"

[5.10,76/86] ext4: fix use-after-free in ext4_search_dir

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