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Baokun Li 277d19ec28 ext4: fix use-after-free in ext4_ext_shift_extents
commit f6b1a1cf1c upstream.

If the starting position of our insert range happens to be in the hole
between the two ext4_extent_idx, because the lblk of the ext4_extent in
the previous ext4_extent_idx is always less than the start, which leads
to the "extent" variable access across the boundary, the following UAF is
triggered:
==================================================================
BUG: KASAN: use-after-free in ext4_ext_shift_extents+0x257/0x790
Read of size 4 at addr ffff88819807a008 by task fallocate/8010
CPU: 3 PID: 8010 Comm: fallocate Tainted: G            E     5.10.0+ #492
Call Trace:
 dump_stack+0x7d/0xa3
 print_address_description.constprop.0+0x1e/0x220
 kasan_report.cold+0x67/0x7f
 ext4_ext_shift_extents+0x257/0x790
 ext4_insert_range+0x5b6/0x700
 ext4_fallocate+0x39e/0x3d0
 vfs_fallocate+0x26f/0x470
 ksys_fallocate+0x3a/0x70
 __x64_sys_fallocate+0x4f/0x60
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
==================================================================

For right shifts, we can divide them into the following situations:

1. When the first ee_block of ext4_extent_idx is greater than or equal to
   start, make right shifts directly from the first ee_block.
    1) If it is greater than start, we need to continue searching in the
       previous ext4_extent_idx.
    2) If it is equal to start, we can exit the loop (iterator=NULL).

2. When the first ee_block of ext4_extent_idx is less than start, then
   traverse from the last extent to find the first extent whose ee_block
   is less than start.
    1) If extent is still the last extent after traversal, it means that
       the last ee_block of ext4_extent_idx is less than start, that is,
       start is located in the hole between idx and (idx+1), so we can
       exit the loop directly (break) without right shifts.
    2) Otherwise, make right shifts at the corresponding position of the
       found extent, and then exit the loop (iterator=NULL).

Fixes: 331573febb ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20220922120434.1294789-1-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-02 17:41:08 +01:00
arch KVM: arm64: pkvm: Fixup boot mode to reflect that the kernel resumes from EL1 2022-12-02 17:41:08 +01:00
block block, bfq: fix null pointer dereference in bfq_bio_bfqg() 2022-12-02 17:41:02 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: akcipher - default implementation for setting a private key 2022-10-26 12:35:25 +02:00
Documentation docs: update mediator contact information in CoC doc 2022-11-26 09:24:48 +01:00
drivers usb: cdnsp: fix issue with ZLP - added TD_SIZE = 1 2022-12-02 17:41:08 +01:00
fs ext4: fix use-after-free in ext4_ext_shift_extents 2022-12-02 17:41:08 +01:00
include rxrpc: Use refcount_t rather than atomic_t 2022-12-02 17:41:04 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-02 17:41:08 +01:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:23:10 +02:00
kernel kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case 2022-11-26 09:24:50 +01:00
lib lib/vdso: use "grep -E" instead of "egrep" 2022-12-02 17:41:08 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: fs: initialize fsdata passed to write_begin/write_end interface 2022-11-26 09:24:51 +01:00
net ipv4: Fix error return code in fib_table_insert() 2022-12-02 17:41:07 +01:00
samples samples/landlock: Format with clang-format 2022-06-09 10:23:23 +02:00
scripts cert host tools: Stop complaining about deprecated OpenSSL functions 2022-11-16 09:58:28 +01:00
security capabilities: fix potential memleak on error path from vfs_getxattr_alloc() 2022-11-10 18:15:39 +01:00
sound ASoC: max98373: Add checks for devm_kcalloc 2022-12-02 17:41:03 +01:00
tools selftests: mptcp: fix mibit vs mbit mix up 2022-12-02 17:41:03 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt kvm: Add support for arch compat vm ioctls 2022-10-29 10:12:54 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Input: goodix - add a goodix.h header file 2022-07-12 16:34:51 +02:00
Makefile Linux 5.15.80 2022-11-26 09:24:52 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.