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ChenXiaoSong 542228db2f cifs: fix use-after-free on the link name
xfstests generic/011 reported use-after-free bug as follows:

  BUG: KASAN: use-after-free in __d_alloc+0x269/0x859
  Read of size 15 at addr ffff8880078933a0 by task dirstress/952

  CPU: 1 PID: 952 Comm: dirstress Not tainted 6.1.0-rc3+ #77
  Call Trace:
   __dump_stack+0x23/0x29
   dump_stack_lvl+0x51/0x73
   print_address_description+0x67/0x27f
   print_report+0x3e/0x5c
   kasan_report+0x7b/0xa8
   kasan_check_range+0x1b2/0x1c1
   memcpy+0x22/0x5d
   __d_alloc+0x269/0x859
   d_alloc+0x45/0x20c
   d_alloc_parallel+0xb2/0x8b2
   lookup_open+0x3b8/0x9f9
   open_last_lookups+0x63d/0xc26
   path_openat+0x11a/0x261
   do_filp_open+0xcc/0x168
   do_sys_openat2+0x13b/0x3f7
   do_sys_open+0x10f/0x146
   __se_sys_creat+0x27/0x2e
   __x64_sys_creat+0x55/0x6a
   do_syscall_64+0x40/0x96
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

  Allocated by task 952:
   kasan_save_stack+0x1f/0x42
   kasan_set_track+0x21/0x2a
   kasan_save_alloc_info+0x17/0x1d
   __kasan_kmalloc+0x7e/0x87
   __kmalloc_node_track_caller+0x59/0x155
   kstrndup+0x60/0xe6
   parse_mf_symlink+0x215/0x30b
   check_mf_symlink+0x260/0x36a
   cifs_get_inode_info+0x14e1/0x1690
   cifs_revalidate_dentry_attr+0x70d/0x964
   cifs_revalidate_dentry+0x36/0x62
   cifs_d_revalidate+0x162/0x446
   lookup_open+0x36f/0x9f9
   open_last_lookups+0x63d/0xc26
   path_openat+0x11a/0x261
   do_filp_open+0xcc/0x168
   do_sys_openat2+0x13b/0x3f7
   do_sys_open+0x10f/0x146
   __se_sys_creat+0x27/0x2e
   __x64_sys_creat+0x55/0x6a
   do_syscall_64+0x40/0x96
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

  Freed by task 950:
   kasan_save_stack+0x1f/0x42
   kasan_set_track+0x21/0x2a
   kasan_save_free_info+0x1c/0x34
   ____kasan_slab_free+0x1c1/0x1d5
   __kasan_slab_free+0xe/0x13
   __kmem_cache_free+0x29a/0x387
   kfree+0xd3/0x10e
   cifs_fattr_to_inode+0xb6a/0xc8c
   cifs_get_inode_info+0x3cb/0x1690
   cifs_revalidate_dentry_attr+0x70d/0x964
   cifs_revalidate_dentry+0x36/0x62
   cifs_d_revalidate+0x162/0x446
   lookup_open+0x36f/0x9f9
   open_last_lookups+0x63d/0xc26
   path_openat+0x11a/0x261
   do_filp_open+0xcc/0x168
   do_sys_openat2+0x13b/0x3f7
   do_sys_open+0x10f/0x146
   __se_sys_creat+0x27/0x2e
   __x64_sys_creat+0x55/0x6a
   do_syscall_64+0x40/0x96
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

When opened a symlink, link name is from 'inode->i_link', but it may be
reset to a new value when revalidate the dentry. If some processes get the
link name on the race scenario, then UAF will happen on link name.

Fix this by implementing 'get_link' interface to duplicate the link name.

Fixes: 76894f3e2f ("cifs: improve symlink handling for smb2+")
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-11-04 23:36:54 -05:00
arch - Rename a perf memory level event define to denote it is of CXL type 2022-10-30 09:49:18 -07:00
block block-6.1-2022-10-28 2022-10-29 18:06:52 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation 23 hotfixes. 2022-10-29 17:49:33 -07:00
drivers fbdev fixes for kernel 6.1-rc3: 2022-10-30 11:31:14 -07:00
fs cifs: fix use-after-free on the link name 2022-11-04 23:36:54 -05:00
include fbdev fixes for kernel 6.1-rc3: 2022-10-30 11:31:14 -07:00
init init: Kconfig: fix spelling mistake "satify" -> "satisfy" 2022-10-20 21:27:22 -07:00
io_uring io_uring: unlock if __io_run_local_work locked inside 2022-10-27 09:52:12 -06:00
ipc ipc/msg.c: fix percpu_counter use after free 2022-10-28 13:37:22 -07:00
kernel - Rename a perf memory level event define to denote it is of CXL type 2022-10-30 09:49:18 -07:00
lib 23 hotfixes. 2022-10-29 17:49:33 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mmap: fix remap_file_pages() regression 2022-10-28 13:37:23 -07:00
net kcm: do not sense pfmemalloc status in kcm_sendpage() 2022-10-27 11:25:13 -07:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts Kbuild fixes for v6.1 2022-10-16 11:12:22 -07:00
security selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context() 2022-10-19 09:55:53 -04:00
sound ALSA: aoa: Fix I2S device accounting 2022-10-27 08:53:08 +02:00
tools Char/Misc fixes for 6.1-rc3 2022-10-30 11:22:33 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm: Add support for arch compat vm ioctls 2022-10-22 05:15:23 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap mailmap: update email for Qais Yousef 2022-10-20 21:27:21 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS USB fixes for 6.1-rc3 2022-10-30 10:35:07 -07:00
Makefile Linux 6.1-rc3 2022-10-30 15:19:28 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.