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Wang Liang 1091860a16 net: tun: Update napi->skb after XDP process
The syzbot report a UAF issue:

  BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
  BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline]
  BUG: KASAN: slab-use-after-free in napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
  Read of size 8 at addr ffff88802ef22c18 by task syz.0.17/6079
  CPU: 0 UID: 0 PID: 6079 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
  Call Trace:
   <TASK>
   dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
   print_address_description mm/kasan/report.c:378 [inline]
   print_report+0xca/0x240 mm/kasan/report.c:482
   kasan_report+0x118/0x150 mm/kasan/report.c:595
   skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
   napi_frags_skb net/core/gro.c:723 [inline]
   napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
   tun_get_user+0x28cb/0x3e20 drivers/net/tun.c:1920
   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
   new_sync_write fs/read_write.c:593 [inline]
   vfs_write+0x5c9/0xb30 fs/read_write.c:686
   ksys_write+0x145/0x250 fs/read_write.c:738
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>

  Allocated by task 6079:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
   unpoison_slab_object mm/kasan/common.c:330 [inline]
   __kasan_mempool_unpoison_object+0xa0/0x170 mm/kasan/common.c:558
   kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline]
   napi_skb_cache_get+0x37b/0x6d0 net/core/skbuff.c:295
   __alloc_skb+0x11e/0x2d0 net/core/skbuff.c:657
   napi_alloc_skb+0x84/0x7d0 net/core/skbuff.c:811
   napi_get_frags+0x69/0x140 net/core/gro.c:673
   tun_napi_alloc_frags drivers/net/tun.c:1404 [inline]
   tun_get_user+0x77c/0x3e20 drivers/net/tun.c:1784
   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
   new_sync_write fs/read_write.c:593 [inline]
   vfs_write+0x5c9/0xb30 fs/read_write.c:686
   ksys_write+0x145/0x250 fs/read_write.c:738
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  Freed by task 6079:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
   kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
   poison_slab_object mm/kasan/common.c:243 [inline]
   __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
   kasan_slab_free include/linux/kasan.h:233 [inline]
   slab_free_hook mm/slub.c:2422 [inline]
   slab_free mm/slub.c:4695 [inline]
   kmem_cache_free+0x18f/0x400 mm/slub.c:4797
   skb_pp_cow_data+0xdd8/0x13e0 net/core/skbuff.c:969
   netif_skb_check_for_xdp net/core/dev.c:5390 [inline]
   netif_receive_generic_xdp net/core/dev.c:5431 [inline]
   do_xdp_generic+0x699/0x11a0 net/core/dev.c:5499
   tun_get_user+0x2523/0x3e20 drivers/net/tun.c:1872
   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
   new_sync_write fs/read_write.c:593 [inline]
   vfs_write+0x5c9/0xb30 fs/read_write.c:686
   ksys_write+0x145/0x250 fs/read_write.c:738
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

After commit e6d5dbdd20 ("xdp: add multi-buff support for xdp running in
generic mode"), the original skb may be freed in skb_pp_cow_data() when
XDP program was attached, which was allocated in tun_napi_alloc_frags().
However, the napi->skb still point to the original skb, update it after
XDP process.

Reported-by: syzbot+64e24275ad95a915a313@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=64e24275ad95a915a313
Fixes: e6d5dbdd20 ("xdp: add multi-buff support for xdp running in generic mode")
Signed-off-by: Wang Liang <wangliang74@huawei.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250917113919.3991267-1-wangliang74@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-19 16:37:29 -07:00
arch Arm: 2025-09-18 09:42:55 -07:00
block vfs-6.17-rc6.fixes 2025-09-08 07:53:01 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: sha512 - Implement export_core() and import_core() 2025-09-02 19:02:39 -07:00
Documentation Including fixes from wireless. No known regressions at this point. 2025-09-18 10:22:02 -07:00
drivers net: tun: Update napi->skb after XDP process 2025-09-19 16:37:29 -07:00
fs 15 hotfixes. 11 are cc:stable and the remainder address post-6.16 issues 2025-09-17 21:34:26 -07:00
include Including fixes from wireless. No known regressions at this point. 2025-09-18 10:22:02 -07:00
init 20 hotfixes. 15 are cc:stable and the remainder address post-6.16 issues 2025-09-10 21:19:34 -07:00
io_uring vfs-6.17-rc6.fixes 2025-09-08 07:53:01 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel Probes fixes for v6.17-rc6: 2025-09-17 16:52:26 -07:00
lib hardening fixes for v6.17-rc4 2025-08-31 08:56:45 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 15 hotfixes. 11 are cc:stable and the remainder address post-6.16 issues 2025-09-17 21:34:26 -07:00
net Including fixes from wireless. No known regressions at this point. 2025-09-18 10:22:02 -07:00
rust Driver core fixes for 6.17-rc6 2025-09-13 10:36:06 -07:00
samples 15 hotfixes. 11 are cc:stable and the remainder address post-6.16 issues 2025-09-17 21:34:26 -07:00
scripts Rust fixes for v6.17 (2nd) 2025-09-06 12:33:09 -07:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/hdmi: Add pin fix for another HP EliteDesk 800 G4 model 2025-09-01 13:51:57 +02:00
tools Including fixes from wireless. No known regressions at this point. 2025-09-18 10:22:02 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap MAINTAINERS: Update Nobuhiro Iwamatsu's email address 2025-09-01 10:36:10 +02:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from wireless. No known regressions at this point. 2025-09-18 10:22:02 -07:00
Makefile Linux 6.17-rc6 2025-09-14 14:21:14 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.