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Kuniyuki Iwashima b3979e3d2f ipv6: Move fib6_config_validate() to ip6_route_add().
syzkaller created an IPv6 route from a malformed packet, which has
a prefix len > 128, triggering the splat below. [0]

This is a similar issue fixed by commit 586ceac9ac ("ipv6: Restore
fib6_config validation for SIOCADDRT.").

The cited commit removed fib6_config validation from some callers
of ip6_add_route().

Let's move the validation back to ip6_route_add() and
ip6_route_multipath_add().

[0]:
UBSAN: array-index-out-of-bounds in ./include/net/ipv6.h:616:34
index 20 is out of range for type '__u8 [16]'
CPU: 1 UID: 0 PID: 7444 Comm: syz.0.708 Not tainted 6.16.0-rc1-syzkaller-g19272b37aa4f #0 PREEMPT
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff80078a80>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:132
[<ffffffff8000327a>] show_stack+0x30/0x3c arch/riscv/kernel/stacktrace.c:138
[<ffffffff80061012>] __dump_stack lib/dump_stack.c:94 [inline]
[<ffffffff80061012>] dump_stack_lvl+0x12e/0x1a6 lib/dump_stack.c:120
[<ffffffff800610a6>] dump_stack+0x1c/0x24 lib/dump_stack.c:129
[<ffffffff8001c0ea>] ubsan_epilogue+0x14/0x46 lib/ubsan.c:233
[<ffffffff819ba290>] __ubsan_handle_out_of_bounds+0xf6/0xf8 lib/ubsan.c:455
[<ffffffff85b363a4>] ipv6_addr_prefix include/net/ipv6.h:616 [inline]
[<ffffffff85b363a4>] ip6_route_info_create+0x8f8/0x96e net/ipv6/route.c:3793
[<ffffffff85b635da>] ip6_route_add+0x2a/0x1aa net/ipv6/route.c:3889
[<ffffffff85b02e08>] addrconf_prefix_route+0x2c4/0x4e8 net/ipv6/addrconf.c:2487
[<ffffffff85b23bb2>] addrconf_prefix_rcv+0x1720/0x1e62 net/ipv6/addrconf.c:2878
[<ffffffff85b92664>] ndisc_router_discovery+0x1a06/0x3504 net/ipv6/ndisc.c:1570
[<ffffffff85b99038>] ndisc_rcv+0x500/0x600 net/ipv6/ndisc.c:1874
[<ffffffff85bc2c18>] icmpv6_rcv+0x145e/0x1e0a net/ipv6/icmp.c:988
[<ffffffff85af6798>] ip6_protocol_deliver_rcu+0x18a/0x1976 net/ipv6/ip6_input.c:436
[<ffffffff85af8078>] ip6_input_finish+0xf4/0x174 net/ipv6/ip6_input.c:480
[<ffffffff85af8262>] NF_HOOK include/linux/netfilter.h:317 [inline]
[<ffffffff85af8262>] NF_HOOK include/linux/netfilter.h:311 [inline]
[<ffffffff85af8262>] ip6_input+0x16a/0x70c net/ipv6/ip6_input.c:491
[<ffffffff85af8dcc>] ip6_mc_input+0x5c8/0x1268 net/ipv6/ip6_input.c:588
[<ffffffff85af6112>] dst_input include/net/dst.h:469 [inline]
[<ffffffff85af6112>] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
[<ffffffff85af6112>] NF_HOOK include/linux/netfilter.h:317 [inline]
[<ffffffff85af6112>] NF_HOOK include/linux/netfilter.h:311 [inline]
[<ffffffff85af6112>] ipv6_rcv+0x5ae/0x6e0 net/ipv6/ip6_input.c:309
[<ffffffff85087e84>] __netif_receive_skb_one_core+0x106/0x16e net/core/dev.c:5977
[<ffffffff85088104>] __netif_receive_skb+0x2c/0x144 net/core/dev.c:6090
[<ffffffff850883c6>] netif_receive_skb_internal net/core/dev.c:6176 [inline]
[<ffffffff850883c6>] netif_receive_skb+0x1aa/0xbf2 net/core/dev.c:6235
[<ffffffff8328656e>] tun_rx_batched.isra.0+0x430/0x686 drivers/net/tun.c:1485
[<ffffffff8329ed3a>] tun_get_user+0x2952/0x3d6c drivers/net/tun.c:1938
[<ffffffff832a21e0>] tun_chr_write_iter+0xc4/0x21c drivers/net/tun.c:1984
[<ffffffff80b9b9ae>] new_sync_write fs/read_write.c:593 [inline]
[<ffffffff80b9b9ae>] vfs_write+0x56c/0xa9a fs/read_write.c:686
[<ffffffff80b9c2be>] ksys_write+0x126/0x228 fs/read_write.c:738
[<ffffffff80b9c42e>] __do_sys_write fs/read_write.c:749 [inline]
[<ffffffff80b9c42e>] __se_sys_write fs/read_write.c:746 [inline]
[<ffffffff80b9c42e>] __riscv_sys_write+0x6e/0x94 fs/read_write.c:746
[<ffffffff80076912>] syscall_handler+0x94/0x118 arch/riscv/include/asm/syscall.h:112
[<ffffffff8637e31e>] do_trap_ecall_u+0x396/0x530 arch/riscv/kernel/traps.c:341
[<ffffffff863a69e2>] handle_exception+0x146/0x152 arch/riscv/kernel/entry.S:197

Fixes: fa76c1674f ("ipv6: Move some validation from ip6_route_info_create() to rtm_to_fib6_config().")
Reported-by: syzbot+4c2358694722d304c44e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6849b8c3.a00a0220.1eb5f5.00f0.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250611193551.2999991-1-kuni1840@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-12 08:12:35 -07:00
arch Notable changes: 2025-06-05 11:45:33 -07:00
block - dm: better error handling when reloading a table 2025-06-03 15:54:46 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto EFI updates for v6.16 2025-05-30 12:42:57 -07:00
Documentation Including fixes from CAN, wireless, Bluetooth, and Netfilter. 2025-06-05 12:34:55 -07:00
drivers net: drv: netdevsim: don't napi_complete() from netpoll 2025-06-12 08:11:52 -07:00
fs four smb3 server fixes 2025-06-04 19:23:37 -07:00
include net_sched: remove qdisc_tree_flush_backlog() 2025-06-12 08:05:50 -07:00
init Rust changes for v6.16 2025-06-04 21:18:37 -07:00
io_uring Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel sched_ext: Fixes for v6.16-rc1 2025-06-04 12:07:16 -07:00
lib bitmap-for-6.16 2025-06-03 07:39:23 -07:00
LICENSES LICENSES: add CC0-1.0 license text 2025-05-21 14:54:17 +02:00
mm slab updates for 6.16 2025-06-04 08:59:59 -07:00
net ipv6: Move fib6_config_validate() to ip6_route_add(). 2025-06-12 08:12:35 -07:00
rust Rust changes for v6.16 2025-06-04 21:18:37 -07:00
samples - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
scripts Rust changes for v6.16 2025-06-04 21:18:37 -07:00
security require gcc-8 and binutils-2.30 2025-05-31 08:16:52 -07:00
sound soundwire updates for 6.16 2025-06-05 08:07:24 -07:00
tools selftests: net: add test case for NAT46 looping back dst 2025-06-11 17:02:29 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge branch 'kvm-lockdep-common' into HEAD 2025-05-28 06:29:17 -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: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap MAINTAINERS: Update Kuniyuki Iwashima's email address. 2025-06-11 17:43:15 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml
COPYING
CREDITS Update Christoph's Email address and make it consistent 2025-05-12 23:50:31 -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 MAINTAINERS: Update Kuniyuki Iwashima's email address. 2025-06-11 17:43:15 -07:00
Makefile A moderately busy cycle for documentation this time around: 2025-05-27 11:22:19 -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.