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Eric Dumazet 1534ff7775 sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto
syzbot reported a possible shift-out-of-bounds [1]

Blamed commit added rto_alpha_max and rto_beta_max set to 1000.

It is unclear if some sctp users are setting very large rto_alpha
and/or rto_beta.

In order to prevent user regression, perform the test at run time.

Also add READ_ONCE() annotations as sysctl values can change under us.

[1]

UBSAN: shift-out-of-bounds in net/sctp/transport.c:509:41
shift exponent 64 is too large for 32-bit type 'unsigned int'
CPU: 0 UID: 0 PID: 16704 Comm: syz.2.2320 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120
  ubsan_epilogue lib/ubsan.c:233 [inline]
  __ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494
  sctp_transport_update_rto.cold+0x1c/0x34b net/sctp/transport.c:509
  sctp_check_transmitted+0x11c4/0x1c30 net/sctp/outqueue.c:1502
  sctp_outq_sack+0x4ef/0x1b20 net/sctp/outqueue.c:1338
  sctp_cmd_process_sack net/sctp/sm_sideeffect.c:840 [inline]
  sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1372 [inline]

Fixes: b58537a1f5 ("net: sctp: fix permissions for rto_alpha and rto_beta knobs")
Reported-by: syzbot+f8c46c8b2b7f6e076e99@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/690c81ae.050a0220.3d0d33.014e.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20251106111054.3288127-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-10 16:21:05 -08:00
arch Rust fixes for v6.18 2025-11-05 11:15:36 -08:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs
crypto
Documentation docs: netlink: Couple of intro-specs documentation fixes 2025-11-06 14:50:59 -08:00
drivers net: phy: micrel: lan8814 fix reset of the QSGMII interface 2025-11-07 19:00:38 -08:00
fs for-6.18-rc4-tag 2025-11-04 14:25:38 +09:00
include Including fixes from bluetooth and wireless. 2025-11-06 08:52:30 -08:00
init
io_uring
ipc
kernel bpf-fixes 2025-10-31 18:22:26 -07:00
lib Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
LICENSES
mm
net sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto 2025-11-10 16:21:05 -08:00
rust rust: kbuild: workaround rustdoc doctests modifier bug 2025-11-04 00:00:06 +01:00
samples
scripts kconfig/nconf: Initialize the default locale at startup 2025-11-01 00:23:22 -04:00
security
sound ASoC: Fixes for v6.18 2025-10-30 13:08:08 +01:00
tools selftests: net: local_termination: Wait for interfaces to come up 2025-11-07 18:46:36 -08:00
usr
virt
.clang-format
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap linux_kselftest-kunit-fixes-6.18-rc4 2025-10-30 19:11:27 -07:00
.pylintrc
.rustfmt.toml
COPYING
CREDITS
Kbuild
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MAINTAINERS Including fixes from bluetooth and wireless. 2025-11-06 08:52:30 -08:00
Makefile Linux 6.18-rc4 2025-11-02 11:28:02 -08:00
README

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

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    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.