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Filename Latest commit message Latest commit date
David Howells 1fc793d68d ipv4, ipv6: Fix handling of transhdrlen in __ip{,6}_append_data()
[ Upstream commit 9d4c75800f61e5d75c1659ba201b6c0c7ead3070 ]

Including the transhdrlen in length is a problem when the packet is
partially filled (e.g. something like send(MSG_MORE) happened previously)
when appending to an IPv4 or IPv6 packet as we don't want to repeat the
transport header or account for it twice.  This can happen under some
circumstances, such as splicing into an L2TP socket.

The symptom observed is a warning in __ip6_append_data():

    WARNING: CPU: 1 PID: 5042 at net/ipv6/ip6_output.c:1800 __ip6_append_data.isra.0+0x1be8/0x47f0 net/ipv6/ip6_output.c:1800

that occurs when MSG_SPLICE_PAGES is used to append more data to an already
partially occupied skbuff.  The warning occurs when 'copy' is larger than
the amount of data in the message iterator.  This is because the requested
length includes the transport header length when it shouldn't.  This can be
triggered by, for example:

        sfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP);
        bind(sfd, ...); // ::1
        connect(sfd, ...); // ::1 port 7
        send(sfd, buffer, 4100, MSG_MORE);
        sendfile(sfd, dfd, NULL, 1024);

Fix this by only adding transhdrlen into the length if the write queue is
empty in l2tp_ip6_sendmsg(), analogously to how UDP does things.

l2tp_ip_sendmsg() looks like it won't suffer from this problem as it builds
the UDP packet itself.

Fixes: a32e0eec70 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6")
Reported-by: syzbot+62cbf263225ae13ff153@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/0000000000001c12b30605378ce8@google.com/
Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Dumazet <edumazet@google.com>
cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: David Ahern <dsahern@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: netdev@vger.kernel.org
cc: bpf@vger.kernel.org
cc: syzkaller-bugs@googlegroups.com
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10 21:46:44 +02:00
arch powerpc/watchpoints: Annotate atomic context in more places 2023-10-10 21:46:40 +02:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs
crypto X.509: if signature is unsupported skip validation 2023-09-23 10:59:55 +02:00
Documentation perf/smmuv3: Enable HiSilicon Erratum 162001900 quirk for HIP08/09 2023-09-23 11:00:03 +02:00
drivers scsi: target: core: Fix deadlock due to recursive locking 2023-10-10 21:46:43 +02:00
fs NFSv4: Fix a nfs4_state_manager() race 2023-10-10 21:46:44 +02:00
include ata: libata-sata: increase PMP SRST timeout to 10s 2023-10-10 21:46:42 +02:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:56:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel ring-buffer: Update "shortest_full" in polling 2023-10-10 21:46:41 +02:00
lib kobject: Add sanity check for kset->kobj.ktype in kset_register() 2023-09-23 11:00:05 +02:00
LICENSES
mm tmpfs: verify {g,u}id mount options correctly 2023-09-23 10:59:40 +02:00
net ipv4, ipv6: Fix handling of transhdrlen in __ip{,6}_append_data() 2023-10-10 21:46:44 +02:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts modpost: add missing else to the "of" check 2023-10-10 21:46:44 +02:00
security ima: Finish deprecation of IMA_TRUSTED_KEYRING Kconfig 2023-10-10 21:46:43 +02:00
sound ALSA: hda: Disable power save for solving pop issue on Lenovo ThinkCentre M70q 2023-10-10 21:46:41 +02:00
tools bpf: Clarify error expectations from bpf_clone_redirect 2023-10-10 21:46:40 +02:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.257 2023-09-23 11:00:07 +02:00
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.