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Laszlo Ersek 32ca6a55e1 net: tap_open(): set sk_uid from current_fsuid()
commit 5c9241f3ce upstream.

Commit 66b2c338ad initializes the "sk_uid" field in the protocol socket
(struct sock) from the "/dev/tapX" device node's owner UID. Per original
commit 86741ec254 ("net: core: Add a UID field to struct sock.",
2016-11-04), that's wrong: the idea is to cache the UID of the userspace
process that creates the socket. Commit 86741ec254 mentions socket() and
accept(); with "tap", the action that creates the socket is
open("/dev/tapX").

Therefore the device node's owner UID is irrelevant. In most cases,
"/dev/tapX" will be owned by root, so in practice, commit 66b2c338ad has
no observable effect:

- before, "sk_uid" would be zero, due to undefined behavior
  (CVE-2023-1076),

- after, "sk_uid" would be zero, due to "/dev/tapX" being owned by root.

What matters is the (fs)UID of the process performing the open(), so cache
that in "sk_uid".

Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 66b2c338ad ("tap: tap_open(): correctly initialize socket uid")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2173435
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 15:13:57 +02:00
Documentation iommu/arm-smmu-v3: Document nesting-related errata 2023-08-11 15:13:49 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch arm64: dts: stratix10: fix incorrect I2C property for SCL signal 2023-08-11 15:13:56 +02:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-23 13:47:37 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-09 10:32:34 +02:00
drivers net: tap_open(): set sk_uid from current_fsuid() 2023-08-11 15:13:57 +02:00
fs exfat: release s_lock before calling dir_emit() 2023-08-11 15:13:56 +02:00
include vxlan: Fix nexthop hash size 2023-08-11 15:13:54 +02:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:58:33 +02:00
io_uring io_uring: gate iowait schedule on having pending requests 2023-08-11 15:13:48 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel bpf, cpumap: Handle skb as well when clean up ptr_ring 2023-08-11 15:13:52 +02:00
lib test_firmware: return ENOMEM instead of ENOSPC on failed memory allocation 2023-07-23 13:47:25 +02:00
mm mm/damon/ops-common: atomically test and clear young on ptes and pmds 2023-07-23 13:47:47 +02:00
net libceph: fix potential hang in ceph_osdc_notify() 2023-08-11 15:13:55 +02:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:47:55 +02:00
scripts kbuild: Disable GCOV for *.mod.o 2023-07-23 13:47:17 +02:00
security security: keys: Modify mismatched function name 2023-07-27 08:47:01 +02:00
sound ASoC: cs42l51: fix driver to properly autoload with automatic module loading 2023-08-03 10:22:47 +02:00
tools perf test uprobe_from_different_cu: Skip if there is no gcc 2023-08-11 15:13:50 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS cifs: missing directory in MAINTAINERS file 2023-08-03 10:22:29 +02:00
Makefile Linux 5.15.125 2023-08-08 19:58:35 +02:00
README

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.