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David Howells 47f9e4c924 keys: Do not cache key in task struct if key is requested from kernel thread
The key which gets cached in task structure from a kernel thread does not
get invalidated even after expiry.  Due to which, a new key request from
kernel thread will be served with the cached key if it's present in task
struct irrespective of the key validity.  The change is to not cache key in
task_struct when key requested from kernel thread so that kernel thread
gets a valid key on every key request.

The problem has been seen with the cifs module doing DNS lookups from a
kernel thread and the results getting pinned by being attached to that
kernel thread's cache - and thus not something that can be easily got rid
of.  The cache would ordinarily be cleared by notify-resume, but kernel
threads don't do that.

This isn't seen with AFS because AFS is doing request_key() within the
kernel half of a user thread - which will do notify-resume.

Fixes: 7743c48e54 ("keys: Cache result of request_key*() temporarily in task_struct")
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: keyrings@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/CAGypqWw951d=zYRbdgNR4snUDvJhWL=q3=WOyh7HhSJupjz2vA@mail.gmail.com/
2023-03-21 16:22:40 +00:00
arch - Disable XSAVES on AMD Zen1 and Zen2 machines due to an erratum. No 2023-03-12 09:12:03 -07:00
block block, bfq: fix uaf for 'stable_merge_bfqq' 2023-03-08 07:34:50 -07:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
Documentation Bug fixes and regressions for ext4, the most serious of which is a 2023-03-12 08:55:55 -07:00
drivers virtio,vhost,vdpa: bugfixes 2023-03-13 10:43:09 -07:00
fs Fixes for 6.3-rc1: 2023-03-12 09:47:08 -07:00
include Bug fixes and regressions for ext4, the most serious of which is a 2023-03-12 08:55:55 -07:00
init Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
io_uring io_uring: silence variable ‘prev’ set but not used warning 2023-03-09 10:10:58 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel kernel.fork.v6.3-rc2 2023-03-12 09:04:28 -07:00
lib cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: avoid gcc complaint about pointer casting 2023-03-04 14:03:27 -08:00
net wifi: cfg80211: Partial revert "wifi: cfg80211: Fix use after free for wext" 2023-03-12 16:21:59 -07:00
rust Rust fixes for 6.3-rc1 2023-03-03 14:51:15 -08:00
samples LoongArch changes for v6.3 2023-03-01 09:27:00 -08:00
scripts Remove Intel compiler support 2023-03-05 10:49:37 -08:00
security keys: Do not cache key in task struct if key is requested from kernel thread 2023-03-21 16:22:40 +00:00
sound sound fixes for 6.3-rc1 2023-03-04 10:53:59 -08:00
tools virtio,vhost,vdpa: bugfixes 2023-03-13 10:43:09 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore .gitignore: ignore *.cover and *.mbx 2023-02-05 18:51:22 +09:00
.mailmap drm fixes for 6.3-rc2 2023-03-10 08:57:46 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS Staging driver fixes and removal for 6.3-rc2 2023-03-12 09:17:30 -07:00
Makefile Linux 6.3-rc2 2023-03-12 16:36:44 -07:00
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.