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Filename Latest commit message Latest commit date
Miklos Szeredi 7328f9a4ad aio: fix async fsync creds
commit 530f32fc370fd1431ea9802dbc53ab5601dfccdb upstream.

Avi Kivity reports that on fuse filesystems running in a user namespace
asyncronous fsync fails with EOVERFLOW.

The reason is that f_ops->fsync() is called with the creds of the kthread
performing aio work instead of the creds of the process originally
submitting IOCB_CMD_FSYNC.

Fuse sends the creds of the caller in the request header and it needs to
translate the uid and gid into the server's user namespace.  Since the
kthread is running in init_user_ns, the translation will fail and the
operation returns an error.

It can be argued that fsync doesn't actually need any creds, but just
zeroing out those fields in the header (as with requests that currently
don't take creds) is a backward compatibility risk.

Instead of working around this issue in fuse, solve the core of the problem
by calling the filesystem with the proper creds.

Reported-by: Avi Kivity <avi@scylladb.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: c9582eb0ff ("fuse: Fail all requests with invalid uids or gids")
Cc: stable@vger.kernel.org  # 4.18+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-17 16:40:24 +02:00
arch KVM: x86: only do L1TF workaround on affected processors 2020-06-17 16:40:23 +02:00
block Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT" 2020-06-03 08:21:27 +02:00
certs
crypto
Documentation x86/speculation: Add Ivy Bridge to affected list 2020-06-10 20:24:58 +02:00
drivers PCI/PM: Adjust pcie_wait_for_link_delay() for caller delay 2020-06-17 16:40:23 +02:00
fs aio: fix async fsync creds 2020-06-17 16:40:24 +02:00
include mm: add kvfree_sensitive() for freeing sensitive data objects 2020-06-17 16:40:23 +02:00
init
ipc
kernel padata: add separate cpuhp node for CPUHP_PADATA_DEAD 2020-06-17 16:40:22 +02:00
lib
LICENSES
mm mm: add kvfree_sensitive() for freeing sensitive data objects 2020-06-17 16:40:23 +02:00
net bridge: Avoid infinite loop when suppressing NS messages with invalid options 2020-06-17 16:40:20 +02:00
samples samples: bpf: Fix build error 2020-06-03 08:21:15 +02:00
scripts bpf: Support llvm-objcopy for vmlinux BTF 2020-06-17 16:40:20 +02:00
security mm: add kvfree_sensitive() for freeing sensitive data objects 2020-06-17 16:40:23 +02:00
sound ASoC: intel - fix the card names 2020-06-07 13:18:49 +02:00
tools selftests: fix flower parent qdisc 2020-06-17 16:40:23 +02:00
usr
virt
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.cocciconfig
.get_maintainer.ignore
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COPYING
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MAINTAINERS
Makefile Linux 5.4.46 2020-06-10 20:24:58 +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.