Alex Markuze a07c0908e3 ceph: improve error handling and short/overflow-read logic in __ceph_sync_read()
commit 9abee475803fab6ad59d4f4fc59c6a75374a7d9d upstream.

This patch refines the read logic in __ceph_sync_read() to ensure more
predictable and efficient behavior in various edge cases.

- Return early if the requested read length is zero or if the file size
  (`i_size`) is zero.
- Initialize the index variable (`idx`) where needed and reorder some
  code to ensure it is always set before use.
- Improve error handling by checking for negative return values earlier.
- Remove redundant encrypted file checks after failures. Only attempt
  filesystem-level decryption if the read succeeded.
- Simplify leftover calculations to correctly handle cases where the
  read extends beyond the end of the file or stops short.  This can be
  hit by continuously reading a file while, on another client, we keep
  truncating and writing new data into it.
- This resolves multiple issues caused by integer and consequent buffer
  overflow (`pages` array being accessed beyond `num_pages`):
  - https://tracker.ceph.com/issues/67524
  - https://tracker.ceph.com/issues/68980
  - https://tracker.ceph.com/issues/68981

Cc: stable@vger.kernel.org
Fixes: 1065da21e5df ("ceph: stop copying to iter at EOF on sync reads")
Reported-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
Signed-off-by: Alex Markuze <amarkuze@redhat.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27 13:58:56 +01:00
2024-12-27 13:58:53 +01:00
2024-12-14 20:00:03 +01:00
2022-09-28 09:02:20 +02:00
2024-12-19 18:11:37 +01:00

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.
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