linux-stable.git/fs/ceph, branch linux-6.13.y

ceph: fix memory leak in ceph_mds_auth_match()

2025-02-17T10:36:51+00:00

commit 3b7d93db450e9d8ead80d75e2a303248f1528c35 upstream.

We now free the temporary target path substring allocation on every
possible branch, instead of omitting the default branch.  In some
cases, a memory leak occured, which could rapidly crash the system
(depending on how many file accesses were attempted).

This was detected in production because it caused a continuous memory
growth, eventually triggering kernel OOM and completely hard-locking
the kernel.

Relevant kmemleak stacktrace:

    unreferenced object 0xffff888131e69900 (size 128):
      comm "git", pid 66104, jiffies 4295435999
      hex dump (first 32 bytes):
        76 6f 6c 75 6d 65 73 2f 63 6f 6e 74 61 69 6e 65  volumes/containe
        72 73 2f 67 69 74 65 61 2f 67 69 74 65 61 2f 67  rs/gitea/gitea/g
      backtrace (crc 2f3bb450):
        [] __kmalloc_noprof+0x359/0x510
        [] ceph_mds_check_access+0x5bf/0x14e0 [ceph]
        [] ceph_open+0x312/0xd80 [ceph]
        [] do_dentry_open+0x456/0x1120
        [] vfs_open+0x79/0x360
        [] path_openat+0x1de5/0x4390
        [] do_filp_open+0x19c/0x3c0
        [] do_sys_openat2+0x141/0x180
        [] __x64_sys_open+0xe5/0x1a0
        [] do_syscall_64+0xb7/0x210
        [] entry_SYSCALL_64_after_hwframe+0x77/0x7f

It can be triggered by mouting a subdirectory of a CephFS filesystem,
and then trying to access files on this subdirectory with an auth token
using a path-scoped capability:

    $ ceph auth get client.services
    [client.services]
            key = REDACTED
            caps mds = "allow rw fsname=cephfs path=/volumes/"
            caps mon = "allow r fsname=cephfs"
            caps osd = "allow rw tag cephfs data=cephfs"

    $ cat /proc/self/mounts
    services@[REDACTED].cephfs=/volumes/containers /ceph/containers ceph rw,noatime,name=services,secret=,ms_mode=prefer-crc,mount_timeout=300,acl,mon_addr=[REDACTED]:3300,recover_session=clean 0 0

    $ seq 1 1000000 | xargs -P32 --replace={} touch /ceph/containers/file-{} && \
    seq 1 1000000 | xargs -P32 --replace={} cat /ceph/containers/file-{}

[ idryomov: combine if statements, rename rc to path_matched and make
            it a bool, formatting ]

Cc: stable@vger.kernel.org
Fixes: 596afb0b8933 ("ceph: add ceph_mds_check_access() helper")
Signed-off-by: Antoine Viallon 
Reviewed-by: Viacheslav Dubeyko 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

ceph: allocate sparse_ext map only for sparse reads

2024-12-16T22:25:44+00:00

If mounted with sparseread option, ceph_direct_read_write() ends up
making an unnecessarily allocation for O_DIRECT writes.

Fixes: 03bc06c7b0bd ("ceph: add new mount option to enable sparse reads")
Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Markuze

ceph: fix memory leak in ceph_direct_read_write()

2024-12-16T22:25:44+00:00

The bvecs array which is allocated in iter_get_bvecs_alloc() is leaked
and pages remain pinned if ceph_alloc_sparse_ext_map() fails.

There is no need to delay the allocation of sparse_ext map until after
the bvecs array is set up, so fix this by moving sparse_ext allocation
a bit earlier.  Also, make a similar adjustment in __ceph_sync_read()
for consistency (a leak of the same kind in __ceph_sync_read() has been
addressed differently).

Cc: stable@vger.kernel.org
Fixes: 03bc06c7b0bd ("ceph: add new mount option to enable sparse reads")
Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Markuze

ceph: improve error handling and short/overflow-read logic in __ceph_sync_read()

2024-12-16T22:25:43+00:00

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) 
Signed-off-by: Alex Markuze 
Reviewed-by: Viacheslav Dubeyko 
Signed-off-by: Ilya Dryomov

ceph: validate snapdirname option length when mounting

2024-12-16T22:25:43+00:00

It becomes a path component, so it shouldn't exceed NAME_MAX
characters.  This was hardened in commit c152737be22b ("ceph: Use
strscpy() instead of strcpy() in __get_snap_name()"), but no actual
check was put in place.

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Markuze

ceph: give up on paths longer than PATH_MAX

2024-12-16T22:25:43+00:00

If the full path to be built by ceph_mdsc_build_path() happens to be
longer than PATH_MAX, then this function will enter an endless (retry)
loop, effectively blocking the whole task.  Most of the machine
becomes unusable, making this a very simple and effective DoS
vulnerability.

I cannot imagine why this retry was ever implemented, but it seems
rather useless and harmful to me.  Let's remove it and fail with
ENAMETOOLONG instead.

Cc: stable@vger.kernel.org
Reported-by: Dario Weißer 
Signed-off-by: Max Kellermann 
Reviewed-by: Alex Markuze 
Signed-off-by: Ilya Dryomov

ceph: fix memory leaks in __ceph_sync_read()

2024-12-16T22:25:43+00:00

In two `break` statements, the call to ceph_release_page_vector() was
missing, leaking the allocation from ceph_alloc_page_vector().

Instead of adding the missing ceph_release_page_vector() calls, the
Ceph maintainers preferred to transfer page ownership to the
`ceph_osd_request` by passing `own_pages=true` to
osd_req_op_extent_osd_data_pages().  This requires postponing the
ceph_osdc_put_request() call until after the block that accesses the
`pages`.

Cc: stable@vger.kernel.org
Fixes: 03bc06c7b0bd ("ceph: add new mount option to enable sparse reads")
Fixes: f0fe1e54cfcf ("ceph: plumb in decryption during reads")
Signed-off-by: Max Kellermann 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov

Merge tag 'ceph-for-6.13-rc1' of https://github.com/ceph/ceph-client

2024-11-30T18:22:38+00:00

Pull ceph updates from Ilya Dryomov:
 "A fix for the mount "device" string parser from Patrick and two cred
  reference counting fixups from Max, marked for stable.

  Also included a number of cleanups and a tweak to MAINTAINERS to avoid
  unnecessarily CCing netdev list"

* tag 'ceph-for-6.13-rc1' of https://github.com/ceph/ceph-client:
  ceph: fix cred leak in ceph_mds_check_access()
  ceph: pass cred pointer to ceph_mds_auth_match()
  ceph: improve caps debugging output
  ceph: correct ceph_mds_cap_peer field name
  ceph: correct ceph_mds_cap_item field name
  ceph: miscellaneous spelling fixes
  ceph: Use strscpy() instead of strcpy() in __get_snap_name()
  ceph: Use str_true_false() helper in status_show()
  ceph: requalify some char pointers as const
  ceph: extract entity name from device id
  MAINTAINERS: exclude net/ceph from networking
  ceph: Remove fs/ceph deadcode
  libceph: Remove unused ceph_crypto_key_encode
  libceph: Remove unused ceph_osdc_watch_check
  libceph: Remove unused pagevec functions
  libceph: Remove unused ceph_pagelist functions

ceph: fix cred leak in ceph_mds_check_access()

2024-11-25T14:51:13+00:00

get_current_cred() increments the reference counter, but the
put_cred() call was missing.

Cc: stable@vger.kernel.org
Fixes: 596afb0b8933 ("ceph: add ceph_mds_check_access() helper")
Signed-off-by: Max Kellermann 
Reviewed-by: Xiubo Li 
Signed-off-by: Ilya Dryomov

ceph: pass cred pointer to ceph_mds_auth_match()

2024-11-25T14:51:13+00:00

This eliminates a redundant get_current_cred() call, because
ceph_mds_check_access() has already obtained this pointer.

As a side effect, this also fixes a reference leak in
ceph_mds_auth_match(): by omitting the get_current_cred() call, no
additional cred reference is taken.

Cc: stable@vger.kernel.org
Fixes: 596afb0b8933 ("ceph: add ceph_mds_check_access() helper")
Signed-off-by: Max Kellermann 
Reviewed-by: Xiubo Li 
Signed-off-by: Ilya Dryomov