linux-stable.git/fs/lockd, branch v4.20.2

lockd: Show pid of lockd for remote locks

2019-01-13T08:24:06+00:00

commit b8eee0e90f9797b747113638bc75e739b192ad38 upstream.

Commit 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific l_pid
for remote locks") specified that the l_pid returned for F_GETLK on a local
file that has a remote lock should be the pid of the lock manager process.
That commit, while updating other filesystems, failed to update lockd, such
that locks created by lockd had their fl_pid set to that of the remote
process holding the lock.  Fix that here to be the pid of lockd.

Also, fix the client case so that the returned lock pid is negative, which
indicates a remote lock on a remote file.

Fixes: 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific...")
Cc: stable@vger.kernel.org

Signed-off-by: Benjamin Coddington 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

lockd: fix access beyond unterminated strings in prints

2018-10-29T20:58:04+00:00

printk format used %*s instead of %.*s, so hostname_len does not limit
the number of bytes accessed from hostname.

Signed-off-by: Amir Goldstein 
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields

nfsd: fix leaked file lock with nfs exported overlayfs

2018-08-09T20:11:21+00:00

nfsd and lockd call vfs_lock_file() to lock/unlock the inode
returned by locks_inode(file).

Many places in nfsd/lockd code use the inode returned by
file_inode(file) for lock manipulation. With Overlayfs, file_inode()
(the underlying inode) is not the same object as locks_inode() (the
overlay inode). This can result in "Leaked POSIX lock" messages
and eventually to a kernel crash as reported by Eddie Horng:
https://marc.info/?l=linux-unionfs&m=153086643202072&w=2

Fix all the call sites in nfsd/lockd that should use locks_inode().
This is a correctness bug that manifested when overlayfs gained
NFS export support in v4.16.

Reported-by: Eddie Horng 
Tested-by: Eddie Horng 
Cc: Jeff Layton 
Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
Cc: stable@vger.kernel.org
Signed-off-by: Amir Goldstein 
Signed-off-by: J. Bruce Fields

lockd: make nlm_ntf_refcnt and nlm_ntf_wq static

2018-03-19T20:38:13+00:00

The variables nlm_ntf_refcnt and nlm_ntf_wq are local to the source and
do not need to be in global scope, so make them static.

Cleans up sparse warnings:
fs/lockd/svc.c:60:10: warning: symbol 'nlm_ntf_refcnt' was not declared.
Should it be static?
fs/lockd/svc.c:61:1: warning: symbol 'nlm_ntf_wq' was not declared.
Should it be static?

Signed-off-by: Colin Ian King 
Signed-off-by: J. Bruce Fields

lockd: Fix server refcounting

2018-01-24T22:33:57+00:00

The server shouldn't actually delete the struct nlm_host until it hits
the garbage collector. In order to make that work correctly with the
refcount API, we can bump the refcount by one, and then use
refcount_dec_if_one() in the garbage collector.

Signed-off-by: Trond Myklebust 
Acked-by: J. Bruce Fields

lockd: convert nlm_rqst.a_count from atomic_t to refcount_t

2018-01-15T04:06:30+00:00

atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable nlm_rqst.a_count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

**Important note for maintainers:

Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.
The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.

For the nlm_rqst.a_count it might make a difference
in following places:
 - nlmclnt_release_call() and nlmsvc_release_call(): decrement
   in refcount_dec_and_test() only
   provides RELEASE ordering and control dependency on success
   vs. fully ordered atomic counterpart

Suggested-by: Kees Cook 
Reviewed-by: David Windsor 
Reviewed-by: Hans Liljestrand 
Signed-off-by: Elena Reshetova 
Signed-off-by: Trond Myklebust

lockd: convert nlm_lockowner.count from atomic_t to refcount_t

2018-01-15T04:06:29+00:00

atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable nlm_lockowner.count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

**Important note for maintainers:

Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.
The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.

For the nlm_lockowner.count it might make a difference
in following places:
 - nlm_put_lockowner(): decrement in refcount_dec_and_lock() only
   provides RELEASE ordering, control dependency on success and
   holds a spin lock on success vs. fully ordered atomic counterpart.
   No changes in spin lock guarantees.

Suggested-by: Kees Cook 
Reviewed-by: David Windsor 
Reviewed-by: Hans Liljestrand 
Signed-off-by: Elena Reshetova 
Signed-off-by: Trond Myklebust

lockd: convert nsm_handle.sm_count from atomic_t to refcount_t

2018-01-15T04:06:29+00:00

atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable nsm_handle.sm_count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

**Important note for maintainers:

Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.
The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.

For the nsm_handle.sm_count it might make a difference
in following places:
 - nsm_release(): decrement in refcount_dec_and_lock() only
   provides RELEASE ordering, control dependency on success
   and holds a spin lock on success vs. fully ordered atomic
   counterpart. No change for the spin lock guarantees.

Suggested-by: Kees Cook 
Reviewed-by: David Windsor 
Reviewed-by: Hans Liljestrand 
Signed-off-by: Elena Reshetova 
Signed-off-by: Trond Myklebust

lockd: convert nlm_host.h_count from atomic_t to refcount_t

2018-01-15T04:06:29+00:00

atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable nlm_host.h_count  is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

**Important note for maintainers:

Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.
The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.

For the nlm_host.h_count it might make a difference
in following places:
 - nlmsvc_release_host(): decrement in refcount_dec()
   provides RELEASE ordering, while original atomic_dec()
   was fully unordered. Since the change is for better, it
   should not matter.
 - nlmclnt_release_host(): decrement in refcount_dec_and_test() only
   provides RELEASE ordering and control dependency on success
   vs. fully ordered atomic counterpart. It doesn't seem to
   matter in this case since object freeing happens under mutex
   lock anyway.

Suggested-by: Kees Cook 
Reviewed-by: David Windsor 
Reviewed-by: Hans Liljestrand 
Signed-off-by: Elena Reshetova 
Signed-off-by: Trond Myklebust

nlm_shutdown_hosts_net() cleanup

2017-11-27T21:45:11+00:00

nlm_complain_hosts() walks through nlm_server_hosts hlist, which should
be protected by nlm_host_mutex.

Signed-off-by: Vasily Averin 
Reviewed-by: Jeff Layton 
Signed-off-by: J. Bruce Fields