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author | Elena Reshetova <elena.reshetova@intel.com> | 2017-10-20 12:53:33 +0300 |
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committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2017-11-17 13:47:59 -0500 |
commit | 2b28a7bee4539d27f4ec3b0298f03bfd83d4f794 (patch) | |
tree | eae9a1b4816de726573ee4367dc47c9a36a1d6a3 /fs/nfs/pnfs.h | |
parent | eba6dd691743a9d7a57735f36bf6946fc58878ec (diff) | |
download | linux-2b28a7bee4539d27f4ec3b0298f03bfd83d4f794.tar.gz |
fs, nfs: convert pnfs_layout_hdr.plh_refcount from atomic_t to refcount_t
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 pnfs_layout_hdr.plh_refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'fs/nfs/pnfs.h')
-rw-r--r-- | fs/nfs/pnfs.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index f0e98e1f04b2..78de7a2052f7 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -180,7 +180,7 @@ struct pnfs_layoutdriver_type { }; struct pnfs_layout_hdr { - atomic_t plh_refcount; + refcount_t plh_refcount; atomic_t plh_outstanding; /* number of RPCs out */ struct list_head plh_layouts; /* other client layouts */ struct list_head plh_bulk_destroy; |