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author | Elena Reshetova <elena.reshetova@intel.com> | 2017-10-20 12:53:30 +0300 |
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committer | J. Bruce Fields <bfields@redhat.com> | 2017-11-08 00:43:59 +0300 |
commit | 818a34eb266449b1c89242596039a5e44c9be04c (patch) | |
tree | 7c9affb6d729a990155f33db99d6e31090aa88d6 /include | |
parent | cff7cb2ece397760195ff8a5fc6bf3c860810246 (diff) | |
download | linux-818a34eb266449b1c89242596039a5e44c9be04c.tar.xz |
fs, nfsd: convert nfs4_file.fi_ref 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 nfs4_file.fi_ref 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: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions