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| author | Jeff Layton <jlayton@poochiereds.net> | 2015-06-24 12:10:23 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-06-25 19:34:40 -0400 |
| commit | a24221dca1868101c9b4b5adde4a6a5b1a3a64a7 (patch) | |
| tree | f8436d89c3ab895df0cc70579c45e6140bd27d17 /fs | |
| parent | 1372a3130a3e0bfd38d82d476f0a907cc72ba816 (diff) | |
| download | linux-a24221dca1868101c9b4b5adde4a6a5b1a3a64a7.tar.bz2 | |
nfs: fix potential credential leak in ff_layout_update_mirror_cred
If we have two tasks racing to update a mirror's credentials, then they
can end up leaking one (or more) sets of credentials. The first task
will set mirror->cred and then the second task will just overwrite it.
Use a cmpxchg to ensure that the creds are only set once. If we get to
the point where we would set mirror->cred and find that they're already
set, then we just release the creds that were just found.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/flexfilelayout/flexfilelayoutdev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c index 77a2d026aa12..c19b9a88f748 100644 --- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c +++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c @@ -324,7 +324,8 @@ static int ff_layout_update_mirror_cred(struct nfs4_ff_layout_mirror *mirror, __func__, PTR_ERR(cred)); return PTR_ERR(cred); } else { - mirror->cred = cred; + if (cmpxchg(&mirror->cred, NULL, cred)) + put_rpccred(cred); } } return 0; |