Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.1 248/267] nfs: fix potential credential leak in ff_layout_update_mirror_cred | Date | Fri, 31 Jul 2015 12:41:39 -0700 |
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4.1-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Layton <jlayton@poochiereds.net>
commit a24221dca1868101c9b4b5adde4a6a5b1a3a64a7 upstream.
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> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nfs/flexfilelayout/flexfilelayoutdev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c +++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c @@ -324,7 +324,8 @@ static int ff_layout_update_mirror_cred( __func__, PTR_ERR(cred)); return PTR_ERR(cred); } else { - mirror->cred = cred; + if (cmpxchg(&mirror->cred, NULL, cred)) + put_rpccred(cred); } } return 0;
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