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NFSD: fix use-after-free on source server when doing inter-server copy
[ Upstream commit 019805fea9
]
Use-after-free occurred when the laundromat tried to free expired
cpntf_state entry on the s2s_cp_stateids list after inter-server
copy completed. The sc_cp_list that the expired copy state was
inserted on was already freed.
When COPY completes, the Linux client normally sends LOCKU(lock_state x),
FREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server.
The nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state
from the s2s_cp_stateids list before freeing the lock state's stid.
However, sometimes the CLOSE was sent before the FREE_STATEID request.
When this happens, the nfsd4_close_open_stateid call from nfsd4_close
frees all lock states on its st_locks list without cleaning up the copy
state on the sc_cp_list list. When the time the FREE_STATEID arrives the
server returns BAD_STATEID since the lock state was freed. This causes
the use-after-free error to occur when the laundromat tries to free
the expired cpntf_state.
This patch adds a call to nfs4_free_cpntf_statelist in
nfsd4_close_open_stateid to clean up the copy state before calling
free_ol_stateid_reaplist to free the lock state's stid on the reaplist.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
14bde62cef
commit
6ea71246b7
1 changed files with 5 additions and 0 deletions
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@ -1049,6 +1049,7 @@ static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
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static void nfs4_free_deleg(struct nfs4_stid *stid)
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{
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WARN_ON(!list_empty(&stid->sc_cp_list));
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kmem_cache_free(deleg_slab, stid);
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atomic_long_dec(&num_delegations);
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}
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@ -1463,6 +1464,7 @@ static void nfs4_free_ol_stateid(struct nfs4_stid *stid)
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release_all_access(stp);
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if (stp->st_stateowner)
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nfs4_put_stateowner(stp->st_stateowner);
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WARN_ON(!list_empty(&stid->sc_cp_list));
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kmem_cache_free(stateid_slab, stid);
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}
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@ -6608,6 +6610,7 @@ static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
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struct nfs4_client *clp = s->st_stid.sc_client;
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bool unhashed;
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LIST_HEAD(reaplist);
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struct nfs4_ol_stateid *stp;
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spin_lock(&clp->cl_lock);
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unhashed = unhash_open_stateid(s, &reaplist);
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@ -6616,6 +6619,8 @@ static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
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if (unhashed)
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put_ol_stateid_locked(s, &reaplist);
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spin_unlock(&clp->cl_lock);
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list_for_each_entry(stp, &reaplist, st_locks)
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nfs4_free_cpntf_statelist(clp->net, &stp->st_stid);
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free_ol_stateid_reaplist(&reaplist);
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} else {
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spin_unlock(&clp->cl_lock);
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