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authorDai Ngo2022-09-26 10:59:16 -0700
committerChuck Lever2022-09-26 14:21:46 -0400
commit019805fea91599b22dfa62ffb29c022f35abeb06 (patch)
tree7f04a8ec3a239ee7bdaeeeac4b4d3782afcbeb4b /fs
parent76ce4dcec0dc08a032db916841ddc4e3998be317 (diff)
NFSD: fix use-after-free on source server when doing inter-server copy
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/nfs4state.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5cfeeeadcb78..bf80ecbc5de7 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1060,6 +1060,7 @@ static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
static void nfs4_free_deleg(struct nfs4_stid *stid)
{
+ WARN_ON(!list_empty(&stid->sc_cp_list));
kmem_cache_free(deleg_slab, stid);
atomic_long_dec(&num_delegations);
}
@@ -1473,6 +1474,7 @@ static void nfs4_free_ol_stateid(struct nfs4_stid *stid)
release_all_access(stp);
if (stp->st_stateowner)
nfs4_put_stateowner(stp->st_stateowner);
+ WARN_ON(!list_empty(&stid->sc_cp_list));
kmem_cache_free(stateid_slab, stid);
}
@@ -6799,6 +6801,7 @@ static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
struct nfs4_client *clp = s->st_stid.sc_client;
bool unhashed;
LIST_HEAD(reaplist);
+ struct nfs4_ol_stateid *stp;
spin_lock(&clp->cl_lock);
unhashed = unhash_open_stateid(s, &reaplist);
@@ -6807,6 +6810,8 @@ static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
if (unhashed)
put_ol_stateid_locked(s, &reaplist);
spin_unlock(&clp->cl_lock);
+ list_for_each_entry(stp, &reaplist, st_locks)
+ nfs4_free_cpntf_statelist(clp->net, &stp->st_stid);
free_ol_stateid_reaplist(&reaplist);
} else {
spin_unlock(&clp->cl_lock);