[PATCH 5.17 169/343] NFSv4.2: fix reference count leaks in _nfs42_proc_copy_notify()

From: Greg Kroah-Hartman
Date: Tue Apr 12 2022 - 04:42:35 EST


From: Xin Xiong <xiongx18@xxxxxxxxxxxx>

[ Upstream commit b7f114edd54326f730a754547e7cfb197b5bc132 ]

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The reference counting issue happens in two error paths in the
function _nfs42_proc_copy_notify(). In both error paths, the function
simply returns the error code and forgets to balance the refcount of
object `ctx`, bumped by get_nfs_open_context() earlier, which may
cause refcount leaks.

Fix it by balancing refcount of the `ctx` object before the function
returns in both error paths.

Signed-off-by: Xin Xiong <xiongx18@xxxxxxxxxxxx>
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/nfs/nfs42proc.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 32129446beca..ca878d021fab 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -591,8 +591,10 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,

ctx = get_nfs_open_context(nfs_file_open_context(src));
l_ctx = nfs_get_lock_context(ctx);
- if (IS_ERR(l_ctx))
- return PTR_ERR(l_ctx);
+ if (IS_ERR(l_ctx)) {
+ status = PTR_ERR(l_ctx);
+ goto out;
+ }

status = nfs4_set_rw_stateid(&args->cna_src_stateid, ctx, l_ctx,
FMODE_READ);
@@ -600,7 +602,7 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,
if (status) {
if (status == -EAGAIN)
status = -NFS4ERR_BAD_STATEID;
- return status;
+ goto out;
}

status = nfs4_call_sync(src_server->client, src_server, &msg,
@@ -609,6 +611,7 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,
if (status == -ENOTSUPP)
src_server->caps &= ~NFS_CAP_COPY_NOTIFY;

+out:
put_nfs_open_context(nfs_file_open_context(src));
return status;
}
--
2.35.1