2020-04-30 14:04:23

by Sasha Levin

[permalink] [raw]
Subject: [PATCH AUTOSEL 4.19 03/30] nfsd: memory corruption in nfsd4_lock()

From: Vasily Averin <[email protected]>

[ Upstream commit e1e8399eee72e9d5246d4d1bcacd793debe34dd3 ]

New struct nfsd4_blocked_lock allocated in find_or_allocate_block()
does not initialized nbl_list and nbl_lru.
If conflock allocation fails rollback can call list_del_init()
access uninitialized fields and corrupt memory.

v2: just initialize nbl_list and nbl_lru right after nbl allocation.

Fixes: 76d348fadff5 ("nfsd: have nfsd4_lock use blocking locks for v4.1+ lock")
Signed-off-by: Vasily Averin <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
fs/nfsd/nfs4state.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ed73e86194fac..c24306af9758f 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -252,6 +252,8 @@ find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
if (!nbl) {
nbl= kmalloc(sizeof(*nbl), GFP_KERNEL);
if (nbl) {
+ INIT_LIST_HEAD(&nbl->nbl_list);
+ INIT_LIST_HEAD(&nbl->nbl_lru);
fh_copy_shallow(&nbl->nbl_fh, fh);
nfsd4_init_cb(&nbl->nbl_cb, lo->lo_owner.so_client,