[PATCH 4.18 099/145] nfsd: fix leaked file lock with nfs exported overlayfs

From: Greg Kroah-Hartman
Date: Fri Sep 07 2018 - 17:23:27 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Amir Goldstein <amir73il@xxxxxxxxx>

commit 64bed6cbe38bc95689fb9399872d9ce250192f90 upstream.

nfsd and lockd call vfs_lock_file() to lock/unlock the inode
returned by locks_inode(file).

Many places in nfsd/lockd code use the inode returned by
file_inode(file) for lock manipulation. With Overlayfs, file_inode()
(the underlying inode) is not the same object as locks_inode() (the
overlay inode). This can result in "Leaked POSIX lock" messages
and eventually to a kernel crash as reported by Eddie Horng:
https://marc.info/?l=linux-unionfs&m=153086643202072&w=2

Fix all the call sites in nfsd/lockd that should use locks_inode().
This is a correctness bug that manifested when overlayfs gained
NFS export support in v4.16.

Reported-by: Eddie Horng <eddiehorng.tw@xxxxxxxxx>
Tested-by: Eddie Horng <eddiehorng.tw@xxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/lockd/clntlock.c | 2 +-
fs/lockd/clntproc.c | 2 +-
fs/lockd/svclock.c | 16 ++++++++--------
fs/lockd/svcsubs.c | 4 ++--
fs/nfsd/nfs4state.c | 2 +-
include/linux/lockd/lockd.h | 4 ++--
6 files changed, 15 insertions(+), 15 deletions(-)

--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockad
continue;
if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
continue;
- if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0)
+ if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0)
continue;
/* Alright, we found a lock. Set the return status
* and wake up the caller
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct n
char *nodename = req->a_host->h_rpcclnt->cl_nodename;

nlmclnt_next_cookie(&argp->cookie);
- memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
+ memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh));
lock->caller = nodename;
lock->oh.data = req->a_owner;
lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, stru
__be32 ret;

dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
- file_inode(file->f_file)->i_sb->s_id,
- file_inode(file->f_file)->i_ino,
+ locks_inode(file->f_file)->i_sb->s_id,
+ locks_inode(file->f_file)->i_ino,
lock->fl.fl_type, lock->fl.fl_pid,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end,
@@ -511,8 +511,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp,
__be32 ret;

dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
- file_inode(file->f_file)->i_sb->s_id,
- file_inode(file->f_file)->i_ino,
+ locks_inode(file->f_file)->i_sb->s_id,
+ locks_inode(file->f_file)->i_ino,
lock->fl.fl_type,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end);
@@ -566,8 +566,8 @@ nlmsvc_unlock(struct net *net, struct nl
int error;

dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
- file_inode(file->f_file)->i_sb->s_id,
- file_inode(file->f_file)->i_ino,
+ locks_inode(file->f_file)->i_sb->s_id,
+ locks_inode(file->f_file)->i_ino,
lock->fl.fl_pid,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end);
@@ -595,8 +595,8 @@ nlmsvc_cancel_blocked(struct net *net, s
int status = 0;

dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
- file_inode(file->f_file)->i_sb->s_id,
- file_inode(file->f_file)->i_ino,
+ locks_inode(file->f_file)->i_sb->s_id,
+ locks_inode(file->f_file)->i_ino,
lock->fl.fl_pid,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end);
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(ch

static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
{
- struct inode *inode = file_inode(file->f_file);
+ struct inode *inode = locks_inode(file->f_file);

dprintk("lockd: %s %s/%ld\n",
msg, inode->i_sb->s_id, inode->i_ino);
@@ -414,7 +414,7 @@ nlmsvc_match_sb(void *datap, struct nlm_
{
struct super_block *sb = datap;

- return sb == file_inode(file->f_file)->i_sb;
+ return sb == locks_inode(file->f_file)->i_sb;
}

/**
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, st
return status;
}

- inode = file_inode(filp);
+ inode = locks_inode(filp);
flctx = inode->i_flctx;

if (flctx && !list_empty_careful(&flctx->flc_posix)) {
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -299,7 +299,7 @@ int nlmsvc_unlock_all_by_ip(st

static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
{
- return file_inode(file->f_file);
+ return locks_inode(file->f_file);
}

static inline int __nlm_privileged_request4(const struct sockaddr *sap)
@@ -359,7 +359,7 @@ static inline int nlm_privileged_request
static inline int nlm_compare_locks(const struct file_lock *fl1,
const struct file_lock *fl2)
{
- return file_inode(fl1->fl_file) == file_inode(fl2->fl_file)
+ return locks_inode(fl1->fl_file) == locks_inode(fl2->fl_file)
&& fl1->fl_pid == fl2->fl_pid
&& fl1->fl_owner == fl2->fl_owner
&& fl1->fl_start == fl2->fl_start