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nfsd: fix leaked file lock with nfs exported overlayfs

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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@gmail.com>
Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Fixes: 8383f17488 ("ovl: wire up NFS export operations")
Cc: stable@vger.kernel.org
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Amir Goldstein
2018-07-13 17:22:24 +03:00
committed by J. Bruce Fields
parent 8163496e78
commit 64bed6cbe3
6 changed files with 15 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
fs/lockd/clntlock.c
View File

@@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
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

2
fs/lockd/clntproc.c
View File

@@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
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",

16
fs/lockd/svclock.c
View File

@@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
__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, struct nlm_file *file,
__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 nlm_file *file, struct nlm_lock *lock)
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, struct nlm_file *file, struct nlm_lock *l
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);

4
fs/lockd/svcsubs.c
View File

@@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
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_file *file)
{
struct super_block *sb = datap;
return sb == file_inode(file->f_file)->i_sb;
return sb == locks_inode(file->f_file)->i_sb;
}
/**