From: Jeff Layton <jlayton@kernel.org>
To: Amir Goldstein <amir73il@gmail.com>,
"J . Bruce Fields" <bfields@fieldses.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
Eddie Horng <eddiehorng.tw@gmail.com>,
linux-unionfs@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs
Date: Fri, 13 Jul 2018 11:40:50 -0400 [thread overview]
Message-ID: <8fc65417ebda26a198e01e8c82f41ae08ab3c803.camel@kernel.org> (raw)
In-Reply-To: <1531491744-13277-1-git-send-email-amir73il@gmail.com>
On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote:
> 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: 8383f1748829 ("ovl: wire up NFS export operations")
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>
> Hi Bruce,
>
> For the purpose of locks, nfsd/lockd should look at locks_inode()
> just like vfs lock functions.
>
> Hopefully, Miklos's work on stacked overlayfs file operations will
> be merged soon and locks_inode() will become the same as file_inode(),
> but we will still need this fix for stable kernels v4.16 through v4.18.
>
> Beyond testing by Eddie, I also verified no regressions when running
> nfstest with exported overlayfs.
>
> Thanks,
> Amir.
>
> 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(-)
>
> diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
> index 96c1d14c18f1..c2a128678e6e 100644
> --- a/fs/lockd/clntlock.c
> +++ b/fs/lockd/clntlock.c
> @@ -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
> diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
> index a2c0dfc6fdc0..d20b92f271c2 100644
> --- a/fs/lockd/clntproc.c
> +++ b/fs/lockd/clntproc.c
> @@ -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",
> diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
> index 3701bccab478..74330daeab71 100644
> --- a/fs/lockd/svclock.c
> +++ b/fs/lockd/svclock.c
> @@ -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);
> diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
> index 4ec3d6e03e76..899360ba3b84 100644
> --- a/fs/lockd/svcsubs.c
> +++ b/fs/lockd/svcsubs.c
> @@ -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;
> }
>
> /**
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 857141446d6b..4a17fad93411 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
> return status;
> }
>
> - inode = file_inode(filp);
> + inode = locks_inode(filp);
> flctx = inode->i_flctx;
>
> if (flctx && !list_empty_careful(&flctx->flc_posix)) {
> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
> index 4fd95dbeb52f..b065ef406770 100644
> --- a/include/linux/lockd/lockd.h
> +++ b/include/linux/lockd/lockd.h
> @@ -299,7 +299,7 @@ int nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);
>
> static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
> {
> - return file_inode(file->f_file);
> + return locks_inode(file->f_file);
> }
>
fwiw, I think the above delta turns out to be the real fix here, as that
affects nlm_file_inuse.
> static inline int __nlm_privileged_request4(const struct sockaddr *sap)
> @@ -359,7 +359,7 @@ static inline int nlm_privileged_requester(const struct svc_rqst *rqstp)
> 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
I think this looks OK. I was a bit hesitant as I wasn't sure whether
this would change the filehandles presented by the nfsd, but I don't
think it will.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
next prev parent reply other threads:[~2018-07-13 15:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 14:22 [PATCH] nfsd: fix leaked file lock with nfs exported overlayfs Amir Goldstein
2018-07-13 15:40 ` Jeff Layton [this message]
2018-07-13 16:05 ` Amir Goldstein
2018-07-17 14:24 ` Miklos Szeredi
2018-08-01 6:18 ` Amir Goldstein
2018-08-01 11:40 ` J . Bruce Fields
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