[PATCH] autofs: clear O_NONBLOCK on the pipe.
From: NeilBrown autofs does not expect the pipe it is given to have O_NONBLOCK set - specifically if __kernel_write() in autofs_write() returns -EAGAIN, this is treated as a fatal error and the pipe is closed. For safety autofs should, therefore, clear the O_NONBLOCK flag. Releases of systemd prior to 8th February 2019 used pipe2(p, O_NONBLOCK|O_CLOEXEC) and thus (inadvertently) set this flag. Signed-off-by: NeilBrown Signed-off-by: Ian Kent --- fs/autofs/autofs_i.h |2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h index b735f2b1e462..70c132acdab1 100644 --- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -216,6 +216,8 @@ static inline int autofs_prepare_pipe(struct file *pipe) return -EINVAL; /* We want a packet pipe */ pipe->f_flags |= O_DIRECT; + /* We don't expect -EAGAIN */ + pipe->f_flags &= ~O_NONBLOCK; return 0; }
Re: [PATCH] autofs: clear O_NONBLOCK on the pipe.
On Mon, 2019-02-11 at 10:37 +1100, NeilBrown wrote: > autofs does not expect the pipe it is given > to have O_NONBLOCK set - specifically if __kernel_write() > in autofs_write() returns -EAGAIN, this is treated > as a fatal error and the pipe is closed. > > For safety autofs should, therefore, clear the O_NONBLOCK flag. > > Releases of systemd prior to 8th February 2019 used > pipe2(p, O_NONBLOCK|O_CLOEXEC) > and thus (inadvertently) set this flag. Thanks Neil, this does look like an obvious problem. > > Signed-off-by: NeilBrown > --- > fs/autofs/autofs_i.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h > index 3e59f0ed777b..331192bed0d5 100644 > --- a/fs/autofs/autofs_i.h > +++ b/fs/autofs/autofs_i.h > @@ -215,6 +215,8 @@ static inline int autofs_prepare_pipe(struct file *pipe) > return -EINVAL; > /* We want a packet pipe */ > pipe->f_flags |= O_DIRECT; > + /* We don't expect -EAGAIN */ > + pipe->f_flags &= ~O_NONBLOCK; > return 0; > } >
[PATCH] autofs: clear O_NONBLOCK on the pipe.
autofs does not expect the pipe it is given to have O_NONBLOCK set - specifically if __kernel_write() in autofs_write() returns -EAGAIN, this is treated as a fatal error and the pipe is closed. For safety autofs should, therefore, clear the O_NONBLOCK flag. Releases of systemd prior to 8th February 2019 used pipe2(p, O_NONBLOCK|O_CLOEXEC) and thus (inadvertently) set this flag. Signed-off-by: NeilBrown --- fs/autofs/autofs_i.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h index 3e59f0ed777b..331192bed0d5 100644 --- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -215,6 +215,8 @@ static inline int autofs_prepare_pipe(struct file *pipe) return -EINVAL; /* We want a packet pipe */ pipe->f_flags |= O_DIRECT; + /* We don't expect -EAGAIN */ + pipe->f_flags &= ~O_NONBLOCK; return 0; } -- 2.14.0.rc0.dirty signature.asc Description: PGP signature
