Commit 4022e7af authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: make sure openat/openat2 honor rlimit nofile 



Dmitry reports that a test case shows that io_uring isn't honoring a
modified rlimit nofile setting. get_unused_fd_flags() checks the task
signal->rlimi[] for the limits. As this isn't easily inheritable,
provide a __get_unused_fd_flags() that takes the value instead. Then we
can grab it when the request is prepared (from the original task), and
pass that in when we do the async part part of the open.

Reported-by: default avatarDmitry Kadashev <dkadashev@gmail.com>
Tested-by: default avatarDmitry Kadashev <dkadashev@gmail.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f1d96a8f

fs/file.c

+6 −1
Original line number Diff line number Diff line
@@ -540,9 +540,14 @@ static int alloc_fd(unsigned start, unsigned flags) 
	return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);

}



int __get_unused_fd_flags(unsigned flags, unsigned long nofile)

{

	return __alloc_fd(current->files, 0, nofile, flags);

}



int get_unused_fd_flags(unsigned flags)

{

	return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);

	return __get_unused_fd_flags(flags, rlimit(RLIMIT_NOFILE));

}

EXPORT_SYMBOL(get_unused_fd_flags);

fs/io_uring.c

+4 −1
Original line number Diff line number Diff line
@@ -397,6 +397,7 @@ struct io_open { 
	struct filename			*filename;

	struct statx __user		*buffer;

	struct open_how			how;

	unsigned long			nofile;

};



struct io_files_update {
@@ -2577,6 +2578,7 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
		return ret;

	}



	req->open.nofile = rlimit(RLIMIT_NOFILE);

	req->flags |= REQ_F_NEED_CLEANUP;

	return 0;

}
@@ -2618,6 +2620,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
		return ret;

	}



	req->open.nofile = rlimit(RLIMIT_NOFILE);

	req->flags |= REQ_F_NEED_CLEANUP;

	return 0;

}
@@ -2636,7 +2639,7 @@ static int io_openat2(struct io_kiocb *req, struct io_kiocb **nxt, 
	if (ret)

		goto err;



	ret = get_unused_fd_flags(req->open.how.flags);

	ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);

	if (ret < 0)

		goto err;

include/linux/file.h

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); 
extern int replace_fd(unsigned fd, struct file *file, unsigned flags);

extern void set_close_on_exec(unsigned int fd, int flag);

extern bool get_close_on_exec(unsigned int fd);

extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);

extern int get_unused_fd_flags(unsigned flags);

extern void put_unused_fd(unsigned int fd);

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