From 4d28e850827a7e89824c4d73188784b618bb0fb1 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 19 Mar 2020 19:23:18 -0600 Subject: [PATCH 1252/2944] io_uring: make sure openat/openat2 honor rlimit nofile to #26323588 commit 4022e7af86be2dd62975dedb6b7ea551d108695e upstream. 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: Dmitry Kadashev Tested-by: Dmitry Kadashev Acked-by: David S. Miller Signed-off-by: Jens Axboe Signed-off-by: Joseph Qi Acked-by: Xiaoguang Wang --- fs/file.c | 7 ++++++- fs/io_uring.c | 5 ++++- include/linux/file.h | 1 + 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/file.c b/fs/file.c index 9dfa54f..7e3349a 100644 --- a/fs/file.c +++ b/fs/file.c @@ -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); diff --git a/fs/io_uring.c b/fs/io_uring.c index f1355ea..238761c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -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 { @@ -2579,6 +2580,7 @@ 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; } @@ -2620,6 +2622,7 @@ 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; } @@ -2638,7 +2641,7 @@ 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; diff --git a/include/linux/file.h b/include/linux/file.h index 3fcddff..82fa606 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -83,6 +83,7 @@ static inline void fdput_pos(struct fd f) 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); -- 1.8.3.1