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authorJens Axboe <axboe@kernel.dk>2020-03-19 19:23:18 -0600
committerJens Axboe <axboe@kernel.dk>2020-03-20 08:47:27 -0600
commit4022e7af86be2dd62975dedb6b7ea551d108695e (patch)
treef8fe39d2782257cac15532721624a766f670442e
parentf1d96a8fcbbbb22d4fbc1d69eaaa678bbb0ff6e2 (diff)
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: Dmitry Kadashev <dkadashev@gmail.com> Tested-by: Dmitry Kadashev <dkadashev@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/file.c7
-rw-r--r--fs/io_uring.c5
-rw-r--r--include/linux/file.h1
3 files changed, 11 insertions, 2 deletions
diff --git a/fs/file.c b/fs/file.c
index a364e1a9b7e8..c8a4e4c86e55 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 b1fbc4424aa6..fe5ded7c74ef 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 {
@@ -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;
diff --git a/include/linux/file.h b/include/linux/file.h
index c6c7b24ea9f7..142d102f285e 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -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);