[PATCH 1/2] file: Export receive_fd() to modules

Xie Yongji xieyongji at bytedance.com
Thu Apr 1 09:09:31 UTC 2021


Export receive_fd() so that some modules can use
it to pass file descriptor across processes without
missing any security stuffs.

Signed-off-by: Xie Yongji <xieyongji at bytedance.com>
---
 fs/file.c            | 6 ++++++
 include/linux/file.h | 7 +++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 56986e55befa..2a80c6c3e147 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -1107,6 +1107,12 @@ int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
 	return new_fd;
 }
 
+int receive_fd(struct file *file, unsigned int o_flags)
+{
+	return __receive_fd(file, NULL, o_flags);
+}
+EXPORT_SYMBOL(receive_fd);
+
 static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
 {
 	int err = -EBADF;
diff --git a/include/linux/file.h b/include/linux/file.h
index 2de2e4613d7b..51e830b4fe3a 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -94,6 +94,9 @@ extern void fd_install(unsigned int fd, struct file *file);
 
 extern int __receive_fd(struct file *file, int __user *ufd,
 			unsigned int o_flags);
+
+extern int receive_fd(struct file *file, unsigned int o_flags);
+
 static inline int receive_fd_user(struct file *file, int __user *ufd,
 				  unsigned int o_flags)
 {
@@ -101,10 +104,6 @@ static inline int receive_fd_user(struct file *file, int __user *ufd,
 		return -EFAULT;
 	return __receive_fd(file, ufd, o_flags);
 }
-static inline int receive_fd(struct file *file, unsigned int o_flags)
-{
-	return __receive_fd(file, NULL, o_flags);
-}
 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
 
 extern void flush_delayed_fput(void);
-- 
2.11.0



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