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authorMatthew Wilcox <willy@infradead.org>2019-04-05 14:02:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-04-14 10:00:04 -0700
commit15fab63e1e57be9fdb5eec1bbc5916e9825e9acb (patch)
tree1353971310401012cf4b108a375e525065d8bec0 /include
parent8fde12ca79aff9b5ba951fce1a2641901b8d8e64 (diff)
fs: prevent page refcount overflow in pipe_buf_get
Change pipe_buf_get() to return a bool indicating whether it succeeded in raising the refcount of the page (if the thing in the pipe is a page). This removes another mechanism for overflowing the page refcount. All callers converted to handle a failure. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Matthew Wilcox <willy@infradead.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/pipe_fs_i.h10
1 files changed, 6 insertions, 4 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 5a3bb3b7c9ad..3f2a42c11e20 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -108,18 +108,20 @@ struct pipe_buf_operations {
/*
* Get a reference to the pipe buffer.
*/
- void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
+ bool (*get)(struct pipe_inode_info *, struct pipe_buffer *);
};
/**
* pipe_buf_get - get a reference to a pipe_buffer
* @pipe: the pipe that the buffer belongs to
* @buf: the buffer to get a reference to
+ *
+ * Return: %true if the reference was successfully obtained.
*/
-static inline void pipe_buf_get(struct pipe_inode_info *pipe,
+static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
- buf->ops->get(pipe, buf);
+ return buf->ops->get(pipe, buf);
}
/**
@@ -178,7 +180,7 @@ struct pipe_inode_info *alloc_pipe_info(void);
void free_pipe_info(struct pipe_inode_info *);
/* Generic pipe buffer ops functions */
-void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
+bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);