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| author | Matthew Wilcox <willy@infradead.org> | 2019-04-05 14:02:10 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-04 09:20:11 +0200 |
| commit | 0311ff82b70fa12e80d188635bff24029ec06ae1 (patch) | |
| tree | f8434ac298b7ab6be99e9851df019b9d2436ba43 /kernel/trace | |
| parent | d972ebbf42ba6712460308ae57c222a0706f2af3 (diff) | |
| download | linux-stable-0311ff82b70fa12e80d188635bff24029ec06ae1.tar.gz linux-stable-0311ff82b70fa12e80d188635bff24029ec06ae1.tar.bz2 linux-stable-0311ff82b70fa12e80d188635bff24029ec06ae1.zip | |
fs: prevent page refcount overflow in pipe_buf_get
commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5455ee05bc3b..1bd7a758583b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6823,12 +6823,16 @@ static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, buf->private = 0; } -static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, +static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; + if (refcount_read(&ref->refcount) > INT_MAX/2) + return false; + refcount_inc(&ref->refcount); + return true; } /* Pipe buffer operations for a buffer. */ |