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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 /fs/fuse
parent8fde12ca79aff9b5ba951fce1a2641901b8d8e64 (diff)
downloadlinux-stericsson-15fab63e1e57be9fdb5eec1bbc5916e9825e9acb.tar.gz
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 'fs/fuse')
-rw-r--r--fs/fuse/dev.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 809c0f2f9942..64f4de983468 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2034,10 +2034,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
ret = -EINVAL;
- if (rem < len) {
- pipe_unlock(pipe);
- goto out;
- }
+ if (rem < len)
+ goto out_free;
rem = len;
while (rem) {
@@ -2055,7 +2053,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
pipe->nrbufs--;
} else {
- pipe_buf_get(pipe, ibuf);
+ if (!pipe_buf_get(pipe, ibuf))
+ goto out_free;
+
*obuf = *ibuf;
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->len = rem;
@@ -2078,11 +2078,11 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
ret = fuse_dev_do_write(fud, &cs, len);
pipe_lock(pipe);
+out_free:
for (idx = 0; idx < nbuf; idx++)
pipe_buf_release(pipe, &bufs[idx]);
pipe_unlock(pipe);
-out:
kvfree(bufs);
return ret;
}