| Message ID | 20201002082734.13925-3-colyli@suse.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Introduce sendpage_ok() to detect misused sendpage in network related drivers | expand |
diff --git a/net/socket.c b/net/socket.c index 0c0144604f81..58cac2da5f66 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3638,9 +3638,11 @@ EXPORT_SYMBOL(kernel_getpeername); int kernel_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags) { - if (sock->ops->sendpage) + if (sock->ops->sendpage) { + /* Warn in case the improper page to zero-copy send */ + WARN_ONCE(!sendpage_ok(page), "improper page for zero-copy send"); return sock->ops->sendpage(sock, page, offset, size, flags); - + } return sock_no_sendpage(sock, page, offset, size, flags); } EXPORT_SYMBOL(kernel_sendpage);
If a page sent into kernel_sendpage() is a slab page or it doesn't have ref_count, this page is improper to send by the zero copy sendpage() method. Otherwise such page might be unexpected released in network code path and causes impredictable panic due to kernel memory management data structure corruption. This path adds a WARN_ON() on the sending page before sends it into the concrete zero-copy sendpage() method, if the page is improper for the zero-copy sendpage() method, a warning message can be observed before the consequential unpredictable kernel panic. This patch does not change existing kernel_sendpage() behavior for the improper page zero-copy send, it just provides hint warning message for following potential panic due the kernel memory heap corruption. Signed-off-by: Coly Li <colyli@suse.de> Cc: Cong Wang <amwang@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David S. Miller <davem@davemloft.net> Cc: Sridhar Samudrala <sri@us.ibm.com> --- net/socket.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)